State of the Bay Report 2011-Final.pdf - Anchor Environmental

Saldanha Bay 

and 

Langebaan Lagoon: 

State of the Bay 

2011 

Technical Report 

September 2012 

ANCHOR 

e n v i r o n m en t a l 

www.anchorenvironmental.co.za

Saldanha Bay and Langebaan Lagoon 

State of the Bay 


Technical Report 

Prepared by: 

Anchor Environmental Consultants 

8 Steenberg House, Silverwood Close, Tokai 7945, South Africa 

Prepared for: 

September 2012 

Authors: 

B.M. Clark, K. Tunley, K. Hutchings, N. Steffani, J. Turpie, C. Jurk and J. Gericke 

© Saldanha Bay Water Quality Trust 2012 

Use of material contained in this document by prior written permission of the Saldanha Bay 

Water Quality Trust only

State of Saldanha Bay & Langebaan Lagoon 2011 

Executive Summary 

EXECUTIVE SUMMARY 

Regular, long-term environmental monitoring is essential to identify and to enable proactive 

mitigation of negative human impacts on the environment (e.g. pollution), and in so doing maintain 

the beneficial value of an area for all users. This is particularly pertinent for an area such as 

Saldanha Bay and Langebaan Lagoon, which serves as a major industrial node and port while at the 

same time supporting important tourism and fishing industries. The development of the Saldanha 

Bay port has significantly altered the physical structure and hydrodynamics of the Bay, whilst all 

developments within the area (industrial, residential, tourism etc.) have the potential to negatively 

impact on ecosystem health. Various techniques are available to monitor the health of the 

environment, including measuring of physical parameters (e.g. water temperature, oxygen levels, 

and circulation patterns), actual pollutants (e.g. heavy metals, hydrocarbons, microbiological 

indicators) and biological components of the ecosystem (e.g. birds, fish and invertebrates). Nearly 

all measurable parameters exhibit substantial natural variability, and it is essential that 

environmental monitoring is conducted over the long term (years to decades) at sufficient frequency 

to enable identification of human-induced changes. 

Saldanha Bay and Langebaan Lagoon have long been the focus of scientific study and 

interest, owing to its conservation importance as well as its many unique features. The 

establishment of the Saldanha Bay Water Quality Trust (SBWQT) in 1996, a voluntary organization 

representing various organs of State, local industry and other relevant stakeholders and interest 

groups, gave much impetus to the monitoring and understanding of changes in the health and 

ecosystem functioning of this unique bay-lagoon ecosystem. Direct monitoring of a number of 

important ecosystem indicators was initiated by the SBWQT in 1999, including water quality (faecal 

coliform, temperature, oxygen and pH), sediment quality (trace metals, hydrocarbons, particulate 

organic carbon and nitrogen) and benthic macrofauna. The range of parameters monitored has 

expanded since then to include surf zone fish and rocky intertidal macrofauna (both initiated in 

2005) and led to the commissioning of a “State of the Bay” technical report series in 2006. This 

report has been produced annually since 2008, presenting data on parameters monitored directly by 

the SBWQT as well as those monitored by others (government, private industry, academic 

establishments and NGOs). 

In this 2011 State of the Bay report, available data on a variety of physical and biological 

parameters are presented, including activities and discharges affecting the health of the Bay 

(residential and industrial development, dredging, coastal erosion, shipping, and sewage and other 

waste waters), water quality in the Bay itself (temperature, oxygen, salinity, nutrients, and pH), 

sediment quality (particle size, heavy metal and hydrocarbon contaminants, particulate organic 

carbon and nitrogen) and ecological indicators (Chlorophyll a, aquatic macrophytes, benthic 

macrofauna, fish and birds). Where possible, trends and areas of concern are identified. 

Recommendations for future monitoring are made with a view to further improving the existing 

environmental monitoring program for the area. 

Activities and Discharges Affecting the Bay 

Human settlements surrounding Saldanha Bay and Langebaan Lagoon have expanded tremendously 

in recent years. This is brought home very strongly by population growth rates of over 9% per 

annum in Langebaan and nearly 7% in Saldanha over the period 2002 to 2004. This translates to a 

doubling in the population size every 8 years in the former case and every 10 years in the latter. 

Numbers of tourists visiting the area every year are increasing a similarly rapid rate. This rate of 

development translates into an equally rapid increase in the amount of waste that is produced and 

has to be dealt with. Major developments within the bay include the construction of the Marcus 

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Island causeway and the iron ore terminal, the establishment of a three small craft harbours, 

mariculture farms and several fish processing factories, while extensive industrial and residential 

development have become established around the periphery of the bay. Anthropogenic pollutants 

and wastes find their way into the bay from a range of activities and developments within the study 

area. These include dredging and port expansion, port activities, shipping, ballast water discharges 

and oil spills, municipal (sewage) and household discharges, discharge from fish processing factories, 

biological waste associated with mariculture and storm water runoff. 

Coastal developments in Langebaan and Saldanha extend right to the waters edge. The lack 

of a development setback zone or coastal buffer places stress on the marine environment due to 

increased risk of erosion, trampling and habitat loss as well as allowing large volumes of storm water 

runoff to enter the bay and lagoon. 

Several dredging events have occurred in Saldanha Bay to facilitate the development of the 

port, namely the construction of the Marcus Island Causeway (1973), General Maintenance Quay 

and Rock Quay (1974-1976), Multi-Purpose Terminal (1980) and the Small Craft Harbour (1984). The 

Multi-Purpose Terminal was extended in 1997/1998 which required further dredging. Maintenance 

dredging was performed at the Mossgas Terminal and the Multi-Purpose Terminal at the end of 

2007. Additional dredging was conducted between Caisson 3 and 4 on the Saldanha side of Iron Ore 

Terminal in 2009/10 when 7 300 m 3 of material was removed from an area of approximately 3 000 

m 2 in extent at the end of the causeway. Transnet has also proposed a Phase 2 expansion of the Iron 

Ore Terminal (Big Bay side) to increase its holding capacity, which would require extensive dredging 

and marine blasting. This proposal is currently on hold, pending improvements in the international 

iron ore market. Other development in and around the Bay include a reverse-osmosis desalination 

plant which has been constructed at the Iron Ore Terminal in Big Bay and the refurbishment and 

expansion of the small craft harbour at Salamander Bay in Langebaan Lagoon. The possibility of 

establishing an Industrial Development Zone along the north shore of the bay and a new LPG gas 

terminal in the bay are also under consideration. 

Human induced changes within Saldanha Bay (mostly changes in current circulation and 

wave activity) have also contributed to the erosion of Langebaan beach and Paradise beach. In 

order to mitigate this and to alter wave dynamics and reduce erosion, groynes have been 

constructed at the mouth of Langebaan Lagoon, which required dredging of marine sands. Dredging 

of the seabed has significantly altered sediment composition and had a devastating effect on the 

Saldanha Bay marine environment in the past, principally through the loss of benthic species. The 

impacts of dredging are mostly observed in the vicinity of the iron ore terminal and within Small Bay. 

Storm water enters Saldanha Bay/Langebaan Lagoon via multiple storm water drains and 

tarred surfaces. Storm water is a major source of non-point pollutants to the bay and typically 

contains contaminants such as metals, bacteria, fertilizers (nutrients), hydrocarbons, plastics, 

pesticides and solvents. Increased volumes of storm water runoff (as a result of development) are 

associated with degradation of aquatic environments. Studies conducted by the CSIR indicate that 

the concentrations of several contaminants (nitrate, ammonia, metals and faecal coliforms) in 

Saldanha Bay storm water runoff are well above water quality guidelines. 

Historically, two fish processing factories have discharged effluent into Small Bay, namely 

Southern Seas Fishing and Sea Harvest. The former ceased operations a few years ago but is likely to 

be recommissioned again soon. Sea Harvest discharges approximately 35 000 m 3 of effluent from 

their fresh fish processing effluent into Small Bay each month. This effluent contains significant 

quantities of organic material (suspended solids, ammonia and other nitrogenous compounds) 

which stimulate primary production (algal growth), consume oxygen, and can lead to deterioration 

in water quality in the Bay. 

Saldanha Bay is the only natural sheltered embayment in South Africa and as a result it is 

regarded as the major area for mariculture. There are currently seven mariculture operators that 

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farm mussels, oysters, and various other species in the bay. A total area of approximately 145 ha 

has been allocated to these operators. Historic studies as well as the State of the Bay surveys have 

shown that these culture operations can lead to organic enrichment and anoxia in sediments under 

the culture rafts and ropes. The source of the contamination is believed to be mainly faeces, 

decaying mussels and fouling species. 

Ships entering the port of Saldanha take up and discharge large volumes of ballast water 

when offloading and loading cargo. Water from foreign ports is thus introduced to Saldanha Bay and 

presents risks such as the introduction of alien species and the release of water containing high 

concentrations of contaminants into the bay. Volumes of ballast water discharged are greatest at 

the iron ore terminal and have increased steadily from 2002 to 2011. Historical measurements 

suggest that the mean concentrations of the trace metals (Cd, Cu, Zn, Pb and Cr) in ballast water 

discharged into Saldanha Bay exceed the South African water quality guidelines, indicating that 

ballast water discharge contributes significantly to metal contamination within the bay. 

Concentrations of trace metals in ballast water at present are unlikely to be as high as the historic 

data suggest, given the introduction of new ballast water management technique such as open 

ocean exchange, but this remains to be confirmed. 

Water Quality 

Aspects of water quality (temperature, salinity and dissolved oxygen, nutrients and chlorophyll 

concentrations) are often measured in an attempt to understand the origin of a body of sea water 

and the impacts it has on the physical and biological processes in the environment. Investigation of 

the available long-term data sets of temperature, salinity and dissolved oxygen suggest no evidence 

of long-term trends (neither increases nor decreases) in these parameters that can solely be 

attributed to anthropogenic factors. Natural, regional oceanographic processes appear to be the 

dominant processes driving the variation in water temperature, salinity, dissolved oxygen, nutrients 

and chlorophyll concentrations observed in Saldanha Bay. However, there is clear evidence of 

altered current strengths and circulation patterns within the Bay which are ascribed to the 

construction of the ore terminal and causeway. The water entering Small Bay appears to remain 

within the confines of the Bay for longer periods than was historically the case. There is also an 

enhanced clockwise circulation and increased current strength flowing alongside unnatural obstacles 

(i.e. enhanced boundary flow, for example alongside the ore terminal). The wave exposure patterns 

in Small Bay and Big Bay have also been altered as a result of harbour developments in Saldanha 

Bay. The extent of sheltered and semi-sheltered areas has increased in both Small and Big Bay. 

Historically, coastal waters in Small Bay had faecal coliform counts well in excess of safety 

guidelines for both mariculture and recreational use. There have been noticeable improvements in 

water quality in Small bay since 2006 in terms of recreational use. However, faecal coliform counts 

are still well above guideline limits for mariculture in some areas. The highest faecal coliform counts 

are routinely recorded at the beach sewage outlet (Bok River) and in Pepper Bay. Faecal coliform 

and E. coli counts are lower in Big Bay and Langebaan Lagoon when compared to Small Bay, but 

several sites (Paradise Beach, Seafarm at TNPA and Mykonos Harbour) still suffer from bacterial 

contamination and may be getting worse. Considering the likely growth of mariculture and tourism 

industries in Saldanha Bay, it is imperative that further steps be taken to curb this source of pollution 

into the bay. Waste water from the Langebaan Waste Water Treatement Works has historically 

been used to water the golf course with little or none of this being discharged to sea. However, the 

supply of treated wastewater from Langebaan Lagoon now outstrips the irrigation requirements, 

and a considerable volume of the water from this plant now makes its way into the bay. This is 

obviously set to increase dramatically in future as development in this area continues to expand 

apace. Further improvements to storm water and sewerage management methods are urgently 

required in the whole of the Saldanha-Langebaan area. It is imperative that monitoring of bacterial 

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contaminants in the bay and lagoon continue into the future and that serious consideration be given 

to further expanding and upgrade the sewage and storm water treatment facilities in these areas. 

Concentrations of trace metals in marine organisms (mostly mussels) in Saldanha Bay were 

historically monitored on a routine basis by the Department of Environmental Affairs (DEA) and by 

the mariculture farm owners. The DEA Mussel Watch Programme records concentrations of 

cadmium, copper, lead, zinc, iron and manganese present in the flesh of mussels at several sites 

along the shoreline of the Bay. Data from the DEA Mussel Watch Programme show that 

concentrations of lead in mussels at the monitored sites were consistently are above guideline limits 

for foodstuffs for as long as these data have been collected (1997-2007), while concentrations of 

cadmium frequently exceed these limits, and those for zinc did so occasionally. Concentrations of 

copper were, however, well below specified levels. No clear trends over time are evident for any of 

the trace metals, although recent data (post 2007) are lacking. High concentrations of trace metals 

along the shore is very clearly of concern and points to the need for management intervention that 

can address this issue as it poses a very clear risk to the health of people harvesting mussels from 

the shore. It is vitally important that this monitoring continue in the future and that data are made 

available to the public for their own safety. 

Data on trace metals concentrations in shellfish from the mariculture farms in the Bay were 

also obtained from DAFF (courtesy of the farm operators). These results show that trace metal 

concentrations away from the shore are much lower than those in nearshore water and mostly meet 

guidelines for foodstuffs for human consumption. The reasons for the lower concentrations of trace 

metals in farmed mussels compared with those on the shore may be linked with higher growth rates 

for the farmed mussels, and the fact that the cultured mussels are feeding on phytoplankton blooms 

in freshly upwelled water that has only recently been advected into the Bay from outside and thus 

relatively uncontaminated. 

Sediments 

The distribution of mud, sand and gravel within Saldanha Bay is influenced by wave action, currents 

and mechanical disturbance (e.g. dredging). Under natural circumstances, the prevailing high wave 

energy and strong currents would tend to flush fine sediment and mud particles out the bay, leaving 

behind the heavier, coarser sand and gravel. Obstructions to current flow and wave energy can 

result in increased deposition of finer sediment (mud). Large-scale disturbances (e.g. dredging) of 

sediments re-suspends fine particles that were buried beneath the sand and gravel. Contaminants 

(trace metals and toxic pollutants) are largely associated with the mud component of the sediment 

and can have a negative impact on the environment. Accumulation of organic matter in benthic 

sediments can also give rise to problems as it depletes oxygen both in the sediments and 

surrounding water column as it decomposes. Historically, it was reported that the proportion of 

mud in the sediments of Saldanha Bay was very low, to the extent that it was considered negligible. 

Reduced water circulation in the bay and dredging activities has resulted in an overall increase in the 

mud fraction in sediments in the bay. The most significant increases in mud content in the surface 

sediments has been observed following dredging events, however, over several years, a significant 

proportion of the mud has either been flushed out or re-buried beneath sand and gravel, and the 

sediment composition has returned to one mostly dominated by sand and gravel. The most recent 

studies investigating the sediment particle size in Saldanha Bay (2004-2011) indicate that the 

sediment in the bay is now predominantly made up of sand and is not considered to contain high 

levels of contaminants, except in the most sheltered parts (e.g. Yacht Club Basin and the 

Multipurpose Quay). 

Particulate organic carbon (POC) and nitrogen (PON) are present at elevated levels in the 

sediments in certain areas of the bay, notably near the Yacht Club Basin and the Mussel Farm. It is 

considered most likely that the origin of the POC and PON is associated with waste discharge from 

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the fish factories and faecal waste from the mussel rafts. Accumulation of organic waste, especially 

in sheltered areas where there is limited water flushing, can lead to anoxic conditions and negatively 

impact on the marine environment as has been seen from the species composition and abundance 

of the benthic communities inhabiting the sediments in the affected areas. Data collected between 

1999 and 2011 indicate generally low organic matter concentrations occurring in Saldanha Bay, 

except at the Yacht Club Basin, Multipurpose Terminal and the Mussel Farm sites. Organic levels 

should thus continue to be monitored on a regular basis, especially in Small Bay. 

Contaminants (metals and toxic pollutants) are commonly associated with fine sediments 

and mud. In areas of the bay where fine sediments tend to accumulate, these contaminants 

sometimes exceed acceptable threshold levels. This is believed to be due either to naturallyoccurring 

high levels of the contaminants in the environment (e.g. in the case of cadmium) or due to 

impacts of human activities (e.g. lead, copper and nickel associated with ore exports). While such 

trace metals are generally biologically inactive when buried in the sediment, they can become toxic 

to the environment when re-suspended as a result of mechanical disturbance. On average, the 

concentrations of all metals were highest in Small Bay, lower in Big Bay and below detection limits in 

Langebaan lagoon. Following the major dredging event in 1999, cadmium concentrations in certain 

areas in Small Bay exceeded internationally accepted safety levels, while concentrations of other 

trace metals (e.g. lead, copper and nickel) approached threshold levels. Subsequent to this time, 

there have been a number of smaller spikes in trace metal levels, mostly as a result of dredging 

operations. For example, trace metals in the entrance to Langebaan Lagoon were significantly 

elevated in 2011 following dredging operations that were conducted as part of the expansion of the 

Naval Boat Yard in Salamander Bay. Currently, trace metal levels are well within safety thresholds at 

most sites owing to the fact that fine sediments, along with the associated contaminants, have 

either been flushed out of the bay or have been reburied. Key areas of concern regarding heavy 

metal pollution within Small Bay include the Yacht Club basin and the multipurpose terminal where 

levels of cadmium, copper and lead are still in excess of internationally-accepted guidelines. Regular 

monitoring of trace metal concentrations is strongly recommended to provide an early warning of 

any future increases. 

Hydrocarbons measured in the sediments of Saldanha Bay in 1999 were reported to be very 

low and not considered an environmental risk. No poly-cyclic, poly-nuclear compounds or pesticides 

were detected in sediments of Saldanha Bay. Sediment samples from the vicinity of the ore terminal 

were collected and tested for hydrocarbon contamination again in 2010 and 2011. The total 

petroleum hydrocarbon contamination for all sites, with the exception of one in 2010, fell below the 

level where toxic effects on marine organisms is expected (the latter site fell exactly on this limit). 

Hydrocarbons are thus not considered to be of major concern at present, but it is recommended 

that petroleum hydrocarbons in the vicinity of the ore terminal continue to be monitored in future. 

Aquatic macrophytes (eelgrass and saltmarshes) 

Three distinct intertidal habitats exist within Langebaan Lagoon: seagrass beds, such as those of the 

eelgrass Zostera capensis (a type of seagrass); saltmarsh dominated by cordgrass Spartina maritime 

and Sarcocornia perennis; and unvegetated sandflats dominated by the sand prawn, Callianassa 

krausii and the mudprawn Upogebia capensis. Eelgrass and saltmarsh beds are extremely important 

as they increase habitat diversity in the lagoon, provide important an food source, increase sediment 

stability, provide protection to juvenile fish and invertebrates from natural predators and generally 

support higher species richness, diversity, abundance and biomass of invertebrate fauna compared 

to unvegetated areas. Eelgrass and saltmarsh beds are also important for waterbirds which feed 

directly on the shoots and rhizomes, forage amongst the leaves or use them as roosting areas at high 

tide. Recent studies show that the aerial extent of seagrass beds in Langebaan Lagoon has declined 

by an estimated 38% since the 1960s, this being more dramatic in some areas than others (e.g. 

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seagrass beds at Klein Oesterwal have declined by almost 99% over this period). Corresponding 

changes have been observed in densities of benthic macrofauna. At sites where eelgrass cover has 

declined, species commonly associated with eelgrass have declined in abundance, while those that 

burrow predominantly in unvegetated sand have increased in density. Fluctuations in the 

abundance of wading birds such as Terek Sandpiper, which feeds exclusively in Zostera beds have 

also been linked to changes in eelgrass, with population crashes in this species coinciding with 

periods of lowest seagrass. The loss of eelgrass beds from Langebaan Lagoon is a strong indicator 

that the ecosystem is undergoing a shift, most likely due to anthropogenic disturbances. It is critical 

that this habitat and the communities associated with it be monitored in future as further reductions 

are certain to have long term implications, not only for the invertebrate fauna but also for species of 

higher trophic levels. 

In contrast, little change has been reported in the extent of saltmarshes in Langebaan 

Lagoon, these having declined by no more than 8% since the 1960s. 

Benthic macrofauna 

Soft-bottom benthic macrofauna (animals living in the sediment that are larger than 1 mm) are 

frequently used as a measure to detect changes in the health of the marine environment resulting 

from anthropogenic impacts. Measures of the numbers, abundance and biomass of species making 

up the benthic community from studies conducted prior to development of Saldanha Bay are 

compared to data from recent surveys (2005, 2008, 2009, 2010 and 2011). Pre-development 

benthic macrofauna surveys of the area were conducted using slightly different methods to those of 

more recent studies. Nevertheless, taking these differences into consideration, it is evident that 

there have been significant changes in benthic communities within the bay. The most dramatic 

changes are evident in Small Bay where there has been a substantial increase in the abundance of 

crustaceans (mudprawns, sandprawns, amphipods and isopods) and tongue worms, and an overall 

decrease in species diversity. The abundance of crustaceans has similarly increased in Big Bay over 

time, although the species diversity appears to have remained fairly consistent. The sea pen 

Virgularia schultzei, a species highly sensitive to disturbance and pollution, had disappeared from 

both Big and Small Bay subsequent to the initial survey in the 1970’s, but was recorded again in 

recent samples from Big Bay, suggesting an improvement in the health of the benthic community in 

this area. Analysis of recent trends in Big Bay and Small Bay suggest that conditions are closely 

linked to large-scale dredging events in the bay. In both Small Bay and Big Bay, species richness and 

abundance started from a low base in 1999, following a major dredging event in 1997/8 (extension 

of the Multi Purpose Terminal), increased in 2004, declined to a low level in 2008 following further 

dredging around the MPT and Mossgass Quay, and has increased steadily since then. Small-scale 

operations around Caisson 3 and 4 on the Saldanha side of the Iron Ore Terminal in 2010/11 did not 

seem to have a significant impact on the bay as a whole. Impacts of the dredging activities in 

Salamander Bay for the expansions of the Naval Boatyard in this area were also clearly evident in the 

data from these sites. Changes in abundance and biomass were mirrored by changes in the main 

feeding groups. When numbers are low, they tend to be dominated by detritivores, but when they 

are high, they are dominated by filter feeders. 

Overall, conditions in Small Bay remain very much poorer than those in Big Bay or 

Langebaan Lagoon. The most severely-impacted sites within Small Bay in 2011 remain the Yacht 

Club basin and the base of the ore terminal. These sites are prone to the accumulation of pollutants 

due to restricted water movement. Benthic fauna have been almost entirely eliminated from the 

Yacht Club basin in Small Bay, which is also the site registering the highest concentrations of metals 

and other contaminants (POC, Cu, Cd and Ni). 

Benthic macrofauna present in Langebaan Lagoon were sampled in 1975 and again in 2004, 

2008, 2009 and 2010. In 1975, as many as six species were found in samples from Langebaan 

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Lagoon, however, data collected in 2004-2011 indicate an almost complete dominance by 

crustaceans, with a low diversity and abundance of polychaetes occurring in the lagoon samples. 

Previous reports suggested that the anthropogenic changes occurring in Saldanha Bay had limited 

impacts on Langebaan Lagoon. However, analysis of recent benthic macrofauna data suggest this 

may not necessarily be the case. Trends in abundance, biomass and diversity of macrofauna in the 

lagoon show an uncanny resemblance to those in Big and Small Bay with a modest peak in 2004, 

followed by a dip in 2008, and a clear increase in all metrics from this point forwards (2009-2011). It 

is strongly recommended that regular benthic macrofauna monitoring continue in Saldanha Bay and 

Langebaan Lagoon. 

Rocky intertidal 

Species occurring in the intertidal rocky shore zone are readily impacted by changes in the 

environment. No known studies have examined the rocky intertidal species composition in Saldanha 

Bay prior to 1980, by which time the alien, the invasive Mediterranean mussel Mytilus 

galloprovincialis had already begun to displace indigenous species from the rocky shore. Studies 

conducted at Marcus Island in 1980 and 2001 show strong links between the invasion of the 

Mediterranean mussel and changes in the intertidal rocky shore communities. The mid-to-low shore 

intertidal area has been impacted the most, and local species like the black mussel and ribbed 

mussel have been displaced from the low shore by the invasive mussel. It is considered most likely 

that the Mediterranean mussel was first introduced with ballast water discharged by ore carriers 

visiting Saldanha Bay and has since spread along the coast as far as Namibia and to Port Elizabeth. 

As a component of this State of the Bay evaluation, baseline conditions relating to rocky 

intertidal biota present at eight sites in Saldanha Bay were first surveyed in 2005 and have been 

resurveyed annually since 2008. The most important factor responsible for community differences 

among sites is the exposure to wave action and to a lesser extent shoreline topography (boulder 

shore being different to large rocky platforms). Species composition and abundance has remained 

similar between years and any differences that are evident are most likely to be natural seasonal and 

inter-annual phenomena, rather than anthropogenically-driven changes. The only exception being 

the alien barnacle Balanus glandula, which was not recorded in the 2005 baseline survey, when it 

was most likely misidentified as the native barnacle Chthamalus dentatus. The alien barnacle 

typically dominates the mid-shores of semi-exposed sites. Its presence in South Africa has only 

recently been noticed, and evidence suggests that it has been present in South Africa since at least 

1992. 

Fish 

The current status of fish and fisheries within Saldanha Bay and Langebaan Lagoon appear to be 

satisfactory. Long-term monitoring by means of experimental seine-netting has revealed no 

statistically significant, negative trends since fish sampling began in 1986-87. It is likely that the 

major changes reflected in the macrobenthos and concurrent reduction in the extent of eelgrass in 

Langebaan lagoon since the 1970s did have a dramatic impact on the ichthyofauna. These changes 

would have caused ecosystem-wide effects that included changes in both the physical habitat 

(extent of eelgrass, sediment structure, etc.) and food sources (reductions in bivalves and 

polychaetes and increases in sand prawns) available to fish. This would have likely favoured some 

fish species and had a negative impact on others. The abundance of two species that tend to favour 

aquatic macrophyte habitats, pipefish and super klipvis, does appear to have declined in Langebaan 

Lagoon since the 1986/87 sampling. However, the major changes that probably occurred in the 

system would have taken place at the same time that the changes in benthos and eelgrass took 

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place (i.e. 1970s-1980s), and as no fish sampling took place over this period, these are not reflected 

in the available data which only exists from the late 1980s. 

The 2011 sampling event recorded remarkably good harder recruitment throughout the 

Saldanha Bay-Langebaan Lagoon system, whilst the estimated abundance of other key species such 

as white stumpnose, gobies and silversides within Big Bay and Langebaan Lagoon compare 

favourably with data from earlier surveys. In Small Bay, however, where the average density of 

commercially-important fish such as white stumpnose have always been traditionally much higher 

than other areas of the bay (e.g. white stumpnose density in Small Bay = 0.8 fish.m -2 vs. 0.1 fish.m -2 

in Big Bay and 0.05 fish.m -2 in Langebaan lagoon), there were clear reductions in the abundance of 

this and other key species (with the exception of harders), with the lowest yet recorded black tail 

density and the second lowest white stumpnose density to date. This follows the trend observed in 

the 2010 report. The fact that the abundance of key species are declining in the area of maximum 

anthropogenic disturbance (Small Bay), while they are increasing in other less-disturbed areas (Big 

Bay and Langebaan Lagoon) is very telling and naturally of some concern. Ongoing, regular 

monitoring of the ichthyofauna and fisheries in Saldanha Bay and Langebaan Lagoon is therefore 

strongly recommended. 

Birds 

Saldanha Bay, Langebaan Lagoon and the associated islands provide important shelter, feeding and 

breeding habitat for at least 53 species of seabirds, 11 of which are known to breed on the islands. 

The islands of Malgas, Marcus, Jutten, Schaapen and Vondeling support breeding populations of 

African Penguin (a red data species), Cape Gannet, four species of marine cormorants, Kelp and 

Hartlaub’s Gulls, and Swift Terns. The islands also support important populations of the rare and 

endemic African Black Oystercatcher. Saldanha Bay and its islands support substantial proportions 

of the total populations of several of these species. 

There has been an overall decrease in the breeding population of African Penguin at all four 

islands in the Bay (Malgas, Marcus, Jutten and Vondeling). This decrease in numbers has been 

attributed to migration to other islands (Robben and Dassen Islands) and a reduced availability of 

anchovy, which is the primary food source for these birds. The population in Saldanha Bay has 

decreased from 2049 breeding pairs in 1987 to 506 breeding pairs in 2010, representing a 75% 

decrease in 24 years. Although penguin numbers in Saldanha Bay in 2011 are slightly up on that in 

2010 (614 vs. 506 pairs), the overall downward trend currently shows no sign of reversing, and 

immediate conservation action is required to prevent further declines. 

Populations of Kelp Gull have showed steady year-on-year increases in the Saldanha Bay 

region until 2000, most likely due to the increase in availability of food as a result of the introduction 

and spread of the invasive alien mussel Mytilus galloprovincialis. Since 2000, however, populations 

on the islands have been steadily decreasing, following large-scale predation by Great White 

Pelicans Pelecanus onocrotalus that was first observed in the mid-1990s. During 2005 and 2006, 

pelicans caused a total breeding failure of Kelp Gulls at Jutten and Schaapen Islands, the effects of 

which are still apparent in 2010. 

Hartlaub’s Gull and Swift Tern populations vary erratically, with numbers fluctuating widely 

each year. There have been no long-term increases or decreases in populations of these birds. 

There is some concern, though, that Swift terns have not bred on any of the islands in the bay for 

four years now. 

Populations of Cape Gannets and Cape Cormorants also vary each year. Cape Gannets on 

the West Coast have been declining since the start of an eastward shift of pelagic fish stocks in the 

late 1990’s. This is, to some extent, compensated for by an increase in the numbers of breeding 

birds on the east coast (Bird Island). Recent increases in predation by Cape fur seals Arctocephalus 

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pusilus pusillus and the Great White Pelican are also of concern, having been responsible for a 25% 

reduction in the size of the colony at Malgas Island between 2001 and 2006, with no evidence of 

improvement since then. No clear trends are discernable in populations of Cape Cormorants in the 

bay in recent years. 

Bank Cormorant numbers in Saldanha Bay declined between 1990 and 2007 from more than 

250 breeding pairs to fewer than 50. Numbers have since increased slightly to just under 60 

breeding pairs in recent years and appear to have stabilised at this level for the moment. 

Overall numbers of White-Breasted Cormorants in Saldanha Bay have been relatively 

constant since detailed records started in 1991, but breeding populations have shifted between 

islands in the bay, mostly from Meeuw to Schaapen and back to Meeuw again. Overall numbers in 

the bay have increased in the last two years, but it is not clear whether this trend will be sustained in 

the long term. 

The islands in Saldanha Bay support an important number of African Black Oystercatchers. 

They are most numerous on Marcus, Malgas and Jutten Islands, where their populations currently 

stand at 126 and 168 birds, respectively. In the last 35 years (since 1980) the population has grown 

by 100 breeding pairs on the three main breeding islands in Saldanha Bay most likely due to the 

introduction and proliferation of the alien mussel Mytilus galloprovincialis, which is a major food 

item for this species. Population growth appears to have slowed in the recent years, most likely due 

to the fact that the new carrying capacity of the islands has now been reached. 

Langebaan Lagoon and its associated warm, sheltered waters and abundance of prey, 

provides an important habitat for migrant waterbirds, specifically from the Palaearctic region of 

Eurasia. As many as 98% of the waterbirds present in the lagoon during summer months are 

migrant species, with an average of only 2% being resident during the remainder of the year. 

Langebaan Lagoon has been identified as the most important wetlands for waders on the west coast 

of southern Africa. Annual counts of the numbers of waders over the period 1975 to 1980 showed 

stable summer populations, but large variations in the number of migrants that remained over 

winter. Since 1980, there has been a dramatic downward trend in the numbers of Palaearctic 

waders at the lagoon, which is at least in part attributed to population declines as a result of 

disturbances to their breeding grounds. However, there has also been a dramatic decline in 

numbers of resident waders, which indicates that disturbances at the lagoon, such as habitat 

changes and human disturbance, are also significant. Numbers of resident waders have been 

relatively stable since 2008. 

Introduced species 

To date, an estimated 85 marine species have been recorded as introduced to South African waters, 

mostly though shipping activities or mariculture. At least 62 of these are thought to occur in 

Saldanha Bay-Langebaan Lagoon. Many of these are considered invasive, including the 

Mediterranean mussel, the European green crab Carcinus maenas and the recently-detected 

barnacle Balanus glandula. An additional twenty five species are currently regarded as cryptogenic 

(of unknown origin – i.e. potentially introduced) but very likely introduced. Most of the introduced 

species in this country have been found in sheltered areas such as harbours, and are believed to 

have been introduced through shipping activities, mostly ballast water. Because ballast water tends 

to be loaded in sheltered harbours the species that are transported originate from these habitats 

and have a difficult time adapting to South Africa’s exposed coast. The status of some of the more 

common alien species in the bay are presented in the main body of the report along with trends in 

their distribution and abundance where these data are available (either from the State of the Bay 

surveys or other data sets). Future surveys in the bay will be used to map changes in the distribution 

of the known alien species and to report on any new introductions. 

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Summary 

In summary, developments in Saldanha Bay and Langebaan Lagoon during the past thirty years have 

inevitably impacted on the environment. Most parameters investigated in this study, with the 

exception of fish (very limited available data), indicated some degree of negative impact occurring. 

Decreasing populations of birds in the bay area are of major concern. These may well be a reflection 

of reductions in fish, benthic macrofauna, and sediment and water quality. Negative environmental 

conditions imposed on the water quality or sediments, will, in time, negatively impact on the top 

predators (birds and fish) of the system. A holistic approach in monitoring and assessing the overall 

health status of the Bay is essential, and regular (in some cases increased) monitoring of all 

parameters reported on here is strongly recommended. 

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Table of Contents 

TABLE OF CONTENTS 

EXECUTIVE SUMMARY 

TABLE OF CONTENTS 

LIST OF FIGURES 

LIST OF TABLES 

GLOSSARY 

XVIII 

1 INTRODUCTION 1 

1.1 BACKGROUND 1 

1.2 STRUCTURE OF THIS REPORT 3 

2 BACKGROUND TO ENVIRONMENTAL MONITORING AND WATER QUALITY MANAGEMENT 4 

2.1 INTRODUCTION 4 

2.2 MECHANISMS FOR MONITORING CONTAMINANTS AND THEIR EFFECTS ON THE ENVIRONMENT 4 

2.3 INDICATORS OF ENVIRONMENTAL HEALTH AND STATUS IN SALDANHA BAY AND LANGEBAAN LAGOON 6 

3 ACTIVITIES AND DISCHARGES AFFECTING THE HEALTH OF THE BAY 10 


3.2 URBAN AND INDUSTRIAL DEVELOPMENT 11 

3.3 DISCHARGES AND ACTIVITIES AFFECTING ENVIRONMENTAL HEALTH 20 

3.3.1 Dredging and port expansion 20 

3.3.2 The Sishen-Saldanha oreline expansion project 23 

3.3.3 Development of a Liquid Petroleum Gas Facility in Saldanha Bay 24 

3.3.4 Development of the Salamander Bay Boat yard 25 

3.3.5 Shipping, ballast water discharges, and oil spills 26 

3.3.6 Reverse Osmosis Desalination Plants 30 

3.3.7 Sewage and associated waste waters 34 

3.3.8 Storm water 47 

3.3.9 Fish processing plants 49 

3.3.10 Mariculture 55 

4 WATER QUALITY 57 

4.1 CURRENTS AND WAVES 57 

4.2 MICROBIOLOGICAL MONITORING 59 

4.2.1 DWAF 1995 and 1996 guidelines 59 

4.2.2 Revised final guidelines for recreational waters of South Africa’s coastal marine 

environment 72 

4.3 TRACE METAL CONTAMINANTS IN THE WATER COLUMN 75 

4.4 SUMMARY OF WATER QUALITY IN SALDANHA BAY AND LANGEBAAN LAGOON 80 

5 SEDIMENTS 81 

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5.1 SHORELINE EROSION IN SALDANHA BAY AND LANGEBAAN LAGOON 81 

5.1.1 Background 81 

5.1.2 Human impacts on the system 81 

5.1.3 Changes in beach and dune morphology 82 

5.2 MONITORING OF SEDIMENT PARTICLE SIZE COMPOSITION IN THE BAY 90 

5.2.1 Historical data 90 

5.2.2 Sediment Particle size results for 2011 92 

5.3 MONITORING OF PARTICULATE ORGANIC CARBON (POC) AND NITROGEN (PON) IN SEDIMENT IN THE BAY 98 

5.3.1 Spatial trends in POC and PON 98 

5.3.2 Temporal trends 99 

5.4 TRACE METALS 104 

5.4.1 Historical data 105 

5.4.2 Analysis and results for 2011 105 

5.4.3 Summary 121 

5.5 HYDROCARBONS 123 

6 AQUATIC MACROPHYTES IN LANGEBAAN LAGOON 124 

6.1 LONG TERM CHANGES IN SEAGRASS IN LANGEBAAN LAGOON 125 

6.2 LONG TERM CHANGES IN SALTMARSHES IN LANGEBAAN LAGOON 127 

7 BENTHIC MACROFAUNA 128 


7.2 HISTORIC DATA ON BENTHIC MACROFAUNA COMMUNITIES IN SALDANHA BAY 128 

7.3 APPROACH AND METHODS USED IN MONITORING BENTHIC MACROFAUNA IN 2011 129 

7.3.1 Sampling 129 

7.3.2 Statistical Analysis 131 

7.4 BENTHIC MACROFAUNA SURVEY RESULTS: 2011 133 

7.4.1 Community Structure and Composition 133 

7.4.2 Species Diversity Indices 147 

7.4.3 Linking Ecological Indices to Environmental Variables 150 

7.5 DISCUSSION 153 

7.6 SMALL BAY 153 

7.7 BIG BAY 155 

7.8 SALAMANDER BAY AND DONKERGAT 156 

7.9 LANGEBAAN LAGOON 157 

7.10 SUMMARY OF BENTHIC MACROFAUNA FINDINGS 159 

8 INTERTIDAL INVERTEBRATES (ROCKY SHORES) 162 


8.2 APPROACH AND METHODOLOGY 163 

8.2.1 Study Sites 163 

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8.2.2 Methods 166 

8.2.3 Data Analysis 167 

8.3 RESULTS AND DISCUSSION 168 

8.3.1 Species Diversity and Zonation 168 

8.3.2 Spatial Variation in Community Composition 174 

8.3.3 Temporal Analysis 181 

8.4 SUMMARY OF FINDINGS 192 

9 FISH COMMUNITY COMPOSITION AND ABUNDANCE 193 

10 BIRDS 218 


9.2 METHODS 194 

9.3 RESULTS 196 

9.3.1 Description of inter annual trends in fish species diversity 196 

9.3.2 Description of inter-annual trends in fish abundance and current status of fish 

communities in Small Bay, Big Bay and Langebaan lagoon 202 

9.3.3 Status of fish populations at individual sites sampled during 2011 204 

9.3.4 Multivariate analysis of spatial and temporal trends in fish communities 208 

9.3.5 Status of the commercial and recreational white stumpnose fishery 211 

9.3.6 Comparisons of white stumpnose catch rates with the seine net survey data 214 

9.4 CONCLUSION 217 


10.2 BIRDS OF SALDANHA BAY AND THE ISLANDS 218 

10.2.1 National importance of Saldanha Bay and the islands for birds 218 

10.2.2 Ecology and status of the principle bird species 219 

10.3 BIRDS OF LANGEBAAN LAGOON 230 

10.3.1 National importance of Langebaan Lagoon for birds 230 

10.3.2 The main groups of birds and their use of habitats and food 231 

10.3.3 Inter-annual variability in bird numbers 232 

10.4 OVERALL STATUS OF BIRDS IN SALDANHA BAY AND LANGEBAAN LAGOON 234 

11 ALIEN INVASIVE SPECIES IN SALDANHA BAY-LANGEBAAN LAGOON 235 

11.1 THE OCCURRENCE AND SPREAD OF THE MARINE ALIEN SPECIES IN SALDANHA BAY 238 

11.1.1 European mussel Mytilus galloprovincialis 238 

11.1.2 European shore crab Carcinus maenas 239 

11.1.3 Shell worm Boccardia proboscidea 239 

11.1.4 Pacific South American mussel Semimytilus algosus 239 

11.1.5 Acorn barnacle Balanus glandula 240 

11.1.6 Disc lamp shell Discinisca tenuis 240 

11.1.7 Lagoon snail Littorina saxatilis 241 

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11.1.8 Brooding anemone Sagartia ornata 241 

11.1.9 Hitchhiker amphipod Jassa slatteri 241 

11.1.10 Dentate moss animal Bugula dentata 241 

11.1.11 Vase tunicate Ciona intestinalis 242 

11.1.12 Jelly crust tunicate Diplosoma listerianum 242 

11.1.13 Dirty sea squirt Ascidiella aspersa 242 

11.1.14 Western pea crab Pinnixa occidentalis in Saldanha Bay 242 

12 MANAGEMENT AND MONITORING RECOMMENDATIONS 245 

12.1 ACTIVITIES AND DISCHARGES AFFECTING THE HEALTH OF THE BAY 245 

12.1.1 Human settlements, storm water and sewage 245 

12.1.2 Dredging 246 

12.1.3 Sewage 246 

12.1.4 Fish factories 246 

12.1.5 Mariculture 247 

12.1.6 Shipping, ballast water discharges and oil spills 247 

12.1.7 Other development in and around the Bay 247 

12.2 WATER QUALITY 248 

12.2.1 Temperature, Salinity and Dissolved Oxygen 248 

12.2.2 Chlorophyll a and Nutrients 248 

12.2.3 Currents and waves 248 

12.2.4 Trace metal concentrations in biota (DEA Mussel Watch Programme and Mariculture 

Operators) 248 

12.2.5 Microbiological monitoring (Faecal coliform) 249 

12.3 SEDIMENTS 249 

12.3.1 Particle size, Particulate Organic Carbon and Trace metals 249 

12.3.2 Hydrocarbons 250 

12.4 BENTHIC MACROFAUNA 250 

12.5 ROCKY INTERTIDAL 250 

12.6 FISH 251 

12.7 BIRDS 251 

12.8 SUMMARY OF ENVIRONMENTAL MONITORING REQUIREMENTS 252 

13 REFERENCES 254 

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List of Figures 

LIST OF FIGURES 

Figure 1.1. 

Figure 3.1. 

Regional map of Saldanha Bay and Langebaan Lagoon showing development (grey 

shading) and conservation areas. ............................................................................... 1 

Possible alterations in abundance/biomass and community composition. Overall 

abundance/biomass is represented by the size of the circles and community 

composition by the various types of shading. After Hellawell (1986). ...................... 7 

Figure 4.1. Composite aerial photo of Saldanha Bay and Langebaan Lagoon taken in 1960. 

(Source Department of Surveys and Mapping). Note the absence of the ore 

terminal and causeway and limited development at Saldanha and Langebaan. ..... 12 


(Source Department of Surveys and Mapping). Note the presence of the ore 

terminal, the causeway linking Marcus Island with the mainland, and expansion of 

settlements at Saldanha and Langebaan. ................................................................. 13 


(Source Department of Surveys and Mapping). Note expansion in residential 

settlements particularly around the town of Langebaan. ........................................ 14 

Figure 4.4. 

Figure 4.5. 

Figure 4.6. 

Figure 4.7. 

Figure 4.8. 

Satellite image of Langebaan showing little or no setback zone between the town 

and the Bay. .............................................................................................................. 15 

Composite aerial photograph of Langebaan showing absence of development 

setback zone between the town and the lagoon. .................................................... 16 

Numbers of tourists visiting the West Coast National Park since 2005 (Data from 

Pierre Nel, WCNP). Day guests include all South African visitors (adults and 

children) while Overnight guests refer those staying in SANPARK accommodation. 

International guests include all SADC and non-African day visitors (adults and 

children) while the category ‘Other’ includes residents, staff, military, school visits, 

etc. .......................................................................................................................... 17 

Location of the maintenance dredging site between Caissons 3 and 4 on the ore 

terminal. ................................................................................................................... 22 

Current layout of Transnet Saldanha Bay Port (Source: Lindokuhle Mkhize, Transnet 

National Port Authority 2012). ................................................................................. 23 

Figure 4.9. An illustration of an LPG transfer scheme (Source: ERM Final Scoping Report 2011) . 

.......................................................................................................................... 24 

Figure 4.10. The Salamander Bay boatpark in Saldanha (central strip of the picture). ............... 25 

Figure 3.11. 

Figure 4.12. 

Figure 4.13. 

Number and types of vessels entering Saldanha Port from 1994-2011. (Sources: 

Marangoni 1998; Awad et al. 2003, Transnet-NPA). ................................................ 28 

Volumes of ballast water discharge in million tonnes by the different types of 

vessels entering Saldanha Port between 1994 and 2011. The data for 1999-2002 is 

an average of the total volume of discharge for those years. (Sources: Marangoni 

1998; Awad et al. 2003, Transnet-NPA unpublished data 2003-2011). ................... 29 

Location of waste water treatment works, sewage pump stations and conservancy 

tanks in Saldanha and Langebaan area (2011). ........................................................ 37 

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Figure 4.14. 

Figure 4.15. 

Figure 4.16. 

Figure 4.17. 

Figure 4.18. 

Figure 4.19. 

Figure 4.20. 

Figure 4.21. 

Figure 4.22. 

Figure 4.23. 

Figure 4.24. 

Figure 4.25. 

Monthly trends in the volume of effluent released from the Saldanha WWTW, Apr 

2003-December 2011, and authorised total volume per year expressed as a daily 

limit (red line). Allowable discharge limits as specified in terms of the exemption 

issued by DWAF under the National Water Act 1998 are represented by the dashed 

red line. ..................................................................................................................... 39 

Monthly trends in the numbers of Faecal Coliforms in effluent released from the 

Saldanha WWTW, April 2003 - December 2011. Allowable limits as specified in 

terms of a General Authorisation under the National Water Act 1998 are 

represented by the dashed red line. ........................................................................ 39 

Monthly trends in the numbers of Total Suspended Solids in effluent released from 

the Saldanha WWTW, April 2003 - December 2011. Allowable limits as specified in 


represented by the dashed red line. ........................................................................ 40 

Monthly trends in the numbers of Chemical Oxygen Demand in effluent released 

from the Saldanha WWTW, April 2003 - December 2011. Allowable limits as 

specified in terms of a General Authorisation under the National Water Act 1998 

are represented by the red line. ............................................................................... 40 

Monthly trends in Ammonia Nitrogen for effluent released from the Saldanha 

WWTW Apr 2003-December 2011. Allowable limits as specified in terms of a 

General Authorisation under the National Water Act 1998 are represented by the 

red line. ..................................................................................................................... 41 

Monthly trends in Nitrate Nitrogen for effluent released from the Saldanha WWTW 

Apr 2003 - December 2011. Allowable limits as specified in terms of a General 

Authorisation under the National Water Act 1998 are represented by the red line. .. 

41 

Monthly trends in water quality parameters Orthophosphate for effluent released 

from the Saldanha WWTW Apr 2003-December 2011. Allowable limits as specified 

in terms of a General Authorisation under the National Water Act 1998 are 

represented by the red line. ..................................................................................... 42 

Monthly trends in Free Active Chlorine for effluent released from the Saldanha 

WWTW Apr 2003-December 2011. Allowable limits as specified in terms of a 


red line. ..................................................................................................................... 42 

Monthly trends in the daily volume of effluent discharged from the Langebaan 

WWTW in the period June 2009-November 2011. .................................................. 43 

Monthly trends in the numbers of Faecal Coliforms in effluent released from the 

Langebaan WWTW, June 2009 - December 2011. Allowable limits as specified in 



Monthly trends in Total Suspended Solids in effluent released from the Langebaan 

WWTW, June 2009 - December 2011. Allowable limits as specified in terms of a 


red line. ..................................................................................................................... 44 

Monthly trends in Chemical Oxygen Demand in effluent released from the 

Langebaan WWTW, June 2009-February 2011. Allowable limits as specified in 



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Figure 4.26. 

Figure 4.27. 

Figure 4.28. 

Figure 4.29. 

Figure 4.30. 

Figure 4.31. 

Figure 4.32. 

Figure 4.33. 

Monthly trends in the concentration of Ammonia Nitrate in effluent from 




Monthly trends in the concentration of Nitrate Nitrogen in effluent from 




Monthly trends in the concentration of Orthophosphate in effluent from 




Monthly trends in the concentration of Free Active Chlorine in effluent from 




Spatial extent of residential and industrial areas surrounding Saldanha Bay and 

Langebaan Lagoon from which storm water runoff is likely to enter the sea (areas 

outlined in white). Note that runoff from the Port of Saldanha and ore terminal 

have been excluded as it is now reportedly all diverted to storm water evaporation 

ponds. ....................................................................................................................... 48 

Location of seawater intakes and discharges for seafood processing in Saldanha 

Bay together with location of current and proposed mariculture operations ......... 50 

Total monthly discharge of fresh fish processing effluent (FFP) disposed to sea by 

Sea Harvest from January 2001 to March 2007. ...................................................... 53 

Monthly trends in the numbers of Faecal coliforms in effluent from the Sea Harvest 

fresh fish processing effluent (FFP) discharged into Small Bay in the period Feb 201 

to Dec 2011. .............................................................................................................. 54 

Figure 4.34. Allocated mariculture concession areas in Saldanha Bay 2010. .............................. 56 

Figure 4.35. Overall annual mussel productivity (tons) in Saldanha Bay between 2000 and 2010 

(source: DAFF 2011) .................................................................................................. 56 

Figure 5.1. 

Figure 5.2. 

Figure 5.3. 

Figure 5.4. 

Schematic representation of the surface currents and circulation of Saldanha Bay 

(A) prior to the harbour development (Pre-1973) and (B) after construction of the 

causeway and iron-ore terminal (Present). (Adapted from Shannon and Stander 

1977 and Weeks et al. 1991a) .................................................................................. 58 

Faecal coliform and E. coli counts at 4 of the 10 sampling stations within Small Bay 

(Feb 1999-Feb 2012). A downward slope of the regression (solid red and blue 

lines) is indicative of improving water quality, while an upward slope in these lines 

in indicative of decreasing water quality. ................................................................. 66 

Faecal coliform and E. coli logarithmic counts at 3 of the 10 sampling stations 

within Small Bay (Feb 1999-Feb 2012). A downward slope of the regression (solid 

red and blue lines) is indicative of improving water quality, while an upward slope 

in these lines in indicative of decreasing water quality............................................ 67 

Faecal coliform and E. coli logarithmic counts at 4 of the 10 sampling stations 

within Big Bay (Feb 1999-Feb 2012). A downward slope of the regression (solid red 

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Figure 5.5. 

Figure 5.6. 

Figure 5.7. 

Figure 5.8. 

Figure 5.9. 

Figure 5.10. 

Figure 6.1. 

Figure 6.2. 

Figure 6.3. 

Figure 6.4 

Figure 6.5. 

Figure 6.6 

Figure 6.7 

and blue lines) is indicative of improving water quality, while an upward slope in 

these lines in indicative of decreasing water quality. .............................................. 68 

Faecal coliform and E. coli logarithmic counts at 4 sampling stations within Big Bay 

(Feb 1999-Feb 2012). A Downward slope of the regression (solid red and blue 

lines) is indicative of improving water quality, while an upward slope in these lines 

in indicative of decreasing water quality. ................................................................. 69 

Faecal coliform and E. coli logarithmic counts at 3 sampling stations within 

Langebaan Lagoon (Feb 1999-Feb 2012). A Downward slope of the regression 

(solid red and blue lines) is indicative of improving water quality, while an upward 

slope in these lines in indicative of decreasing water quality. ................................. 70 

Faecal coliform and E. coli logarithmic counts at 3 sampling stations within 

Langebaan Lagoon (Feb 1999-Feb 2012). A Downward slope of the regression 

(solid red and blue lines) is indicative of improving water quality, while an upward 

slope in these lines in indicative of decreasing water quality. ................................. 71 

An illustration of the proposed routine monitoring programme to be trialled in 

South Africa. Source: South African Water Quality Guidelines for Coastal Marine 

Waters (RSADEA 2011). ............................................................................................ 73 

Trace metal concentrations in mussels collected from five sites in Saldanha Bay as 

part of the Mussel Watch Programme. (Source of data: G. Kiviets, Marine and 

Coastal Management, Department of Environmental Affairs and Tourism). 

Recommended maximum limits for trace metals in seafood as stipulated in South 

African legislation are shown as a dotted red line. .................................................. 78 

Concentrations of Cadmium, Lead and Mercury in mussels and oysters from four 

bivalve culture operations in Saldanha Bay covering the period 1993 to 2010. 

Recommended maximum limits for trace metals in seafood as stipulated in South 

African legislation are shown as a dotted red line. .................................................. 79 

A) Under natural circumstances, dune vegetation can “move” with the beach as it 

erodes and accrete under the influence of natural processes. B) Protection of 

infrastructure erected too close to the high water mark, on the other hand, 

necessitates construction of artificial barriers and leads to the loss of the beach 

ecosystem and associated amenities. ...................................................................... 83 

Graph showing the relative change in area over time for Spreeuwalle and 

Langebaan Beach (1960 – 2012). .............................................................................. 84 

Spreeuwalle beach showing the position of the transect line in the middle of the 

beach (Source: Gericke 2012). .................................................................................. 84 

Variation in beach width across a transect of the central section of Spreeuwalle 

beach (Source: Gericke 2012). .................................................................................. 85 

Rock revetments constructed along the beach at Langebaan in an effort to protect 

coastal infrastructure. .............................................................................................. 86 

Groyne construction site Langebaan north beach. 1st groyne is completed and 

position of 2nd groyne is show in white. Area A and B are sand “slurry” sites (see 

text for explanation). Area C sand dredging site for beach reclamation. Source: 

Prestedge Retief Dresner Wijnberg. ......................................................................... 87 

State of the beach north of Groyne 2 in May 2010. (view looking south from the 

middle of Leentjiesklip 1 beach towards the groyne) .............................................. 88 

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Figure 6.8 

Figure 6.9 

State of the beach north of Groyne 2 in May 2010 (looking north from the middle 

of the beach towards Leentjiesklip 1)....................................................................... 88 

State of the beach north of Groyne 2 in May 2010 (looking north towards 

Leentjieklip from the position where the sea still reaches right up to the rock 

revetment. ................................................................................................................ 88 

Figure 6.10 Coastal erosion at Paradise Beach near Club Mykonos. .......................................... 89 

Figure 6.11. 

Figure 6.12. 

Figure 6.13. 

Figure 6.14. 

Figure 6.15. 

Figure 6.16. 

Figure 6.17. 

Figure 6.18. 

Figure 6.19. 

Figure 6.20. 

Figure 6.21. 

Figure 6.22. 

Figure 6.23. 

Figure 6.24. 

Figure 6.25 

Figure 6.26. 

Particle size composition (percentage gravel, sand and mud) of sediments at six 

localities in the small bay area of Saldanha Bay between 1977 and 2011. .............. 94 

Sediment sampling sites in Saldanha Bay and Langebaan Lagoon for 2011. Sites 

sampled from pre-1980 to 2011 are marked and labelled in red ............................ 95 

Variation in the percentage mud in sediments in Saldanha Bay and Langebaan 

Lagoon as indicated by the 2010 survey results. ...................................................... 97 


Lagoon as indicated by the 2011 survey results. ...................................................... 97 

Variation in the % Organic Carbon in the sediments in Saldanha Bay and Langebaan 

Lagoon as revealed by the 2010 survey results ...................................................... 101 

Variation in the % Organic Carbon in the sediments in Saldanha Bay and Langebaan 

Lagoon as revealed by the 2011 survey results ...................................................... 101 

Particulate Organic Nitrogen (PON) percentage occurring in sediments of Saldanha 

Bay at six locations between 1999 and 2011 ......................................................... 102 

Variation in the % Organic Nitrogen in the sediments in Saldanha Bay and 

Langebaan Lagoon as revealed by the 2011 survey results .................................. 103 

Metal:Al ratios for Copper, Lead, Cadmium and Nickel for sediments sampled in 

2011 from Saldanha Bay-Small Bay (SB), Big Bay (BB), Langebaan Lagoon (LL), 

Donkergat (D) and Salamander Bay (S) .................................................................. 107 

Variation in the concentration of Cadmium (Cd) in the sediments in Saldanha Bay 

and Langebaan Lagoon as revealed by the 2011 survey results. ........................... 109 

Concentrations of Cadmium (Cd) in mg/kg recorded at six sites in Saldanha Bay 

between 1980 and 2011. Dotted lines indicate Effects Range Low values for 

sediments ............................................................................................................... 110 

Variation in the concentration of Copper (Cu) in the sediments in Saldanha Bay and 

Langebaan Lagoon as revealed by the 2011 survey results. ................................. 112 

Concentrations of Copper (Cu) in mg/kg recorded at six sites in Saldanha Bay 


sediments ............................................................................................................... 113 

Variation in the concentration of Lead (Pb) in the sediments in Saldanha Bay and 

Langebaan Lagoon as revealed by the 2011 survey results. .................................. 115 

Concentrations of Lead (Pb) in mg/kg recorded at six sites in Saldanha Bay between 

1980 and 2011. Dotted lines indicate Effects Range Low values for sediments .... 116 

Variation in the concentration of Nickel (Ni) in the sediments in Saldanha Bay and 

Langebaan Lagoon as revealed by the 2011 survey results. .................................. 117 

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Figure 6.27. 

Figure 6.28. 

Figure 6.29. 

Figure 7.1. 

Figure 7.2. 

Figure 7.3. 

Figure 7.4. 

Figure 8.1. 

Figure 8.2. 

Figure 8.3 

Figure 8.4 

Figure 8.5. 

Figure 8.6. 

Figure 8.7. 

Figure 8.8. 

Figure 8.9. 

Concentrations of Nickel (Ni) in mg/kg recorded at six sites in Saldanha Bay 


sediments ............................................................................................................... 118 

Concentrations of Iron (Fe) in mg/kg recorded at five sites in Saldanha Bay between 

2004 and 2011. ....................................................................................................... 120 

Geographic representation of the results of a PRIMER analysis showing significant 

clustering of sites based on the similarity of trace metal concentrations. Group A 

generally had the highest concentrations for all metals and group E the lowest 

(SIMPER analysis) .................................................................................................... 122 

Seagrass (black) and saltmarsh (green) near Bottelary in Langebaan Lagoon. 

Source: Google Earth. ............................................................................................. 124 

Width of the Zostera beds and density of Siphonia at Klein Oesterwal and Bottelary 

in Langebaan Lagoon, 1972-2006. .......................................................................... 126 

Change in saltmarsh area over time in Langebaan Lagoon. (Data from Gerricke 

2008) ....................................................................................................................... 127 

Change in the number of discrete saltmarsh patches over time in Langebaan 

Lagoon. (Data from Gerricke 2008) ........................................................................ 127 

Sites sampled for benthic macrofauna between 1975 and 2011 in Saldanha Bay and 

Langebaan Lagoon. ................................................................................................. 130 

Dendrogram representing the similarity of sites (Bray Curtis Similarity) based on 

the benthic macrofaunal community composition sampled at Small Bay (SB), Big 

Bay (BB), Salamander Bay (S), Donkergat (D) and Langebaan Lagoon (LL) in 2011. 

The 30% level of similarity is indicated by the slice. Clusters of sites significantly 

similar are represented by the red dotted lines (SIMPROF). ................................. 134 


clustering of sites based on the similarity of trace metal concentrations (Euclidean 

Distance). Group A generally had the highest concentrations for all metals and 

group E the lowest (SIMPER analysis) .................................................................... 136 


Lagoon as indicated by the 2011 survey results. .................................................... 136 


clustering of sites based on the similarity of benthic macrofaunal community 

composition (Bray-Curtis coefficient) ..................................................................... 138 

Overall trends in the biomass and abundance of benthic macrofauna in Small Bay 

as shown by taxonomic and functional groups. ..................................................... 144 

Overall trends in the biomass and abundance of benthic macrofauna in Big Bay as 

shown by taxonomic and functional groups. ......................................................... 145 

Overall trends in the biomass and abundance of benthic macrofauna in Langebaan 

Lagoon as shown by taxonomic and functional groups. ........................................ 146 

Variation in the diversity of the benthic macrofauna in Saldanha Bay and 

Langebaan Lagoon as indicated by the 2010 survey results. (H’ = 1.5 indicates low 

diversity, H’ = 3.5 indicates high diversity) ............................................................. 148 

x 

ANCHOR 




Figure 8.10. 

Figure 8.11. 

Figure 8.12. 

Figure 8.13. 

Figure 8.14. 

Figure 8.15. 

Figure 8.16. 

Average Shannon Weiner diversity indices (H’) (± 0.95 confidence intervals) for Big 

Bay, Small Bay and Langebaan Lagoon in 1999, 2004, 2008, 2009, 2010 and 2011. 

149 

Two-dimensional PCA ordination of the environmental variables (metals, POC and 

PON; transformed and normalized) for Saldanha Bay 2010. Sites are labelled 

according to significant groupings revealed by the SIMPROF analysis. ................. 150 

MDS of Saldanha Bay and Langebaan Lagoon benthic macrofauna abundance 

(2011) with superimposed circles representing depth (Increasing circle size = 

deeper) ................................................................................................................... 151 

MDS plot of Saldanha Bay and Langebaan Lagoon benthic macrofauna abundance 

(2011) with superimposed circles representing abiotic factors: Total Organic 

Carbon (TOC), and % Mud (Increasing circle size = larger measurement). ............ 152 

MDS of Saldanha Bay benthic macrofauna abundance (2011) with superimposed 

circles representing concentrations of select metals: Cu, Cd, Pb and Ni. Circle size is 

proportional to magnitude of concentration (increasing circle size = larger 

concentration) ........................................................................................................ 152 

Benthic macrofauna species frequently found to occur in Saldanha Bay and 

Langebaan Lagoon, photographs by: Nina Steffani. ............................................... 160 

Benthic macrofauna species frequently found to occur in Saldanha Bay and 

Langebaan Lagoon, photographs by: Charles Griffiths. .......................................... 161 

Figure 9.1, Location of the eight rocky shore study sites in Saldanha Bay. .............................. 163 

Figure 9.2. 

Figure 9.3. 

Figure 9.4. 

Figure 9.5. 

Figure 9.6. 

Figure 9.7. 

Rocky shore study sites in Saldanha Bay (top right to left bottom): Dive School, 

Jetty, Schaapen Island East, and Schaapen Island West......................................... 164 

Rocky shore study sites in 2010 (top right to bottom left): Iron Ore Terminal, Lynch 

Point, North Bay, and Marcus Island. ..................................................................... 165 

From top left clockwise: High shore at Dive School showing Oxystele variegata and 

sand/gravel accumulation among the boulders; high shore at North Bay showing 

the Afrolittorina knysnaensis on rock and accumulating in crevices; blue-green 

algae patch at Schaapen East high shore; and low growing Ulva carpet with 

Porphyra capensis tufts at the high shore at Marcus Island. See text for more 

information. ............................................................................................................ 169 

From top left clockwise: Ulva-Balanus band at the mid shore at Schaapen Island 

East; the sand-tubeworm compact mixture at Schaapen Island West with Ulva; 

dense Balanus glandula cover at Iron Ore Terminal; and Mytilus patches 

interspersed with Balanus and Scutellastra granularis patches at Marcus Island. 

See text for more information. ............................................................................... 170 

From top to bottom right: Parechinus angulosus and Pseudoactinia flagellifera in 

the low shore pool at Dive School; overview of low shore at Schaapen Island East; 

close-up of tube-building polychaete emerging from sand; the sea cucumber 

Pseudocnella insolens embedded in sand; overview of low shore at Iron Ore 

Terminal; and close up of the giant barnacle Austromegabalanus cylindricus. See 

text for more information. ..................................................................................... 172 

From top left clockwise: Scutellastra cochlear patch in association with ‘pink’ 

encrusting coralline algae on a low shore boulder at Lynch Point; overview of the 

low shore at North Bay showing kelp growing in the infratidal; Aulacomya ater 

xi 

ANCHOR 




Figure 9.8. 

Figure 9.9. 

Figure 9.10. 

Figure 9.11. 

Figure 9.12. 

Figure 9.13. 

patch at the low shore at Marcus Island; overview of the low shore at Marcus 

Island. ...................................................................................................................... 173 

Box & whisker plots of per cent cover, species number, evenness and Shannon- 

Wiener diversity at the eight rocky shore sites. Sites are sorted from left to right 

according to increasing wave exposure. ................................................................ 175 

Mean abundance (number/0.5 m2) of the most common mobile species at the 

eight rocky shores in 2011. Sites are sorted from top to bottom according to 

increasing wave exposure. ..................................................................................... 176 

The periwinkle Afrolittorina knysnaensis nestling in amongst the alien barnacle 

Balanus glandula at the mid shore at Iron Ore Terminal. ...................................... 177 

Relationship between Afrolittorina knysnaensis and Balanus glandula for all zones 

combined (left) and for the mid shore only (right). Equations and statistical 

significances are provided for each graph. ............................................................. 177 

Contribution of the functional groups to the biotic cover (%) across the whole rocky 

shore at the eight study sites (sorted from left to right according to increasing wave 

exposure). ............................................................................................................... 178 

Dendrogram (top) and multi-dimensional scaling (MDS) plot (bottom) of the rocky 

shore communities at the eight study sites in 2011. The circles in the MDS plot 

indicate a 50% (red) and 60% (blue) similarity level. See text for further 

explanation. ............................................................................................................ 179 

Figure 9.14. Temporal changes of % cover and species number (mean ± SE) from 2005 to 2011 

at the eight rocky shore sites (DS = Dive School, J = Jetty, SE = Schaapen East, SW = 

Schaapen West, IO = Iron Ore Terminal, L = Lynch Point, NB = North Bay, M = 

Marcus Island). ....................................................................................................... 183 

Figure 9.15. 

Figure 9.16. 

Figure 9.17. 

Figure 9.18. 

Figure 10.1. 

Figure 10.2. 

Temporal changes of evenness and Shannon-Wiener diversity indices (mean ± SE) 

from 2005 to 2011 at the eight rocky shore sites. (DS = Dive School, J = Jetty, SE = 

Schaapen East, SW = Schaapen West, IO = Iron Ore Terminal, L = Lynch Point, NB = 

North Bay, M = Marcus Island). .............................................................................. 185 

Multi-dimensional scaling (MDS) plot of the rocky shore communities at the eight 

study sites from 2005 to 2011. The circles delineate a 40% similarity level. ........ 185 

The mean percentage cover of the various functional groups at the study sites in 

2005, 2008, 2009, 2010, and 2011 (from top to bottom). ..................................... 188 

Mean percentage cover of the indigenous Aulacomya ater (green) and the aliens 

Mytilus galloprovincialis (red) and Balanus glandula (blue) at the eight study sites 

over the years. Note the difference in scale between the top four and bottom four 

graphs. .................................................................................................................... 189 

Sampling sites within Saldanha Bay and Langebaan lagoon where seine net hauls 

were conducted during 2005, 2007, 2008, 2009 ,2010 and 2011 sampling events, 1: 

North Bay west, 2: North Bay east, 3:Small craft harbour, 4: Hoedtjiesbaai, 5: 

Caravan site, 6: Blue water Bay, 7: Sea farm dam, 8: Spreeuwalle, 9: Lynch point, 

10: Strandloper, 11: Schaapen Island, 12: Klein Oesterwal, 13: Botelary, 14: 

Churchaven, 15: Kraalbaai. ..................................................................................... 196 

Fish species richness during seven seine-net surveys in Saldanha Bay and 

Langebaan lagoon conducted over the period 1986-2010. The total area netted in 

each area and survey is shown. .............................................................................. 197 

xii 

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Figure 10.3. 

Figure 10.4. 

Figure 10.5. 

Figure 10.6. 

Figure 10.7. 

Figure 10.8. 

Figure 10.9. 

Figure 10.10. 

Figure 10.11. 

Figure 10.12. 

Figure 10.13. 

Figure 10.14. 

Figure 11.1. 

Figure 11.2. 

Figure 11.3. 

Average fish abundance (all species combined) during eight seine-net surveys 

conducted in Saldanha Bay and Langebaan lagoon. (Error bars show one Standard 

Error of the mean). ................................................................................................. 203 

Abundance (no. m-2) of the most common fish species recorded in annual seinenet 

surveys within Saldanha Bay and Langebaan Lagoon (1986/87, 1994, 2005, 

2007, 2010 & 2011) (Error bars show one standard error of the mean). .............. 204 

Average abundance of the four most common fish species at each of the sites 

sampled within Small Bay during the earlier surveys (1994, 2005, 2007-2010) and 

during the 2011 survey. Errors bars show plus 1 Standard error. Note the scale 

change on vertical axis shows a maximum of either 1, 4 or 150 fish.m-2.............. 205 


sampled within Big Bay during the earlier surveys (1994, 2005, 2007-2010) and 

during the 2011 survey. Errors bars show plus 1 Standard error. Note the scale 

change on vertical axis shows a maximum of either 1, 4 or 150 fish.m-2.............. 206 


sampled within Langebaan lagoon during the earlier surveys (1994, 2005, 2007- 

2010) and during the 2011 survey. Errors bars show plus 1 standard error. Note the 

scale change on vertical axis shows a maximum of between 1 and 9 fish.m-2. .... 207 

Multidimensional scaling plots showing similarities between the fish communities 

sampled at four sites within Small Bay during 1994, 2005, 2007, 2008, 2009, 2010 

and 2011 sampling events. ..................................................................................... 208 

Multidimensional scaling plot showing similarities between the fish communities 

sampled at seven Big Bay sites during 1994, 2005, 2007, 2008, 2009, 2010 and 

2011 sampling events. ............................................................................................ 210 

Multidimensional scaling plots showing similarities between the fish communities 

sampled at six Lagoon sites during 1994, 2005, 2007, 2008, 2009, 2010 and 2011 

sampling events. ..................................................................................................... 211 

White stumpnose catch-per-unit-effort (CPUE) for shore based anglers in the 

Saldanha Langebaan area over the period January 1996 - January 2009. ............. 212 

White stumpnose catch-per-unit-effort (CPUE) for boat based anglers in the 

Saldanha Langebaan area over the period January 1996 – September 2010. ....... 213 

White stumpnose catch-per-unit-effort (CPUE) for commercial and recreational 

boat based anglers and commercial linefish permit holders catch returns in the 

Saldanha Langebaan area over the period January 2006 – December 2011. ........ 214 

Comparison between the average annual juvenile white stumpnose abundance as 

estimated from seine net surveys and the observed boat (inspections) and 

commercial (catch returns) catch-per-unit-effort two years later ......................... 216 

Trends in African Penguin populations at Malgas, Marcus, Jutten and Vondeling 

islands in Saldanha Bay (Data source: Rob Crawford, DEA: Oceans & Coasts). ..... 220 

Trends in breeding population of Kelp gulls at Malgas, Jutten, Schaapen, Vondeling 

and Meeuw Islands in Saldanha Bay (Data source: Rob Crawford, DEA: Oceans & 

Coasts). ................................................................................................................... 221 

Trends in breeding population of Hartlaub’s Gulls at Malgas, Marcus, Jutten, 

Schaapen and Vondeling Islands in Saldanha Bay (Data source: Rob Crawford, DEA: 

Oceans & Coasts). ................................................................................................... 222 

xiii 

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Figure 11.4. 

Figure 11.5. 

Figure 11.6. 

Figure 11.7. 

Figure 11.8. 

Figure 11.9. 

Figure 11.10. 

Figure 11.11. 

Figure 11.12. 

Trends in breeding population of Swift Terns at Malgas, Marcus, Jutten and 

Schaapen islands in Saldanha Bay (Data source: Rob Crawford, DEA: Oceans & 

Coasts). ................................................................................................................... 223 

Trends in breeding population of Cape Gannets at Malgas Island, Saldanha Bay. 

Open data points are interpolated (no data). (Data source: Rob Crawford, DEA: 

Oceans & Coasts). ................................................................................................... 224 

Trends in breeding population of Cape Cormorants at Malgas, Jutten, Schaapen, 

Vondeling and Meeuw islands in Saldanha Bay (Data source: Rob Crawford, Oceans 

& Coasts, Department of Environmental Affairs). .................................................. 225 

Trends in breeding population of Bank Cormorants at Malgas, Marcus, Jutten and 

Vondeling islands in Saldanha Bay (Data source: Rob Crawford, Oceans & Coasts, 

Department of Environmental Affairs). .................................................................. 226 

Trends in breeding population of White-breasted Cormorants on the islands in 

Saldanha Bay (Data source: Rob Crawford, DEA: Oceans & Coasts). ..................... 228 

Trends in breeding population of Crowned Cormorants on the islands in Saldanha 

Bay (Data source: Rob Crawford, DEA: Oceans & Coasts). ..................................... 229 

Trend in breeding population of African Black Oystercatchers older than 1 year, on 

Marcus, Malgas and Jutten Islands. (Data source: Douglas Loewenthal, 

Oystercatcher Conservation Programme). ............................................................. 230 

Average numerical composition of the birds on Langebaan Lagoon during summer 

and winter. .............................................................................................................. 232 

Long term trends in the numbers of summer migratory waders on Langebaan 

Lagoon .................................................................................................................... 233 

Figure 11.13. Long term trends in the numbers of winter resident waders on Langebaan Lagoon .. 

........................................................................................................................ 234 

Figure 12.1 European mussel Mytilus galloprovincialis. Photo: C.L. Griffiths. ......................... 238 

Figure 12.2 European shore crab Carcinus maenas. Photo: C.L. Griffiths. ............................... 239 

Figure 12.3 Acorn barnacle Balanus glandula. Photo: C.L. Griffiths. ........................................ 240 

Figure 12.4 Disc lamp shell Discinisca tenuis. Photo: C.L. Griffiths. ......................................... 240 

Figure 12.5 Western pea crab Pinnixa occidentalis. Photo: C.L. Griffiths. ............................... 242 

Figure 12.6 

Figure 12.7. 

No of sites (top) at which the Western Pea crab Pinnixa occidentalis has been 

recorded in Saldanha Bay and Langebaan lagoon in the period 2004-2011 and trend 

in abundance (bottom) of this organism in the Bay . ............................................. 243 

Map showing changes in the distribution of the Western Pea crab Pinnixa 

occidentalis in Saldanha Bay and Langebaan lagoon in the period 2004-2010. .... 244 

xiv 

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List of Tables 

LIST OF TABLES 

Table 3.1. 

Ranking categories and classification thereof as applied to Saldanha Bay and 

Langebaan Lagoon for the purposes of this report. ...................................................... 8 

Table 4.1. Summary of major development in Saldanha Bay ...................................................... 13 

Table 4.2. 

Table 4.3. 

Table 4.4. 

Table 4.5. 

Table 4.6. 

Table 4.7. 

Table 4.8. 

Table 4.9. 

Table 5.1. 

Table 5.2. 

Table 5.3. 

Total human population and population growth rates for the towns of Saldanha and 

Langebaan from 1996 to 2004 (Saldanha Bay Municipality, 2005). ........................... 15 

Projected total human population and population growth rates for the towns of 

Saldanha and Langebaan (Saldanha Bay Municipality, 2005). .................................... 15 

Mean trace metal concentrations in ballast water (mg/l) and ballast tank sediments 

from ships deballasting in Saldanha Bay (Source: Carter 1996) and SA Water Quality 

Guideline limits (DWAF 1995a). Those measurements in red denote non-compliance 

with the guidelines. ..................................................................................................... 28 

General standards as specified under the Water Act 54 (1956) and revised general 

limits specified under the National Water Act 36 of 1998. ......................................... 38 

Monthly rainfall data (mm) for Saldanha Bay over the period 1895-1999 (source 

Visser et al. 2007). MAP = mean annual precipitation. ............................................... 48 

Typical concentrations of water quality constituents in storm water runoff 

(residential and Industrial) (from CSIR 2002) and South Africa 1998 Water Quality 

Guidelines for the Natural Environment (*) and Recreational Use (**). Values that 

exceed guideline limits are indicated in red. .............................................................. 49 

Characterisation of effluent from Sea Harvest (data for 2001 and 2011) and Southern 

Seas Fishing factories (data for 1996/7) (Data from Entech 1996 In CSIR 2002 and 

Paul Cloete, Environmental Office for Sea Harvest 2012). SA WQ guidelines are based 

on those published in 1998, as the 2009 revised guidelines do not offer 

recommended physio-chemical targets except for temperature and pH. ................. 52 

Details of marine aquaculture rights issued in Saldanha Bay (source: DAFF pers. 

comm. 2011)................................................................................................................ 55 

Maximum acceptable count of faecal coliforms (per 100 ml sample) for mariculture 

and recreational use .................................................................................................... 60 

Sampling site compliance (based on faecal coliform counts) for 10 sites in Small Bay, 

5 sites in Big Bay and 3 sites in Langebaan Lagoon. Average faecal coliform 

concentration of samples calculated within the 80th percentile limit specified in 

South African Water Quality Guidelines for recreational use (100 organisms/100 ml) 

for 18 sites. Numbers in black indicate compliance with regulations, while red 

numbers indicate non-compliance. “-” indicates that no samples were collected in 

that year. (Source: Saldanha Bay Water Quality Forum Trust). .................................. 62 




South African Water Quality Guidelines for recreational use (2000 organisms/100 ml) 


numbers indicate non-compliance. “-” indicates that no samples were collected in 


xv 

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Table 5.4. 

Table 5.5. 

Table 5.6. 

Table 5.7. 

Table 5.8. 

Table 6.1. 

Table 6.2. 




South African Water Quality Guidelines for mariculture use (20 organisms/100 ml) 


numbers indicate non-compliance. “ND” indicates that no samples were collected in 





South African Water Quality Guidelines for mariculture use (60 organisms/100 ml) 


numbers indicate non-compliance. “ND” indicates that no samples were collected in 


Target limits for Enterococci and E. coli based on revised final guidelines for 

recreational waters of South Africa’s coastal marine environment (RSADEA 2011) .. 72 

Sampling site compliance (based on E. coli counts) for 10 sites in Small Bay, 5 sites in 

Big Bay and 5 sites in Langebaan Lagoon. Ratings are calculated using Hazen 

percentiles, (with the 90 th and 95 th percentile results being grouped together to give 

an overall rating per annum. “ID” indicates that samples were collected that year, 

but there were insufficient data to allow calculation of Hazen percentiles. “-” 

indicates that no data were collected in that year. .................................................... 74 

Regulations relating to maximum levels for metals in molluscs in different countries 

..................................................................................................................................... 77 

Particle size composition and percentage organic carbon and nitrogen in surface 

sediments collected from Small Bay (SB), Big Bay (BB), Langebaan Lagoon (LL), 

Salamander Bay (S) and Donkergat (D) in 2011. (Particle size and TOC analysed by 

Scientific Services, TON analysed by CSIR). *The loss on ignition method was used to 

estimate TOC. These are not comparable to previous years where a CHN analyzer 

was used. ..................................................................................................................... 96 

Summary of BCLME and NOAA metal concentrations in sediment quality guidelines 

................................................................................................................................... 104 

Table 6.3. Concentrations (mg/kg) of metals in sediments collected from Saldanha Bay in 2011. 

................................................................................................................................... 106 

Table 6.4. 

Enrichment factors for Cadmium, Copper and Lead in sediments collected from 

Saldanha Bay in 2009 relative to sediments from 1980 ........................................... 108 

Table 8.1. Depth at each of the sites sampled in 2011. ............................................................. 131 

Table 8.2. 

Table 8.3. 

Table 9.1. 

Top ten species characterising the benthic macrofaunal communities in Small Bay, 

Salamander Bay and Donkergat in 2011. .................................................................. 139 

Top ten species characterising the benthic macrofaunal communities in Central Big 

Bay and Langebaan Lagoon in 2011. ......................................................................... 140 

PERMANOVA pairwise-testing results following significant main-tests. Only the 

relevant pairwise comparisons for the years 2005 vs 2008, 2008 vs 2009, 2009 vs 

2010, and 2010 vs 2011 per site are shown. Significant (p < 0.05) differences are 

highlighted in italic. Number of permutations are 462 for all pairwise comparisons. 

Percent similarity among the years tested are also provided. ................................. 186 

xvi 

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Table 9.2. 

Table 10.1 

Table 10.2 

Table 10.3. 

Table 10.4. 

Table 10.5. 

Table 11.1. 

Table 12.1. 

SIMPER results listing the species that contribute >5% to the dissimilarity between 

2010 and 2011 at each site. The % cover data are averages across the six replicates 

per site, and are on the fourth-root transformed scale. ........................................... 187 

Average abundance of fish species (number.m -2 ) recorded during annual beach 

seine-net surveys in Small Bay Saldanha. (Ave. = average, SE = standard error). 

Species not previously recorded are shown in bold font. ......................................... 199 


seine-net surveys in Big Bay Saldanha SE = standard error. .................................... 200 


seine-net surveys in Langebaan Lagoon. SE = standard error.................................. 201 

Results of the multivariate PERMANOVA pairwise tests between Small Bay fish 

samples collected in different years. NS: not significant, *: P < 0/05, **: P < 0.01 .. 209 

Results of the multivariate PERMANOVA pairwise tests between Langebaan lagoon 

fish samples collected in different years. NS: not significant, *: P < 0/05, **: P < 0.01 . 

........................................................................................................................ 211 

Taxonomic composition of waterbirds in Langebaan Lagoon (excluding rare or 

vagrant species)......................................................................................................... 231 

List of introduced and cryptogenic species from Saldanha Bay-Langebaan Lagoon. 

Occurrence is listed as confirmed or likely (not confirmed from the Bay but inferred 

from their distribution in the region). Region of origin and likely vector for 

introduction (SB = ship boring, SF = ship fouling, BW = ballast water, BS = solid 

ballast, OR = oil rigs, M = mariculture, F = Fisheries activities, I = intentional release) 

are also listed. (Data from Mead et al. 2011 a & b) .................................................. 235 

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Glossary 

GLOSSARY 

Alien species 

Articulated coralline algae 

Biodiversity 

Biota 

Community structure 

Coralline algae 

Corticated algae 

Crustose coralline algae 

Ephemeral algae 

Fauna 

Flora 

Foliose algae 

Filter-feeders 

Functional group 

Grazer 

Indigenous 

Intertidal 

Invertebrate 

Kelp 

Opportunistic 

Rocky shore community 

Scavenger 

Shore height zone 

Thallus 

Topography 

Trappers 

An introduced species that has become naturalized. 

Articulated corallines are branching, tree-like plants which are attached 

to the substratum by crustose or calcified, root-like holdfasts. 

The variability among living organisms from all terrestrial, marine, and 

other aquatic ecosystems, and the ecological complexes of which they 

are part: this includes diversity within species, between species and of 

ecosystems. 

All the plant and animal life of a particular region. 

Taxonomic and quantitative attributes of a community of plants and 

animals inhabiting a particular habitat, including species richness and 

relative abundance structurally and functionally. 

Coralline algae are red algae in the Family Corallinaceae of the order 

Corallinales characterized by a thallus that is hard as a result of 

calcareous deposits contained within the cell walls. 

An alga that has a secondarily formed outer cellular covering over part 

or all of an algal thallus. Usually relatively large and long-lived. 

Crustose corallines are typically slow growing crusts of varying thickness 

that can occur on rock, shells, or other algae. 

Opportunistic algae with a short life cycle that are usually the first 

settlers on a rocky shore. 

General term for all of the animals found in a particular location. 

General term for all of the plant life found in a particular location. 

Leaf-like, broad and flat; having the texture or shape of a leaf. 

Animals that feed by straining suspended matter and food particles 

from water. 

A collection of organisms of specific morphological, physiological, 

and/or behavioral properties. 

An herbivore that feeds on plants/algae by abrasion from the surface. 

Native to the country not introduced. 

The shore area between the high- and the low-tide levels. 

Animals that do not have a backbone. Invertebrates either have an 

exoskeleton (e.g. crabs) or no skeleton at all (worms). 

A member of the order Laminariales, the more massive brown algae. 

Capable of rapidly occupying newly available space. 

A group of interdependent organisms inhabiting the same rocky shore 

region and interacting with each other. 

An animals that eats already dead or decaying animals. 

Zone on the intertidal shore recognizable by its community. 

General form of an alga that, unlike a plant, is not differentiated into 

stems, roots, or leaves. 

The relief features or surface configuration of an area. 

Limpets that trap kelp fronds beneath their shells. 

xviii 

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Introduction 

1 INTRODUCTION 

1.1 Background 

Saldanha Bay is situated on the west coast of South Africa, approximately 100 km north of Cape 

Town and is directly linked to the shallow, tidal Langebaan Lagoon. The Bay and Lagoon are 

considered to be one of the biodiversity “hot spots” in the country and an area of exceptional 

beauty. 

A number of marine protected areas have been proclaimed in and around the Bay, while 

Langebaan Lagoon and much of the surrounding land falls within the West Coast National Park 

(Figure 1.1). Langebaan Lagoon was also declared a Ramsar Site in 1988, along with a series of 

islands within Saldanha Bay (Schaapen, Marcus, Malgas and Jutten). 

Figure 1.1. 

Regional map of Saldanha Bay and Langebaan Lagoon showing development (grey shading) 

and conservation areas. 

1 

ANCHOR 



Introduction 

In spite of these noteworthy successes, the history of the area has been one that is also 

tainted with overexploitation and abuse, the environment generally being the loser in both 

instances. 

Saldanha Bay and Langebaan Lagoon have long been the focus of scientific study and 

interest largely owing to the conservation importance and it’s many unique features. A symposium 

on research in the natural sciences of Saldanha Bay and Langebaan Lagoon was hosted by the Royal 

Society of South Africa in 1976 in an attempt to draw together information from the various 

research studies that had been and were being conducted in the area. The symposium served to 

focus the attention of scientific researchers from a wide range of disciplines on the Bay and resulted 

in the development of a large body of data and information on the status of the Bay and Lagoon at a 

time prior to any major developments in the Bay. 

More recently (in 1996), the Saldanha Bay Water Quality Forum Trust (SBWQFT), a voluntary 

organization representing various organs of State, local industry and other relevant stakeholders and 

interest groups, was inaugurated with the aim of promoting an integrated approach to the 

management, conservation and development of the waters of Saldanha Bay and the Langebaan 

Lagoon, and the land areas adjacent to, and influencing it. Since its inauguration the SBWQFT has 

played an important role in guiding and influencing management of the Bay and in commissioning 

scientific research aimed at supporting informed decision making and sustainable management of 

the Saldanha Bay/Langebaan Lagoon ecosystem. Monitoring of a number of important ecosystem 

indicators was initiated by the SBWQFT in 1999 including water quality (faecal coliform, 

temperature, oxygen and pH), sediment quality (trace metals, hydrocarbons, particulate organic 

carbon and nitrogen) and benthic macrofauna. The range of parameters monitored has since 

increased to include surf zone fish and rocky intertidal macrofauna (both initiated in 2005) and has 

culminated in the commissioning of a “State of the Bay” report series that has been produced 

annually since 2008. 

The first State of the Bay report was produced in 2006 by Anchor Environmental and served 

to draw together all available information on the heath status and trends in a wide range of 

parameters that provide insights into the health of the Saldanha Bay/Langebaan Lagoon ecosystem. 

The 2006 report incorporated information on trends in a full range of physico-chemical indicators 

including water quality (temperature, oxygen, salinity, nutrients, and pH), sediment quality (particle 

size, heavy metal and hydrocarbon contaminants, particulate organic carbon and nitrogen) and 

ecological indicators (chlorophyll a, benthic macrofauna, fish and birds). This information was drawn 

from work commissioned by the SBWQFT as well as a range of other scientific monitoring 

programmes and studies. The 2006 report was presented in two formats – one data rich form that 

was designed to provide detailed technical information in trends in each of the monitored 

parameters and the second in an easy to read form that was accessible to all stakeholders. 

The success of the first State of the Bay report and the ever increasing pace of development 

in and around the Saldanha Bay encouraged the SBWQFT to produce the second Sate of the Bay 

report in 2008, and annually since this time. This (2011) report is the 5 th in the series and provides 

an update on the health of all monitored parameters in Saldanha Bay and Langebaan Lagoon in the 

time since the last State of the Bay assessment (2010), and includes information on trends in all of 

the parameters reported on in the previous reports (2006, 2008, 2009, and 2010). It also 

incorporates a number of additional indicators not previously covered by the State of the Bay 

reports (focussing mostly on activities and discharges that affect the health of the system). 

2 

ANCHOR 



Introduction 

1.2 Structure of this report 

This report draws together all available information on water quality and aquatic ecosystem health 

of Saldanha Bay and Langebaan Lagoon, and on activities and discharges affecting the health of the 

Bay. The emphasis has been on using data from as wide a range of parameters as possible that are 

comparable in both space and time and cover extended periods which provide a good reflection of 

the long term environmental health in the Bay as well as recent changes in the health status of the 

system. The report is composed of twelve chapters each of which addresses different aspects of the 

health of the system. 

Chapter One introduces the State of the Bay Reporting programme and explains the origin 

of and rationale for the programme, and provides the report outline. 

Chapter Two provides background information to anthropogenic impacts on the 

environment and the range of different approaches to monitoring these impacts, which captures the 

differences in the nature and temporal and spatial scale of these impacts. 

Chapter Three provides a summary of available information on historic and ongoing 

activities, discharges and other anthropogenic impacts to the Bay that are likely to have had or are 

having some impact on environmental health. 

Chapter Four summarises available information on water quality parameters that have 

historically been monitored in the Bay and Lagoon and reflects on what can be deduced from these 

parameters regarding the health of the Bay. 

Chapter Five summarises available information on sediment monitoring that has been 

conducted in Saldanha Bay and Langebaan Lagoon with further interpretation of the implication of 

the changing sediment composition over time and/or related to dredging events. 

Chapter Six summarises available information on long-term trends in aquatic macrophytes 

(seagrasses and salt marshes) in Langebaan Lagoon 

Chapter Seven presents data on changes in benthic macrofauna in Saldanha Bay and 

Langebaan Lagoon from the 1970’s to the present day 

Chapter Eight addresses changes that have occurred in the rocky intertidal zones in and 

around Saldanha Bay over the past 20 years and presents results from a rocky intertidal monitoring 

survey initiated in 2005. 

Chapter Nine summarises all available information on the fish community and composition 

in the Bay and Lagoon, as deduced from both seine and gill net surveys, and presents results from a 

surf zone fish monitoring survey initiated in 2005. 

Chapter Ten provides detailed information on the status of key bird species utilising the 

offshore islands around Saldanha Bay and both resident and migrant waders utilising the feeding 

grounds in Langebaan Lagoon as well as providing an indication of the national importance of the 

area for birds. 

Chapter Eleven summarise available information of marine alien species known to be 

present in Saldanha Bay and Langebaan Lagoon as well as trends in their distribution and 

abundance. 

Chapter Twelve provides a tabulated summary of the key changes detected in each 

parameter covered in this report and assigns a health status rank to each. This chapter also provides 

recommendations for future environmental monitoring for the Bay and of management measures 

that ought to be adopted in the future. 

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Background to monitoring 

2 BACKGROUND TO ENVIRONMENTAL MONITORING AND 

WATER QUALITY MANAGEMENT 

2.1 Introduction 

Pollution is defined by the United Nations Convention on the Law of the Sea as ‘the introduction by 

man, directly or indirectly, of substances or energy into the marine environment, including estuaries, 

which results in such deleterious effects as harm to living resources and marine life, hazards to 

human health, hindrance to marine activities, including fishing and other legitimate uses of the sea, 

impairment of quality for use of the sea water and reduction of amenities’. A wide variety of 

pollutants are generated by man, many of which are discharged to the environment in one form or 

another. Pollutants or contaminants can broadly be grouped into five different types: trace metals, 

hydrocarbons, organochlorines, radionuclides, and nutrients. Certain metals, normally found in very 

low concentrations in the environment (hence referred to as trace metals) are highly toxic to aquatic 

organisms. These include for example Mercury, Cadmium, Arsenic, Lead, Chromium, Zinc and 

Copper. These metals occur naturally in the earth’s crust, but mining of metals by man is increasing 

the rate at which these are being mobilised which is enormously over that achieved by geological 

weathering. Many of these metals are also used as catalysts in industrial processes and are 

discharged to the environment together with industrial effluent and waste water. Hydrocarbons 

discharged to the marine environment include mostly oil (crude oil and bunker oil) and various types 

of fuel (diesel and petrol). Sources of hydrocarbons include spills from tankers, other vessels, 

refineries, storage tanks, and various industrial and domestic sources. Hydrocarbons are lethal to 

most marine organisms due to their toxicity, but particularly to marine mammals and birds due to 

their propensity to float on the surface of the water where they come into contact with seabirds and 

marine mammals. Organochlorines do not occur naturally in the environment, and are 

manufactured entirely by man. A wide variety of these chemicals exists, the most commonly known 

ones being plastics (e.g. polyvinylchloride or PVC), solvents and insecticides (e.g. DDT). Most 

organochlorines are toxic to marine life and have a propensity to accumulate up the food chain. 

Nutrients are derived from a number of sources, the major one being sewage, industrial effluent, 

and agricultural runoff. They are of concern owing to the vast quantities discharged to the 

environment each year which has the propensity to cause eutrophication of coastal and inland 

waters. Eutrophication in turn can result in proliferation of algae, phytoplankton (red tide) blooms, 

and deoxygenation of the water (black tides). 

It is important to monitor both the concentration of these contaminants in the environment 

and their effects on biota such that negative effects on the environment can be detected at an early 

stage before they begin to pose a major risk to environmental and/or human health. 

2.2 Mechanisms for monitoring contaminants and their effects on the 

environment 

The effects of pollutants on the environment can be detected in a variety of ways as can the 

concentrations of the pollutants themselves in the environment. Three principal ways exists for 

assessing the concentration of pollutants in aquatic ecosystems - through the analysis of pollutant 

concentrations in the water itself, in sediments or in living organisms. Each has their advantages and 

disadvantages. For example, the analysis of pollutant concentrations in water samples is often 

problematic owing to the fact that even at concentrations lethal to living organisms, they are 

difficult to detect without highly sophisticated sampling and analytical techniques. Pollutant 

concentrations in natural waters may vary with factors such as season, state of the tide, currents, 

extent of freshwater runoff, sampling depth, and the intermittent flow of industrial effluents, which 

complicates matters even further. In order to accurately elucidate the degree of contamination of a 

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particular environment, a large number of water samples usually have to be collected and analysed 

over a long period of time. The biological availability of pollutants in water also presents a problem 

in itself. It must be understood that some pollutants present in a water sample may be bound 

chemically to other compounds that renders them unavailable or non-toxic to biota (this is common 

in the case of heavy metals). 

Another way of examining the degree of contamination of a particular environment is 

through the analysis of pollutant concentrations in sediments. This has several advantages over the 

analysis of water samples. Most contaminants of concern found in aquatic ecosystems tend to 

associate preferentially with (i.e. adhere to) suspended particulate material rather than being 

maintained in solution. This behaviour leads to pollutants becoming concentrated in sediments over 

time. By analysing their concentrations in the sediments (as opposed to in the water) one can 

eliminate many of the problems associated with short-term variability in contaminant 

concentrations (as they reflect conditions prevailing over several weeks or months) and 

concentrations tend to be much higher which makes detection much easier. The use of sediments 

for ascertaining the degree of contamination of a particular system or environment is thus often 

preferred over the analysis of water samples. However, several problems still exist with inferring the 

degree of contamination of a particular environment from the analysis of sediment samples. 

Some contaminants (e.g. bacteria and other pathogens) do not accumulate in sediments and 

can only be detected reliably through other means (e.g. through the analysis of water samples). 

Concentrations of contaminants in sediments can also be affected by sedimentation rates (i.e. the 

rate at which sediment is settling out of the water column) and the sediment grain size and organic 

content. As a general rule, contaminant concentrations usually increase with decreasing particle 

size, and increase with increasing organic content, independent of their concentration in the 

overlying water. Reasons for this are believed to be due to increases in overall sediment particle 

surface area and the greater affinity of most contaminants for organic as opposed to inorganic 

particles (Phillips 1980, Phillips & Rainbow 1994). The issue of contaminant bioavailability remains a 

problem as well, as it is not possible to determine the biologically available portion of any 

contaminant present in sediments using chemical methods of analysis alone. 

One final way of assessing the degree of contamination of a particular environment is by 

analysing concentrations of contaminants in the biota themselves. There are several practical and 

theoretical advantages with this approach. Firstly, it eliminates any uncertainty regarding the 

bioavailability of the contaminant in question as it is by nature ‘bio-available’. Secondly, biological 

organisms tend to concentrate contaminants within their tissues several hundred or even thousands 

of times above the concentrations in the environment and hence eliminate many of the problems 

associated with detecting and measuring low levels of contaminants. Biota also integrates 

concentrations over time and can reflect concentrations in the environment over periods of days, 

weeks, or months depending on the type of organism selected. Not all pollutants accumulate in the 

tissues of living organisms, including for example nutrients and particulate organic matter. Thus, 

while it is advantageous to monitor contaminant concentrations in biota, monitoring of sediment 

and water quality is often also necessary. 

Different types of organisms tend to concentrate contaminants at different rates and to 

different extents. In selecting what type of organism to use for bio monitoring it is generally 

recommended that it should be sedentary (to ensure that it is not able to move in and out of the 

contaminated area), should accumulate contaminants in direct proportion with their concentration 

in the environment, and should be able to accumulate the contaminant in question without lethal 

impact (such that organisms available in the environment reflect prevailing conditions and do not 

simply die after a period of exposure). Giving cognisance to these criteria, the most commonly 

selected organisms for bio monitoring purposes include bivalves (e.g. mussels and oysters) and algae 

(i.e. seaweed). 

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Aside from monitoring concentrations of contaminant levels in water, sediments, and biota, 

it is also possible, and often more instructive, to examine the species composition of the biota at a 

particular site or in a particular environment to ascertain the level of health of the system. Some 

species are more tolerant of certain types of pollution than others. Indeed, some organisms are 

extremely sensitive to disturbance and disappear before contaminant concentrations can even be 

detected reliably whereas others proliferate even under the most noxious conditions. Such highly 

tolerant and intolerant organisms are often termed biological indicators as they indicate the 

existence or concentration of a particular contaminant or contaminants simply by their presence or 

absence in a particular site, especially if this changes over time. Changes in community composition 

(defined as the relative abundance or biomass of all species) at a particular site can thus indicate a 

change in environmental conditions. This may be reflected simply as: (a) an overall 

increase/decrease in biomass or abundance of all species, (b) as a change in community structure 

and/or overall biomass/abundance but where the suite of species present remain unchanged, or (c) 

as a change in species and community structure and/or a change in overall biomass/abundance 

(Figure 2.1). Monitoring abundance or biomass of a range of different organisms from different 

environments and taxonomic groups with different longevities, including for example invertebrates, 

fish and birds, offers the most comprehensive perspective on change in environmental health 

spanning months, years and decades. 

The various methods for monitoring environmental health all have advantages and 

disadvantages. A comprehensive monitoring programme typically requires that a variety of 

parameters be monitored covering water, sediment, biota and community health indices. 

2.3 Indicators of environmental health and status in Saldanha Bay and 

Langebaan Lagoon 

For the requirements of the Saldanha Bay and Langebaan Lagoon State of the Bay monitoring 

programme a ranking system has been devised that incorporates both the drivers of changes (i.e. 

activities and discharges that affect environmental health) and a range of different measures of 

ecosystem health from contaminant concentrations in seawater to change in species composition of 

a range of different organisms (Figure 2.1 and Table 2.1). Collectively these parameters provide a 

comprehensive picture of the State of the Bay and also a baseline against which future 

environmental change can be measured. Each of the threats and environmental parameters 

incorporated within the ranking system was allocated a health category depending on the ecological 

status and management requirements in particular areas of Saldanha Bay and Langebaan Lagoon. 

An overall Desired Health category is also proposed for each environmental parameter in each area, 

which should serve as a target to be achieved or maintained through management intervention. 

Various physical, chemical and biological factors influence the overall health of the 

environment. Environmental parameters or indices were selected that can be used to represent the 

broader health of the environment and are feasible to measure, both temporally and spatially. The 

following environmental parameters or indices are reported on: 

Activities and discharges affecting the environment: Certain activities (e.g. shipping and 

small vessel traffic, the mere presence of people and their pets, trampling) can cause disturbance in 

the environment especially to sensitive species, that, along with discharges to the marine 

environment (e.g. effluent from fish factories, treated sewage, and ballast water discharged by 

ships) can lead to degradation of the environment through loss of species (i.e. loss of biodiversity), 

or increases in the abundance of pest species (e.g. red tides), or the introduction of alien species. 

Monitoring activity patterns and levels of discharges can provide insight into the reasons for any 

observed deterioration in ecosystem health and can help in formulating solutions for addressing 

negative trends. 

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(a) Species composition 

remains the same and 

overall abundance/biomass 

changes 

(b) Species present remain the 

same , community composition 

changes and overall abundance/ 

biomass may also change. 

(c) Species and community 

composition changes and overall 

Abundance/biomass may also change. 

Figure 2.1. Possible alterations in abundance/biomass and community composition. Overall 

abundance/biomass is represented by the size of the circles and community composition by 

the various types of shading. After Hellawell (1986). 

Water Quality: Water quality is a measure of the suitability of water for supporting aquatic 

life and the extent to which key parameters (temperature, salinity, dissolved oxygen, nutrients and 

chlorophyll a, faecal coliforms and heavy metal concentrations) have been altered from their natural 

state. Water quality parameters can vary widely over short time periods and are principally affected 

by the origin of the water, physical and biological processes and effluent discharge. Water quality 

parameters provide only an immediate (very short term – hours to days) perspective on changes in 

the environment and do not integrate changes over time. 

Sediment quality: Sediment quality is a measure of the extent to which the nature of 

benthic sediments (particle size composition, organic content and contaminant concentrations) has 

been altered from its natural state. This is important as it influences the types and numbers of 

organisms inhabiting the sediments and is in turn, strongly affected by the extent of water 

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movement (wave action and current speeds), mechanical disturbance (e.g. dredging) and quality of 

the overlying water. Sediment parameters respond quickly to changes in the environment but are 

able to integrate changes over short periods of time (weeks to months) and are thus good indicators 

or short to very short-term changes in environmental health. 

Coastal development: Coastal development includes development activities such as 

infrastructure (harbours and launch sites, cities, towns, housing, roads and tourism), as well as 

dredging and the disposal of dredge spoil. Coastal developments pose a major threat to many 

components of marine and coastal environments, owing to their cumulative effects, which are often 

not taken into account by impact assessments. Associated impacts include organic pollution of 

runoff and sewerage, transformation of the supratidal environment, alteration of dune movement, 

increased access to the coast and sea, and the negative impacts on estuaries. 

Shoreline erosion: Anthropogenic activities, particularly structures erected in the coastal 

zone (e.g. harbours, breakwaters, buildings) and dredging activities, can also profoundly influence 

shorelines composed of soft sediment (i.e. sandy beaches) leading to erosion of the coast in some 

areas and the accumulation of sediment in others. Many of the beaches in Saldanha Bay have 

experienced severe erosion in recent decades to the extent that valuable infrastructure is severely 

threatened in some areas. 

Table 2.1. 

Ranking categories and classification thereof as applied to Saldanha Bay and Langebaan 

Lagoon for the purposes of this report. 

Health category Ecological perspective Management perspective 

Natural 

No or negligible modification 

from the natural state 

Relatively little human impact 

Good 

Some alteration to the 

physical environment. Small 

to moderate loss of 

biodiversity and ecosystem 

integrity. 

Some human-related disturbance, but 

ecosystems essentially in a good state, 

however, continued regular monitoring is 

strongly suggested 

Fair 

Significant change evident in 

the physical environment and 

associated biological 

communities. 

Moderate human-related disturbance 

with good ability to recover. Regular 

ecosystem monitoring to be initiated to 

ensure no further deterioration takes 

place. 

Poor 

 

 

 

 

Extensive changes evident in 

the physical environment and 

associated biological 

communities. 

High levels of human related disturbance. 

Urgent management intervention is 

required to avoid permanent damage to 

the environment or human health. 

Macrofauna: Benthic macrofauna are mostly short lived organisms (1-3 years) and hence are 

good indicators of short to medium term (months to years) changes in the health of the 

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environment. They are particularly sensitive to changes in sediment composition (e.g. particle size, 

organic content and heavy metal concentrations) and water quality. 

Rocky intertidal: Rocky intertidal invertebrates are also mostly short lived organisms (1-3 

years) and as such are good indicators of short to medium term changes in the environment (months 

to years). Rocky intertidal communities are susceptible to invasion by exotic species (e.g. 

Mediterranean mussel), deterioration in water quality (e.g. nutrient enrichment), structural 

modification of the intertidal zone (e.g. causeway construction) and human disturbance resulting 

from trampling and harvesting (e.g. bait collecting). 

Fish: Fish are mostly longer lived animals (3-10 years +) and as such are good indicators of 

medium to long term changes in the health of the environment. They are particularly sensitive to 

changes in water quality, changes in their food supply (e.g. benthic macrofauna) and fishing 

pressure. 

Birds: Birds are mostly long lived animals (6-15 years +) and as such are good indicators of 

long term changes in the health of the environment. They are particularly susceptible to disturbance 

by human presence and infrastructural development (e.g. housing development), and changes in 

food supply (e.g. pelagic fish and intertidal invertebrates). 

Alien species: A large number of alien marine species have been recorded as introduced to 

southern African waters. South Africa has at least 85 confirmed alien species, some of which are 

considered invasive, including the Mediterranean mussel Mytilus galloprovincialis, the European 

green crab Carcinus maenas, and the barnacle Balanus glandula. Most of the introduced species in 

South Africa have been found in sheltered areas such as harbours, and are believed to have been 

introduced through shipping activities, mostly ballast water. Ballast water tends to be loaded in 

sheltered harbours, thus the species that are transported often originate from these habitats and 

have a difficult time adapting to the more exposed sections of the southern African coastline, but 

are easily able to gain a foothold in sheltered bays such as Saldanha Bay. 

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Activities & discharges 

3 ACTIVITIES AND DISCHARGES AFFECTING THE HEALTH OF THE 

BAY 


Industrial development of Saldanha Bay dates back to the early 1900’s with the establishment of a 

commercial fishing and rock lobster industry in the Bay. By the mid-1900’s Southern Seas Fishing 

Enterprises and Sea Harvest Corporation had been formed, with Sea Harvest becoming the largest 

fishing operation in Saldanha Bay to date. Human settlement and urbanization grew from village 

status in 1916, to an important city today with well over 28 000 people and an average population 

growth rate of 5.73% per year. With increasing numbers of fishing vessels operating in Saldanha 

Bay, and to facilitate the export of iron ore from the Northern Cape, the harbour was targeted for 

development in the early 1970’s. The most significant developments introduced at this time were 

the causeway linking Marcus Island to the mainland, to provide shelter for ore-carriers, and the 

construction of the iron ore terminal. By the end of the 1970’s Saldanha Bay harbour was an 

international port able to accommodate large ore-carriers and deep-sea trawlers. During the 1980’s 

a multi-purpose terminal was added to the ore terminal and a small-craft harbour was built to 

accommodate increasing recreational and tourism activities in the bay. Development of the port is 

ongoing. The growth in industry and urban development has meant an increase in the different 

types of discharges into the bay such as fish factory and mariculture discharges, storm water, and 

discharges relating to shipping activities such as ballast water and oil spills. Shipping channels in the 

Bay are also periodically dredged to ensure unrestricted access to the ore terminal by bulk carriers 

and oil tankers. 

Sewage discharge is arguably the most important waste product in terms of continuous 

environmental impact that is discharged into Saldanha Bay. Sewage is harmful to biota due to its 

high concentrations of nutrients which stimulate primary productivity that in turn leads to changes 

in species composition, decreased biodiversity, increased dominance, and toxicity effects. The 

changes to the surrounding biota are likely to be permanent depending on distance to outlets and 

are also likely to continue increasing in future given the growth in industrial development and 

urbanisation in the area. These impacts are however manageable, can be monitored and mitigated 

so as to cause minimum effects. 

Ballast water discharges are by far the highest in terms of volume and also continuous due 

to constant and increasing shipping traffic. Ballast water has, through the transport of potentially 

alien invasive species to new areas, the potential to impact native species and ecosystem functions, 

fishing and aquaculture industries, as well as public health. Ballast water discharges can, however, 

be effectively managed and the remit of the International Maritime Organization (IMO) is to reduce 

the risks posed by ballast water to a minimum through the direct treatment of the water while on 

board the ship, as well as by regulating the way in which ballast water is managed while the ship is at 

sea. 

Storm water discharges are a seasonal concern and can introduce large volumes of polluted 

surface water such as pesticides and trace metals which can in turn be harmful to the environment 

and have been shown to exceed permissible concentrations in Saldanha Bay particularly after the 

rainy season. Storm water discharges are very difficult to manage and are bound to increase with 

increasing urbanization and industrial development in the areas surrounding the Bay. 

Dredging in Saldanha Bay has had tremendous immediate impact on benthic micro and 

macrofauna, the particle suspension in the water column kills many suspension feeders like fish and 

zooplankton. It also blocks sunlight from penetrating the water column and causes die offs of algae 

and phytoplankton. The damage caused is reversible in the long term, and although the particle 

composition of the settled material is likely to be different, ecological functions as well as major 

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species groups will probably return. The mitigation options for this kind of activity are limited and 

extremely costly. 

The final important type of discharge to the Bay are oil spills. Although, extremely harmful 

to all biota, large oil spills are fortunately rare, and Saldanha Bay has never experienced a major spill 

to date. The management options in place in Saldanha are the best in South Africa with prevention 

being the primary focus. 

3.2 Urban and industrial development 

The first mention of Saldanha Bay in recorded history dates to 1601 when Joris van Spilbergen 

mistook the present Saldanha Bay for Table Bay. Since then the name has remained, while the 

original Aguada de Saldanha “watering place of Saldanha” has become known as Table Bay (Axelson 

1977). In 1623, an Icelander by the name of Jon Olaffsson entered Saldanha Bay in search of whaling 

opportunities, only to find that French sailors had already commenced with such lucrative activities 

in the Bay. 

Shortly after his arrival in Table Bay in 1652, Jan van Riebeek sent a small vessel to explore 

the possibility of local trade opportunities in Saldanha Bay (Axelson 1977). At this stage the French 

had virtually hunted out the seal population, which fetched a high price for their skins. However, the 

abundance of sheep, fish (4 000 harders being caught in a single day) and bird’s eggs rendered the 

Bay sufficiently valuable for the Dutch East India Company to erect markers denoting their 

possession of the Bay in 1657. A shortage of freshwater, however, limited development or 

permanent European colonization in Saldanha Bay, although four small communities eventually 

became established near Langebaan Lagoon. 

Saldanha Bay was reported to be “rich in fish” and although the price for fish was deemed 

“poor”, there are records of a fish trading post being established at Oostewal, Langebaan Lagoon in 

the early 1700’s (Axelson 1977). A commercial fishing industry was slow to develop in Saldanha Bay, 

however, by the early 1900’s fishing was considered a growing industry. In 1903, a rock lobster 

fishery was introduced in Saldanha Bay with the North Bay Canning Company and the Saldanha Bay 

Canning Company being established in the early 1900’s (Axelson 1977). With increasing catches of 

sardines in the vicinity of the Bay, canning companies soon expanded their business to incorporate 

sardine canning. In 1948 the North Bay Canning Company was absorbed into Southern Seas Fishing 

Enterprises, while in 1964 Sea Harvest Corporation was formed, subsequently becoming the largest 

fishing operation in Saldanha Bay, operating a fleet of deep-sea trawlers and purse seiners and 

providing an onshore fish packing and freezing facility. 

The first whaling factory was built in 1909 at Donkergat, followed by a second in 1911 at 

Salamander Bay. In 1930 however, the international price for whale oil plummeted, resulting in the 

closure of both these factories. Whaling activities were re-established for a short period between 

1960 and 1967, after which no further whaling took place in Saldanha Bay (Axelson 1977). 

The establishment of fish processing factories and the substantial growth of the fishing 

industry in Saldanha Bay resulted in an ever increasing number of pelagic fishing vessels harbouring 

in the Bay and offloading their catch. During the early 1970’s, the methods employed to offload the 

catch involved releasing substantial amounts of water, loaded with organic matter (biological waste 

and fish factory effluent), back into the Bay (known as “wet offloading”). Within a short period of 

time the marine environment within the Bay began showing severe signs of organic overloading and 

in 1972 a mass mortality event of marine organisms (fish and shellfish) brought the pollution 

situation to attention. By 1974, official waste management practices (primarily “dry offloading” of 

the catch) were being implemented by the fish factories to reduce the amount of organic loading in 

the Bay (Christie and Molden 1977). 

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Saldanha Bay, being considered the only natural harbour of significant size on the west coast 

of South Africa, was targeted for development, and in 1971 was upgraded into an international port 

(Fuggle 1977). The primary purpose of the port at that stage was to facilitate the export of iron ore 

as part of the Sishen-Saldanha Bay Ore Export Project. The first major development in the Bay was a 

causeway built in 1973 that linked Marcus Island to the mainland, providing shelter for ore-carriers. 

During 1973 and 1974 the General Maintenance Quay and Rock Quay were built, making up the iron 

ore terminal. Between 1974 and 1976 extensive dredging was conducted to accommodate a deepwater 

port for use by large ore-carriers. The iron ore terminal was built with the initial intention of 

being used for export of ore, however, was later extended to provide for the import of oil. The 

construction of the iron ore terminal essentially divided Saldanha Bay into two sections: a smaller 

area bounded by the causeway, the northern shore and the ore terminal (called Small Bay); and a 

larger , more exposed area adjacent called Big Bay, leading into Langebaan lagoon (Figure 1.1). A 

multi-purpose terminal had been added to the ore terminal by 1980 and a small-craft harbour was 

built in 1984 to cater for the increase in recreational and tourism activities in the Bay. Due to the 

increase in heavy industries in the area in the 1990’s (Namakwa Sands, Saldanha Steel), the Multi- 

Purpose Terminal was extended in 1998. During each phase of development undertaken in Saldanha 

Bay, dredging and submarine blasting has been necessary. Development of the causeway and ironore 

terminal in Saldanha Bay greatly modified the natural water circulation and current patterns 

(Weeks et al. 1991) in the Bay. This led to reduced water exchange and increased nutrient loading of 

water within the Bay. 

Figure 3.1. Composite aerial photo of Saldanha Bay and Langebaan Lagoon taken in 1960. (Source 

Department of Surveys and Mapping). Note the absence of the ore terminal and causeway and 

limited development at Saldanha and Langebaan. 

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In addition to the increasing fish factory effluent and the structural modifications of the Bay, 

the establishment of mussel mariculture ventures (of the Spanish mussel Mytilus galloprovincialis) in 

the sheltered waters of Small Bay in 1984, exacerbated the pollution and organic loading problems 

in the area (Stenton-Dozey et al. 1999). 

Aerial photographs taken in 1960 (Figure 3.1), 1989 (Figure 3.2) and in 2007 (Figure 3.3) 

clearly show the extent of development that has taken place within Saldanha By over the last 50 

years. 

Table 3.1. Summary of major development in Saldanha Bay 

Year 

Development 

1973 Causeway built linking Marcus Island and mainland 

1973 – 1974 General Maintenance Quay and Rock Quay 

1974 – 1976 Iron-ore terminal 

1980 Multi-purpose terminal added to Iron-ore terminal 

1984 Small craft harbour 

1998 Multi-purpose Terminal extended 


Department of Surveys and Mapping). Note the presence of the ore terminal, the causeway 

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linking Marcus Island with the mainland, and expansion of settlements at Saldanha and 

Langebaan. 


Department of Surveys and Mapping). Note expansion in residential settlements particularly 

around the town of Langebaan. 

Data on population growth in the town of Saldanha and Langebaan Lagoon are available 

from the 1996 census and 2001 census. Those from the 2011 census are still pending. The total 

population of Saldanha Bay increased from 16 820 in 1996 to 21 636 in 2001, with a growth rate of 

5.73%/yr. The total population in Langebaan increased from 2 735 to 4 272 between 1996 and 2001, 

with a growth rate of 7.02%/yr (Table 3.2). The human population in Saldanha Bay is thus expanding 

rapidly which has been attributed to the in-migration of people from surrounding municipalities in 

search of real or perceived jobs (IDP 2006 – 2011). It is projected that by 2020 Saldanha and 

Langebaan will have a total human population of 77 006 and 22 312 respectively (Table 3.3.). This 

will place increasing pressure on the marine environment and the health of the Bay through 

increased demand for resources, trampling of the shore and coastal environments, increased 

municipal (sewage) and household discharges (which are ultimately disposed of in Saldanha Bay) and 

increased storm water runoff due to expansion of tarred and concreted areas. 

Urban development around Langebaan Lagoon has encroached right up to the coastal 

margin, leaving little or no coastal buffer zone (Figure 3.4 and Figure 3.5). Allowing an urban core to 

extend to the waters’ edge places the marine environment under considerable stress due to 

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trampling and habitat loss. It also increases the risks of erosion due to removal of vegetation and 

interferes with certain coastal processes such as sand deposition and migration. Expansion of tarred 

areas will also increase the volumes of storm water entering the marine environment, which 

ultimately has a detrimental effect on ecosystem health via the input of various contaminants and 

nutrients (See section §1 for more detail on these issues). 

Table 3.2. 

Location 

Total human population and population growth rates for the towns of Saldanha and 

Langebaan from 1996 to 2004 (Saldanha Bay Municipality, 2005). 

Total Population 

1996 

Total Population 

2001 

Growth 1996-2001 

(%/yr) 

Saldanha 16 820 21 626 5.73 

Langebaan 2 735 4 272 7.02 

Table 3.3. 

Projected total human population and population growth rates for the towns of Saldanha and 

Langebaan (Saldanha Bay Municipality, 2005). 

Location 2005 2010 2015 2020 

Saldanha 28 265 39 477 55 136 77 006 

Langebaan 6 050 9 348 14 442 22 312 

Figure 3.4. 

Satellite image of Langebaan showing little or no setback zone between the town and the Bay. 

Urban development around Langebaan Lagoon has encroached right up to the coastal 

margin, leaving little or no coastal buffer zone (Figure 3.4 and Figure 3.5). Allowing an urban core to 

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extend to the waters’ edge places the marine environment under considerable stress due to 

trampling and habitat loss. It also increases the risk of erosion due to removal of vegetation and 

interferes with certain coastal processes such as sand deposition and migration. Expansion of tarred 

areas will also increase the volumes of storm water entering the marine environment, which 

ultimately has a detrimental effect on ecosystem health via the input of various contaminants and 

nutrients (See section §3.3 for more detail on these issues). 

Figure 3.5. 

Composite aerial photograph of Langebaan showing absence of development setback zone 

between the town and the lagoon. 

An application for development was recently proposed on the Remainder of the Farm 

Oostewal No. 292, Langebaan (Shark Bay). The developer requested permission to divide the 82 

hectare plot into 109 single residential erven, roads, public parking and ablution facilities, open 

spaces and conservation areas. 

The application was rejected by the Department of Environmental Affairs and Development 

Planning: Directorate Land Management on the 7 th of April 2012 on several grounds: 

The land contains critically endangered and endangered vegetation types. It is estimated 

that 85% of the site can be considered a Critical Biodiversity Area. 

The development would negatively impact on the sense of place, as the location is visually 

linked to the West Coast National Park. 

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Jul-05 

Sep-05 

Nov-05 

Jan-06 

Mar-06 

May-06 

Jul-06 

Sep-06 

Nov-06 

Jan-07 

Mar-07 

May-07 

Jul-07 

Sep-07 

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Mar-08 

May-08 

Jul-08 

Sep-08 

Nov-08 

Jan-09 

Mar-09 

May-09 

Jul-09 

Sep-09 

Nov-09 

Jan-10 

Mar-10 

May-10 

Jul-10 

Sep-10 

Nov-10 

Jan-11 

Mar-11 

May-11 

Jul-11 

Sep-11 

Nov-11 

Jan-12 



 

 

 

The development does not fit the West Coast Provincial Spatial Development Framework 

(despite the socio-economic benefits) as it will only reiterate unsustainable development 

patterns of the past. 

Social inequalities will be enforced, as the benefits will be mostly felt by society members 

belonging to a higher-income bracket. 

There is no need for further development, as currently 50% of existing residential properties 

in Langebaan are vacant. 

Industrial and urban development in and around Saldanha Bay has been matched with 

increasing tourism development in the area, specifically with the declaration of the West Coast 

National Park, Langebaan Lagoon being declared a National Wetland RAMSAR site and 

establishment of holiday resorts like Club Mykonos and Blue Water Bay. The increased capacity for 

tourism results in higher levels of impact on the environment in the form of increased pollution, 

traffic, fishing and disturbance. Recent data on numbers of visitors to the West Coast National Park 

indicate strong seasonal trends in numbers of people visiting the area (peaking in the summer 

months and during the flower season) but there is no clear indication of growth in numbers in recent 

years (Figure 3.6). 

35000 

30000 

25000 

Day guests 

Overnight guests 

International 

guests 

20000 

15000 

10000 

5000 

0 

Figure 3.6. 

Numbers of tourists visiting the West Coast National Park since 2005 (Data from Pierre Nel, 

WCNP). Day guests include all South African visitors (adults and children) while Overnight 

guests refer those staying in SANPARK accommodation. International guests include all SADC 

and non-African day visitors (adults and children) while the category ‘Other’ includes 

residents, staff, military, school visits, etc. 

In terms of the Municipal Systems Act 2000 (Act 32 of 2000) every local municipality must 

prepare an Integrated Development Plan (IDP) to guide development, planning and management 

over the five year period in which a municipality is in power. A core component of an IDP is the 

Spatial Development Framework (SDF) which is meant to relate the development priorities and the 

objectives of geographic areas of the municipality and indicate how the development strategies will 

be co-ordinated. An SDF aims to guide decision making on an ongoing basis such that changes, 

needs and growth in the area can be managed to the benefit of the environment and its inhabitants. 

The 2006 Saldanha Municipality IDP has been revised and replaced with the 2011/2012 IDP. The 

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revised SDF for the Saldanha Bay Municipality was produced in 2011 and is available on the 

municipality website. The revised version has adopted a holistic approach, ensuring that the 

municipal spatial planning of the rural and urban areas is integrated for the first time since the 

establishment of the municipality. 

A study by Van der Merve et al. (2005) assessing the growth potential of towns in the 

Western Cape (as part of the provincial SDF) identified Langebaan and Saldanha as towns with high 

growth potential. It was estimated that, given the projected population figures, there would be a 

future residential demand of 9 132 units in Saldanha and 3 781 units in Langebaan. The SDF 

proposes addressing these demands by increasing the residential density in specified nodes in both 

towns and by extending the urban edge of Saldanha in a northerly direction towards Vredenberg, 

and that of Langebaan inland towards the North-East. 

Western Cape Department of Economic Development and Tourism (DEDT), through Wesgro 

(the official Investment and Trade Promotion Agency of the Western Cape), embarked on a Pre- 

Feasibility Study to identify and assess the opportunities available in the industrial and business 

market and ascertain whether there are any binding constraints to establishing an IDZ programme at 

Saldanha Bay. 

The National Environmental Management: Integrated Coastal Management Act 24 of 2008 

(ICMA), which came into effect in December 2009, aims to ensure the integrated management of 

the coastline and the sustainable use of its resources. ICMA obligates municipalities to prepare and 

adopt Coastal Management Programmes for the coastal zone, or specific parts of the coastal zone in 

areas under their jurisdiction, within four years of the Act coming into effect. These statutory 

programmes must incorporate a vision and management objectives for the coastal zone; priorities 

and strategies to achieve the objectives; and performance indicators to measure management 

effectiveness. The Coastal Management Programme must be consistent with other municipal plans, 

such as the IDP. Moreover section 51 requires that an IDP be aligned with, contain the provisions of, 

and give effect to national and the applicable provincial coastal management programmes. 

The coastal zone, as defined by ICMA, includes the following areas and any aspect of the 

environment on, in, under and above these areas: 

 

 

 

 

 

 

All coastal public property (Comprises of coastal waters; land submerged by coastal waters; 

islands within coastal waters; the sea shore, excluding that which was lawfully alienated 

before this Act came into force; State owned land declared as coastal public property; and 

the natural resources on or in coastal public property, the exclusive economic zone (up to 

200 nautical miles offshore) and any harbour, work or other installation in coastal public 

property); 

The coastal protection zone (Comprises all land 1 km inland from the high water mark 

zoned for agricultural or undetermined use and the wetlands, lakes, lagoons or dams 

situated on this land; any land within 100 m inland of the high water mark in areas zones for 

residential or industrial use; the seashore and admiralty reserves which are not coastal 

public property; and land inundated by 1:50 year floods or storm events); 

All coastal access land; (Strips of land designated by municipal by-laws to secure public 

access to coastal public property); 

Coastal protected areas (those protected areas situated wholly or partially in the coastal 

zone and recognised under the Protected Areas Act. Marine Protected Areas declared under 

the Marine Living Resources Act are recognised as protected areas); 

The seashore (the area between the low water mark and the high water mark); 

Coastal waters (territorial and internal waters of the Republic). 

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Future developments in and around Saldanha and Langebaan will have to be conducted in 

accordance with the provisions of ICMA. The following aspects of ICMA will affect future 

development activities in Saldanha and Langebaan: 

 

 

 

 

Section 15 of ICMA prevents any person, owner or occupier of land adjacent to the seashore 

from requiring any organ of state or any other person to take measures to prevent the 

erosion or accretion of the seashore, or of land adjacent to coastal public property, unless 

the erosion is caused by an intentional act or omission of that organ of state or other 

person. Moreover it prohibits the construction, maintenance or extension of any structure, 

or the conduct of any other measures on coastal public property to prevent or promote 

erosion or accretion of the seashore except as provided for in ICMA. 

Section 58 places a duty of care on every person who causes, has caused or may cause 

significant pollution or degradation of the environment, including an adverse effect to the 

coastal environment, to take reasonable measures to prevent such pollution or degradation 

from occurring, continuing or recurring, and to minimise and rectify such pollution or 

degradation of the coastal environment; 

Section 60 provides the Minister or MEC with the power to give notice to repair or remove 

structures in the coastal zone if the structures are likely to cause adverse effects to the 

coastal environment. 

Coastal setback lines, determined by an MEC in accordance with section 25 of the Act, will 

demarcate an area within which development will be prohibited or controlled in order to 

achieve the objectives of ICMA or coastal management objectives. 

Designated coastal setback lines will help to protect biodiversity and heritage sites, ensure 

the safety of developments while minimizing maintenance issues. Due to the variation in conditions 

around the South African coast, the methodology for defining and adopting coastal setback lines is 

complex. WSP Africa Coastal Engineers (2010) recommend basing these setback lines on several 

findings: i) the long term erosion trend; ii) short term erosion trends (from storm damage); and iii) 

the predicted sea level rise. 

The adoption of two types of setback lines has been proposed (WSP 2010). A ‘coastal 

processes/no development’ line allows for no development seaward of this line, with the exception 

of boardwalks to access beaches. Alternatively a ‘limited or controlled development’ line may be 

imposed which would either be equal to the ‘no development’ line or even further landward. These 

lines will be set based on a period of 100 years (to accommodate a 1:100 year storm erosion, 100 

years of sea level rise and the erosion trend (where applicable) over 100 years). Currently, any 

development of infrastructure (temporary or permanent) which is undertaken within 100 metres of 

the high-water mark, requires the completion of an Environmental Impact Assessment. 

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3.3 Discharges and activities affecting environmental health 

3.3.1 Dredging and port expansion 

Dredging of the seabed is performed worldwide in order to expand and deepen existing 

harbours/ports or to maintain navigation channels and harbour entrances (Erftemeijer and Lewis 

2006), and dredging has thus been touted as one of the most common anthropogenic disturbance of 

the marine environment (Bonvicini Pagliai et al. 1985). The potential impacts of dredging on the 

marine environmental can stem from both the removal of substratum from the seafloor and the 

disposal of dredged sediments, and include: 

 

 

 

 

 

 

Direct destruction of benthic fauna populations due to substrate removal 

Burial of organisms due to disposal of dredged sediments 

Alterations in sediment composition which changes nature and diversity of benthic 

communities (e.g. decline in species density, abundance and biomass) 

Enhanced sedimentation 

Changes in bathymetry which alters current velocities and wave action 

Increase in concentration of suspended matter and turbidity due to suspension of 

sediments. The re-suspension of sediments may give rise to: 

o Decrease in water transparency 

o Release in nutrients and hence eutrophication 

o Release of toxic metals and hydrocarbons due to changes in physical/chemical 

equilibria 

o Decrease in oxygen concentrations in the water column 

o Bioaccumulation of toxic pollutants 

o Transport of fine sediments to adjacent areas, and hence transport of pollutants 

o Decreased primary production due to decreased light penetration to water column 

(Erftemeijer and Lewis 2006, Bonvicini Pagliai et al. 1985, OSPAR Commission 2004, National 

Ports Authority 2007). 

Aside from dredging itself, dredged material may be suspended during transport to the 

surface, overflow from barges or leaking pipelines, during transport to dump sites and during 

disposal of dredged material (Jensen and Mogensen 2000 in Erftemeijer and Lewis 2006). 

Saldanha Bay is South Africa’s largest and deepest natural port and as a result has 

undergone extensive harbour development and has been subjected to several bouts of dredging and 

marine blasting. Saldanha is perfectly situated for the shipment of large quantities of iron ore from 

the Sishen mines in the Northern Cape. However, before the first shipment could be loaded the port 

had to be protected from strong wave activity. To remedy this, the first major development 

occurred in 1973 whereby Marcus Island was joined to the mainland via the construction of a 

causeway. Further development involved the construction of the General Maintenance Quay and 

the Rock Quay over the period 1974 to 1976. During this process 25 million m 3 of sediment were 

dredged from the Bay to facilitate the entrance of large ore carriers, and the resulting dredged 

material was used to construct the harbour wall (Moldan 1978). A Multi-Purpose Terminal was 

added to the iron ore terminal in 1980 and the Small Craft Harbour was built in 1984. These 

developments all required extensive dredging and submarine blasting which significantly impacted 

sediment composition and benthic community structure. Since this time three further dredging 

operations have been implemented in Saldanha Bay. 

The first of these was associated with the expansion of the Multi-Purpose Terminal in 

1996/7 when 2 million m 3 of material was removed from an area approximately 500 000 m 2 in 

extent on the Small Bay side of the ore terminal. The dredge spoil was disposed of on land in a 

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retention pond on the eastern side of the causeway. The bottom material in Saldanha Bay consists 

mainly of sand interspersed with thin layers of calcrete, some silt/clay and shell fragments. Early 

borehole samples collected in 1995 from proposed dredging areas revealed that the substrate 

contained an average of 33% silt/clay of which ~73% of the silt/clay fraction had a grain size of less 

than 5 microns. It is thus apparent that a significant proportion of the substrate that was dredged in 

1997 comprised very fine particles such as clay and calcrete (chalk is simply pulverized calcrete). 

When calcrete is dredged white plumes of fine particles are released into the water column 

(Schoonees et al. 1995), which occurred during the 1997 Saldanha Bay dredge event. 

Maintenance dredging was required at the Mossgas quay and the Multi Purpose Terminal in 

order to deepen the berth. Maintenance dredging took place at these locations from the end of 

2007 to March/April 2008 with an estimated 50 000 m 3 of seabed material being removed from both 

terminals. The Mossgas terminal was constructed in the 80s and the depth has reduced from 

approximately 9 m to 6 m over the last 20 years due to sediment build-up. A similar reduction in 

depth has also occurred at the Multi Purpose Terminal. The sediment that was to be dredged was 

mainly fine silt, fine to coarse sand, shell fragments and seaweed. At the Multipurpose berth 201 it 

was also expected that lead and copper would occur in elevated concentrations in the dredged 

sediments. The concentrations of lead (Pb) at several sites within the proposed dredge area fall in 

the range of special care requirements in terms of the London Convention for off-shore disposal of 

sediments. It has been calculated that of the 3 000 m 3 of sediments to be dredged at berth 201, 

approximately 300 m 3 would be Pb product that had accumulated over two decades of loading 

operations (National Ports Authority 2007). This material was not dumped offshore but was mixed 

with the rest of the dredged material to achieve appropriate dilution and disposed of on land. 

Environmental specifications have been published by the National Ports Authority in which the 

potential impacts of this maintenance dredging were outlined and recommendations were proposed 

for avoiding, minimizing and controlling the impacts (National Ports Authority 2007). It is expected 

that farther maintenance dredging at the Mossgas and Multi Purpose terminals will not be required 

for a further 10 – 20 years (Mr Lyndon Metcalf, pers. comm.). This is due to the fact that the port is 

situated in a sheltered area and most loose sediments were removed during harbour construction. 

The depth of the port further reduces sediment transport, which might have otherwise filled in 

navigation channels more rapidly (Schoonees et al. 1995). 

The third of these dredge events was undertaken in 2009/10, during which 7 300 m 3 of 

material was removed from an area of approximately 3 000 m 2 at the end of the cause way, 

between Caisson 3 and 4 on the Saldanha side of the ore terminal (Figure 3.7) (N. Jansen – Port of 

Saldanha pers. comm. 2011). The environmental impact assessment for the proposed dredge event 

was undertaken by Environmental Resources Management (ERM) in April 2008. The aim of the 

dredging was to increase the export capacity of the iron ore terminal though the use of a staggered 

ship loading arrangement, that enables both ship loaders to operate independently and 

simultaneously. The dredged material was used to fill the two scour holes between Caissons 5 and 

6. These were revealed, during a bathymetric survey in June 2007, to have been caused by the 

scouring currents produced by the propellers of bulk carriers while berthing and un-berthing (ERM 

2008). A final report of the outcome of the dredging operation is still to be made available by Ports 

of Saldanha. It was considered a successful operation (N. Jansen – National Port Authority pers. 

comm. 2012). 

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Figure 3.7. 

Location of the maintenance dredging site between Caissons 3 and 4 on the ore terminal. 

Transnet proposed a Phase 2 Expansion of the Iron ore quay (Figure 3.8) in order to increase 

its export capacity from 45 million tonnes/annum to 90 million tonnes/annum. This would have 

required extensive dredging of soft sediments, powder calcrete, limestone, calcernite/calcretes and 

the removal of 90 000 m 3 granite by underwater blasting (PRDW, 2007a, b). The proposed 

expansion also involved the development of two new berths on the southern side (Big Bay side) of 

the iron ore quay and three new stockpile areas for ore. 

Three alternatives were considered for the addition of the stockpile areas (PDNA and SRK 

Consulting 2007), namely; 

1. Southward expansion requiring reclamation of approximately 50 ha of the bay 

2. Northward expansion of approximately 36 ha into the undeveloped dune area 

3. Eastward expansion of approximately 55 ha into the reclamation dam 

An environmental impact assessment was initiated for the project in 2008 based on the final 

scoping report, but was cancelled prior to completion (N. Jansen – Port of Saldanha pers. comm. 

2011). 

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Figure 3.8. 

Current layout of Transnet Saldanha Bay Port (Source: Lindokuhle Mkhize, Transnet National 

Port Authority 2012). 

3.3.2 The Sishen-Saldanha oreline expansion project 

Transnet in conjunction with six mining companies (Aquila Steel, Assmang, Kumba Iron Ore, PMG, 

Tshipi e Ntle and UMK) are now proposing an oreline expansion project. This would increase the 

capacity of the current Sishen-Saldanha railway and port from 60 million tonnes/annum to 90 million 

tonnes/annum by 2017 in order to satisfy the global demand for iron ore. 

Iron ore is mined in Hotazel, Postmasburg and Sishen before being transported on a freight 

train 861 km to Saldanha Bay. From the train, it is loaded onto conveyor belts and then placed in 

stockpiles to be loaded into the holds of cargo ships. An increase in rail capacity will result in a 

greater volume of ore arriving in Saldanha and accordingly an increase in ship traffic will be 

necessary in order to transport this product globally. At present, 276 iron ore ships arrive and 

depart on an annual basis. In order to accommodate an increase in ship volume, further adaptations 

may be required of the port. These could involve further dredging of the Bay to increase the width 

of shipping channels, and also increased infrastructure in the port itself to improve capacity. 

Environmental Resource Management (ERM) has been appointed to conduct a pre-feasibility 

study for the project. They are currently in the public participation phase (M. January, ERM, pers. 

comm. 2012). 

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3.3.3 Development of a Liquid Petroleum Gas Facility in Saldanha Bay 

Sunrise Energy (Pty) Ltd has proposed to build an import facility for Liquid Petroleum Gas (LPG) in 

Saldanha Bay. LPG is a fuel mix of propane and butane which is in a gaseous form at ambient 

temperature, but is liquefied under increased pressure or by a temperature decrease. This plant 

has been proposed in order to supplement current LPG refineries in the Western Cape and ensure 

that industries dependant on LPG can remain in operation. The information presented below is 

based upon the information contained in the License Application to the Department of 

Environmental Affairs and Development Planning (NERSA 2010), and conveyed in a presentation to 

the Saldanha Bay Water Quality Forum Trust in 2010. The project includes the following components 

(Figure 3.9): 

(i) An offshore marine component for the off-loading of LPG; 

(ii) Onshore storage facility comprising six mild steel storage bullets (6 m in diameter and 60 

m long) lying horizontally alongside each other in a mounded (buried) storage area (total 

capacity 15 000 tons); 

(iii) A pipeline to the on-shore storage facility; 

(iv) Two transfer bullets; 

(v) Rail and road gantries and access; and 

(vi) A wrapped buried pipeline to industrial customers in Saldanha Bay. 

Figure 3.9. An illustration of an LPG transfer scheme (Source: ERM Final Scoping Report 2011) 

An Environmental Impact Assessment (EIA) process in terms of section 24 of the National 

Environmental Management Act (Act No 107 of 1998) (NEMA) was initiated by ERM with a Final 

Scoping Report completed in December 2011. Potential sites being considered for the off-loading 

facility are in the vicinity of the ore terminal in both Big Bay and Small Bay. The preferred site is to 

the east of the Ore Terminal in Big Bay. 

Three alternative marine off-loading options were initially investigated in the EIA process, 

namely; jetty off-loading, single point mooring and a conventional buoy mooring (preferred option) 

(ERM 2010). Protracted discussions regarding these options has delayed this component of the EIA 

process. Agreement has, however, recently been reached on the way forward regarding the marine 

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facilities for the proposed Sunrise Energy LPG in Saldanha and these will be outlined in the scoping 

report for the study due for release at the end of July 2012 (Claire Alborough, ERM, pers. comm.). 

Potential impacts to the marine environment, that need to be considered, include changes in water 

quality, change in sediment dynamics, impacts to benthic fauna, visual and landscape impacts, noise, 

socio-economic impacts and cumulative impacts (ERM 2010). Impacts to the marine environment 

may also be incurred as a result of storm water effluents from the on-shore storage facility. 

3.3.4 Development of the Salamander Bay Boat yard 

The Special Forces Regiment of the South African National Defence Force (SANDF) commenced the 

construction of a boat park in Salamander Bay at the entrance to Langebaan Lagoon in 2009, 

designed to house boats belonging to the regiment (Figure 3.10). The shores within Salamander Bay 

are dominated by sandy beaches and are considered sheltered. Soft bottom habitat dominates the 

subtidal benthos, which attains depths of no greater than 5 m. In order to increase the size of the 

boat house an area of 550 m 2 within the rocky intertidal zone was excavated and an area of 275 m 2 

of subtidal soft bottom habitat was dredged to allow for the placement of two column footings and 

25 wet column bases. 

Figure 3.10. The Salamander Bay boatpark in Saldanha (central strip of the picture). 

The construction activities commenced before an Environmental Impact Assessment (EIA) 

had been conducted. An EIA was commissioned retrospectively in terms of section 24G of the 

National Environmental Management Act (Act no 107 of 1998). A marine ecology report was 

compiled as part of the EIA to assess the impacts which had already occurred through the 

development of the boat yard, and the potential impacts which may result through the long-term 

use of the facility. The excavation of the intertidal and subtidal areas involved the mechanical 

removal of large boulders and the dredging of sediments. It was indicated that the impact of this 

excavation was of a high consequence as it resulted in a permanent loss of habitat and organisms in 

both the intertidal and subtidal zones. However, the affected area was acknowledged to be small, 

and the habitat common to the Saldanha Bay system. 

The dredging of the subtidal zone, which took place between May 2009 and May 2010, led 

to the release of a grey coloured sediment plume. Chemical analyses of the water and the dredged 

sediment indicated that there had been no contamination of cadmium or arsenic and only slightly 

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elevated levels of lead and organic material were detected. The impact of the dredging was 

considered to be of a low intensity as it was local in extent and occurred intermittently, while the 

impacts associated with the presence of the plume were considered to be of low consequence and 

significance for the marine environment. The potentially very serious impacts that may result from 

the unearthing of iron-sulphide rich sediment were prevented by a combination of natural features 

and mitigation measures. Sediments were contained behind the quay wall and then removed from 

the construction site, while the calcites present in the surface sediments minimised the release of 

sulphuric acid into the environment through oxidation of the iron sulphide present. 

The potential impacts, which may result from the long-term use of the new facility, were 

identified to include beach erosion and accretion, oil and diesel spills, disturbance of fauna and flora 

associated with increased boat traffic, and the unintentional release of chemicals used in boat 

cleaning and maintenance. Erosion and accretion of the beaches may occur as the hard flat surfaces 

of the quay increase flow rates in Salamander Bay. Rocks and sediment were to be reinstated 

against the quay wall and it was anticipated that this would mitigate any changes to water flow. The 

impacts of oil and diesel spills, disturbance of fauna and flora associated with increased boat traffic, 

and the unintentional release of chemicals used in boat cleaning and maintenance were considered 

to be of low significance given that oil and diesel spills are improbable and that the actual number of 

boats to be housed at the facility will remain relatively low. Taking into consideration all the impacts 

caused by the construction of the facility and all the potential impacts associated with the use 

thereof, it was concluded that the development of the Salamander boat yard was not expected to 

have significantly negative impacts on the marine environment of Salamander Bay. 

Baseline data for trace metals and benthic macrofauna were collected in Salamander Bay in 

June 2010 (following the dredge events). Follow-up monitoring to assess long-term impacts of the 

project on sediments and invertebrate macrofauna in Saldanha Bay and Langebaan Lagoon were 

collected at the same time as the State of the Bay samples in 2011 and are presented in Section 

5.4.2 of this report. 

3.3.5 Shipping, ballast water discharges, and oil spills 

3.3.5.1 Shipping and ballast water 

Shipping traffic comes with a number of attendant risks, especially in a port environment, 

where the risks of collisions and breakdowns increase owing to the fact that shipping traffic is 

concentrated, vessels are required to perform difficult manoeuvres, and are required to discharge or 

take up ballast water in lieu of cargo that has been loaded or unloaded. Saldanha Bay is home to the 

Port of Saldanha, which is one of the largest ports in South Africa receiving over 400 ships per 

annum. The Port comprises of an Iron export terminal for export of iron ore, an oil terminal for 

import of crude oil, a multi-purpose terminal dedicated mostly for export of lead, copper and zinc 

concentrates, and the Sea Harvest/Cold Store terminal that is dedicated to frozen fish products 

(Figure 3.8). There are also facilities for small vessel within the Port of Saldanha including the 

Government jetty used mostly by fishing vessels, the TNPA small boat harbour used mainly for the 

berthing and maintenance of TNPA workboats and tugs, and the Mossgas quay. Discharge of ballast 

by vessels visiting the iron ore terminal in particular poses a significant risk to the health of Saldanha 

Bay and Langebaan Lagoon. 

Ships carrying ballast water has been recorded since the late nineteenth century and by the 

1950s had completely phased out the older practice of carrying dry ballast. Ballast is essential for 

the efficient handling and stability of ships during ocean crossings and when entering a port. Ballast 

water is either freshwater or seawater taken up at ports of departure and discharged on arrival 

where new water can be pumped aboard, the volume dependant on the cargo load. The conversion 

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to ballast water set off a new wave of marine invasions, as species with a larval or planktonic phase 

in their life cycle were now able to be transported long distances between ports onboard ships. 

Furthermore, because ballast water is usually loaded in shallow and often turbid port areas, 

sediment is also loaded along with the water and this can support a host of infaunal species (Hewitt 

et al 2009). The global nature of the shipping industry makes it inevitable that many ships must load 

ballast water in one area and discharge it in another, which has an increasing potential to transport 

non-indigenous species to new areas. It has been estimated that major cargo vessels annually 

transport nearly 10 billion tonnes of ballast water worldwide, indicating the global dimension of the 

problem (Gollasch et al. 2002). It is estimated that on average, 3,000-4,000 species are transported 

between continents by ships each day (Carlton and Geller 1993). Once released into ports, these 

non-indigenous species have the potential to establish in a new environment which is potentially 

free of predators, parasites and diseases, and thereby outcompete and impact on native species and 

ecosystem functions, fishing and aquaculture industries, as well as public health (Gollasch et al. 

2002). Invasive species include planktonic dinoflagellates and copepods, nektonic Scyphozoa, 

Ctenophora, Mysidacea, benthos such as annelid oligochaeta and polychaeta, crustacean brachyura 

and molluscan bivalves, and fish (Carlton and Geller 1993). Carlton and Geller (1993) record 45 

'invasions' attributable to ballast water discharges in various coastal states around the world. In 

view of the recorded negative effects of alien species transfers, the International Maritime 

Organisation (IMO) considers the introduction of harmful aquatic organisms and pathogens to new 

environments via ships ballast water as one of the four greatest threats to the world’s oceans (Awad 

et al. 2003). 

In South Africa to date, an estimated total of 85 marine species are recorded as introduced 

mostly through shipping activities or mariculture and at least 62 of these are thought to occur in 

Saldanha Bay-Langebaan Lagoon (Mead et al. 2011). Three of the species recorded in Saldanha Bay 

are considered invasive: the Mediterranean mussel Mytilus galloprovincialis, the European green 

crab Carcinus maenas (Griffiths et al. 1992; Robinson et al. 2005) and the recently detected barnacle 

Balanus glandula (Laird and Griffiths 2008). Most of the introduced species are found in sheltered 

areas such as harbours and are believed to have been introduced through shipping activities, mostly 

ballast water and biofouling. Because ballast water is normally loaded in sheltered harbours, the 

species that are transported also originate from these habitats and thus have a difficult time 

adapting to South Africa’s exposed coast. This might, in part, explain the low number of introduced 

species that have become invasive along the coast (Griffiths et al. 2008). Most introduced species in 

South Africa occur along the west and south coasts and very few have been recorded north of Port 

Elizabeth. This corresponds with the predominant trade routes being between South Africa and the 

cooler temperate regions of Europe, from where most of the marine introductions in South Africa 

originate (Awad et al. 2003). (Section 11 of this report deals with alien invasive species in Saldanha 

Bay in more detail.) 

Other potentially negative effects of ballast water discharges are contaminants that may be 

transported with the water. Carter (1996) reports on concentrations of trace metals such as 

cadmium, copper, zinc and lead amongst others that have been detected in ballast water and ballast 

tank sediments from ships deballasting in Saldanha Bay. Of particular concern are the high 

concentrations of copper and zinc that in many instances exceeded the South African Water Quality 

Criteria (DWAF 1995a) (Table 3.4). These discharges are almost certainly contributing to trace metal 

loading in the water column (as indicated by their concentration in filter-feeding organisms in the 

Bay - see § 4.3 for more on this) and in sediments in the Bay (see §5.4 for more on this issue). 

Ballast water carried by ships visiting the Port of Saldanha is released in two stages - a first 

release is made upon entering Saldanha Bay (i.e. Big Bay) and the second once the ship is berthed 

and loading (Awad et al. 2003). As a result as much as 50% of the ballast water is released in the 

vicinity of the iron ore quay on either the Small Bay side or Big Bay side of the quay depending on 

which side the ship is berthed. 

27 

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Number and type of vessels entering Saldanha Port 



Table 3.4. 

Mean trace metal concentrations in ballast water (mg/l) and ballast tank sediments from ships 

deballasting in Saldanha Bay (Source: Carter 1996) and SA Water Quality Guideline limits 

(DWAF 1995a). Those measurements in red are non-compliant with the guidelines. 

Water Sediment SA WQ Guideline limit 

Cd 0.005 0.040 0.004 

Cu 0.005 0.057 0.005 

Zn 0.130 0.800 0.025 

Pb 0.015 0.003 0.012 

Cr 0.025 0.056 0.008 

Ni 0.010 0.160 0.025 

The total number of ships entering the Port of Saldanha has nearly doubled in the last two 

decades and in 2011, there were 463 ships which visited the port (Figure 3.11). The average size of 

vessels in use has also increased over the years, and as a result, the volume of ballast water 

discharged to the Bay has increased by more than double since 2004, with over 20 million tons of 

ballast water being discharged each year (Figure 3.12). Iron ore tankers are responsible for most of 

the observed increase in vessel traffic and are the ones responsible for discharging the greatest 

volume of ballast water into the Bay. 

500 

450 

400 

350 

TOTAL 

MPT 

Other 

IOT 

Tanker 

300 

250 

200 

150 

100 

50 

0 

1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 

Figure 3.11. Number and types of vessels entering Saldanha Port from 1994-2011. (Sources: Marangoni 

1998; Awad et al. 2003, Transnet-NPA). 

Associated with this increase in shipping traffic, is an increase in the incidence and risk of oil 

spills, the risk of introducing alien species, increases in the volume of trace metals entering the Bay, 

and direct disturbance of marine life and sediment in the Bay. While the risks associated with 

introduction of alien species to the Bay are being addressed through various mechanisms including 

open-ocean exchange and treatment of ballast water, risks of oil spills are being addressed through 

oil spill contingency planning, no measures have yet been put in place to address trace metal 

28 

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discharges to the Bay. Trace metals discharges thus pose possibly the greatest shipping-associated 

risk to the Bay at present. 

25000000 

TOTAL IOT MPT 

20000000 

Tanker 


15000000 

10000000 

5000000 

0 

1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 

Figure 3.12. Volumes of ballast water discharge in million tonnes by the different types of vessels entering 

Saldanha Port between 1994 and 2011. The data for 1999-2002 is an average of the total 

volume of discharge for those years. (Sources: Marangoni 1998; Awad et al. 2003, Transnet- 

NPA unpublished data 2003-2011). 

3.3.5.2 Oil spills 

In South Africa there have been a total of four major oil spills, two off Cape Town (1983 and 2000), 

one in the vicinity of Dassen Island (1994), and one in close to St. Lucia wetlands (2002). In Saldanha 

Bay there have to date been no comparable oils spills (Martin Slabber – SAMSA, pers. comm.). 

Minor spills do occur however, which have the potential to severely impact the surrounding 

environment. In April 2002, about 10 tons of oil spilled into the sea in Saldanha Bay when a relief 

valve malfunctioned on a super-tanker. Booms were immediately placed around the tanker and the 

spill was contained. More recently in July 2007, a Sea Harvest ship spilled oil into the harbour while 

re-fuelling, the spill was managed but left oil on rocks and probably affected small invertebrates 

living on the rocks and in the surrounding sand. 

In 2007 Transnet National Ports Authority and Oil Pollution Control South Africa (OPC), a 

subsidiary of CEF (Central Energy Fund) signed an agreement which substantially improved 

procedures in the event of oil spills and put in place measures to effectively help prevent spills in the 

Port of Saldanha. These are laid out in detail in the “Port of Saldanha oil spill contingency plan” 

(Transnet 2010). The plan is intended to ensure a rapid response to oil spills within the port itself 

and by approaching vessels. The plan interfaces with the “National oil spill contingency plan” and 

with the “Terminal oil spill contingency plan” and has a three tiered response to oils spills: 

Tier 1: Spill up to approximately 7 tonnes 

Response where the containment, clean up and rescue of contaminated fauna can 

be dealt with within the boundaries of the vessel, berth or a small geographical 

area. The incident has no impact outside the operational area but poses a 

29 

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potential emergency condition. 

Tier 2: Spill between 7-300 tonnes 

Response where the nature of the incident puts it beyond the containment, clean 

up and rescue of contaminated fauna capabilities of the ship or terminal operator. 

The containment of clean up requires the use of some of or the government and 

industry resources. 

Tier 3: Spill in excess of 300 tonnes. 

Response where the nature of the incident puts it beyond containment, clean up 

and rescue of contaminated fauna capabilities of a national or regional response. 

This is a large spill which has the probability of causing severe environmental and 

human health problems. 

Upon entry to the port, all vessels undergo an inspection by the Pollution Control Officer 

(PCO) to minimise risks of pollution in the port through checking overboard valves and ensuring the 

master and crew of the vessel are familiar with the Port’s environmental requirements. Every tanker 

is contained by booms while oil is being pumped, ensuring immediate containment of any minor 

spills (Martin Sabber – SAMSA, pers. comm.). The OPC has facilities and equipment to effectively 

secure an oil spill as well as for the handling of shore contamination including oiled sea birds and 

beach-cleaning equipment. However, given the environmental sensitivity of the Saldanha Bay area, 

particularly Langebaan Lagoon, prevention is the most important focus (CEF 2008). 

3.3.6 Reverse Osmosis Desalination Plants 

Desalination refers to a water treatment process whereby salts are removed from saline water to 

produce fresh water. Reverse Osmosis (RO) involves forcing water through a semi-permeable 

membrane under high pressure, leaving the dissolved salts and other solutes behind on the surface 

of the membrane. One desalination plant has been built in Saldanha and discharges brine into the 

Bay (belonging to Transet_NPA) while a second has been proposed (by the West Coast District 

Municipality). 

3.3.6.1 Transnet-NPA Desalination Plant 

Transnet-NPA (TPNA) have recently built 1 200 m³/day RO desalination facility to supplement the 

supply of freshwater to the Iron Ore Terminal in the Port of Saldanha. Freshwater is required at the 

terminal for dust mitigation during the loading and offloading of iron ore. An additional 1 200 

m³/day (1 RO module) of fresh water is currently required to supplement the current municipal 

allocation, however, in the long-term it is envisioned that the RO Plant will produce a total capacity 

of 3 600 m³/day potable water (up to 3 RO modules). The project which involved the design, 

manufacture, supply, delivery to site, installation, testing and commissioning of one 1 200 m³/day 

RO train, was awarded to VWS Envig in 2008. The installation of the plant commenced in 2010 and 

is currently in the commissioning phase, following receipt of the Water Use License from the 

Department of Water Affairs in January 2012. This phase is due to be completed by the end of July, 

so the plant is expected be online as of August 2012. 

30 

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3.3.6.1.1 Technical details and design 

To achieve the planned 1 200 m³/day production of potable water, the plant will require an intake of 

more than twice that amount of seawater (2 667 m³/day); with approximately 45% being converted 

to potable water, and 55% being returned to the sea as brine (1 467 m³/day) and backwash waste. 

The seawater will be passed through a pre-treatment process to remove suspended solids, biological 

matter and other particles that may clog the RO membranes. Pre-treatment will also entail the 

addition of a non-oxidising biocide to control biological activity, and a coagulant to assist with the 

removal of suspended solids and organics and reduce the turbidity. Water will be passed through a 

dual media filter (DMF) to remove suspended solids and organics. This filter will need be 

backwashed periodically. The pre-treated sea water will then be dosed with anti-scalant and forced 

through a semi-permeable membrane (within the RO modules) by a high pressure pump. This 

process results in a high salinity solution (brine) and a very low salinity solution (fresh water). The 

brine and DMF backwash water will be discharged into the sea and the potable water will be 

diverted to the storage reservoir(s), with a capacity of 5 000 m 3 , for use in dust mitigation. 

The flocculant and non-oxidising biocide used during the pre-treatment process as well as 

the anti-scalant will be blended and discharged with the brine into the sea. Cleaning In Place (CIP) 

chemicals will be used for the cleaning of the RO membranes, and the wash water containing these 

chemicals will be disposed of either via the municipal sewer system (with approval from the 

municipality) or at a suitable disposal site, and will not be contained in the brine discharged back 

into the ocean. 

The RO plant is located on the southern section of the quay of the iron ore handling facility, 

on a gravel area adjacent to the Multi-Purpose Terminal. The environment at this site was entirely 

transformed and there was no indigenous vegetation found on the site prior to the construction. 

The intake system was designed as 6 boreholes located on the beach, alongside the Multi-Purpose 

Terminal. However, during the pilot operational phase, it was discovered that these beach wells 

contained oil deposits. As a result, the intake pipelines are now located in the Bay. The discharge 

pipeline is located at Caisson 3 and consists of a single port diffuser at 16 to 18 m water depth. 

3.3.6.1.2 Potential Impacts 

A Basic Assessment commenced in 2007 and was conducted by PD Naidoo & Associates (Pty) Ltd and 

SRK Consulting Scientists and Engineers Joint Venture (PDNA/SRK Joint Venture). A total of four 

specialist studies were commissioned to assess the potential impacts. These studies included a 

botanical study, a marine study, a groundwater resources study and a heritage resources 

assessment. Three alternative sites for the location of the RO Plant and various site specific 

alternatives with regards to intake and discharge location and infrastructure were considered in 

each of the studies. The site and specifications authorised for the construction of the RO plant 

(described above) are hereafter referred to as the “authorized site”. The botanical study, 

groundwater resources study and heritage study indicated that the construction and operation of 

the RO plant would have no significant impacts on the indigenous flora or vegetation, the 

groundwater or any heritage resources, at the authorized site respectively. 

The key impacts to the marine environment that were identified in the marine study fell into 

two main categories; those associated with the construction phase and those associated with the 

operational phase (Van Ballegooyen et al. 2007). The issues associated with the construction phase 

included: 

31 

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Onshore construction issues: human activity, air, noise and vibration pollution, dust, blasting 

and piling driving, disturbance of coastal flora and fauna); 

Construction and installation of a water discharge and intake pipeline issues: construction 

site, pipe lay-down areas, trenching of pipeline(s) in the marine environment and 

consequent disturbance of subtidal biota); and 

Construction and installation of intake boreholes. 

The issues associated with the operational phase included: 

 

 

 

 

 

 

 

altered flows at the discharge resulting in ecological impacts (e.g. flow distortion/changes at 

the discharge, and affects on natural sediment dynamics); 

the effect of elevated salinities in the brine water discharged to the bay; 

biocidal action of non-oxidising biocides such as dibromonitrilopropionamide (DBNPA) in the 

effluent; 

the effects of co-discharged waste water constituents, including possible tainting effects 

affecting both mariculture activities and fish factory processing in the bay; 

the effect of the discharged effluent having a higher temperature than the receiving 

environment; 

direct changes in dissolved oxygen content due to the difference between the ambient 

dissolved oxygen concentrations and those in the discharged effluent; and 

indirect changes in dissolved oxygen content of the water column and sediments due to 

changes in phytoplankton production as a result of altered nutrient dynamics (both in terms 

of changes in nutrient inflows and vertical mixing of nutrients) and altered remineralisation 

rates (with related changes in nutrient concentrations in near bottom waters) associated 

with near bottom changes in seawater temperature due to the brine discharge plume. 

The marine specialist report assessed the impacts of RO plants with several different designs 

at three sites. It was expected that the impacts of construction at the authorized site would be very 

low as these construction activities would have utilized existing infrastructure as their basis and 

construction activities would not have been extensive. Operational impacts associated with the 

intake of water through boreholes were expected to be insignificant to low. All potential impacts 

associated with the discharge of brine through a pipeline at Caisson 3 (the authorized site) were 

expected to be of a low to very low level, with the exception of the use of oxygen scavengers with no 

mitigation measures, which was expected to have a medium level impact. A monitoring programme 

was outlined in the marine specialist report. Aspects of the environment which require monitoring 

include the benthic macrofauna communities, dissolved oxygen levels in the near bottom waters in 

the immediate vicinity, trace metals and tainting substances in the RO plant effluent, toxicity of the 

effluent, and temperature, salinity and suspended solids in the near-field. Monitoring activities 

commenced during the second half of 2010 in order to establish a baseline prior to the RO plant 

coming into operation. Follow-up monitoring is planned when the plant is finally brought on line. 

3.3.6.2 West Coast District Municipality Desalination Plant 

The West Coast District Municipality (WCDM) has proposed the construction of an additional 

RO plant in the Saldanha Bay area. The West Coast has limited water resources (due to its semi-arid 

nature) but yet is required to supply 22 towns and 876 farms across the region with potable water. 

Currently water is supplied by the Voelvlei Dam, Misverstand Dam and the Langebaan road aquifer, 

however the volume allocated from these sources for this is close to the maximum possible. During a 

feasibility study in 2007 to assess the most viable solution to the water scarcity issue in the WCDM, 

several sources of additional water were considered. These included: 

32 

ANCHOR 




 

 

 

 

 

 

The Twenty-four Rivers Scheme 

Lowlift pumps at the Misverstand Dam 

The Mitchell’s pass Diversion 

Groundwater potential 

Water Quality Management 

Alien vegetation clearing 

The most cost-effective solution was a 25 500 m 3 /day sea water desalination plant in the 

vicinity of Small Bay. This would be a climate-independent solution, offering 100% water security. It 

would facilitate sustainable economic development in towns such as Malmesbury and Langebaan, 

both of which have been identified as high growth potential areas. 

3.3.6.2.1 Technical details and design 

The proposed plant will have an intake capacity of approximately 60 000 m 3 /day with a production 

of 25 500 m 3 /day permeate water when operating at full capacity. An estimated 34 500 m 3 of brine 

will be discharged daily into the sea. However, the intake capacity could be increased to 58 million 

m 3 /annum to assist with brine dispersion and allow for recirculation which will help minimise 

biofouling of the pipes. 

The plant will have a lifespan of 25 years (with a possibility of extension) and will be built in 

three phases (of 8 500 m 3 /day production) to be completed and running at full capacity by 2026. 

The plant (excluding pipelines) will cover an area of approximately ± 50 000 m 2 and be 

composed of the following elements: 

Feedwater intake and brine discharge structures and associated terrestrial and marine 

pipelines 

Feedwater pump station 

Feedwater transfer pipelines from the pump station to the SWRO plant 

Pre-treatment facility to pre-filter the water before it enters the RO membranes 

Buildings housing RO membranes to produce the permeate for potable water 

Extension/upgrading of existing roads and infrastructure 

Development of internal access roads 

Chemical infrastructure for conditioning of the pre- and post-filtered water 

Pump stations for permeate and brine 

Electrical power lines and transformer yards 

Holding reservoir (size TBC) 

Sludge handling and disposal facilities 

Formation of dunes with excess material 

Operational site of ± 50 000 m 2 including all infrastructures and surrounded by a security 

fence 

Distribution terrestrial pipelines for permeate from the holding reservoir to the Municipal 

Besaansklip Reservoir along existing servitudes, road reserves or cadastral boundaries. 

3.3.6.2.2 Potential Impacts 

A Scoping and Environmental Impact Assessment Process is required in order to ensure compliance 

with the National Environmental Management Act (Act no 107 of 1998) as amended and the EIA 

Regulations (2010). 

33 

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A Draft Scoping report prepared by the CSIR (commissioned by Worley Parsons South Africa 

(Pty) Ltd) in 2012 identified potential impacts with ten alternative locations and the associated 

infrastructure routes for power and pipelines. Taking into account technical, financial and 

environmental concerns, two sites were identified as the most feasible with minimal impacts. 

One potential site is located on the property of the ArcelorMittal Smelter in Saldanha Bay. 

The marine feed water intake would operate in Big Bay, while the brine discharge site is currently 

under investigation for either Big Bay or Danger Bay. 

The other location for the RO plant is located toward the northern head of Danger Bay on a 

portion of municipal owned land. This is the preferred site proposes both discharge and intake lines 

be situated in Danger Bay. 

The report highlighted that the biggest concern is in the design and location of the brine 

discharge outlets. The salinity of brine is around 60 PSU (compared to the 34 PSU of natural 

seawater) and it may also contain certain waste products such as coagulants, anti-scalant and 

cleaning chemicals. Therefore in order to minimise environmental impacts, the discharge pipelines 

should be placed in areas exposed to high energy waves which will allow for more efficient brine 

dissipation. However, there a trade-off between the remoteness of the discharge outlets and the 

extent of terrestrial pipeline required over valuable or threatened land. This will be investigated 

further during the EIA phase of the assessment. 

3.3.7 Sewage and associated waste waters 

Sewage is by far the most dominant (by volume) waste product discharged into rivers, estuaries and 

coastal waters worldwide. However, sewage is not the only organic constituent of waste water, 

received by sewage treatment plants, other degradable organic wastes, which can result in nutrient 

loading, include: 

 

 

 

 

 

 

Agricultural waste 

Food processing wastes (e.g. from fish factories and slaughter houses) 

Brewing and distillery wastes 

Paper pulp mill wastes 

Chemical industry wastes 

Oil spillages 

Our present knowledge, of the impacts of waste waters on water systems, has until recently 

largely been based on lake-river eutrophication studies. However, recent focus on how 

anthropogenic nutrient enrichment is affecting near-shore coastal ecosystems is emerging (for a 

review see Cloern 2001; Howarth et al 2011). In general, the primarily organic discharge in waste 

water effluents contains high concentrations of nutrients such as nitrates and phosphates 

(essentially the ingredients in fertilizers). Existing records provide compelling evidence of a rapid 

increase in the availability of Nitrogen and Phosphorus to coastal ecosystems since the mid-1950’s 

(Cloern 2001). These will stimulate the growth and primary production of fast-growing algae such as 

phytoplankton and ephemeral macroalgae, at the expense of slower-growing vascular plants and 

perennial macroalgae (seagrasses) which are better adapted to low-nutrient environments. This 

process requires oxygen, and with high nutrient input oxygen concentrations in the water can 

become reduced which would lead to deoxygenation or hypoxia in the receiving water (Cloern 

2001). When the phytoplankton die and settle to the bottom, aerobic and anaerobic bacteria 

continue the process of degradation. However, if the supply rate of organic material continues for 

an extended period, sediments can become depleted of oxygen leaving only anaerobic bacteria to 

process the organic matter, This then generates chemical by-products such as hydrogen sulphide 

34 

ANCHOR 




and methane which are toxic to most marine organisms (Clark, 1986). The sediments and the 

benthic communities they support are thus amongst the most sensitive components of coastal 

ecosystems to hypoxia and eutrophication (Cloern 2001). The ecological responses associated with 

decreasing oxygen saturation in shallow coastal systems include the initial escape of sensitive 

demersal fish, followed by mortality of bivalves and crustaceans, and finally mortality of molluscs, 

with extreme loss of benthic diversity (Vaquer-Sunyer and Duarte 2008; Howarth et al 2011). 

Vaquer-Sunyer and Duarte (2008) propose a precautionary limit for oxygen concentrations at 4.6 mg 

O 2 /litre equivalent to the 90th percentile of mean lethal concentrations, to avoid catastrophic 

mortality events, except for the most sensitive crab species, and effectively conserve marine 

biodiversity. 

Some of the indirect consequences of an increase in phytoplankton biomass and high levels 

of nutrient loading are a decrease in water transparency and an increase in epiphyte grown, both of 

which have been shown to limit the habitat of benthic plants such as seagrasses (Orth and Moore 

1983). Furthermore, there are several studies documenting the effects that shifts in natural marine 

concentrations, and ratios of nitrates, phosphates and elements such ammonia and silica, have on 

marine organisms (Herman et al 1996; van Katwijk et al 1997; Hodgkiss and Ho 1997; Howarth et al 

2011). For instance, the depletion of dissolved Silica in coastal systems, as a result of nutrient 

enrichment, water management and the building of dams, is believed to be linked to worldwide 

increases in flagellate/dinoflagellate species which are associated with harmful algal blooms, and are 

toxic to other biota (Hodgkiss and Ho 1997; Howarth et al 2011). The toxic effect that elevated 

concentrations of ammonia have on plants has been documented for Zostera marina, and shows 

that plants held for two weeks in concentrations as low as 125 µmol start to become necrotic and 

die (van Katwijk et al 1997). 

The effects of organic enrichment, on benthic macrofauna in Saldanha Bay, have been well 

documented (Jackson and McGibbon 1991, Kruger 2002, Kruger et al. 2005, Stenton-Dozey 2001). 

Tourism and mariculture are both important growth industries in and around Saldanha Bay, and 

both are dependent on good water quality (Jackson and Gibbon 1991). The growth of attached 

algae such as Ulva sp. and Enteromorpha sp. on beaches is a common sign of sewage pollution (Clark 

1986). Nitrogen loading in Langebaan Lagoon associated with leakage of conservancy/septic tanks 

and storm water runoff has resulted in localised blooms of Ulva sp. in the past. In the summer 1993- 

94, a bloom of Ulva lactuca in Saldanha Bay was linked to discharge of nitrogen from pelagic fish 

processing plants (Monteiro et al. 1997). Dense patches of Ulva sp. are also occasionally found in 

the shallow embayment of Oudepos (CSIR 2002). Organic loading is a particular problem in Small 

Bay due to reduced wave action and water movement in this part of the Bay caused by harbour 

structures such as the Ore Terminal and the Causeway, as well as the multitude of organic pollution 

sources within this area (e.g. fish factories, mariculture farms, sewage outfalls, sewage overflow 

from pump stations, and storm water runoff). Langebaan Lagoon is also sheltered from wave action 

but strong tidal action and the shallow nature of the lagoon make it less susceptible to the long term 

deposition of pollutants and organic matter (Monteiro 1999 in CSIR 2002). 

There is one waste water treatment works (WWTW) in Saldanha and one in Langebaan. The 

WWTW in Saldanha disposes of treated effluent into the Bok River where it drains into Small Bay 

adjacent to the Blouwaterbaai Resort. In addition to sewage waste, the WWTW in Saldanha also 

receives and treats industrial waste water from a range of industries in Saldanha: 

 

 

 

 

 

 

Sea Harvest 

Hoedtjiesbaai Hotel 

Protea Hotel 

Southern Seas Fishing (not currently operation) 

Bongolethu Fishing Enterprises 

SA Lobster 

35 

ANCHOR 




 

 

 

 

 

 

Cape Reef Products 

TNPA 

Arcelor Mittal 

Namaqua Sands 

Abattoir 

Duferco 

These discharges reportedly often place the plant under considerable stress and result in the 

discharge of substandard effluent (CSIR 2002). 

Until recently the Langebaan WWTW did not discharge any effluent into the sea as all of it 

was used it to irrigate the local golf course. However, increasing volumes of effluent received by this 

plant is yielding more water than is required for irrigation and some of this is now discharged into 

the Bay. There are nine sewage pump stations in Saldanha Bay and two conservancy tanks, all of 

which are situated on the western border of Small Bay. The conservancy tanks are positioned 

adjacent to the Yacht Club. There are eighteen sewage pump stations in Langebaan situated 

throughout the town, many of which are near the edge of the lagoon, and three conservancy tanks 

spread around the edge of the lagoon at Oostewal, Stofbergsfontein and Oudepos (Figure 3.13). 

Sewage effluent can enter the Saldanha/Langebaan marine environment via three routes, 

namely: 

 

 

 

Discharge of treated sewage effluent in the Bok River which drains into Small Bay; 

Overflow of sewage pump stations as a result of pump malfunction of power failures; 

Seepage or overflow from septic or conservancy tanks. 

36 

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Bok River 

Saldanha 

Bay 

Small Bay 

Big Bay 

Club Mykonos 

o 

33 3’S 

Langebaan 

Oudepos 

Oosterwal 

Langebaan 

Lagoon 

Stofbergsfontein 

o 

33 10’S 

Waste water treatment works 

Sewage pump stations 

Conservance tanks 

0m 1500m 3000m 4500m 6000m 

o 

17 50’E 

Figure 3.13. Location of waste water treatment works, sewage pump stations and conservancy tanks in 

Saldanha and Langebaan area (2011). 

37 

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Historically a number of these pump stations used to overflow from time to time directly 

into the Bay when the pumps malfunctioned. This is now a rare event, however, as much of the 

associated infrastructure has been upgraded recently and is now regularly maintained. 

The Saldanha WWTW operates under an exemption issued by the Department of Water 

Affairs (DWAF) in terms of the Water Act of 1956 which authorises the release of a total volume of 

958 000 m 3 per year. The volume of waste water that is permitted to be released from the 

Langebaan WWTW is unknown at this stage. Up until recently at least, most of the waste water 

from this plan was used to irrigate the golf course. Table 3.5 shows the general standards as 

specified under the Water Act 54 (1956), and the revised general limits specified under the National 

Water Act 36 of 1998 for various other parameters and substances contained in the released waters 

of the WWTW of Saldanha and Langebaan. 

Table 3.5. 

General standards as specified under the Water Act 54 (1956) and revised general limits 

specified under the National Water Act 36 of 1998. 

Substance/parameter 

General standards under 

the Water Act (1956) 

General limit for general 

authorisation under the 

National Water Act (1998) 

Temperature 35 o C - 

Electrical Conductivity measured in milliSiemens 

per meter (mS/m) 

75 

70 above intake to a 

maximum of 150 

pH 5.5-9.5 5.5-9.5 

Chemical Oxygen Demand (mg/l) 75 75 (after removal of algae) 

Suspended Solids (mg/l) 25 25 

Soap, oil or grease (mg/l) 2.5 2.5 

Ortho-Phosphate as P (mg/l) - 10 

Nitrate/Nitrite as Nitrogen (mg/l) - 15 

Ammonia (ionised and un-ionised) as N (mg/l) 10 3 

Fluoride (mg/l) 1 1 

Chlorine as Free Chlorine (mg/l) 0.1 0,25 

Dissolved Cyanide (mg/l) 0.5 0.02 

Dissolved Arsenic (mg/l) 0.5 0.02 

Dissolved Cadmium(mg/l) 0.05 0.005 

Dissolved Chromium (VI) (mg/l) 0.05 0.05 

Dissolved Copper (mg/l) 1 0.01 

Dissolved Iron (mg/l) - 0.3 

Dissolved Lead (mg/l) 0.1 0.01 

Dissolved Manganese (mg/l) 0.4 0.1 

Mercury and its compounds (mg/l) 0.02 0.005 

Dissolved Selenium (mg/l) 0.05 0.02 

Dissolved Zinc (mg/l) 5.0 0.1 

Boron (mg/l) 1 1 

Phenolic compounds as phenol (mg/l) 0.1 - 

Faecal Coliforms (per 100 ml) 100 1000 

38 

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Average Daily Flow (m3/day) 

Apr-03 

Jul-03 

Nov-03 

Mar-04 

Jul-04 

Nov-04 

Mar-05 

Jul-05 

Nov-05 

Mar-06 

Jul-06 

Nov-06 

Mar-07 

Jul-07 

Nov-07 

Mar-08 

Jul-08 

Oct-08 

Feb-09 

Jun-09 

Oct-09 

Feb-10 

Jun-10 

Oct-10 

Feb-11 

Jun-11 

Oct-11 

Feb-12 



3.3.7.1 Water quality parameters associated with the Saldanha WWTW 

Before 2005, the average daily volume discharged rarely exceeded 2000 m 3 , but volumes of effluent 

released have subsequently been increasing steadily over time and are now approaching the 

maximum annual limit allowed in terms of the exemption issued by DWAF (Figure 3.14). 

3000 

2500 

2000 

1500 

1000 

500 

0 

Figure 3.14. Monthly trends in the volume of effluent released from the Saldanha WWTW, Apr 2003- 

December 2011, and authorised total volume per year expressed as a daily limit (red line). 

Allowable discharge limits as specified in terms of the exemption issued by DWAF under the 

National Water Act 1998 are represented by the dashed red line. 

Figure 3.15. Monthly trends in the numbers of Faecal Coliforms in effluent released from the Saldanha 

WWTW, April 2003 - December 2011. Allowable limits as specified in terms of a General 

Authorisation under the National Water Act 1998 are represented by the dashed red line. 

Concentrations of faecal coliforms in the effluent from the WWTW exceeded allowable 

limits specified on 15 occasions since 2003 (15% of the time) (Figure 3.15). Allowable limits for Total 

Suspended Solids were exceeded on 11% of the occasions on which measurements were made 

(Figure 3.16), and measurements for Chemical Oxygen Demand (COD) exceeded allowable limits 

39 

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26% of the time (Figure 3.17). Chemical Oxygen Demand is commonly used to indirectly measure 

the amount of organic compounds in water. 

Figure 3.16. Monthly trends in the numbers of Total Suspended Solids in effluent released from the 

Saldanha WWTW, April 2003 - December 2011. Allowable limits as specified in terms of a 

General Authorisation under the National Water Act 1998 are represented by the dashed red 

line. 

Figure 3.17. 

Monthly trends in the numbers of Chemical Oxygen Demand in effluent released from the 

Saldanha WWTW, April 2003 - December 2011. Allowable limits as specified in terms of a 

General Authorisation under the National Water Act 1998 are represented by the red line. 

A worrying sign is the levels of Ammonia Nitrogen discharged which are consistently above 

the allowable margin of 3 mg/l; allowable limits being exceeded 94% of the time (Figure 3.18). 

Nitrate Nitrogen limits were exceeded on 17% of the occasions (Figure 3.19). 

40 

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Figure 3.18. Monthly trends in Ammonia Nitrogen for effluent released from the Saldanha WWTW Apr 

2003-December 2011. Allowable limits as specified in terms of a General Authorisation under 

the National Water Act 1998 are represented by the red line. 

Figure 3.19. Monthly trends in Nitrate Nitrogen for effluent released from the Saldanha WWTW Apr 2003 - 

December 2011. Allowable limits as specified in terms of a General Authorisation under the 

National Water Act 1998 are represented by the red line. 

The concentration of phosphorus in the effluent has only been measured since October 

2007 showing a distinct seasonal pattern, with the highest values occurring mostly during the 

summer months and lowest values in winter. This is consistent with the higher influx of visitors 

during summer. In recent years values have remained mostly below the allowable limit of 10 mg/l 

(Figure 3.20). 

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Figure 3.20. Monthly trends in water quality parameters Orthophosphate for effluent released from the 

Saldanha WWTW Apr 2003-December 2011. Allowable limits as specified in terms of a General 

Authorisation under the National Water Act 1998 are represented by the red line. 

Chlorine gas, generated through a process of electrolysis, is toxic to most organisms and is 

used to sterilise the final effluent (i.e. kill bacteria and other pathogens present in the effluent) 

before it is released into settling ponds or the environment. Chlorine breaks down naturally through 

reaction with organic matter and in the presence of sunlight, but must not exceed a concentration 

0.25 mg/l in terms of the general authorisation under which the Saldanha WWTW operates. The 

frequency of exceedence for this parameters since 2003 is 49.5% (i.e. nearly 50% of the readings are 

above the allowable limit) (Figure 3.21). 

Figure 3.21. Monthly trends in Free Active Chlorine for effluent released from the Saldanha WWTW Apr 

2003-December 2011. Allowable limits as specified in terms of a General Authorisation under 

the National Water Act 1998 are represented by the red line. 

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Average daily flow (m 3 /day) 

Faecal Coliforms (org/100 ml) 

May-09 

May-09 

Jul-09 

Jul-09 

Aug-09 

Aug-09 

Oct-09 

Oct-09 

Dec-09 

Dec-09 

Jan-10 

Jan-10 

Mar-10 

Mar-10 

May-10 

May-10 

Jun-10 

Jun-10 

Aug-10 

Aug-10 

Sep-10 

Sep-10 

Nov-10 

Nov-10 

Jan-11 

Jan-11 

Feb-11 

Feb-11 

Apr-11 

Apr-11 

Jun-11 

Jun-11 

Jul-11 

Jul-11 

Sep-11 

Sep-11 

Nov-11 

Nov-11 

Dec-11 

Dec-11 



3.3.7.2 Water quality parameters associated with the Langebaan WWTW 

Water quality parameters associated with effluent from the Langebaan WWTW have only been 

measured since June 2009 (Figure 3.22). Volume allowed release for Langebaan still to enter. Faecal 

coliforms counts have exceeded the allowable limits specified on 5 occasions since 2009, which 

correspond to 16% of time (Figure 3.23). 

7000 

6000 

5000 

4000 

3000 

2000 

1000 

0 

Figure 3.22. Monthly trends in the daily volume of effluent discharged from the Langebaan WWTW in the 

period June 2009-November 2011. 

1400 

1200 

1000 

800 

600 

400 

200 

0 

Figure 3.23. Monthly trends in the numbers of Faecal Coliforms in effluent released from the Langebaan 

WWTW, June 2009 - December 2011. Allowable limits as specified in terms of a General 


Total Suspended Solids have only once exceeded the allowable limits (Figure 3.24), while 

measurements for Chemical Oxygen Demand exceeded allowable limits on 32% of the occasions 


43 

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Chemical Oxygen Demand (mg/l) (Filtered) 

Total Suspended Solids (mg/l) 

May-09 

May-09 

Jul-09 

Jul-09 

Aug-09 

Aug-09 

Oct-09 

Oct-09 

Dec-09 

Dec-09 

Jan-10 

Jan-10 

Mar-10 

Mar-10 

May-10 

May-10 

Jun-10 

Jun-10 

Aug-10 

Aug-10 

Sep-10 

Sep-10 

Nov-10 

Nov-10 

Jan-11 

Jan-11 

Feb-11 

Feb-11 

Apr-11 

Apr-11 

Jun-11 

Jun-11 

Jul-11 

Jul-11 

Sep-11 

Sep-11 

Nov-11 

Nov-11 

Dec-11 

Dec-11 



60 

50 

40 

30 

20 

10 

0 

Figure 3.24. Monthly trends in Total Suspended Solids in effluent released from the Langebaan WWTW, 

June 2009 - December 2011. Allowable limits as specified in terms of a General Authorisation 

under the National Water Act 1998 are represented by the red line. 

120.0 

100.0 

80.0 

60.0 

40.0 

20.0 

0.0 

Figure 3.25. Monthly trends in Chemical Oxygen Demand in effluent released from the Langebaan WWTW, 

June 2009-February 2011. Allowable limits as specified in terms of a General Authorisation 


The levels of Ammonia Nitrogen discharged from the Langebaan WWTW have exceeded the 

allowable limit of 3 mg/l since measurements began in June 2009, however, concentrations are now 

more acceptable, with only the occasional reading above the limit (Figure 3.26). The levels of Nitrate 

Nitrogen have not exceeded allowable limits since measurements began in 2009 (Figure 3.27) 

Orthophosphate concentrations fluctuate in a seasonal pattern similar to that seen at the Saldanha 

WWTW and have in the last two years remained mostly below the allowable (Figure 3.28). Levels of 

free active chlorine have exceeded allowable limits 61% of the time since monitoring commenced 


44 

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Ammonia Nitrogen (mg/l as N) 

Nitrate Nitrogen (mg/l as N) 

May-09 

Apr-03 

Jul-09 

Jul-03 

Nov-03 

Aug-09 

Mar-04 

Oct-09 

Jul-04 

Nov-04 

Dec-09 

Mar-05 

Jan-10 

Jul-05 

Nov-05 

Mar-10 

Mar-06 

May-10 

Jul-06 

Nov-06 

Jun-10 

Mar-07 

Aug-10 

Jul-07 

Nov-07 

Sep-10 

Mar-08 

Nov-10 

Jul-08 

Oct-08 

Jan-11 

Feb-09 

Feb-11 

Jun-09 

Oct-09 

Apr-11 

Feb-10 

Jun-11 

Jun-10 

Oct-10 

Jul-11 

Feb-11 

Sep-11 

Jun-11 

Oct-11 

Nov-11 

Feb-12 

Dec-11 



70 

60 

50 

40 

30 

20 

10 

0 

Figure 3.26. Monthly trends in the concentration of Ammonia Nitrate in effluent from Langebaan WWTW, 



60 

50 

40 

30 

20 

10 

0 

Figure 3.27. Monthly trends in the concentration of Nitrate Nitrogen in effluent from Langebaan WWTW, 



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Orthoohosphate (mg/l as P) 

Free Active Chlorine (mg/l) 

Apr-03 

Apr-03 

Jul-03 

Jul-03 

Nov-03 

Nov-03 

Mar-04 

Mar-04 

Jul-04 

Jul-04 

Nov-04 

Nov-04 

Mar-05 

Mar-05 

Jul-05 

Jul-05 

Nov-05 

Nov-05 

Mar-06 

Mar-06 

Jul-06 

Jul-06 

Nov-06 

Nov-06 

Mar-07 

Mar-07 

Jul-07 

Jul-07 

Nov-07 

Nov-07 

Mar-08 

Mar-08 

Jul-08 

Jul-08 

Oct-08 

Oct-08 

Feb-09 

Feb-09 

Jun-09 

Jun-09 

Oct-09 

Oct-09 

Feb-10 

Feb-10 

Jun-10 

Jun-10 

Oct-10 

Oct-10 

Feb-11 

Feb-11 

Jun-11 

Jun-11 

Oct-11 

Oct-11 

Feb-12 

Feb-12 



16 

14 

12 

10 

8 

6 

4 

2 

0 

Figure 3.28. Monthly trends in the concentration of Orthophosphate in effluent from Langebaan WWTW, 



14 

12 

10 

8 

6 

4 

2 

0 

Figure 3.29. Monthly trends in the concentration of Free Active Chlorine in effluent from Langebaan 

WWTW, June 2009 - December 2011. Allowable limits as specified in terms of a General 


3.3.7.3 Summary 

In general the waste water treatment plans at Saldanha and Langebaan are having difficulties in 

keeping effluent levels and water quality parameters under the general limits specified under the 

National Water Act 36 of 1998. Of particular concern are the consistently high concentrations of 

Nitrates, in the form of Ammonia, being discharged at Saldanha. Ammonia has been shown to be 

toxic to plants and seagrasses at very low concentrations. Chlorine levels in the effluent from both 

WWTWs are high, exceeding the limits of a general authorisation at least half of the time. 

46 

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3.3.8 Storm water 

Storm water runoff, which occurs when rain flows over impervious surfaces into waterways, is one 

of the major non-point sources of pollution in Saldanha Bay (CSIR 2002). Sealed surfaces such as 

driveways, streets and pavements prevent rainwater from soaking into the ground and the runoff 

typically flows directly into rivers, estuaries or coastal waters. Storm water running over these 

surfaces accumulates debris and chemical contaminants, which then enter water bodies untreated 

and may eventually lead to environmental degradation. Contaminants that are commonly 

introduced into coastal areas via storm water runoff include metals (Lead and Zinc in particular), 

fertilizers, hydrocarbons (oil and petrol from motor vehicles), debris (especially plastics), bacteria 

and pathogens and hazardous household wastes such as insecticides, pesticides and solvents (EPA, 

2003). 

It is very difficult to characterise and treat storm water runoff prior to discharge, and this is 

due to the varying composition of the discharge as well as the large number of discharge points. The 

best way of dealing with contaminants in storm water runoff is to target the source of the problem 

by finding ways that prevent contaminants from entering storm water systems. This involves public 

education as well as effort from town planning and municipalities to implement storm water 

management programmes. 

The volume of storm water runoff entering waterways is directly related to the catchment 

characteristics and rainfall. The larger the urban footprint and the higher rainfall, the greater the 

runoff will be. At the beginning of a storm a “first flush effect” is observed, in which accumulated 

contaminants are washed from surfaces resulting in a peak in the concentrations of contaminants in 

the waterways (CSIR 2002). Several studies have shown degradation in aquatic environments in 

response to an increase in the volume of storm water runoff (Booth and Jackson 1997, Bay et al. 

2003). 

Storm water runoff that could potentially impact the marine environment in Saldanha and 

Langebaan thus originates from industrial areas (490 ha), the Saldanha Bay residential area (475 ha), 

industrial sites surrounding the Port of Saldanha (281 ha), and Langebaan to Club Mykonos (827 ha) 

(Figure 3.30). All residential and industrial storm water outlets drain into the sea. There are 

approximately 15 outlets in the Saldanha Bay residential area. Historically, storm water from the 

Port of Saldanha and ore terminal was allowed to overflow into the Bay but now most of this is 

diverted to storm water evaporation ponds and any material settling in these ponds is trucked to a 

landfill site. The number of storm water outlets in Saldanha Bay industrial zone (along the western 

margin of Small Bay) is not known, nor is the number of drains between Langebaan and Club 

Mykonos (CSIR 2002). 

The CSIR (2002) estimated the monthly flow of storm water entering Saldanha Bay and 

Langebaan Lagoon using rainfall data and runoff coefficients for residential and industrial areas. In 

this report, these estimates have been updated by obtaining more recent area estimates of 

industrial and residential developments surrounding Saldanha Bay and Langebaan Lagoon using 

Google Earth and acquiring longer term rainfall data (Figure 3.30 and Table 3.6). Runoff coefficients 

used to calculate storm water runoff from rainfall data were 0.3 for residential areas and 0.45 for 

industrial areas (CSIR 2002). Note that runoff from the Port of Saldanha and ore terminal have been 

excluded from these calculations. 

47 

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Figure 3.30. Spatial extent of residential and industrial areas surrounding Saldanha Bay and Langebaan 

Lagoon from which storm water runoff is likely to enter the sea (areas outlined in white). Note 

that runoff from the Port of Saldanha and ore terminal have been excluded as it is now 

reportedly all diverted to storm water evaporation ponds. 

Table 3.6. 

Monthly rainfall data (mm) for Saldanha Bay over the period 1895-1999 (source Visser et al. 

2007). MAP = mean annual precipitation. 

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Total 

MAP 6 8 11 25 47 61 64 46 25 18 13 8 332 

Ave. rain days 1.4 1.4 2.2 3.8 6.2 7.1 7.5 6.4 4.8 3.0 1.9 1.8 47.5 

Ave./day 4.1 5.5 5.1 6.6 7.6 8.5 8.5 7.3 5.2 6.0 6.6 4.6 7.0 

Typical concentrations of various storm water constituents (metals, nutrients, 

bacteriological) for industrial and residential storm water from South Africa and elsewhere were 

extracted from the literature by the CSIR in 2002 (Table 3.7). These values are obviously rough 

estimates as site specific activities will have a strong influence on storm water composition and 

ideally more accurate data should be acquired by monitoring of contaminants in the storm water 

systems of Saldanha and Langebaan. Storm water contaminant concentrations entering the sea 

from the Port of Saldanha were available from average monthly concentrations measured from four 

sites (concentrate shed wash bay, concentrate shed, multi-purpose quay and the concentrate quay) 

over four years (1999-2002). It is clear that the estimated concentrations of many of the potentially 

toxic compounds are above the South African 1998 water quality guidelines for coastal and marine 

waters (values indicated in red). It is likely that introduction of contaminants via storm water runoff 

48 

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negatively impact the health of the marine environment, especially during the “first flush” period as 

winter rains arrive. 

Storm water runoff is highly seasonal and peaks in the wet months of May to August. Due to 

the rapid pace of holiday and retail development in the area, Langebaan residential area produces 

the greatest volumes of storm water runoff, followed by the industrial areas, with lower volumes 

arising from the Saldanha residential area (CSIR 2002). The actual load of pollutants entering the 

Bay and Lagoon via this storm water can only be accurately estimated when measurements of storm 

water contaminants in the storm water systems of these areas are made. 

Table 3.7. 

Typical concentrations of water quality constituents in storm water runoff (residential and 

Industrial) (from CSIR 2002) and South Africa 1998 Water Quality Guidelines for the Natural 

Environment (*) and Recreational Use (**). Values that exceed guideline limits are indicated in 

red. 

Parameter Residential Industrial 

Water Quality 

Guidelines 

Total Suspended Solids (mg/l) 500 600 - 

Chemical Oxygen Demand (mg/l) 60 170 - 

Nitrate-N (mg/l) 1.2 1.4 0.015* 

Total Ammonia-N (mg/l) 0.3 0.4 0.6* 

Orthophosphate-P (mg/l) 0.07 0.1 - 

Cadmium (mg/l) 0.006 0.005 0.004* 

Copper (mg/l) 0.05 0.05 0.005* 

Lead (mg/l) 0.3 0.1 0.012* 

Zinc (mg/l) 0.4 1.1 0.025* 

Faecal coliform counts (counts/100 ml) 48 000 48 000 100** 

3.3.9 Fish processing plants 

Three fishing companies currently discharge wastewater into Saldanha Bay: Sea Harvest, SA Lobster 

Exporters (Marine Products), Live Fish Tanks (West Coast) – Lusithania (CSIR 2002). The locations of 

the fish factory intake and discharge points are shown in Figure 3.31. 

Southern Seas Fishing (now trading as Premier Fishing) previously discharged wastewater 

into the Bay but closed its factories approximately 5 years ago. Premier Fishing now intends on recommissioning 

and upgrading the existing fishmeal and fish oil processing plant. The plant was 

operational for 50 years prior to operations being suspended in 2008 for commercial reasons. 

A Scoping and Environmental Impact Assessment process is required in terms of the 

National Environmental Management Act 107 of 1998, the Environmental Impact Assessment 

Regulations 2010 and the National Environmental Management: Air Quality Act 39 of 2004 for the 

proposed activities. SRK Consulting (South Africa) (Pty) Ltd was appointed by Premier fishing as the 

independent Environmental Assessment Practitioner to undertake the S&EIA process. Anchor 

Environmental Consultants in turn were appointed to provide a specialist assessment of the likely 

impacts of effluent discharges from the processing plant on the water quality and marine ecology in 

Saldanha Bay and recommend mitigation measures. 

49 

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SA Lobster 

Live Fish Tanks 

Sea Harvest 

Blue Bay Aquafarm 

Current Mariculture Areas 

Proposed Mariculture Areas 

Figure 3.31. Location of seawater intakes and discharges for seafood processing in Saldanha Bay together 

with location of current and proposed mariculture operations 

Potential risks associated with the upgrade and re-commissioning of the fishmeal plant on 

the marine environment in Saldanha Bay were identified as falling into three main categories: 

‣ Disturbance to and/or mortality of marine life and coastal birds due to upgrading of existing 

facilities, including the removal of old equipment and infrastructure, the upgrading of 

equipment and reconstruction of portions of the plant (Construction impacts) 

‣ Disturbance to and/or mortality of marine life due to the intake and discharge of sea water, 

used for cooling purposes, in the near shore environment (Seawater cooling operational 

impacts) 

‣ Disturbance to and/or mortality of marine life due to discharge of wastes into the marine 

environment from the fishmeal plant (Fish factory operational impacts) 

Results of this investigation indicate that impacts of the proposed upgrade and 

refurbishment of the Southern Seas Fish Processing Plant are likely to be of Low to Very-Low 

significance or even insignificant provided appropriate mitigation measures are put in place 

including the following: 

 

 

 

 

 

Ensure no hydrocarbon leaks from vehicles used on the plant; 

Ensure no leaks or spillages of matter from the plant during the removal of equipment and 

cleaning of infrastructure; 

Inform & empower all staff about sensitive marine species & suitable disposal of 

construction waste; 

Filter effluent on start up of plant to remove plastic particles; 

Velocity of the intake flow not to exceed 0.15m/s; 

50 

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The intake pipes to draw seawater in horizontally; 

The intake pipes to be positioned at least 2 m off the seabed; 

The intake pipes to be positioned at least 0.5m below the Mean Low Water Spring; 

The outfall to be designed in accordance with either Scenario 3 or 4 as specified by Toms 

(2012) (discharge point on the seabed, angled at 45° to the horizontal, or discharge 

horizontally at 3 m below MLWS); 

The outfall pipe diameter not to exceed 300 mm diameter; 

No bloodwater to be discharged within 5 NM of the coast. 

Total volume of effluent o be discharged to the marine environment (cooling water and 

condensed liquids only) must not exceed 30 m 3 /h and concentrations of ammonia and 

suspended solids in the effluent not to exceed levels as follows: Ammonia: 20 mg/l, 

suspended solids: 500 mg/l; 

Samples of effluent discharged to the marine environment should be collected on a weekly 

basis whilst the plant is in full production and must be submitted to an independent 

analytical laboratory for characterisation. Results of the analyses should be submitted to the 

Branch Oceans and Coasts of the Department of Environmental Affairs to ensure compliance 

with permit conditions. 

No spillages on the Terminal or within the processing plant to come into contact with the 

marine environment; 

A contingency plan to be formulated to address instances of equipment failure or 

malfunction to divert any fish material or liquids away from the marine environment; 

An environmental control officer to be appointed and be present during the offloading of 

fish to ensure that protocols are followed and, if a contravention is made, ensure that the 

stipulated enforcement actions are taken; 

Runoff from hardened surfaces should rather be diverted to evaporation ponds and residual 

material from these ponds should be disposed of at an approved landfill site 

Runoff from such surfaces to be diverted to evaporation ponds and residual material from 

these ponds should be disposed of at an approved landfill site 

The composition of the effluent from Southern Seas Fishing and Sea Harvest was surveyed in 

1996/7 and 2001, respectively (Entech 1996 In CSIR 2002) (Table 3.8). Monthly discharge for the Sea 

Harvest factory was in the region of 70 000 m 3 /month in 2001 and from Southern Seas Fishing more 

than double that (160 000 m 3 /month) in 1996/7. Although the water quality of the outflow from SA 

Lobster Exporters and Live Fish Tanks are not monitored, it is reported to be not markedly different 

from ambient seawater, as it basically cycles through tanks where live lobsters are kept prior to 

packaging (CSIR 2002). 

Discharges from the fish factories are subject to National Water Act (1998) under the 

jurisdiction of the Department of Water Affairs. These activities are classified as a water use and 

require a license (DWAF, 2000a). The National Environmental Management: Integrated Coastal 

Management Act (Act No. 24, 2008) states that no person is allowed to discharge effluent from a 

source on land into coastal waters. 

51 

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Table 3.8. 

Characterisation of effluent from Sea Harvest (data for 2001 and 2011) and Southern Seas 

Fishing factories (data for 1996/7) (Data from Entech 1996 In CSIR 2002 and Paul Cloete, 

Environmental Office for Sea Harvest 2012). SA WQ guidelines are based on those published in 

1998, as the 2009 revised guidelines do not offer recommended physio-chemical targets 

except for temperature and pH. 

Sea Harvest 

(2001) 

Sea Harvest 

(2011) 

Southern Sea Fishing 

(1996/1997) 

SA WQ 

Guidelines 

Effluent volume (m 3 /month) 69 595 - 160 674 - 

Suspended solids(mg/l) 164 332 652 * 

Combustable solids (mg/l) 144 - 522 * 

Fat, Oil and grease(mg/l) 212 - 390 * 

Ammonia-N (mg/l) 164 147 137 0.020 mg/l 

Kjeldahl Nitrogen-N (mg/l) 83 83 317 - 

Phosphate-P (mg/l) 34 - 28 - 

Faecal coliform (CFU/100 ml) 751 965 - - 

E. coli (CFU/100ml) 5 941 - † 

* Water should not contain floating particulate matter, debris, oil, grease, wax, scum, foam or any 

similar floating materials and residues from land-based sources in concentrations that may cause 

nuisance. 

Water should not contain materials from non-natural land-based sources which will settle to form 

putrescence. 

† Max 100 CFU in 80 % of the samples and max 2 000 in 95 % of the samples 

Sea Harvest discharge fresh fish processing (FFP) effluent into the sea daily. This includes 

seawater that has been used as wash-water as well as freshwater effluent originating from the fish 

processing. Monthly volumes of effluent discharged in the sea from 2004 to 2007 by Sea Harvest are 

shown in Table 3.8. The volume of effluent disposed by Sea Harvest increased radically from August 

2006 to November 2007, and then decreased drastically again. It is not clear why this increase 

occurred, as data reporting and environmental monitoring at Sea Harvest have suffered irregularities 

due to high staff turnover (F Hickley, pers. Comm.). The volumes of effluent discharge released from 

May 2004 to May 2006 resemble those reported by the CSIR for 2001 and 2002, which ranged 

between 50 000 to 90 000 m 3 /month. Regular monitoring of effluent quality produced was reinitiated 

in 2010. It is estimated that approximately 1 152 m 3 of effluent is released on a daily basis 

(35 000 m 3 /month, Paul Cloete, Environmental Officer, Sea Harvest Corporation (Pty) Ltd, pers. 

comm.). Variations in the characteristics of this effluent are shown in Figure 3.32. Measured levels 

of faecal coliforms in the effluent are relatively high, in the range of 0 to 3 300 CFU/100 ml, 

averaging 611 cfu/100 ml (Figure 3.32). The source of this contamination is not clear, as faecal 

coliforms are derived from the guts of warm blooded animals such as human and livestock rather 

than cold blooded animals such as fish. Levels of suspended solids, ammonia and nitrate/nitrite are 

similar to those reported for the earlier period (1996/7, Figure 3.32). It is not clear what permit 

conditions are attached to the discharge of effluent from the Sea Harvest factor but these levels are 

certainly well in excess of those permissible in terms of a General Authorisation under the National 

Water Act (1998). 

52 

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Volume of Effluent (kL) 

Jan-01 

Mar-01 

May-01 

Jul-01 

Sep-01 

Nov-01 

May-04 

Jul-04 

Sep-04 

Dec-04 

Feb-05 

Apr-05 

Jun-05 

Aug-05 

Oct-05 

Dec-05 

Feb-06 

Apr-06 

Jun-06 

Aug-06 

Oct-06 

Dec-06 

Feb-07 



450000 

400000 

350000 

300000 

250000 

200000 

150000 

100000 

50000 

0 

Figure 3.32. Total monthly discharge of fresh fish processing effluent (FFP) disposed to sea by Sea Harvest 

from January 2001 to March 2007. 

SA Lobster Exporters discharges seawater from their operations into Pepper Bay. The 

average monthly effluent volumes range from 40 000 m 3 to approximately 60 000 m 3 , and this water 

cycles through tanks where live lobsters are kept prior to packing (CSIR 2002). Live Fish Tanks (West 

Coast)-Lusithania take up and release wash water from Pepper Bay. Neither discharge volume or 

water quality is being monitored on a routine basis (CSIR 2002). 

53 

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Faecal coliforms (CFU/100ml) 

Total suspended solids (mg/l) 

Nitrate/Nitrite(mg/l) 

Ammonia (mg/l) 

Feb-10 

Mar-10 

Mar-10 

Mar-10 

Apr-10 

Apr-10 

Apr-10 

Apr-10 

Jun-10 

Jun-10 

Jun-10 

Jun-10 

Jul-10 

Aug-10 

Aug-10 

Aug-10 

Sep-10 

Sep-10 

Sep-10 

Sep-10 

Oct-10 

Nov-10 

Nov-10 

Nov-10 

Dec-10 

Dec-10 

Dec-10 

Dec-10 

Feb-11 

Feb-11 

Feb-11 

Feb-11 

Apr-11 

Mar-11 

Apr-11 

Apr-11 

May-11 

May-11 

May-11 

May-11 

Jul-11 

Jul-11 

Jul-11 

Jul-11 

Sep-11 

Aug-11 

Sep-11 

Sep-11 

Oct-11 

Oct-11 

Oct-11 

Oct-11 

Dec-11 

Dec-11 

Dec-11 

Dec-11 



3 500 

3 000 

2 500 

2 000 

1 500 

1 000 

500 

0 

800 

700 

600 

500 

400 

300 

200 

100 

0 

250 

200 

150 

100 

50 

0 

180 

160 

140 

120 

100 

80 

60 

40 

20 

0 

Figure 3.33. Monthly trends in the numbers of Faecal coliforms in effluent from the Sea Harvest fresh fish 

processing effluent (FFP) discharged into Small Bay in the period Feb 201 to Dec 2011. 

54 

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Mussels 

Oysters 

Abalone 

Scallops 

Red Bait 

Seaweed 



3.3.10 Mariculture 

Saldanha Bay is the only natural sheltered embayment in South Africa and as a result it is regarded 

as the major area for mariculture (Stenton-Dozey et al. 2001). The Bay was zoned to cater for 

mariculture operations in 1997 and approximately 1 000 ha were demarcated for mariculture 

(Stenton-Dozey et al. 2001). A total area of approximately 145 ha has been allocated to seven 

mariculture operators within Saldanha Bay (Table 3.9). All operators farm mussels and six of the 

operators also farm oysters. Abalone, scallops, red bait and seaweed are each cultured on one of 

the farms. Blue Bay Aquafarm, the largest and oldest of the current farms, have had rights to 

approximately 50 hectares of water at the entrance of Small Bay since 2002. The other six operators 

have had rights to smaller areas in both Small Bay and Big Bay since 2010. All rights have a 

maximum duration of 14 years. 

Table 3.9. Details of marine aquaculture rights issued in Saldanha Bay (source: DAFF pers. comm. 2011) 

Products 

Company 

Area (Location*) 

Duration of 

right 

Blue Bay Aquafarm (Pty) Ltd x x 50.9 ha (SB) 2002-2016 

Blue Sapphire Pearls CC x x x x 5 ha (SB) 2010-2024 

Imbaza Mussels (Pty) Ltd 

(previously trading as Masiza 

Mussel Farm (Pty) Ltd) 

x 30 ha (SB) 2010-2024 

Striker Fishing CC x x x 25 (BB) 2010-2024 

West Coast Aquaculture (Pty) 

Ltd 

x x x 15 ha (SB) 2010-2024 

West Coast Oyster Growers CC x x 5 ha (SB) 5 ha (BB) 2010-2024 

West Coast Seaweeds (Pty) Ltd x x 5 ha (SB) 5 ha (BB) 2010-2024 

Raft culture of mussels has taken place in Saldanha Bay since 1985 (Stenton-Dozey et al. 

2001). Larvae of the mussels Mytilus galloprovincialis and Choromytilus meridionalis attach 

themselves to ropes hanging from rafts and are harvested when mature. Mussels are graded, 

washed and harvested on board a boat. Overall mussel productivity peaked at approximately 740 

tons in 2008 following a lull in productivity between 2005 and 2007 (Figure 3.35). There was a 

decrease in productivity in 2009 which was followed by an increase in 2010 (with the peak 

productivity at 700 tons). In 2009 and 2010 the mussel sub-sector (based in Saldanha Bay) was the 

second highest contributor to the overall mariculture productivity for the country (DAFF 2010, DAFF 

2011). 

A study conducted between 1997 and 1998 found that the culture of mussels in Saldanha 

Bay created organic enrichment and anoxia in sediments under mussel rafts (Stenton-Dozey et al. 

2001). The ratios of carbon to nitrogen indicated that the source of the contamination was mainly 

faeces, decaying mussels and fouling species. In addition, it was found that the biomass of 

macrofauna was reduced under the rafts and the community structure and composition had been 

altered (Stenton-Dozey et al. 2001). 

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Production (tons) 



West Coast Oyster Growers 

Blue Sapphire Pearls 

West Coast Aquaculture 

West Coast Seaweeds 

Striker Fishing 

West Coast 

Oyster Growers 

Blue Bay Aqua Farm 

West Coast Seaweeds 

±0.5 0 1 2 km 

Figure 3.34. Allocated mariculture concession areas in Saldanha Bay 2010. 

800 

700 

600 

500 

400 

300 

200 

100 

0 

2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 

Figure 3.35. Overall annual mussel productivity (tons) in Saldanha Bay between 2000 and 2010 (source: 

DAFF 2011) 

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4 WATER QUALITY 

The temperature, salinity (salt content), dissolved oxygen concentration, nutrient levels (specifically 

dissolved nitrate – a limiting nutrient for phytoplankton growth), and chlorophyll concentration (a 

measure of primary production), occurring in marine waters are the variables most frequently 

measured by oceanographers in order to understand the origins, physical and biological processes 

impacting on, or occurring within a body of sea water. Some historic data exist for these three 

variables exist for Saldanha Bay but no recent data are available. This historic data has been 

presented in previous versions of the State of the Bay report (Anchor Environmental Consultants 

2004. 2006, 2008, 2009, 2010, 2011) and are not repeated here. Suffice is to say that there have 

been no obvious changes in temperature, salinity, or nutrient or chlorophyll concentrations in the 

Bay, but that levels of dissolved oxygen, particularly in Small Bay have declined significantly since the 

construction of the Iron Ore Jetty and causeway linking Marcus Island to the mainland. This is 

though to be a result of increasing inputs of organic matter, mainly from fish processing factories, 

sewage and mussel farms, coupled with the reduced flushing capacity of the bay (particularly Small 

Bay) following the development of the port facilities (more detail on this below - §4.1). 

Concentrations faecal coliforms (bacteria typically associated with faecal pollution) are 

commonly monitored in areas used for human recreation or where marine organisms are harvested 

for human consumption. While these organisms themselves do not necessarily pose a risk to human 

health, they are a good indicator of levels of other pathogenic organisms in the environment that are 

also associated with sewage waste and do pose a risk (e.g. Steptococci and Cholera) but are much 

more tricky to quantify. Concentrations of faecal coliforms in waters around the periphery of the 

bay have been monitored by the SBWQT since 1999 and are presented below (§4.2). 

Information on concentrations of trace metals in the water column are presented in §4.3). 

4.1 Currents and waves 

Circulation patterns and current strengths prior to the development (1974-75) in Saldanha Bay were 

investigated using several techniques (drogues, dye-tracing, drift cards and sea-bed drifters). 

Surface currents (within the upper five meters) are complex and appeared to be dependent on wind 

strength and direction as well as the tidal state. Within Small Bay, currents were weak (5-15 cm.s -1 ) 

and tended to be clockwise (towards the NE) irrespective of the tidal state or the wind (Figure 4.1A). 

Greater current strengths were observed within Big Bay (10-20 cm.s -1 ) and current direction within 

the main channels was dependent on the tidal state (Figure 4.1A). The strongest tidal currents were 

recorded at the mouth of Langebaan Lagoon (50-100 cm.s -1 ), these being either enhanced or 

retarded by the prevailing wind direction (Figure 4.1A). Currents within the main channels in 

Langebaan Lagoon were also relatively strong (20-25 cm.s -1 ). Outside of the main tidal channels, 

surface currents tended to flow in the approximate direction of the prevailing wind with velocities of 

2-3 % of the wind speed (Shannon and Stander 1977). Current strength and direction at 5 m depth 

was similar to that at the surface, but was less dependent on wind direction and velocity and 

appeared to be more influenced by the tidal state. Currents at 10 m depth at the mouth of the Bay 

were found to be tidal (up to 10 cm. s -1 , either eastwards or westwards) and in the remainder of the 

Bay, a slow (5 cm.s -1 ) southward or eastward movement, irrespective of the tidal state, was 

recorded. 

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Figure 4.1. 

Schematic representation of the surface currents and circulation of Saldanha Bay (A) prior to the harbour development (Pre-1973) and (B) after 

construction of the causeway and iron-ore terminal (Present). (Adapted from Shannon and Stander 1977 and Weeks et al. 1991a) 

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The currents and circulation of Saldanha Bay subsequent to the construction of the Marcus 

Island causeway and the iron ore/oil Terminal were described by Weeks et al. (1991a). Historical 

data of drogue tracking collected by the Sea Fisheries Research Institute during 1976-1979 were 

analysed in this paper. This study confirmed that wind is the primary determinant of surface 

currents in both Small Bay and Big Bay; although tidal flows do influence currents below the 

thermocline and are the dominant forcing factor in the proximity of Langebaan Lagoon. Weeks et al. 

(1991a) noted that because much of the drogue tracking was conducted under conditions of weak or 

moderate wind speeds, the surface current velocities measured (5-20cm.s -1 ), were probably 

underestimated. The authors concluded that the harbour construction had constrained water 

circulation within Small Bay, enhancing the general clockwise pattern and increasing current speeds 

along the boundaries, particularly the south-westward current flow along the iron ore/oil Terminal 

(Figure 4.1B). More recent data collected during strong NNE wind conditions in August 1990 

revealed that greater wind velocities do indeed influence current strength and direction throughout 

the water column (Weeks et al. 1991b). These strong NNE winds were observed to enhance the 

surface flowing SSW currents along the ore terminal in Small Bay (out of the Bay), but resulted in a 

northward replacement flow (into the Bay) along the bottom, under both ebb and flood tides. The 

importance of wind as the dominant forcing factor of bottom, as well as surface, waters was further 

confirmed by Monteiro and Largier (1999) who described the density driven inflow-outflow of cold 

bottom water into Saldanha Bay during summer conditions when prevailing SSW winds cause 

regional scale upwelling. 

Construction of the iron ore terminal and the Marcus Island causeway altered the wave 

exposure zones evident in the Bay. Prior to harbour development in Saldanha Bay, Flemming (1977) 

distinguished four wave-energy zones in the Bay, defined as being a centrally exposed zone in the 

area directly opposite the entrance to the Bay, two adjacent semi-exposed zones on either side and 

a sheltered zone in the far northern corner of the Bay (Figure 4.1A). The iron ore terminal essentially 

divided the Bay into Small Bay and Big Bay and altered the wave energy and exposure patterns 

within the Bay. The causeway increased the extent of sheltered and semi-sheltered zones in Small 

Bay with no semi-exposed degree of wave energy being present in this area (Luger et al. 1999). 

Wave exposure in Big Bay was altered less dramatically, however, the extent of sheltered and semisheltered 

wave exposure areas increased after harbour development (Luger et al. 1999). 

4.2 Microbiological monitoring 

Faecal pollution contained in, for example, untreated sewage or storm water runoff, may introduce 

disease-causing micro-organisms into coastal waters. These pathogenic micro-organisms constitute 

a threat to recreational water users and consumers of seafood. Bacterial indicators are used to 

detect the presence of faecal pollution. These bacterial indicators, however, only provide indirect 

evidence of the possible presence of water borne pathogens and may not accurately represent the 

risk to water users (Monteiro et al. 2000). Historically, the DWAF (1995) and (1996b) guidelines for 

inland and coastal waters respectively, have been used to assess compliance in respect of human 

health criteria. However as of 2011, these have been replaced with the South African Water Quality 

Guidelines for Coastal Marine Waters Volume 2: Interim Guidelines for Recreational Use 

(Department of Environmental Affairs, 2011). 

4.2.1 DWAF 1995 and 1996 guidelines 

The DWAF (1995) and (1996b) guidelines for inland and coastal waters respectively, identified three 

recreational user groups; full-contact, intermediate-contact and non-contact recreation. Full contact 

recreation included swimming and diving among other activities. Partial-contact recreation covered 

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activities such as waterskiing, canoeing and angling as well as paddling and wading. Non-contact 

recreation activities included picnicking and hiking alongside water bodies. Target limits were based 

on counts of faecal coliforms in a sample of water and were linked to the estimated amount of water 

that needed to be ingested to become ill from pathogenic organisms, Table 4.1. In addition to 

recreational users, water was analysed to assess compliance with mariculture guidelines as these 

filter feeding organism can accumulate pathogenic organisms in their bodies and thereby infect 

people that consume them. 

In 1998 the council for Scientific and Industrial research (CSIR) were contracted by the 

Saldanha Bay Water Quality Trust (SBWQT) to undertake fortnightly sampling of microbiological 

indicators at 15 stations within Saldanha Bay. The initial report by the CSIR, covering the period 

February 1999 to March 2000, revealed that within Small Bay, faecal coliform counts frequently 

exceeded the guidelines for both mariculture and contact recreation (100 faecal coliforms occurring 

in 80% of samples analysed) at 9 of 10 sampling stations. These results indicated that there was 

indeed a health risk associated with the collection and consumption of filter feeding shellfish 

(mussels) and with contact recreation water (i.e. swimming, diving etc.) in Small Bay. Much lower 

faecal coliform counts were recorded at stations within Big Bay, with the exception of the 80 th 

percentile guideline for mariculture being exceeded at one station (Paradise beach); all other 

stations ranged within the guidelines for mariculture and recreational use (Monteiro et al. 2000). 

Table 4.1. 

Purpose/Use 

Maximum acceptable count of faecal coliforms (per 100 ml sample) for mariculture and 

recreational use 

Guideline value 

Recreational (full water contact) 

Mariculture 

100 faecal coliforms in 80% of samples 




Regular monitoring of microbiological indicators within Saldanha Bay undertaken by the 

SBWQT continues to the present day. Additional stations were added in Saldanha Bay Langebaan in 

2001 (Leentjiesklip and Langebaan Beach), in 2004 (Langebaan Yacht Club and Tooth Rock) and in 

2010 (two sites in Kraalbaai). This brings the total number of stations currently being monitored to 

20 stations (10 in Small Bay, 5 in Big Bay and 5 in Langebaan Lagoon). 

In general the data from the microbial monitoring programme suggest that nearshore 

coastal waters in Saldanha Bay have improved since 1999. Only one site in the Bay (specifically Site 

7, the beach at Hoedjies Bay Hotel) did not meet the 80th (Table 4.2) and 95th percentile (Table 4.3) 

guideline limits for recreational use in 2011, exceeding in particular the 95th percentile limits by a 

significant margin. Levels of compliance in 2011 for the 80th percentile are an improvement on the 

levels recorded in 2009 and 2010, however the number of sites complying with 95th percentile limits 

has decreased (with Site 7 showing non-compliance in 2011, compared to all sites demonstrating 

compliance from 2007 to 2010). 

As far as the guideline limits for mariculture are concerned, which are much stricter than the 

recreational limits, levels of compliance were predictably much lower. A total of 5 sites (out of a 

total of 18) were not compliant in respect of the 80 th percentile limits for faecal coliforms (Table 4.4), 

while 8 were not compliant in respect of the 95 th percentile limits in 2011 (Table 4.5). Many of the 

non-compliant sites exceeded the limit by quite a large margin (especially site 7 in the case of the 

80% limit and sites 7, 8, 9 and 17 in the case of the 95% limit). The worst site was at the beach 

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Water quality 

beside Hoedjies bay hotel (Site 7). Overall levels of compliance for the 80 th percentile guidelines 

were similar to that observed in 2010, however the results for the 95 th percentile analysis showed 

deterioration in faecal coliform levels from the previous year. 

Time series plots and linear regression analysis of the faecal coliform and E. coli counts were 

carried out for selected sites within Small Bay, Big Bay and Langebaan. Most stations within Small 

Bay show a statistically significant decrease in faecal coliform and E. coli concentrations over the last 

ten years. Stations 2 (Small craft harbour), 7 (Hoedjies Bay), 8 (Beach at Caravan park) and 10 

(General cargo Quay) are the exceptions, showing either no significant change, with constantly high 

concentrations faecal coliform and E. coli, or a significant increase over time (Figure 4.2, Figure 4.3 

and Figure 4.4). 

Time series plots for the four most frequently sampled sites in Big Bay are shown in Figure 

4.4 and Figure 4.6. Although the levels of faecal coliforms and E. coli at these stations are mostly 

lower than at stations in Small Bay, the trend over time is that of deterioration in four of the sites, 

Seafarm at TNPA, Mykonos (Paradise Beach and Harbour sites) and Langebaan North - Leentjiesklip. 

This has increased from 2010, where only two sites were noted as deteriorating. Station 16 

(Leentjiesklip) shows a significant improvement over the past 10 years, although there are large gaps 

in the data. 

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Table 4.2. 



Langebaan 

Sampling site compliance (based on faecal coliform counts) for 10 sites in Small Bay, 5 sites in Big Bay and 3 sites in Langebaan Lagoon. Average faecal 

coliform concentration of samples calculated within the 80th percentile limit specified in South African Water Quality Guidelines for recreational use (100 

organisms/100 ml) for 18 sites. Numbers in black indicate compliance with regulations, while red numbers indicate non-compliance. “-” indicates that no 

samples were collected in that year. (Source: Saldanha Bay Water Quality Forum Trust). 

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 

1. Beach at Mussel Rafts 157 2 0 4 0 0 0 0 2 0 3 0 0 

2. Small Craft Harbour 111 14 8 6 14 7 4 0 0 0 11 0 0 

3. Small Quay - Sea Harvest 476 89 37 93 93 93 15 7 13 5 23 4 16 

4. Saldanha Yacht Club 996 514 972 240 240 460 240 9 20 7 7 5 6 

5. Pepper Bay - Big Quay 834 172 2400 186 460 240 93 93 23 23 15 23 23 

6. Pepper Bay - Small Quay 758 182 240 43 83 93 23 15 15 4 7 240 6 

7. Hoedjies Bay Hotel - Beach 442 105 1052 240 222 181 150 27 128 43 240 240 186 

8. Beach at Caravan Park 94 38 201 62 83 43 75 9 41 93 93 168 51 

9. Beach - Bok Rver Mouth 938 190 692 1100 460 240 240 35 93 412 460 53 63 

10. General Cargo Quay - TNPA 8 2 4 0 0 0 0 0 0 0 0 0 0 

11. Seafarm - TNPA 7 6 0 0 0 0 0 0 0 0 0 0 4 

12. Mykonos - Paradise Beach 3 6 0 0 0 0 9 0 0 0 7 0 0 

13. Mykonos - Harbour 18 21 3 7 9 0 0 4 9 9 23 4 22 

14. Langebaan North - Lentjiesklip 5 5 6 9 9 2 0 2 4 5 4 0 13 

16. Leentijiesklip - - 240 93 36 15 10 9 15 4 9 9 18 

15. Langebaan Main Beach - - 79 0 0 0 4 0 0 0 43 4 3 

17. Langebaan Yacht Club - - - - - 17 4 2 12 1 23 4 6 

18. Tooth Rock - - - - - 5 7 2 4 12 9 5 0 

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Table 4.3. 



Langebaan 


coliform concentration of samples calculated within the 95th percentile limit specified in South African Water Quality Guidelines for recreational use (2000 

organisms/100 ml) for 18 sites. Numbers in black indicate compliance with regulations, while red numbers indicate non-compliance. “-” indicates that no 

samples were collected in that year. (Source: Saldanha Bay Water Quality Forum Trust). 

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 











11. Seafarm - TNPA 13 20 21 3 0 0 23 4 4 0 8 0 4 




16. Leentijiesklip - - 284 876 93 88 28 22 23 16 76 37 43 



18. Tooth Rock - - - - - 18 23 4 20 91 37 20 20 

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Table 4.4. 



Langebaan 


coliform concentration of samples calculated within the 80th percentile limit specified in South African Water Quality Guidelines for mariculture use (20 

organisms/100 ml) for 18 sites. Numbers in black indicate compliance with regulations, while red numbers indicate non-compliance. “ND” indicates that 

no samples were collected in that year. (Source: Saldanha Bay Water Quality Forum Trust). 

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 











11. Seafarm - TNPA 7 6 0 0 0 0 0 0 0 0 0 0 4 




16. Lentijiesklip - - 240 93 36 15 10 9 15 4 9 9 18 



18. Tooth Rock - - - - - 5 7 2 4 12 9 5 0 

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Table 4.5. 



Langebaan 


coliform concentration of samples calculated within the 95th percentile limit specified in South African Water Quality Guidelines for mariculture use (60 

organisms/100 ml) for 18 sites. Numbers in black indicate compliance with regulations, while red numbers indicate non-compliance. “ND” indicates that 

no samples were collected in that year. (Source: Saldanha Bay Water Quality Forum Trust). 

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 











11. Seafarm - TNPA 13 20 21 3 0 0 23 4 4 0 8 0 4 




16. Lentijiesklip - - 284 876 93 88 28 22 23 16 76 37 43 



18. Tooth Rock - - - - - 18 23 4 20 91 37 20 20 

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Figure 4.2. 

Faecal coliform and E. coli counts at 4 of the 10 sampling stations within Small Bay (Feb 1999-Feb 2012). A downward slope of the regression (solid red 

and blue lines) is indicative of improving water quality, while an upward slope in these lines in indicative of decreasing water quality. 

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Figure 4.3. 

Faecal coliform and E. coli logarithmic counts at 3 of the 10 sampling stations within Small Bay (Feb 1999-Feb 2012). A downward slope of the regression 

(solid red and blue lines) is indicative of improving water quality, while an upward slope in these lines in indicative of decreasing water quality. 

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Figure 4.4. 

Faecal coliform and E. coli logarithmic counts at 4 of the 10 sampling stations within Big Bay (Feb 1999-Feb 2012). A downward slope of the regression 


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Figure 4.5. 

Faecal coliform and E. coli logarithmic counts at 4 sampling stations within Big Bay (Feb 1999-Feb 2012). A Downward slope of the regression (solid red 

and blue lines) is indicative of improving water quality, while an upward slope in these lines in indicative of decreasing water quality. 

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Figure 4.6. 

Faecal coliform and E. coli logarithmic counts at 3 sampling stations within Langebaan Lagoon (Feb 1999-Feb 2012). A Downward slope of the regression 


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Figure 4.7. 

Faecal coliform and E. coli logarithmic counts at 3 sampling stations within Langebaan Lagoon (Feb 1999-Feb 2012). A Downward slope of the regression 


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4.2.2 Revised final guidelines for recreational waters of South Africa’s coastal marine 

environment 

The DWAF guidelines were re-written following an international review of guidelines for coastal 

waters, which highlighted several shortcomings in those developed by South Africa. The revised 

guidelines (RSADEA 2011) do not distinguish between different levels of contact recreation. Instead, 

aesthetics (which includes bad odours, discolouration of water and presence of objectionable 

matter), human health and safety (gastrointestinal problems, skin, eye, ear and respiratory 

irritations, physical injuries and hypo-/hyperthermia), and mechanical interference are considered. 

Indicators used are the presence of objectionable matter, water temperature and pH and the levels 

of intestinal Enterococci (and E. coli where necessary). 

Rather than a using a measure of actual condition, a compliance index is used to determine 

deviation from a fixed limit. This method is increasingly used across Europe to determine the 

compliance in meeting stringent water quality targets within specified time frames (e.g. Carr and 

Rickwood 2008). Compliance data are usually grouped into broad categories, indicating the relative 

acceptability of different levels of compliance. For example, a low count of bacteria would be 

“Excellent” while a “Poor” rating would indicate high levels of bacteria. These methods are to be 

trialled in South Africa over a few years to assess applicability and feasibility while determining 

target limits. 

The Hazen statistical method is recommended for dealing with non-parametric data 

(assumes data does not belong to a particular distribution). The data is ranked into ascending order 

and then percentile values are calculated using a formula. Target limits, based on counts of 

intestinal Enterococci and E. coli, for recreational water use are indicated below (Table 4.6). In order 

to calculate 95 th percentiles, a minimum of 10 data points are required, while the 90 th percentile 

estimates require only 5 data points. 

Table 4.6. 

Category 

Target limits for Enterococci and E. coli based on revised final guidelines for recreational 

waters of South Africa’s coastal marine environment (RSADEA 2011) 

Estimated risk per 

exposure 

Enterococci (count/100 

ml) 

E. coli (count/100ml) 

Excellent 2.9% (GI) illness risk ≤ 100 (95 percentile) ≤ 250 (95 percentile) 

Good 5% GI illness risk ≤ 200 (95 percentile) ≤ 500 (95 percentile) 

Sufficient/Fair 

8.5% GI illness risk ≤ 185 (90 percentile) ≤ 500 (90 percentile) 

(minimum requirement) 

Poor (unacceptable) >8.5 % GI illness risk >185 (90 percentile) >500 (90 percentile) 

Data from January 1999 to December 2011 has been re-analysed using the Hazen method 

(Table 4.7) to assess overall health rankings. Due to the absence of data on intestinal Enterococci 

over the sampling period, E. coli has been used as an indicator species to evaluate the 

microbiological health of the bay. The data for each year was assessed for compliance by evaluating 

both the 90 th and 95 th percentiles. Therefore 10 samples were required from each site per year to 

assess compliance. Many of the sites did not meet this minimum limit and are thus listed as having 

‘Insufficient Data’. Several sites appeared to have no data collected in some years. Sampling at the 

Langebaan Yacht Club, Tooth Rock and Kraalbaai North and South was only initiated once the 

sampling programme had begun, so the ‘No data’ status is understandable for these sites. However, 

sampling at Seafarm – TNPA has been insufficient, with no data collected in recent years (2008, 2009 

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and 2011). In order to prevent this pattern being repeated in future, data should be collected at all 

twenty sites on a bi-monthly basis throughout the year. 

The revised ranks of 20 sites around the Saldanha Bay area are presented in Table 4.7. Two 

sites in Small Bay (Small Quay – Sea Harvest and Hoedjies Bay) were ranked as ‘Poor’ (a decrease in 

water quality from ‘Good’ and ‘Fair’ respectively in 2010). The Beach at Caravan Park was ranked as 

‘Fair’ in 2011, an improvement on the situation in the previous three years where it was classed as 

‘Poor’. The remaining four sites for which there was sufficient data available (Pepper Bay- Small 

quay; Beach at Bok River Mouth; Leentijiesklip and Langebaan Yacht Club), were ranked as 

‘Excellent’. In 2011, there were 12 sites which did not have sufficient data to assign a compliance 

ranking, with one site (Seafarm – TNPA) having no data whatsoever available for analysis. 

Guidelines state that samples should be collected 15-30 cm below the surface. In order to 

minimise contamination and reduce sediment content, samples should be collected on the seaward 

side of a recently broken wave. Samples to be tested for E. coli counts should be analysed within 6-8 

hours of collection, and those to be tested for intestinal Enterococci, within 24 hours. Analyses 

should be completed by an accredited laboratory, preferably one with ISO 17025 accreditation. 

It is recommended that samples are analysed for intestinal Enterococci preferably over E. 

coli. Several studies have shown that thermotolerant coliforms and E.coli to be relatively poor 

indicators of health risks in marine waters. These organisms are also less resilient than Enterococci 

(and other pathogenic bacteria) so if analysis is focussed on coliforms, the risk could be 

underestimated due to mortality occurring in the time taken between collection and analysis. 

In addition to this, an operational management process was recommended for South Africa, 

following Enterococci counts (Figure 4.8). A mode is assigned based on the levels of Enterococci in a 

single count (Green or Amber) or on consecutive counts (Red). Each mode outlines a plan of action 

to be undertaken to deal with the problem. 

Figure 4.8. 

An illustration of the proposed routine monitoring programme to be trialled in South Africa. 

Source: South African Water Quality Guidelines for Coastal Marine Waters (RSADEA 2011). 

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Table 4.7. 

Sampling site compliance (based on E. coli counts) for 10 sites in Small Bay, 5 sites in Big Bay and 5 sites in Langebaan Lagoon. Ratings are calculated using 

Hazen percentiles, (with the 90 th and 95 th percentile results being grouped together to give an overall rating per annum. “ID” indicates that samples were 

collected that year, but there were insufficient data to allow calculation of Hazen percentiles. “-” indicates that no data were collected in that year. 

Sample Location 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 

Small Bay 1. Beach at Mussel Rafts Fair ID Excellent Excellent Excellent Excellent Excellent Excellent Excellent Excellent Excellent Excellent Excellent 

2. Small Craft Harbour Excellent ID Good Excellent Excellent Excellent Good Excellent Excellent Excellent Excellent Excellent Excellent 

3. Small Quay - Sea Harvest Fair ID Excellent Excellent Fair Excellent Fair Excellent Excellent Excellent Good Excellent Fair 

4. Saldanha Yacht Club Poor ID Poor Fair Poor Poor Poor Excellent Excellent Excellent Excellent Excellent Excellent 

5. Pepper Bay - Big Quay Poor ID Poor Fair Fair Fair Fair Poor Excellent Excellent Fair Excellent Excellent 

6. Pepper Bay - Small Quay Poor ID Fair Good Excellent Good Excellent Excellent Good Excellent Good Good Excellent 

7. Hoedjies Bay Hotel - Beach Fair ID Poor Fair Good Poor Poor Good Fair Excellent Fair Fair Poor 

8. Beach at Caravan Park Fair ID Fair Poor Excellent Fair Poor Excellent Good Poor Fair Good Fair 

9. Beach - Bok Rver Mouth Poor ID Poor Poor Poor Poor Poor Excellent Fair Poor Poor Fair Excellent 

10. General Cargo Quay - TNPA Excellent ID Excellent Excellent Excellent Excellent Good Excellent Excellent Excellent Excellent Excellent Excellent 

Big Bay 11. Seafarm - TNPA Excellent ID Excellent Excellent Excellent Excellent Excellent Excellent Excellent ID Excellent Good ID 

12. Mykonos - Paradise Beach Excellent ID Excellent Excellent Excellent Excellent Excellent Excellent Excellent Excellent Excellent Excellent Excellent 

13. Mykonos - Harbour Fair ID Excellent Excellent Fair Excellent Excellent Excellent Excellent Excellent Excellent Excellent Fair 

14. Langebaan North - Lentjiesklip Excellent ID Good Excellent Excellent Excellent Excellent Excellent Excellent Excellent Excellent Excellent Excellent 

16. Lentijiesklip - - Good Fair Good Excellent Excellent Excellent Excellent Excellent Excellent Excellent Excellent 

Langebaan 15. Langebaan Main Beach - - Fair Excellent Excellent Excellent Excellent Excellent Excellent Excellent Good Excellent Excellent 

17. Langebaan Yacht Club - - - - - ID Excellent Excellent Excellent Excellent Excellent Excellent Excellent 

18. Tooth Rock - - - - - ID Excellent Excellent Excellent Excellent Fair Excellent Excellent 

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4.3 Trace metal contaminants in the water column 

There is an increasing global trend emerging in countries like Canada, Australia, New Zealand and 

South Africa to monitor the long‐term effects of water quality by assessing the impacts thereof on 

specific marine species or species assemblages. Mussels and oysters, i.e. filter feeding organisms, 

are considered to be good indicator species for the purpose of monitoring water quality as they tend 

to accumulate trace metals, hydrocarbons and pesticides in their flesh. Mussels are sessile 

organisms (anchored in one place for their entire life) and will be affected by both short‐term and 

long‐term trends in water quality. Monitoring the contaminant levels in mussels can therefore 

provide early warnings for poor water quality and dramatic changes in contaminant levels in the 

water column. 

Trace/heavy metals are often regarded as pollutants of aquatic ecosystems. However, they 

are naturally occurring elements, some of which (e.g. copper & zinc) are actually required by 

organisms in considerable quantities (Phillips 1980). Aquatic organisms accumulate essential trace 

metals that occur naturally in water as a result of, for example, geological weathering. All of these 

metals, however, have the potential to be toxic to living organisms at elevated concentrations 

(Rainbow 1995). Human activities greatly increase the rates of mobilization of trace metals from the 

earth’s crusts and this can lead to increases in their bioavailability in coastal waters via natural runoff 

and pipeline discharges (Phillips 1995). Dissolved metal concentrations in water are typically low 

(and therefore present analytical problems), have high temporal and spatial variability (e.g. with 

tides, rainfall events etc.) and most importantly reflect the total metal concentration rather than the 

portion that is available for uptake by aquatic organisms (Rainbow 1995). Measuring metal 

concentrations in sediments resolves some of the analytical and temporal variability problems (as 

metals accumulate in sediments over time & typically occur at higher concentrations than dissolved 

levels), but still does not reflect their bioavailability. Measuring metal concentrations in the tissues 

of aquatic organisms appears to be the most suitable method for assessing ecotoxicity as the metals 

are frequently accumulated to high (easily measurable) concentrations and reflect a time-integrated 

measure of bioavailable metal levels (Rainbow 1995). 

Filter feeding organisms such as mussels of the genus Mytilus have been successfully used as 

bio-indicator organisms in environmental monitoring programs throughout the world (Kljakovic- 

Gaspic et al. 2010). These mussels are abundant, have a wide spatial distribution, are sessile, are 

able to tolerate changes in salinity, are resistant to stress, and have the ability to accumulate a wide 

range of contaminants (Phillips & Rainbow 1993, Desideri et al. 2009, Kljakovic-Gaspic et al. 2010). 

Elevated levels of cadmium reduce the ability of bivalves to efficiently filter water and 

extract nutrients, thereby impeding successful metabolism of food. Cadmium can also lead to injury 

of the gills of bivalves further reducing the effectiveness of nutrient extraction. Similarly elevated 

levels of lead result in damage to mussel gills and increased growth deficiencies and mortality. 

Elevated levels of zinc are known to suppress growth of bivalves and at levels between 470 to 860 

mg/l and can result in mortality of the mussels (South African Water Quality Guidelines for Coastal 

Marine Waters, Mariculture). 

In 1985 the then Directorate: Marine and Coastal Management (MCM) of the Department of 

Environmental Affairs and Tourism initiated a “Mussel Watch” Programme whereby mussels (either 

brown mussels Perna perna or Mediterranean mussels Mytilus galloprovincialis) are collected every 

six months (Apr/May and October) from 26 coastal sites. Mussels have been collected from five 

stations in Saldanha Bay since 1997. Data from the Saldanha Bay Mussel Watch programme are 

currently, however, only available between 1997-2001 and 2005-2007 due to a backlog in processing 

of samples. No new data were received for the 2011 period. 

75 

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Water quality 

The mussel samples are analysed for the metals cadmium (Cd), copper (Cu), lead (Pb), zinc 

(Zn), iron (Fe) and manganese (Mn), hydrocarbons and pesticides. A new automated method for 

sample preparation, including microwave digestion, has recently been adopted (Watling 1981; G. 

Kiviet pers. comm.). Data from the mussel watch programme are represented in Figure 4.9 where 

the maximum legal limits prescribed for each contaminant in shellfish for human consumption in 

South Africa, as stipulated by the Regulation R.500 (2004) published under the Foodstuffs, Cosmetics 

and Disinfectants Act, 1972 (Act 54 of 1972), are indicated in red text. Where guidelines have not 

been specified in national legislation those adopted by other countries have been used (Table 4.8). 

Data supplied by the Mussel Watch Programme (Figure 4.10) show that concentrations of 

Lead in mussels at the monitored sites are consistently above guideline limits for foodstuffs over the 

period 1997–2007, while concentrations of Cadmium frequently exceed these limits, and those for 

Zinc do so occasionally. Concentrations of Copper are, however, well below specified levels (Table 

4.8). No clear trends over time are evident for any of the trace metals, although recent data (post 

2007) are lacking. 

Concentrations of Lead in mussels from Saldanha Bay tend to be consistently high at the 

TNPA site (at the base of the iron ore terminal on the Small Bay side, values generally greater than 

60 ppm), occasionally spiking to very high level at this site (715 ppm in Oct 2001), but tend to be 

lower at the other sites (mostly below 10 ppm), although they occasionally spike to high levels at 

these sites as well (e.g. 250 ppm at the mussel rafts site at the base of the Marcus Island causeway). 

Compared with the guideline limit of 0.5 ppm these levels are extremely high and are very 

concerning. These high levels of Lead in are almost certainly linked to the export of Lead ore from 

the multipurpose quay, which is situated in close proximity to the TNPA site. Levels of Cadmium in 

mussels from Saldanha Bay are less variable than Lead and appear to be of a similar magnitude at all 

sites (mostly between 1-10 ppm) but occasionally exceed this level. Relative to guideline levels this 

is very high and is also cause for concern for anyone who may be consuming these mussels. Levels 

of Zinc are mostly within the range of 50-200 ppm but occasionally have been observed to spike to 

levels as high as 400 ppm or more which is way in excess of the guideline limit of 150 ppm listed by 

the Canadian authorities (Table 4.8). 

Rights holders engaged in bivalve culture (mussels and oysters) in South Africa are also 

required to report on concentrations in harvested organisms on an annual basis. Data were 

obtained for three trace metal indicators (Cadmium, Lead and Mercury) for three farms (Blue Bay 

Aquafarm, West Coast Aquaculture, West Coast Oyster Growers and Striker Fishing) in Saldanha Bay 

covering the period 1993-2010 (Figure 4.10). Data from these farms suggest that the situation in the 

deeper parts of the Bay where the farms are located is less of a problem than in the case with the 

nearshore coastal water where the Mussel Watch programme samples are collected. 

Concentrations of Lead were consistently above guideline levels in the period prior to 2000, albeit 

nowhere near as high as for the nearshore mussel samples (never more than 3 ppm), but since this 

time have been mostly within guideline limits (i.e. less than 0.5 ppm). Concentrations of Mercury in 

the mussel flesh from the farms has also mostly been within guideline limits (i.e. less than 0.5 ppm), 

apart from one or two spikes above this level (maximum concentration recorded = 1.7 ppm in 1994). 

Concentrations of Cadmium have always been within guideline limits (


Water quality 

Table 4.8. 

Regulations relating to maximum levels for metals in molluscs in different countries 

Country Cu (ppm) Pb (ppm) Zn (ppm) As (ppm) Cd (ppm) Hg (ppm) 

South Africa 1 0.5 3.0 3.0 0.5 

Canada 2 70.0 2.5 150.0 1.0 2.0 

Australia & NZ 3 2.0 2.0 0.5 

European Union 4 1.5 1.0 0.5 

Japan 5 10.0 2.0 0.2 

Switzerland 2 1.0 0.6 0.5 

Russia 6 10.0 2.0 

South Korea 2 0.3 

USA 7, 8 1.7 4.0 

China 9 2.0 

Brazil 10 0.5 

Israel 10 1.0 

1. Regulation R.500 (2004) published under the Foodstuffs, Cosmetics and Disinfectants Act, 1972 (Act 54 of 

1972) 

2. Fish Products Standard Method Manual, Fisheries & Oceans, Canada (1995). 

3. Food Standard Australia and New Zealand (website) 

4. Commission Regulation (EC) No. 221/2002 

5. Specifications and Standards for Foods. Food Additives, etc. Under the Food Sanitation Law JETRO (Dec 

1999) 

6. Food Journal of Thailand. National Food Institute (2002) 

7. FDA Guidance Documents 

8. Compliance Policy Guide 540.600 

9. Food and Agricultural Import Regulations and Standards. 

10. Fish Products Inspection Manual, Fisheries and Oceans, Canada, Chapter 10, Amend. No. 5 BR-1, 1995. 

77 

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Concentrations (ppm) 






























250 

200 

150 

100 

50 

0 

May- 

97 

Oct- 

97 

May- 

98 

May- 

99 

Oct- 

99 

May- 

00 

Oct- 

00 

May- 

01 

Oct- 

01 

Oct- 

05 

Apr- 

06 

Oct- 

06 

Apr- 

07 


Water quality 

14 

Cadmium 

14 

Cadmium 

9 

8 

Cadmium 

12 

12 

7 

10 

8 

6 

4 

10 

8 

6 

4 

6 

5 

4 

3 

2 

2 

2 

1 

0 

0 

0 

May- Oct- May- May- Oct- May- Oct- May- Oct- Oct- Apr- Oct- Apr- 

97 97 98 99 99 00 00 01 01 05 06 06 07 


97 97 98 99 99 00 00 01 01 05 06 06 07 


97 97 98 99 99 00 00 01 01 05 06 06 07 

12 

Copper 

16 

Copper 

16 

Copper 

10 

8 

Recommended limit = 70 ppm 

14 

12 

10 


14 

12 

10 


6 

8 

8 

4 

2 

0 

300 

250 


97 97 98 99 99 00 00 01 01 05 06 06 07 

Lead 

6 

4 

2 

0 

300 

250 


97 97 98 99 99 00 00 01 01 05 06 06 07 

Lead 

6 

4 

2 

0 

300 

250 


97 97 98 99 99 00 00 01 01 05 06 06 07 

Lead 

714.6↑ 

200 

200 

200 

150 

100 

50 

Recommended limit = 0.5 ppm 

150 

100 

50 


150 

100 

50 

Recommended limit 

= 0.5 ppm 

0 

0 

0 


97 97 98 99 99 00 00 01 01 05 06 06 07 


97 97 98 99 99 00 00 01 01 05 06 06 07 


97 97 98 99 99 00 00 01 01 05 06 06 07 

450 

Zinc 

450 

Zinc 

450 

Zinc 

400 

400 

400 

350 

350 

350 

300 

300 

300 

250 

250 

250 

200 

200 

200 

150 

100 

50 

0 

150 

100 

50 

0 

150 

100 

50 

0 


97 97 98 99 99 00 00 01 01 05 06 06 07 


97 97 98 99 99 00 00 01 01 05 06 06 07 


97 97 98 99 99 00 00 01 01 05 06 06 07 

250 

Iron 

250 

Iron 

Iron 

200 

200 

150 

150 

100 

100 

50 

50 

0 

0 

14 


97 97 98 99 99 00 00 01 01 05 06 06 07 

Manganese 

12 


97 97 98 99 99 00 00 01 01 05 06 06 07 

Manganese 

9 

Manganese 

12 

10 

10 

8 

8 

7 

6 

8 

6 

4 

2 

6 

4 

2 

5 

4 

3 

2 

1 

0 

0 

0 


97 97 98 99 99 00 00 01 01 05 06 06 07 

Fish factory 


97 97 98 99 99 00 00 01 01 05 06 06 07 

Saldanha Bay North 


97 97 98 99 99 00 00 01 01 05 06 06 07 

Portnet 

14 

Cadmium 

14 

Cadmium 

12 

12 

10 

10 

8 

8 

6 

6 

4 

4 

2 

2 

0 

0 

12 


97 97 98 99 99 00 00 01 01 05 06 06 07 

Copper 

12 


97 97 98 99 99 00 00 01 01 05 06 06 07 

Copper 

10 


10 


8 

8 

6 

6 

4 

4 

2 

2 

0 

0 

300 


97 97 98 99 99 00 00 01 01 05 06 06 07 

Lead 

300 


97 97 98 99 99 00 00 01 01 05 06 06 07 

Lead 

250 

250 

200 

200 

150 

150 

100 

100 

50 


50 


0 

0 


97 97 98 99 99 00 00 01 01 05 06 06 07 


97 97 98 99 99 00 00 01 01 05 06 06 07 

450 

Zinc 

450 

Zinc 

400 

400 

350 

350 

300 

300 

250 

250 

200 

200 

150 

150 

100 

100 

50 

50 

0 

0 


97 97 98 99 99 00 00 01 01 05 06 06 07 


97 97 98 99 99 00 00 01 01 05 06 06 07 

250 

Iron 

250 

Iron 

200 

200 

150 

150 

100 

100 

50 

50 

0 

0 

10 

9 


97 97 98 99 99 00 00 01 01 05 06 06 07 

Manganese 

12 


97 97 98 99 99 00 00 01 01 05 06 06 07 

Manganese 

8 

10 

7 

6 

8 

5 

4 

3 

6 

4 

2 

1 

2 

0 

0 


97 97 98 99 99 00 00 01 01 05 06 06 07 


97 97 98 99 99 00 00 01 01 05 06 06 07 

Mussel Raft 26/27 

Iron Ore Jetty 

Figure 4.9. 

Trace metal concentrations in mussels collected from five sites in Saldanha Bay as part of the 

Mussel Watch Programme. (Source of data: G. Kiviets, Marine and Coastal Management, 

Department of Environmental Affairs and Tourism). Recommended maximum limits for trace 

metals in seafood as stipulated in South African legislation are shown as a dotted red line. 

78 

ANCHOR 


Cadmium (mg/kg) 

Lead(mg/kg) 

Mercury (mg/kg) 

Aug-87 

Aug-87 

Aug-87 

Dec-88 

Dec-88 

Dec-88 

May-90 

May-90 

May-90 

Sep-91 

Sep-91 

Sep-91 

Jan-93 

Jan-93 

Jan-93 

Jun-94 

Jun-94 

Jun-94 

Oct-95 

Oct-95 

Oct-95 

Mar-97 

Mar-97 

Mar-97 

Jul-98 

Jul-98 

Jul-98 

Dec-99 

Dec-99 

Dec-99 

Apr-01 

Apr-01 

Apr-01 

Sep-02 

Sep-02 

Sep-02 

Jan-04 

Jan-04 

Jan-04 

May-05 

May-05 

May-05 

Oct-06 

Oct-06 

Oct-06 

Feb-08 

Feb-08 

Feb-08 

Jul-09 

Jul-09 

Jul-09 

Nov-10 

Nov-10 

Nov-10 


Water quality 

3.5 

3 

2.5 

West Coast Aquaculture (Pty) Ltd 




2 

1.5 

1 

0.5 

0 

4 

3.5 

3 

2.5 





2 

1.5 

1 

0.5 

0 

2 

1.8 

1.6 

1.4 

1.2 

1 

0.8 

0.6 

0.4 

0.2 

0 





Figure 4.10. Concentrations of Cadmium, Lead and Mercury in mussels and oysters from four bivalve 

culture operations in Saldanha Bay covering the period 1993 to 2010. Recommended 

maximum limits for trace metals in seafood as stipulated in South African legislation are 

shown as a dotted red line. 

79 

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Water quality 

4.4 Summary of Water Quality in Saldanha Bay and Langebaan Lagoon 

There are no long term trends evident in the water temperature, salinity and dissolved oxygen data 

series that solely indicate anthropogenic causes. In the absence of actual discharge of industrially 

heated sea water into the Bay, water temperature is unlikely to show any change that is discernable 

from that imposed by natural variability. Admittedly there is limited pre-development data (pre 

1975), so although it is conceivable that construction of the causeway and ore/oil Terminal has 

impeded water flow thus increasing residence time and increasing water temperatures, salinity and 

likely decreasing oxygen concentration, particularly in Small Bay, there is little data to support this. 

Given that cold, nutrient rich water influx during summer is density driven; dredging shipping 

channels could have facilitated this process which would be evident as a decrease in water 

temperature and salinity and an increase in nitrate and chlorophyll concentrations. Once again 

there is little evidence of this in the available data series. Natural, regional oceanographic processes 

(wind driven upwelling or downwelling and extensive coast–Bay exchange) rather than internal, 

anthropogenic causes, appear to remain the major factors affecting physical and chemical water 

characteristics in Saldanha Bay. The construction of physical barriers (the iron ore/oil Terminal and 

the Marcus Island causeway) do appear to have changed current strengths and circulation within 

Small Bay, resulting in increased residence time (decreased flushing rate), enhanced clockwise 

circulation and enhanced boundary flows. There has also been an increase in sheltered and semisheltered 

wave exposure zones in both Small and Big Bay subsequent to harbour development. 

The microbiological monitoring program provides evidence that while many of the 

monitoring sites in Small Bay still have faecal coliform counts in excess of the safety guidelines for 

both mariculture and recreational use, there is a trend of improving compliance at many sites for 

which the relevant authorities should be commended. However, the situation in Small Bay remains 

a concern, with many sites exceeding levels for safe recreational activities. Given the current 

importance and likely future growth of both the mariculture and tourism industries within Saldanha 

Bay, it is imperative that whatever efforts have been taken in recent years (e.g. upgrading of sewage 

and storm water facilities to keep pace with development and population growth) to combat 

pollution by faecal coliforms in Small Bay should be increased and applied more widely. Continued 

monitoring of bacterial indicators (intestinal Enterococci in particular), to assess the effectiveness of 

adopted measures, is also required and should be undertaken at all sites on a bimonthly basis. 

Large volumes of ballast water are discharged into Saldanha Bay on an annual basis. This 

poses an enormous risks in respect of the introduction of alien species as well as contaminants in the 

ballast water (trace metals, E. coli, etc.). Compliance with ballast water treatment requirements 

(e.g. open ocean exchange, on-board treatment systems) designed to minimize the risks of alien 

introductions should be rigorously enforced and voluntary compliance with any additional measures 

strongly encouraged. 

Data supplied by the Mussel Watch Programme (DEA) and mariculture operators in Saldanha 

Bay suggest that concentrations of trace metals are high along the shore (particularly for Lead near 

the multipurpose quay) and frequently or even consistently (in the case of Lead) above published 

guidelines for foodstuff, concentrations offshore are clearly much lower and less of a concern. High 

concentrations of trace metals along the shore is very clearly of concern and points to the need for 

management intervention that can address this issue as it poses a very clear risk to the health of 

people harvesting mussels from the shore. Regrettably no new data have been available from this 

programme since 2007. 

80 

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Sediments 

5 SEDIMENTS 

5.1 Shoreline erosion in Saldanha Bay and Langebaan lagoon 

5.1.1 Background 

The majority of sandy beaches worldwide are affected by erosion - a problem which has been greatly 

exacerbated by development of human settlements in the coastal zone (Bird 1985). Globally, 70% of 

beaches are classed as receding; 20–30% are stable, while 10% are accreting (Schlacher et al. 2008). 

Under natural conditions, sea level rise would cause the entire coastal system, including beach and 

dune systems, to retreat inland. In instances where coastal systems are bound by barriers, walls, or 

heavily vegetated dunes, these features are likely to restrict inland migration and would result in 

beach loss rather than migration (Feagin et al. 2005). Salt marshes are under immediate threat if the 

rate of sea level rise exceeds that of vertical accretion. 

Beach erosion in Saldanha Bay, particularly at Langebaan Beach, has been the subject of 

much controversy in recent years. Ongoing erosion for the past 30 years has been documented with 

the loss of over 100 m of beach since 1960 with 40 m just in the last 5 years (McClarty et al. 2006, 

Gericke 2008). 

Windblown sand is likely to have been, a major part of the Langebaan/Saldanha system. 

Many of the beaches, particularly Spreeuwalle, have dune fields associated with them. The largest 

dune field in the area is the Geelbek dunefield. This dune field lies directly to the southeast of the 

Langebaan Lagoon. The south-easterly wind that predominates in summer would tend to transport 

sand from 17 mile beach (Yzerfontein) to the Geelbek dunes and in turn from the Geelbek Dunes 

into Langebaan (Gericke 2008). 

Inside Saldanha Bay, where wave action is of greater significance than inside the protected 

Langebaan Lagoon, littoral drift is a major factor in sediment transport. While waves on the west 

coast typically originate in the South or South West, they tend to refract around the headlands at the 

mouth of the Bay and approach the shore from the West or North West, particularly along the 

section of coast between Spreeuwalle and the North Langebaan beach. The predominant littoral 

drift is therefore in a southerly direction, rather than a northerly direction as observed on the rest of 

the West Coast (Compton, 2004). 

It is not clear whether storms in the Saldanha/Langebaan region will increase in frequency or 

intensity but it is a possible scenario of global climate change, which coupled with long term changes 

in sea level and average wave height, could result in greater shifts in shoreline over less time. This 

may necessitate greater setback lines for development that those currently in place (Gericke 2008). 

5.1.2 Human impacts on the system 

Over the years, several major changes have taken place in Saldanha Bay which are likely to have 

affected the sedimentary system. These include construction of the Marcus Island causeway and the 

Transnet Ore Terminal in the early 1970s, the ongoing construction of residential and commercial 

properties on the beachfront, dredging in the bay, the slow, steady encroachment of vegetation on 

the Geelbek dune system, and ongoing dredging that takes place around the Ore Terminal. 

81 

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Sediments 

5.1.2.1 Construction of the Marcus Island Causeway and the Transnet Ore Terminal 

The Marcus Island causeway and the Transnet Ore Terminal are similar structures from a 

sedimentary point of view. They both extend far beyond the littoral zone where waves have limited 

ability to influence sediment movement. They are therefore barriers separating areas where littoral 

drift could occur. In the case of the Ore Terminal, this structure separates the beach to the north 

west of the terminal from Spreeuwalle to the south east. As a result, Spreeuwalle has lost access to 

one of its sediment sources. 

The ore terminal may also have changed the wave dynamics in the area by refracting or 

reflecting some of the incoming swells. This could cause the angle of wave incidence at beaches 

near the pier (such as Spreeuwalle) to have changed sufficiently for the littoral drift to reverse, or 

decrease significantly. 

Before the construction of the Marcus Island Causeway, waves could travel on both sides of 

the island. These waves would have been refracted inward around the island cause both 

constructive and destructive interference. At a point opposite the island, the shoreline would have 

been subject to much larger and more powerful waves. This generally causes beach slopes to form 

at less steep gradients, but also tends to remove smaller sediment particles. 

5.1.2.2 Stabilisation of the Geelbek dune system 

The Geelbek dunes have been subjected to continuous encroachment by vegetation over the last 70 

years (Gericke 2008). When dune encroachment occurs, sediment is held in place by the roots of 

plants and the wind speed at ground level is considerably reduced. This means that the dune system 

become less effective as a sediment source. However it does still function as a sediment sink. This 

means that sand which is taken by the north-westerly wind from Langebaan’s beaches to the 

Geelbek dune systems will not return as quickly when the south-easterly wind returns. This is likely 

to have resulted in a net loss of sediment from the beaches to the dunes. 

5.1.2.3 Shoreline development 

When sea level, wind or wave conditions change, shorelines react by changing their nature, their 

shape, or their position. Many of Langebaan’s residential or holiday developments have been built 

in very close proximity to the sandy shorelines. These communities are all vulnerable to beach 

erosion. In some places the width of the beach has been reduced by as much as 150 m, leaving the 

house built on the first set of dunes unprotected against storm damage (Gericke 2008, Figure 5.1). 

5.1.3 Changes in beach and dune morphology 

Gericke (2008) studied changes in the sedimentary features of the Langebaan Lagoon and Saldanha 

Bay area between 1960 and 2000. It was found that the beaches in particular had changed 

significantly over this period, with a large section of the North Langebaan beach having completely 

disappeared between 1988 and 2000. 

Gericke’s (2008) study was updated this year and includes new data from 2000 to 2012 

(Gericke 2012). Five rocky outcrops were selected across the study site and a change in width for 

each site and for each image measured. The mean for each image taken between 1960 and 2012 

was used as a proxy for tidal applitude at the time that each photo was taken. This was simply 

82 

ANCHOR 



Sediments 

multiplied by beach length to find the expected tidal variation for each beach area. All data were 

corrected for tidal variation. 

Figure 5.1. 

A) Under natural circumstances, dune vegetation can “move” with the beach as it erodes and 

accrete under the influence of natural processes. B) Protection of infrastructure erected too 

close to the high water mark, on the other hand, necessitates construction of artificial barriers 

and leads to the loss of the beach ecosystem and associated amenities. 

The marked dip in the sediment area in 1977 (Figure 5.2) is unexplained and could relate to 

the tide variation the day the picture was taken (which was not recorded) or transitory storm 

influence. The significant increase in sediment accumulation from 1977 to 1988 on Spreeuwal beach 

can be attributed to the construction of the harbour wall between 1973 and 1976, and subsequent 

support of the wall using approximately 250,000 m2 of beach sand. After the construction, 

however, sediment became trapped at Spreeuwal beach as a result of the harbour decreasing the 

longshore drift south towards Langebaan beach and (McClarty 2008). The sediment area at 

Langebaan beach also increased between 1977 and 1988, and is attributed to the additional beach 

sand added to Spreeuwal beach and an increase in the littoral drift of the sediment to Langebaan 

beach. After 1988, there was a significant drop in sediment area of about 270,000 m 2 , which may be 

partially related to sediment transport being prevented by the harbour wall. It can be expected that 

should the beaches at Lentjiesklip 1, 2 and 3 become depleted, Langebaan beach would lose 

sediment at a more rapid rate. 

Both Spreeuwalle and Langebaan beach are showing increasing variability in beach area 

since 2000 (Figure 5.2). The variation also appears to be synchronised for the two beaches, implying 

a common cause for both. It is not clear exactly what the cause is, but variability in local or regional 

wind or wave characteristics may play a role. Dredging may also have contributed. 

Gericke (2008) did not distinguish between small-scale (within beach) and large scale 

(between beach) variation. There is also no recognition of the redistribution of sediment along a 

beach. For example, a small section in the middle of Spreeuwalle has been severely eroded over 

time, much more so than other sections of this beach. This can be much more effectively illustrated 

by defining a transect line at the most eroded section of this beach (Figure 5.3) and measuring 

variation in the width of the beach at this point over time, correcting for tidal variation. 

From this, it is clear that the width of this section of beach has decreased from 27 m to 7m 

between 2000 and 2012. It is not known what is causing the erosion but it is recommended that a 

study be conducted focussing on the possible reversal of littoral drift by diffraction of waves passing 

the Marcus Island Causeway and Transnet Iron Ore Terminal (Gericke 2012). 

83 

ANCHOR 


Relative area (x1 000 m 2 ) 


Sediments 

This trend is concerning as it implies that the beach will disappear altogether in less than a 

decade. A much more likely scenario, however, is that the absolute rate of change will decrease in 

future, but that the size of the affected area will increase, engulfing larger sections of Spreeuwalle 

Beach. 

200 

150 

100 

Langebaan Beach 

Spreeuwal 

50 

0 

1950 

-50 

1960 1970 1980 1990 2000 2010 2020 

-100 

-150 

-200 

-250 

-300 

Figure 5.2. 

Graph showing the relative change in area over time for Spreeuwalle and Langebaan Beach 

(1960 – 2012). 

Transect Line 

Figure 5.3. 

Spreeuwalle beach showing the position of the transect line in the middle of the beach 

(Source: Gericke 2012). 

84 

ANCHOR 


Beach Width (m) 


Sediments 

30 

25 

20 

15 

10 

5 

0 

1998 2000 2002 2004 2006 2008 2010 2012 2014 

Figure 5.4 

Variation in beach width across a transect of the central section of Spreeuwalle beach (Source: 

Gericke 2012). 

Gericke (2008) also analysed the Geelbek dune system and the loss of bare sands in this area 

over the period 1960 to 2000. He recorded a massive 70% reduction of bare sands from close to 13 

million m 2 present in 1960 to less than 4 million m 2 in 2000. 

Gericke (2008) concluded that the construction of the ore terminal had led to a reduction in 

sediment transport from Spreeuwalle beach which is currently being trapped in the northern corner 

of the beach, reducing the supply of sands to the beaches further south. Changes on the two 

beaches are often out-of-sync with one another, with major accretion and erosion events on 

Langebaan beach lagging behind Spreeuwalle by a period of up to five years. The reasons advocated 

for this include the possibility that beaches in between these two sites are acting as intermediate 

reservoirs for sediment. If this is indeed correct, then changes on these beaches, notably the recent 

erosion observed on the southern end of Spreeuwalle beach (possibly linked to a severe storm event 

in 2008) does not bode well for what will happen to Langebaan beach in the future. 

Alien vegetation encroachment by Port Jackson (Acacia saligna) and Rooikraans (Acacia 

cyclops) is thought to be a contributing factor in the loss of sand from the Geelbek dune system. The 

consequences of this encroachment at Langebaan have not yet been studied. However, it is known 

that heavily vegetated dunes restrict the natural movement of dune systems and possible inland 

migration of the coastal system (Feagin 2005). The salt marshes on Langebaan Lagoon have not 

suffered any significant changes in area over the same time period (Gericke 2008). 

5.1.3.1 Northern Langebaan beach erosion management measures 

In 1997, after severe storms resulted in the loss of residential properties, the need to protect and 

restore northern Langebaan beach became apparent. A temporary solution was sought through the 

construction of three sections of rock revetment along the beach (Figure 5.5), mostly in an effort to 

prevent any further loss of property. Erosion continued along the sections of coastline adjacent to 

the revetment, however. This prompted the then Department of Environmental Affairs and Tourism 

(now the Branch: Oceans and Coasts, of the Department of Environmental Affairs) to contract 

85 

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Sediments 

Southern Oceaneering CC in 2003, to carry out an urgent beach reclamation programme following 

intensive investigations into various solutions by coastal engineers, PRDW, and the necessary EIA 

approvals granted by DECAS in 2001. This involved the construction of two groynes using Geotextile 

Sand Containers (GSCs) and the deposition of large quantities of sand dredged from Saldanha Bay to 

extend the beach area (Figure 5.6). 

Figure 5.5. 

Rock revetments constructed along the beach at Langebaan in an effort to protect coastal 

infrastructure. 

Different sized GSCs (i.e. 2.5 m³, 12 m³ and 20 m³) were filled with sand collected from two 

adjacent areas (Figure 5.6 - Area A or B) where sand was mixed continually with pumped sea water 

creating a “slurry” which was then emptied into the bags and stitched closed. The GSC units were 

then positioned by crane in the water, assisted by a team of divers. The first 250 m groyne (reduced 

from the planned 448 m due to strong currents at the face) was completed in 2005 and the second 

360 m groyne in 2007. Critical to the project was the beach replenishment programme which 

involved dredging large amounts of sand from areas in the vicinity of groyne 1 (Figure 5.6 – Area C), 

and depositing sand north of the 2 nd groyne up to the southern extent of Leentjiesklip No.1 (Figure 

5.6-Figure 5.9). Approximately 380 000 m³ of material was dredged until the end of the programme 

in November 2008. 

Monitoring in the form of bi-annual beach profile surveys are conducted by the Saldanha 

Bay Municipality (in collaboration with Prestedge Retief Dresner Wijnberg (PRDW) since completion 

of the groynes and reclamation in October 2009. The beach profile survey record extends back to 

before 1997 and provides a good basis for long-term monitoring of impacts to the coastline resulting 

from the Langebaan Beach Restoration Project. 

The beach profile surveys indicate that there is little unseasonal erosion and accretion in the 

area. The rock revetments which were supposed to be a temporary solution cannot be removed as 

they still serve a critical role in erosion prevention. The revetments to the South have been covered 

partially with sand but to the North the main revetment is still exposed. It is not know at this stage 

whether further reclamation of the beach to the North will eventually enable the revetment to be 

removed. It is more likely that the revetment will remain and will eventually be covered with sand 

through artificial deposition and some natural accretion. The beaches south of Groyne 1, adjacent to 

the channel, appear dynamically stable (Mclarty, PRDW, pers. comm. 2012). However, there is still 

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Sediments 

considerable structural damage on the northern Groyne (the second one constructed), with some of 

the bags suffering from wave damage during storms between 2007 and present (Anton Vonk, PRDW 

2010 pers. comm.). There are currently sub-optimal volumes of sand at the North end of the beach 

(Common Ground 2012). Regardless of the cause, it is apparent that while the groynes installed at 

Langebaan may have trapped some sand and prevented extensive beach loss in their immediate 

vicinity, they have not succeeded in stabilising the greater Langebaan Beach (Gericke 2012). 

In addition to this, there has been further damage to the geotextile bags on both groynes 

caused by vandalism. Saldanha Bay Municipality is currently waiting for funding to undertake these 

repairs. Funding has been a continuous issue for this project with miscommunications between the 

Saldanha Bay Municipality and the Department of Environmental Affairs (and within DEAT) which led 

to a large sum of money being withdrawn from the project. An updated report on the current status 

of the project is in the process of being compiled by PRDW and Common Ground (K. Leslie, Common 

Ground, pers. comm.). 

Figure 5.6 

Groyne construction site Langebaan north beach. 1st groyne is completed and position of 2nd 

groyne is show in white. Area A and B are sand “slurry” sites (see text for explanation). Area C 

sand dredging site for beach reclamation. Source: Prestedge Retief Dresner Wijnberg. 

The way forward was discussed at a recent public meeting organised to give feedback on the 

Environmental Audit of the Beach Restoration Project at Langebaan (Common Ground 2012). It was 

decided that no further medium to long term action should be taken on the restoration project 

before a bay wide study (involving both monitoring and modeling) is undertaken allowing for 

confident decisions to be made regarding the future of Langebaan’s beaches. In the interim, the 

municipality is applying to the provincial authorities for authorisation to conduct much needed 

repairs and ongoing maintenance work on the groynes. 

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Sediments 

Figure 5.7 State of the beach north of Groyne 2 in May 2010. (view looking south from the middle of 

Leentjiesklip 1 beach towards the groyne) 

Figure 5.8 

State of the beach north of Groyne 2 in May 2010 (looking north from the middle of the beach 

towards Leentjiesklip 1) 

Figure 5.9 

State of the beach north of Groyne 2 in May 2010 (looking north towards Leentjieklip from the 

position where the sea still reaches right up to the rock revetment. 

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Sediments 

5.1.3.2 Paradise beach erosion management 

Paradise Beach is located close to the town of Langebaan next to the Club Mykonos Holiday 

Resort and is within the jurisdiction of the Saldanha Local Municipality. Erosion along Paradise 

Beach has been ongoing at least since 2005 (Karen Opitz, Common Ground pers. comm. 2007) and is 

currently threatening the houses built along the beach front (Figure 5.10). Unmitigated erosion also 

threatens to destroy sewage collection tanks, which at the moment lie buried 3-4m from the duneedge, 

and this would result in pollution of the marine environment via leaking sewage. 

Figure 5.10 

Coastal erosion at Paradise Beach near Club Mykonos. 

An environmental impact assessment was commissioned by the Paradise Beach 

Homeowners Association (PBHA) in 2007 and undertaken by Common Ground Consulting (Coetzee 

2007), with input from coastal engineer Anton Vonk and a botanist. They listed various possible 

reasons for the erosion at Paradise beach including the construction of the Marcus island causeway, 

iron ore jetty and other large-scale developments in the Bay that might have influenced current 

patterns or wave action in this area, as well as the destruction of dune vegetation which would 

otherwise have helped stabilize the dunes and prevent erosion, and inappropriate discharge of 

storm water within the frontal dune area in the past. 

To prevent further erosion and protect the houses, the construction of a gabion wall (rockfilled 

wire mesh cages) was proposed as a short-term solution to prevent further erosion while an 

appropriate long-term solution was investigated. The gabion wall, some 190-230 m long with 1:1 

slope, would run at the foot of the existing frontal dune. The proposed long -term solution included 

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Sediments 

the construction of an offshore structure, such as a groyne, to change the wave and current 

dynamics suspected to be underlying cause of the erosion. A positive Record of Decision (ROD) for 

the construction of the gabion wall was issued by the Department of Environmental Affairs and 

Development Planning, Western Cape (DEADP), and construction was initiated during 2010 (J. Kotze 

– Langebaan Ratepayers Association, pers. comm. 2011). 

A study undertaken (WSP 2010) to investigate the methodology involved in determining 

setback lines within the coastal zone, demonstrated that the recommended erosion setback line for 

Paradise Beach is well behind the first line of properties on the beachfront. They calculated the total 

setback line by estimating short term erosion, the erosion distance predicted to occur in 100 years 

and the predicted sea-level rise (distance calculated by assuming a 1 metre vertical rise in sea level 

together with average beach slope). Using five points of reference on the beach, the total setback 

distance recommended ranged from 92 m to 120 m from the high water mark. 

5.2 Monitoring of sediment particle size composition in the Bay 

The particle size composition of the sediments occurring Saldanha Bay and Langebaan Lagoon are 

strongly influenced by the wave energy and current circulation patterns in the system. Courser or 

heavier sand and gravel particles are found in areas with high wave energy and strong currents as 

the movement of water in these areas suspends fine particles (mud and silt) and flushes these out of 

the area. Disturbances to the wave action and current patterns which reduce the movement of 

water can result in the deposition of mud in some areas. Since 1975, industrial developments in 

Saldanha Bay (Marcus Island causeway, iron ore terminal, multi-purpose Terminal and establishment 

of a yacht harbour) have resulted in some level of obstruction to the natural patterns of wave action 

and current circulation prevailing in the Bay. The extent to which changes in wave exposure and 

current patterns has impacted on sediment deposition and consequently on benthic macrofauna 

(animals living in the sediments), has been an issue of concern for many years. The quantity and 

distribution of different sediment grain particle sizes (gravel, sand and mud) through Saldanha Bay 

prescribes the status of biological communities and the extent of possible organic loading that may 

occur in Saldanha Bay. 

Contaminants, such as metals and organic toxic pollutants, are predominantly associated 

with fine sediment particles (mud or cohesive sediments). This is due to the fact that fine grained 

particles have a larger surface area for the adsorption and binding of pollutants. Higher proportions 

of mud, relative to sand or gravel, can thus lead to high organic loading and trace metal 

contamination. It follows then that with a disturbance to natural wave action and current patterns, 

an increase in the proportion of mud in the sediments of Saldanha Bay, could result in higher organic 

loading and dangerous levels of metals occurring (assuming that these pollutants continue to be 

introduced to the system). Furthermore disturbance to the sediment (e.g. dredging) can lead to resuspension 

of the mud component from underlying sediments, along with the associated organic 

pollutants and metals. It may take several months or years following a dredging event before the 

mud component that has settled on surface layers is scoured out of the Bay by prevailing wave and 

tidal action. Changes in sediment particle size in Saldanha Bay are of particular interest here and are 

summarised in this section. 

5.2.1 Historical data 

The earliest studies reporting on the sediments of Saldanha Bay and Langebaan Lagoon were 

conducted by Flemming (1977) prior to large scale development of the area. Flemming (1977), 

however, did not report on the distribution of the mud component of the sediments in Saldanha Bay 

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Sediments 

and Langebaan Lagoon as, at that time, they were considered to have an “overall low content”. The 

mud component in Saldanha Bay prior to development (1977) was thus considered to be negligible 

and the sediments comprised predominantly sand particles (size range from 1 mm to 60 µm, Figure 

5.11). 

Due to concern in the deteriorating water quality in Saldanha Bay, however, sediment 

samples were collected again in 1989 and 1990, these data are presented in this report (Jackson and 

McGibbon 1991). At the time of the Jackson and McGibbon study, the iron ore terminal had been 

established dividing the Bay into Small Bay and Big Bay, the multi-purpose quay had been added to 

the ore terminal, various holiday complexes had been established on the periphery of the Bay and 

the mariculture industry had begun farming mussels in the sheltered waters of Small Bay. The 1989 

and 1990 studies revealed that sediments occurring in both Small Bay and Big Bay were still primarily 

comprised of sand particles but that mud now made up a noticeable, albeit small, component at 

most sites in the Bay (Figure 5.11). The Jackson and McGibbon (1991) study concluded that an 

increase in organic loading in the Bay had indeed occurred although this was not strongly reflected 

in the sediment analysis conducted at the time. 

The next study on sediment particle size in Saldanha Bay occurred nearly a decade later, in 

1999. However, immediately preceding this (in 1997/98) an extensive area adjacent to the ore 

terminal was dredged (indicated by arrows in Figure 5.11), resulting in a massive disturbance to the 

sediments of the Bay. The 1999 study clearly shows a substantial increase in the percentage of mud 

particles making up the sediment composition, specifically at the Multi-purpose Quay, Channel end 

of the ore terminal, the Yacht Club Basin and the Mussel Farm area (Figure 5.11). Two sites least 

affected by the dredging event were the North Channel site in Small Bay and the site in Big Bay. The 

North Channel site is located in shallow water where the influence of strong wave action and current 

velocities are expected to have facilitated in flushing out the fine sediment particles (mud) that are 

likely to have arisen from dredging activities. Big Bay remained largely unaffected by the dredging 

event that occurred in Small Bay and is presumably mediated to some extent by the scouring action 

of oceanic waves prevalent at this site. 

Subsequent studies conducted in 2000 and 2001 indicated that the mud content of the 

sediment remained high but that there was an unexplained influx of coarse sediment (gravel) in 

2000 followed by what appears to be some recovery over the 1999 situation. The 2000 results are 

somewhat anomalous and may be related to an unidentified processing error that arose when the 

samples were analysed. Sampling conducted in 2004 shows almost complete recovery of sediments 

over the 1999 situation to a majority percentage of sand in five of the six sites examined for this 

report (Figure 5.11). The only site where a substantial mud component remains is at the Multipurpose 

Quay. The shipping channel adjacent to the Quay is the deepest section of Small Bay 

(artificially maintained to allow passage of vessels) and is expected to concentrate the denser 

(heavier) mud component of sediment occurring in the Bay. 

The survey conducted in 2008 revealed that there had been an increase in the percentage of 

mud at all sites, most notably in the Yacht Club Basin and at the Multi-purpose Quay. This was 

probably due the maintenance dredging that took place at the Mossgas and multipurpose quays at 

the end of 2007/beginning of 2008 (see §3.3.1). The Yacht Club basin and the Small Bay side of the 

Multi-purpose quay are sheltered sites with reduced wave energy and are subject to long term 

deposition of fine grained particles. The 2008 benthic macrofauna survey revealed that benthic 

health at both the Yacht Club basin and adjacent to the Multi-purpose Quay is severely 

compromised, with benthic organisms being virtually absent from the former (see (see §7.2– BMF 

for more details on this). 

Smaller dredging programmes were also undertaken in the Bay 2009/10, when 7 300 m 3 of 

material was removed from an area of approximately 3 000 m 2 between Caisson 3 and 4 near the 

base of the Iron ore terminal on the Saldanha side, and a 275 m 2 area in Salamander Bay was 

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Sediments 

dredged to accommodate an expanded the SANDF Boat park. The former programme seems to 

have had a minimal impact of the Bay while the latter was potential more significant and is discussed 

in detail in §5.2.2 and 5.4.2. 

The percentage mud in the Bay sediments was reduced at most sites in Small Bay between 

2008 and 2009, between 2009 and 2010, and again between 2010 and 2011. This bay-wide 

progressive reduction in mud content suggests a shift in the balance between the rate at which fine 

sediments are suspended and deposited and the rate at which currents and wave activities flush fine 

sediments from the Bay. 

Unfortunately no early historical data is available for grain size distribution in Langebaan 

Lagoon, and only the recent results from the 2004, 2008, 2009, 2010 and 2011 surveys could be 

included in this report. During these surveys, the sediments in Langebaan Lagoon were principally 

composed of medium to fine grained sands with a very small percentage of mud. This is most likely 

due to the strong tidal currents experienced in the Lagoon. 

In summary, the natural, pre-development state of sediment in Saldanha Bay comprised 

predominantly sand particles; however, developments and activities in the bay (causeway, ore 

terminal, Yacht Club Harbour and mussel rafts) reduced the overall wave energy and altered the 

current circulation patterns. This compromised the capacity of the system to flush the bay of fine 

particles and led to the progressive accumulation of mud (cohesive sediment) in surface sediments 

in the Bay, followed in more decent times by a reduction in the mud fraction. Dredge events, which 

re-suspended large amounts of mud from the deeper lying sediments, seem to be a dominant 

contributor to the elevated mud content in the Bay and results of surveys have shown a general 

pattern of an increase in mud content following dredge events followed by a recovery in subsequent 

years. Any future dredging or other such large-scale disturbance to the sediment in Saldanha Bay 

are likely to result in similar increases in the mud proportion as was evident in 1999, with 

accompanying increase in metal content (refer to § 5.4 for more details on this). 

5.2.2 Sediment Particle size results for 2011 

Sediment samples were collected from a total of 30 sites in April 2011 to be tested for particle size 

composition, particulate organic carbon and nitrogen and trace metals. Ten of the sites were in 

Small Bay, seven in Big Bay, two in Donkergat, two in Salamander Bay and nine in Langebaan Lagoon 


Results from the 2011 survey are presented in Figure 5.14 and Table 5.1. These results 

indicate that fine muddy sediments made up a small proportion of the particle size composition 

throughout the Bay and Lagoon in 2011. Areas prone to the accumulation of muddy sediments 

include the Yacht Club Basin, which is a very sheltered site, and deeper sites along the ore terminal 

and in the middle of Big Bay. These spatial variations are most likely a reflection of the flushing 

capacity at these sites. Flushing of sediments is influenced by the current strength and the depth at 

the sites. Langebaan Lagoon has extremely low to negligible mud content in the sediments 

throughout. The deposition of fine grained particles in Langebaan Lagoon is most likely prevented 

by the strong tidal currents and the shallow nature of the Lagoon. 

A comparison to a similar image based on the results from the 2010 survey (Figure 5.13) 

reveals that the percentage composition of mud in the sediments has reduced to varying degrees at 

all sites throughout the system between 2010 and 2011. This result is an indication of the ongoing 

recovery of the system since the last dredge event. Over time more and more fine sediment is 

continuously being removed from the system. It is likely that the alteration to the current patterns 

and wave energy caused by the infrastructure in Saldanha Bay has reduced the rate of recovery at 

certain positions in the system. This recovery rate has been significantly impaired at the Yacht Club 

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Sediments 

Basin where the rate of removal of fine sediments is possibly lower than that experienced at other 

sites in Small Bay. Figure 5.11 shows a decreasing trend in the proportion of fine sediments at five 

Small Bay Sites and one Big Bay site between 1999 and 2004 (dredge events in 1997/8) and again 

between 2008 and 2011 (dredge events in 2007/8 and 2009/10), which further supports the premise 

that dredging events are the primary contributor of fine sediments in Saldanha Bay. 

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Dredge 1997 

Dredge 1997 

Dredge 1997 

Dredge 1997 


Sediments 

100% 

90% 

80% 

70% 

60% 

50% 

40% 

30% 

20% 

10% 

0% 

1977 1989 1990 1999 2000 2001 2004 2008 2009 2010 2011 

North channel Small Bay 

Gravel 

Sand 

Mud 

100% 

90% 

80% 

70% 

60% 

50% 

40% 

30% 

20% 

10% 

0% 

1977 1989 1990 1999 2000 2001 2004 2008 2009 2010 2011 

Multi-purpose Quay 

Gravel 

Sand 

Mud 

100% 

90% 

80% 

70% 

60% 

50% 

40% 

30% 

20% 

10% 

0% 

1977 1989 1990 1999 2000 2001 2004 2008 2009 2010 2011 

Yacht club basin 

Gravel 

Sand 

Mud 

100% 

90% 

80% 

70% 

60% 

50% 

40% 

30% 

20% 

10% 

0% 

1977 1989 1990 1999 2000 2001 2004 2008 2009 2010 2011 


Gravel 

Sand 

Mud 

100% 

90% 

80% 

70% 

60% 

50% 

40% 

30% 

20% 

10% 

0% 

1977 1989 1990 1999 2000 2001 2004 2008 2009 2010 2011 

Mussel Farm 

Gravel 

Sand 

Mud 

100% 

90% 

80% 

70% 

60% 

50% 

40% 

30% 

20% 

10% 

0% 

1977 1989 1990 1999 2000 2001 2004 2008 2009 2010 2011 

Gravel 

Sand 

Mud 

Channel end of ore jetty 

Figure 5.11. Particle size composition (percentage gravel, sand and mud) of sediments at six localities in the small bay area of Saldanha Bay between 1977 and 2011. 

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Sediments 

Figure 5.12. Sediment sampling sites in Saldanha Bay and Langebaan Lagoon for 2011. Sites sampled from 

pre-1980 to 2011 are marked and labelled in red 

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Sediments 

Table 5.1. 

Particle size composition and percentage organic carbon and nitrogen in surface sediments 

collected from Small Bay (SB), Big Bay (BB), Langebaan Lagoon (LL), Salamander Bay (S) and 

Donkergat (D) in 2011. (Particle size and TOC analysed by Scientific Services, TON analysed by 

CSIR). *The loss on ignition method was used to estimate TOC. These are not comparable to 

previous years where a CHN analyzer was used. 

Station %Gravel %Sand % Mud % TOC* % TON 

SB 1 0.00 87.18 12.82 18.12 0.735 

SB 2 0.61 98.54 0.84 2.81 0.049 

SB 3 2.54 95.43 2.02 3.24 0.06 

SB 8 0.00 97.31 2.69 3.40 0.038 

SB 9 1.63 94.32 4.04 2.21 0.109 

SB 10 1.65 97.81 0.54 3.53 0.056 

SB 14 0.00 93.97 6.03 9.68 0.494 

SB 15 9.96 86.25 3.79 3.83 0.143 

SB 16 0.27 94.66 5.07 3.47 0.159 

SB 42 18.39 79.15 2.45 3.30 0.12 

BB 20 3.80 93.97 2.23 0.77 0.331 

BB 21 0.00 96.82 3.18 1.20 0.08 

BB 22 0.37 94.35 5.29 3.89 0.076 

BB 25 0.00 98.78 1.22 2.11 0.038 

BB 26 1.46 91.90 6.63 5.06 0.099 

BB 29 0.22 94.43 5.35 4.71 0.093 

BB 30 0.00 99.71 0.29 1.95 0.014 

LL 31 0.00 99.30 0.70 3.12 0.032 

LL 32 0.14 99.67 0.19 1.88 0.023 

LL 33 0.00 99.76 0.24 1.32 0.014 

LL 34 0.81 98.48 0.71 2.38 0.022 

LL 37 2.17 97.56 0.27 1.96 0.017 

LL 38 4.50 94.22 1.28 4.44 0.112 

LL 39 0.42 99.34 0.24 1.94 0.022 

LL 40 0.66 98.99 0.35 2.12 0.039 

LL 41 0.00 99.82 0.18 1.09 0.013 

D1 0.85 97.88 1.27 4.54 

D2 0.00 97.76 2.24 3.86 

S1 4.92 92.99 2.08 3.96 

S2 0.00 97.86 2.14 3.76 

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Sediments 

Figure 5.13. Variation in the percentage mud in sediments in Saldanha Bay 

and Langebaan Lagoon as indicated by the 2010 survey results. 

Figure 5.14. Variation in the percentage mud in sediments in Saldanha Bay 

and Langebaan Lagoon as indicated by the 2011 survey results. 

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5.3 Monitoring of Particulate Organic Carbon (POC) and Nitrogen (PON) in 

sediment in the Bay 

Particulate organic carbon (POC) and particulate organic nitrogen (PON) accumulates in the same 

areas as mud (cohesive sediment) as most organic particulate matter is of a similar particle size 

range and density to that of mud particles (size


Sediments 

at different rates. The elevated POC at Donkergat and Salamander Bay are likely to be a result of the 

dredging activities that took place in this area between 2009 and 2010. The mud content in this area 

also indicates that it is not an area subject to a high deposition or retention rate. It therefore follows 

that the POC in the area is of local origin from a fairly recent event. 

The ratios of POC: PON are high for all sites, with the exception of site BB20, a deep site at 

the opening to the Bay, where the ratio is 2:1. The POC was very low at this site in relation to other 

sites in the Bay and Lagoon suggesting that this site may be less influenced by organic matter from 

anthropogenic sources. Indeed this site is positioned at the greatest distance from anthropogenic 

activities likely to contribute to the POC (waste water treatment works, fish factories and septic 

tanks). 

5.3.2 Temporal trends 

5.3.2.1 Particulate organic carbon 

A total of six sites have been sampled and POC compared at various stages between 1974 and 2010. 

The sediments from the Yacht Club Basin (SB1), Mussel Farm (SB9) and Multi-purpose Quay (SB14) 

consistently had the highest POC content of the six sites sampled since 1989. The much elevated 

organic carbon content of the sediments at the Yacht Club Basin has most likely been due to a 

combination of input of organic matter from dredge events and the fish factories and a high 

retention rate due to the sheltered nature of the area. The elevated organic carbon concentrations 

at the mussel farm site were attributed to the deposition of faecal pellets and biogenic waste. The 

elevated organic carbon concentrations at the Multi-purpose Quay is also most likely attributable to 

the historical dredging that took place at the site and a relatively higher retention rate of organic 

matter and fine sediments, given the depth and the sheltered nature of the site. The historical data 

revealed that organic matter concentrations increased following dredging events and decreased in 

years following the dredging. This suggests the re-suspension of organic matter from deeper 

sediments and the subsequent settling of this matter is a primary contributor to organic matter in 

surface sediments in the Bay. The only exception to this trend was that of the mussel farm site. This 

suggests that the mussel farm activities had a stronger local influence at that particular site than that 

of the dredging activities. 

As mentioned previously no direct comparison of the percentage particulate organic carbon 

could be conducted for 2011, however a comparison of spatial trends between 2010 and 2011 was 

conducted. The concentrations of organic carbon were, as in 2010 and previous years, greatest at 

the Yacht Club Basin and at the Multi-purpose Quay. Interestingly the POC at the mussel farm sites 

was moderate to low in relation to other Small Bay and Big Bay sites, suggesting that the mussel 

farming activities have had a lower influence on the POC than in previous years. Relatively 

moderate to high concentrations of POC were detected at the deeper sites within Big Bay, while the 

lowest concentrations were detected at the opening to Big Bay. These spatial variations are most 

likely a reflection of the flushing capacity at these sites. Flushing of sediments is influenced by the 

current strength and the depth at the sites. Interestingly these spatial variations in Big Bay were not 

detected in 2010. This change in the spatial pattern suggests that factors influencing retention of 

organic particles are having a greater influence over the concentration of POC than in previous 

years. On the basis of trends revealed in previous years as well as the consideration of the reduced 

mud content in the Bay it is understood that the system is in a state of recovery and that this 

recovery varies based on the extent of exposure and depth at different sites. This variation is 

revealed in the spatial analysis of the 2011 POC results. 

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Sediments 

5.3.2.2 Particulate organic nitrogen 

Sources of organic nitrogen in Small Bay include fish factory wastes, biogenic waste from mussel and 

oyster culture, sewage effluent from the waste water treatment works and leaking of sewage from 

septic tanks. PON had not been measured in early (historic) studies of the Bay, and data are only 

available from 1999 onwards. Similar to the spatial trends of POC, the PON concentrations have 

consistently been greatest at the Yacht Club Basin, Multi-purpose Quay and near the Mussel rafts 

(Figure 5.17). This is predicted to be as a result of fish factory waste discharge in the Yacht Club 

Basin and faecal waste accumulating beneath the mussel rafts. The likely sources of PON at the 

Multi-purpose Terminal are unclear; however it is likely to be a response to dredging given the 2008 

increase in PON following the 2007/8 dredging event. PON concentrations at this site have 

remained relatively high and fairly constant since 2008 suggesting that inputs of PON in this area are 

equivalent to that removed by flushing. The PON concentrations elsewhere in Small Bay are 

relatively low and have remained stable over time. 

PON concentrations decreased at the mussel farm site since 2009 which suggests that the 

faecal waste from the mussel farms has reduced or that flushing has improved in the area. 

Alarmingly PON concentrations in the Yacht Club Basin have shown an increasing trend since 2009. 

Given that there have been no dredging events since 2008 and that the mud content in this area has 

shown a decreasing trend, this suggests that organic waste inputs into the Yacht Club Basin are 

increasing. High organic loading of the sediments generally results in hypoxic conditions, which are 

unsuitable for most life forms. The high organic loading at the Yacht Club Basin has had a notable 

detrimental impact on marine benthic fauna as is evident from the macrofauna survey results (see 

Section 1 for more details on this). 

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Sediments 

Figure 5.15. Variation in the % Organic Carbon in the sediments in Saldanha 

Bay and Langebaan Lagoon as revealed by the 2010 survey results 

Figure 5.16. Variation in the % Organic Carbon in the sediments in Saldanha 

Bay and Langebaan Lagoon as revealed by the 2011 survey results 

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% PON 

% PON 

% PON 

% PON 

% PON 

% PON 


Sediments 

1.2 

1.2 

1 

0.8 

% PON 

1 

0.8 

0.6 

0.6 

0.4 

0.4 

0.2 

0.2 

0 

1999 2000 2001 2004 2008 2009 2010 2011 

North Channel - Small Bay 

0 

1999 2000 2001 2004 2008 2009 2010 2011 

Multi -purpose Quay 

1.2 

1.2 

1 

0.8 

0.6 

0.4 

0.2 

1 

0.8 

0.6 

0.4 

0 

1999 2000 2001 2004 2008 2009 2010 2011 

Yacht club basin 

0.2 

0 

1999 2000 2001 2004 2008 2009 2010 2011 


1.2 

1 

0.8 

1.2 

1 

0.8 

0.6 

0.6 

0.4 

0.4 

0.2 

0.2 

0 

1999 2000 2001 2004 2008 2009 2010 2011 

0 

1999 2000 2001 2004 2008 2009 2010 2011 

Mussel farm 


Figure 5.17. Particulate Organic Nitrogen (PON) percentage occurring in sediments of Saldanha Bay at six locations between 1999 and 2011 

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Sediments 

Figure 5.18. Variation in the % Organic Nitrogen in the sediments in Saldanha Bay and Langebaan Lagoon 

as revealed by the 2011 survey results 

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Sediments 

5.4 Trace Metals 

Trace metals occur naturally in the marine environment, and some are important in fulfilling 

key physiological roles. Disturbance to the natural environment by either anthropogenic or natural 

factors can lead to an increase in metal concentrations occurring in the environment particularly 

sediments. An increase in metal concentrations above natural level or at least above established 

safety thresholds can result in negative impacts on marine organisms, especially filter feeders like 

mussels that tend to accumulate metals in their flesh. High concentrations of metals can also render 

these species unsuitable for human consumption. Metals are strongly associated with the cohesive 

fraction of sediment (i.e. the mud component) and with particulate organic carbon (POC). Metals 

occurring in sediments are generally inert (non-threatening) when buried in the sediment but can 

become toxic to the environment when they are converted to the more soluble form of metal 

sulphides. Metal sulphides are known to form as a result of natural re-suspension of the sediment 

(strong wave action resulting from storms) and from anthropogenic induced disturbance events like 

dredging activities. 

The Benguela Current Large Marine Ecosystem (BCLME) Programme reviewed international 

sediment quality guidelines in order to develop a common set of sediment quality guidelines for the 

coastal zone of the BCLME (Angola, Namibia and west coast of South Africa) (Table 5.2). The BCLME 

guidelines cover a broad concentration range and still need to be refined to meet the specific 

requirements of each country within the BCLME region (BCLME 2006). There are thus no official 

sediment quality guidelines that have been published for the South African marine environment as 

yet, and it is necessary to adopt international guidelines when screening sediment metal 

concentrations. The National Oceanic and Atmospheric Administration (NOAA) has published a 

series of sediment screening values, which cover a broad spectrum of concentrations from toxic to 

non-toxic levels as shown in Table 5.2. 

The Effects Range Low (ERL) represents the concentration at which toxicity may begin to be 

observed in sensitive species. The ERL is calculated as lower 10 th percentile of sediment 

concentrations reported in literature that co-occur with any biological effect. The Effects Range 

Median (ERM) is the median concentration of available toxicity data. It is calculated as lower 50 th 

percentile of sediment concentrations reported in literature that co-occur with a biological effect 

(Buchman 1999). The ERL values represent the most conservative screening concentrations for 

sediment toxicity proposed by the NOAA, and ERL values have been used to screen the Saldanha Bay 

sediments. 

Table 5.2. 

Summary of BCLME and NOAA metal concentrations in sediment quality guidelines 

Metal 

(mg/kg dry wt.) BCLME region (South Africa. Namibia, Angola) NOAA 2 

Special care Prohibited ERL ERM 

Cd 1.5 – 10 > 10 1.2 9.6 

Cu 50 – 500 >500 34 270 

Pb 100 – 500 > 500 46.7 218 

Ni 50 – 500 > 500 20.9 51.6 

Zn 150 – 750 > 750 150 410 

1 (BCLME 2006), 2 (Long et al. 1995, Buchman 1999) 

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Sediments 

5.4.1 Historical data 

Dramatic increases in trace metal concentrations, especially those of cadmium and lead 

after the start of the iron ore export from Saldanha Bay, raised concern for the safety and health of 

marine organisms, specifically those being farmed for human consumption (mussels and oysters). Of 

particular concern were the concentrations of cadmium which exceeded the lower toxic effect level 

published by the NOAA. Both lead and copper concentrates are exported from Saldanha Bay and it 

was hypothesised that the overall increase of metal concentrations was directly associated with the 

export of these metals. The concentrations of twelve different metals have been evaluated on 

various occasions in Saldanha Bay; however, the overall fluctuations in concentrations are similarly 

reflected by several key metals throughout the time period. For the purposes of this report, four 

metals that have the greatest potential impact on the environment were selected from the group. 

These are cadmium (Cd), lead (Pb), copper (Cu) and nickel (Ni). 

The earliest data on metal concentrations in Saldanha Bay were collected in 1980, prior to 

the time at which iron ore concentrate was first exported from the ore terminal. The sites sampled 

were 2 km north of the Multi-purpose Quay (Small Bay) and 3 km south of the Multi-purpose Quay 

(Big Bay) and metals reported on included lead (Pb), cadmium (Cd) and copper (Cu). Concentrations 

of these metals in 1980 were very low, well below the sediment toxicity thresholds (Figure 5.21, 

Figure 5.25, Figure 5.23 and Figure 5.27). Subsequent sampling of metals in Saldanha Bay (for which 

data is available) only took place nearly 20 years later in 1999. During the period between these 

sampling events, a considerable volume of ore had been exported from the Bay, areas of Saldanha 

Bay had been dredged (1997/98), and the Mussel Farm and the small craft harbour (Yacht Club 

Basin) had been established (1984). As a result of these activities, the concentrations of metals in 

1999 were very much higher (up to 60 fold higher) at all stations monitored (Figure 5.21, Figure 5.25, 

Figure 5.23 and Figure 5.27). This reflects the accumulation of metals in the intervening 20 years, 

much of which had recently been re-suspended during the dredging event and had settled in the 

surficial (surface) sediments in the Bay. Concentrations of most metals in Saldanha Bay were 

considerably lower in the period 2000-2010, although nowhere near levels measured in 1980. This 

closely mirrors changes in the proportion of mud in the sediments, and most likely reflects the 

removal of fine sediments together with the trace metal contaminants from the Bay, by wave and 

tidal action. Monitoring surveys between 2001 and 2011, revealed that with a few exceptions, metal 

concentrations had continued to decrease in Saldanha Bay and were much reduced from the 

exceptionally high concentrations recorded in 1999 and 2000. 

5.4.2 Analysis and results for 2011 

Sediments were analyzed for concentrations of aluminium (Al), iron (Fe), copper (Cu), 

cadmium (Cd), nickel (Ni), lead (Pb) and zinc (Zn). For the purpose of this report only the data for Cd, 

Cu, Pb, Ni and Fe are presented as these are the metals deemed to pose the greatest threat to the 

health of the marine environment. Metals in the sediments were analyzed by Scientific Services 

using a Nitric Acid (HNO 3 ) / Perchloric Acid (HClO 3 )/ Hydrogen Peroxide (H 2 O 2 )/ Microwave digestion 

and JY Ultima Inductively Coupled Plasma Optical Emission Spectrometer. The concentrations of 

metals in the sediments of Saldanha Bay and Langebaan Lagoon in 2011 are shown in Table 5.3. The 

concentrations of trace metals at the sites sampled in 2011 were used to interpolate the metal 

concentrations over the full extent of the Bay and Lagoon using GIS software. These interpolations 

provide an indication of the spatial variation in the concentration of the various trace metals in the 

Bay and the Lagoon. 

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Sediments 

Table 5.3. Concentrations (mg/kg) of metals in sediments collected from Saldanha Bay in 2011. 

Sample Al Fe Cd Cu Ni Pb Zn 

*ERL Guideline (mg/kg) - - 1.2 34 20.9 46.7 150 

Small Bay (SB) SB1 9450 9554 2.1 40.7 8.4 23.3 82.7 

SB2 2436 4614 0.3 4.9 3.1 6.4 10.1 

SB3 1588 2571 0.2 2.5 0.5 13.7 6.4 

SB8 2006 3251 0.3 1.5 2.4 4.9 7.5 

SB9 3676 5464 0.4 3.1 2.5 5.6 14.4 

SB10 1346 2716 0.1 0.4 0.6 5.3 5.6 

SB14 8093 9359 1.2 15.2 6.3 64.1 39.5 

SB15 2387 2957 0.2 1.4 0.6 5.6 8.8 

SB16 2989 4087 0.4 2.0 1.7 3.8 10.5 

SB42 2548 3345 0.2 2.2 1.0 11.8 10.5 

Big Bay (BB) BB20 1534 2066 0.3 0.2 0.5 0.3 5.1 

BB21 2350 3123 0.2 0.5 0.8 2.7 7.9 

BB22 3443 4521 0.4 2.5 1.8 3.6 12.6 

BB25 944 1567 0.1 0.0 0.0 0.2 2.3 

BB26 2488 3228 0.3 0.1 0.8 2.8 12.9 

BB29 1774 2018 0.2 0.0 0.3 0.0 5.1 

BB30 931 1709 0.1 0.0 0.1 0.0 1.9 

Donkergat D1 4442 5695 0.8 2.3 3.7 23.8 14.5 

D2 3364 5469 0.3 1.0 2.8 2.0 10.7 

Salamander Bay S1 4540 6359 0.6 8.7 1.7 24.2 38.2 

S2 2948 3575 0.3 0.5 1.7 2.6 8.5 

Langebaan Lagoon (LL) LL31 2222 3384 0.1 0.0 1.1 2.5 5.2 

LL32 2013 4830 0.2 0.6 1.4 1.7 5.3 

LL33 1507 3731 0.1 1.2 2.2 1.9 3.2 

LL34 2038 3107 0.1 0.8 1.4 0.1 4.6 

LL37 1010 2566 0.0 0.5 1.2 0.0 3.1 

LL38 5118 8261 0.5 5.7 6.0 4.3 13.4 

LL39 1244 2222 0.1 0.0 0.0 0.9 3.0 

LL40 1884 3261 0.1 0.8 1.6 0.0 3.5 

LL41 677 2199 0.0 0.6 0.9 0.0 0.8 

*Effects Range Low guideline stipulated by NOAA at which toxic effects are likely to be observed in sensitive marine 

species. 

DL = Detection Limit 

The concentrations of metals in sediments are affected by grain size, total organic content 

and mineralogy. Since these factors vary in the environment, one cannot simply use high absolute 

concentrations of metals as an indicator for anthropogenic metal contamination. Metal 

concentrations are therefore commonly normalized to a grain-size parameter or a suitable 

substitute for grain size, and only then can the correct interpretation of sediment metal 

concentrations be made (Summers et al. 1996). A variety of sediment parameters can be used to 

normalize metal concentrations, and these include Al, Fe and total organic carbon. Aluminium or 

106 

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Sediments 

iron are commonly used as normalizes for trace metal content as they ubiquitously coat all 

sediments and occur in proportion to the surface area of the sediment (Gibbs 1994); they are 

abundant in the earth’s crust and are not likely to have a significant anthropogenic source (Gibbs 

1994, Summers et al. 1996); and ratios of metal concentrations to Al or Fe concentrations are 

relatively constant in the earth’s crust (Summers et al. 1996). Normalized metal/aluminium ratios 

can be used to estimate the extent of metal contamination within the marine environment, and to 

assess whether there has been enrichment of metals from anthropogenic activities. In this study 

metal concentrations were normalized against (divided by) aluminium and not iron due to the 

known anthropogenic input of iron from the iron ore quay and industrial activity in Saldanha Bay. 

Figure 5.19. Metal:Al ratios for Copper, Lead, Cadmium and Nickel for sediments sampled in 2011 from 

Saldanha Bay-Small Bay (SB), Big Bay (BB), Langebaan Lagoon (LL), Donkergat (D) and 

Salamander Bay (S) 

Metal enrichment factors were calculated for Cd, Pb and Cu relative to the 1980 sediments 

(Table 5.4). Unfortunately historic enrichment factors could not be calculated for Ni as no data was 

available for this metal in 1980. Enrichment factors equal to (or less than) 1 indicate no elevation 

relative to pre-development sediments, while enrichment factors greater that 1 indicate a degree of 

metal enrichment within the sediments over time. Enrichment factors were not calculated for 

Langebaan Lagoon since all concentrations were below the detection limits. 

5.4.2.1 Cadmium 

Cadmium (Cd) is a trace metal used in electroplating, in pigment for paints, in dyes and in 

photographical process. The likely sources of Cd to the marine environment are in emissions from 

industrial combustion process, from metallurgical industries, from road transport and waste streams 

(OSPAR 2010). A likely point source for Cd contamination in the marine environment is that of 

stormwater drains. Cd is toxic and liable to bioaccumulation, and is thus a concern for both the 

marine environment and human consumption (OSPAR 2010). The Cd concentrations detected in 

2011 exceeded the ERL prescribed by NOAA at the Yacht Club Basin and at the multi-purpose quay 

(Figure 5.20 and Table 5.3). Both areas had a relatively high mud content which suggests that these 

areas are subject to high retention rates. The normalized Cd:Al ratios were high at the Yacht Club 

107 

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Sediments 

Basin and the multi-purpose quay suggesting that the contamination is not of natural origin (Figure 

5.19). Indeed, both areas are in close proximity to various industrial activities which are likely to be 

contributing Cd to the system through emissions and stormwater run-off collectively. The second 

highest normalized Cd:Al ratio was recorded at BB20 situated at the opening to Big Bay (Figure 5.19). 

This site had a negligible mud content and low over concentration of Cd. This indicates a low level of 

anthropogenic input of Cd at this site. This is, however, not a cause for concern given the exposed 

nature of the site and the low Cd concentration. Cd concentrations were relatively high at sites in 

Salamander Bay and Donkergat, though these did not exceed the ERL (Figure 5.20 and Table 5.3). 

This result did not correlate with that of the particle size composition as both sites had a low mud 

fraction. This indicates that these sites are not subject to high rates of retention and that the source 

of the high Cd concentrations was likely to be fairly recent and local to these sites. The relatively 

elevated Cd:Al ratio at these sites suggests the source was not of natural origin. Both sites are 

situated in close proximity to the Special Forces Regiment of the South African National Defence 

Force (SANDF) who commenced the construction of a boat yard in 2009. Dredging was conducted in 

the area in 2009 and 2010. It is likely that the dredging activities resuspended Cd accumulations 

from deeper sediments. 

Table 5.4. Enrichment factors for Cadmium, Copper and Lead in sediments collected from Saldanha Bay 

in 2009 relative to sediments from 1980 

Sample Cd Cu Pb 

1980 average 0.075 0.41 0.8 

Small Bay SB1 27.81333 99.37561 29.095 

SB2 4.213333 11.86341 7.99125 

SB3 2.36 6.143902 17.125 

SB8 3.573333 3.580488 6.16875 

SB9 5.586667 7.495122 6.9375 

SB10 1.4 0.968293 6.665 

SB14 16.09333 37.07805 80.17125 

SB15 2.853333 3.373171 7.01875 

SB16 5.773333 4.9 4.71625 

Big Bay BB20 4.213333 0.419512 0.31875 

BB21 2.72 1.204878 3.39 

BB22 5.026667 6.060976 4.535 

BB25 1.106667 - 0.21625 

BB26 4.373333 0.353659 3.52125 

BB29 2.266667 - - 

BB30 0.666667 - 0.0075 

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Sediments 

Figure 5.20. Variation in the concentration of Cadmium (Cd) in the sediments in Saldanha Bay and 

Langebaan Lagoon as revealed by the 2011 survey results. 

There was a considerable increase in the concentrations of Cadmium detected in the 

sediments of Saldana Bay between 1980 and 1999. In 1999, the levels of cadmium recorded at the 

Mussel Farm, the Yacht Club Basin and the Channel End of the Ore Terminal exceeded the ERL 

toxicity threshold of 1.2 mg/kg established by NOAA (Figure 5.21). Since 1999, cadmium 

concentrations have shown a progressive decrease over time (2000-2010) in the Yacht Club Basin, at 

Mussel Farm, at the end of ore terminal and in Big Bay. Cadmium concentrations fell below 

detection limits at all the sites other than the Yacht Club Basin in 2010 and the concentration 

detected at the Yacht Club Basin had reduced below the ERL. 

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Sediments 

8 

7 

6 

5 

4 

3 

2 

1 

0 

1980 1999 2000 2001 2004 2008 2009 2010 2011 


Cadmium 

8 

7 

6 

5 

4 

3 

2 

1 

0 

1980 1999 2000 2001 2004 2008 2009 2010 2011 

Multi -Purpose Quay 

8 

7 

6 

5 

4 

3 

2 

1 

0 

1980 1999 2000 2001 2004 2008 2009 2010 2011 

Yacht Club Basin 

8 

7 

6 

5 

4 

3 

2 

1 

0 

1980 1999 2000 2001 2004 2008 2009 2010 2011 

Mussel Farm 

8 

7 

6 

5 

4 

3 

2 

1 

0 

1980 1999 2000 2001 2004 2008 2009 2010 2011 


Figure 5.21. Concentrations of Cadmium (Cd) in mg/kg recorded at six sites in Saldanha Bay between 1980 and 2011. Dotted lines indicate Effects Range Low values for 

sediments 

110 

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Sediments 

Enrichment factors calculated for both Small Bay and Big Bay indicated that the Cd levels 

recorded in 2011 exceeded pre-development levels at all sites. The Yacht Club Basin was 

approximately 28 times higher, while the multi-purpose quay site was 16 time higher (Table 5.4). 

The results of 2011 indicate that the concentrations of Cd have increased at all sites within Small 

Bay. Furthermore Cd was not detected in Big Bay or Langebaan Lagoon in 2010, however; in 2011 

Cd was detected at all sites, with the exception of two in Langebaan Lagoon. This indicates a system 

wide increase since 2010. Given the relatively pristine nature of some of the sites (southern lagoon) 

and the great distance from storm water drains, it is likely that this increase is the result of natural 

fluctuations. Indeed, Cd concentrations have been found to occur in naturally high concentrations in 

the organic rich sediments of the near shore zone of the southern Benguela (including Saldanha Bay 

area). It is important to note, however, that Cd levels did not increase consistently and in some 

areas, notably the Yacht Club Basin, multi-purpose quay, Salamander Bay and Donkergat, the 

increase is most likely attributable to anthropogenic activities in close proximity. Furthermore it 

must be noted that neither Salamander Bay nor Donkergat were tested for trace metals prior to 

2011 so it is unclear as to whether contamination occurred during 2009 or 2010. 

5.4.2.2 Copper 

Copper (Cu) is used as a biocide in antifouling products as it very effective for killing marine 

organisms that attach themselves to the surfaces of boats and ships. Anti-fouling paints release Cu 

into the sea and can make a significant contribution to Cu concentrations in the marine environment 

(Clark 1986). Concentrations of Cu were detected at most sites in Saldanha Bay and Langebaan 

Lagoon in 2011 (Table 5.3), with the exception of three sites in Big Bay and two in Langebaan 

Lagoon. All sites with the exception of the Yacht Club Basin, the multi-purpose quay and Salamander 

Bay had relatively low concentrations of Cu. The concentration of Cu at the Yacht Club Basin 

exceeded the ERL. 

The Yacht Club Basin had dramatically higher normalized Cu:Al ratio compared to other sites. 

This area is subject to high boating activity. The input of Cu at this site may thus be related to the 

use of antifouling paints, which characteristically have a high Cu content, and the sheltered nature of 

this site. Other sites with high Cu:Al ratios included SB2, SB3, SB14 (multi-purpose quay) and S1 

(Salamander Bay). The high ratios at SB14 are most likely attributable to a combination of the 

depositional nature of the site and export and shipping activities, while that in Salamander Bay may 

to be related to boating and, in all likelihood, the recent dredging activities. There is no apparent 

reason for the elevated Cu:Al ratios found at SB2 and SB3. 

Concentrations of Cu are 99 and 37 times greater than the historical average at sites SB1 and 

SB14 respectively (Yacht Club Basin and Multi-purpose Quay). These sites are both depositional 

zones for organic matter and are also associated with a high degree of boating/shipping activity. The 

combination of boating activities as well at as the reduction of currents are most likely the primary 

contributors to this long-term build up of Cu at these sites. 

Figure 5.23 shows the temporal variation in Cu concentrations within Saldanha bay 

sediments. As with all the other metals in Saldanha Bay sediments, Cu concentrations peaked in 

1999 after the major 1997 dredging event. There was a subsequent decline in Cu concentrations 

over the period 1999-2004 at the Mussel Farm, Channel end of the ore terminal, at the Multipurpose 

quay, and within Big Bay. The concentrations of Cu in Big Bay and at the Mussel Farm have 

remained low (


Sediments 

The Yacht Club Basin has consistently suffered the highest concentrations of Cu, with levels 

exceeding the ERL threshold in 1999, 2008, 2010 and 2011. It is thus not surprising that macrofauna 

which live in soft bottom sediments had virtually disappeared from the Yacht Club Basin in 2008 

given the extremely high Cu concentrations at this site (see §7.4.1 for more details on this). 

Figure 5.22. Variation in the concentration of Copper (Cu) in the sediments in Saldanha Bay and Langebaan 

Lagoon as revealed by the 2011 survey results. 

112 

ANCHOR 


Copper (mg/kg) 





Cu (mg/kg) 


Sediments 

45 

40 

35 

30 

25 

20 

15 

10 

5 

0 

1980 1999 2000 2001 2004 2008 2009 2010 2011 


Copper 

45 

40 

35 

30 

25 

20 

15 

10 

5 

0 

1980 1999 2000 2001 2004 2008 2009 2010 2011 


45 

40 

35 

30 

25 

20 

15 

10 

5 

0 

1980 1999 2000 2001 2004 2008 2009 2010 2011 

45 

40 

35 

30 

25 

20 

15 

10 

5 

0 

1980 1999 2000 2001 2004 2008 2009 2010 2011 



45 

40 

35 

30 

25 

20 

15 

10 

5 

0 

1980 1999 2000 2001 2004 2008 2009 2010 2011 

45 

40 

35 

30 

25 

20 

15 

10 

5 

0 

1980 1999 2000 2001 2004 2008 2009 2010 2011 

Mussel Farm 


Figure 5.23. Concentrations of Copper (Cu) in mg/kg recorded at six sites in Saldanha Bay between 1980 and 2011. Dotted lines indicate Effects Range Low values for 

sediments 

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Sediments 

5.4.2.3 Lead 

There has been a widespread elevation of lead (Pb) concentrations in the environment due to 

mining, smelting and the industrial use of Pb (OSPAR 2010). Pb is a persistent compound which is 

toxic aquatic organism and mammals, and thus the contamination is of concern for the marine 

environment and human consumption (OSPAR 2010). Pb was detected at all sites in Saldanha- 

Langebaan, with the exception of three sites in the lagoon and two in Big Bay. The concentration of 

lead at site SB 14 (Multi-purpose Quay) exceeded the ERL value in 2011 (Figure 5.24 and Table 5.3). 

Other sites with high concentrations included the Yacht Club Basin, Donkergat and Salamander Bay 

(Figure 5.24 and Table 5.3). The normalized Pb:Al ratios were highest at sites SB3 (north end of the 

channel), SB14 (multi-purpose quay), SB42 (close proximity to multi-purpose quay), D1 (Donkergat) 

and S1 (Salamander Bay), suggesting anthropogenic input at these points (Figure 5.19). The 

normalized Pb:Al ratios were also elevated at SB3 and SB14 in 2008 and 2009. The high PB 

concentrations and Pb:Al ratios in close proximity to the multi-purpose quay and landward (SB3) are 

most likely attributable to the export activities that take place in this area. The high PB 

concentrations and Pb:Al ratios at Donkergat and Salamander Bay are in all likelihood attributable to 

the dredging activities that took place in the area in 2009/10. 

Pb concentrations are 29 and 80 times higher at the Yacht Club Basin and at the multipurpose 

quay compared to 1980 concentrations respectively (Table 5.4). Elevated Pb along the 

multi-purpose quay can be attributed to the export of lead ore, storm water runoff and the 

discharge of ballast water (in which Pb concentrations are higher than guideline limits). 

Furthermore, both sites are depositional zones which have lead to the long-term accumulation of Pb 

in these areas. 

The temporal variations in the concentration of Pb in Saldanha Bay sediments can be seen in 

Figure 5.25. In 1980, the concentrations of lead in the sediments were very low at all sites (~0.8 

mg/kg), but increased notably at all sites after the 1997 dredge event. In 1999 the concentrations of 

lead at the Yacht Club Basin and Mussel Farm exceeded the lower threshold value set by NOAA at 

which toxic effects are likely to be observed in sensitive species (ERL = 46.7 mg/kg). Concentrations 

of Pb at the Multi-purpose quay exceeded the ERL value in 2000 and again in 2008 and 2009. The 

sediments from all sites within Small Bay (except the end of the ore terminal) showed an increase in 

lead concentrations in 2008. This is concerning given that there was an apparent decline in Pb 

concentrations at these sites between 1999/2000-2004. This increase in Pb in the sediments may be 

linked to the maintenance dredging that took place at the multipurpose quay and Mossgas Quay at 

the end of 2007/beginning of 2008 (see §3.3.1). The concentration of Pb decreased again at all sites 

within Small Bay except the Multi-purpose Quay and the Channel End of the Ore Terminal in 2009. 

Subsequent samples taken in 2010 revealed that Pb concentrations had declined further at all sites 

with the exception of the Yacht Club Basin, which increased very slightly. Pb concentrations at all 

sites fell below the ERL in 2010, suggesting some recovery of the system since the 2007/2008 dredge 

event. The 2011 survey revealed that Pb concentrations at all sites within Small Bay increased 

between 2010 and 2011 and decreased at the majority of sites in Big Bay and Langebaan Lagoon. 

This result is concerning given that the mud fraction in the sediments decreased over the same time 

period. This suggests that Pb inputs into Small Bay exceeded the rate at which the area is being 

flushed. The sites where Pb concentrations are most concerning are those around the multi-purpose 

quay where concentration greatly exceeded ERL levels. 

114 

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Sediments 

Figure 5.24. Variation in the concentration of Lead (Pb) in the sediments in Saldanha Bay and Langebaan 


115 

ANCHOR 


Lead (mg/kg) 

Lead (mg/kg) 

Lead (mg/kg) 

Lead (mg/kg) 

Lead (mg/kg) 

Lead (mg/kg) 


Sediments 

80 

70 

60 

50 

40 

30 

20 

10 

0 

1980 1999 2000 2001 2004 2008 2009 2010 2011 


Lead 

80 

70 

60 

50 

40 

30 

20 

10 

0 

1980 1999 2000 2001 2004 2008 2009 2010 2011 


80 

70 

60 

50 

40 

30 

20 

10 

80 

70 

60 

50 

40 

30 

20 

10 

0 

1980 1999 2000 2001 2004 2008 2009 2010 2011 

0 

1980 1999 2000 2001 2004 2008 2009 2010 2011 



80 

70 

60 

50 

40 

30 

20 

10 

0 

1980 1999 2000 2001 2004 2008 2009 2010 2011 

80 

70 

60 

50 

40 

30 

20 

10 

0 

1980 1999 2000 2001 2004 2008 2009 2010 2011 

Mussel Farm 


Figure 5.25 

Concentrations of Lead (Pb) in mg/kg recorded at six sites in Saldanha Bay between 1980 and 2011. Dotted lines indicate Effects Range Low values for 

sediments 

116 

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Sediments 

5.4.2.4 Nickel 

Nickel was recorded at all the sites with the exception of one site in the Lagoon and one in Big Bay 

(Figure 5.26 and Table 5.3). The concentrations were well below the toxic effects guidelines 

stipulated by the NOAA. Normalized nickel concentration show a considerable amount of spatial 

variability. Since nickel was found ubiquitously throughout Small Bay, Big Bay and Langebaan 

Lagoon at low concentrations it is likely to be of natural origin. The concentrations of nickel peaked 

at all sites in either 1999 or 2000, after which they decreased considerably between 2000 and 2011 

(Figure 5.27). Nickel concentrations have always been highest in the Yacht Club Basin, which mirrors 

the patterns for cadmium and copper. 

Figure 5.26. Variation in the concentration of Nickel (Ni) in the sediments in Saldanha Bay and Langebaan 


117 

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Nickel (mg/kg) 







Sediments 

35 

30 

25 

Nickel 

35 

30 

20 

25 

15 

20 

10 

15 

5 

10 

0 

5 

1999 2000 2001 2004 2008 2009 2010 2011 


0 

1999 2000 2001 2004 2008 2009 2010 2011 


35 

35 

30 

25 

20 

15 

10 

5 

30 

25 

20 

15 

10 

5 

0 

1999 2000 2001 2004 2008 2009 2010 2011 

0 

1999 2000 2001 2004 2008 2009 2010 2011 



35 

35 

30 

30 

25 

25 

20 

20 

15 

15 

10 

10 

5 

5 

0 

1999 2000 2001 2004 2008 2009 2010 2011 

0 

1999 2000 2001 2004 2008 2009 2010 2011 

Mussel Farm 


Figure 5.27. Concentrations of Nickel (Ni) in mg/kg recorded at six sites in Saldanha Bay between 1980 and 2011. Dotted lines indicate Effects Range Low values for 

sediments 

118 

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Sediments 

5.4.2.5 Iron 

The temporal variations in the concentration of iron in sediments around the ore terminal in 

Saldanha Bay can be seen in Figure 5.28. The concentration of iron increased between 1999 and 

2004 at sites 14 and 15 which are in closest proximity to and on the downwind side (of the 

predominant southerly winds) of the multi-purpose quay. This may have been due to increases in 

volumes of ore handled or increases in losses into the sea over this period, or simply reflects 

accumulation of iron in the sediments over time. There was a reduction in the concentration of iron 

in the sediments at most sites on the Small Bay side of the ore terminal between 2004 and 2010. 

Dredging took place at the multi-purpose quay in 2007 and the removal of iron rich sediment at Site 

15 is probably the reason for the dramatic decrease in iron concentration recorded at this station 

between 2008 and 2009 sampling. Sediment iron concentration at this site did increase to the 

highest levels yet recorded in 2009, but decreased again in 2010 samples. The 2011 survey revealed 

that iron concentrations had increased at most sites around the ore terminal despite reductions in 

the mud contents at all sites. This suggests that fluctuations in iron content are a result of iron 

inputs rather than the flushing experienced at the sites. 

Transnet has implemented numerous new and improvements to existing dust suppression 

ion measures in recent years (SRK 2009, Viljoen et al. 2010). Dust suppression mitigation measures 

implemented since mid 2007 include conveyer covers, a moisture management system, chemical 

dust suppression, surfacing of roads and improved housekeeping (road sweeper, conveyer belt 

cleaning, vacuum system, dust dispersal modelling and monitoring) amongst others. The volume of 

ore handled at the bulk quay has increased from around 4.5 million tons per month during 2007- 

2008 to around 6.5 million tons during 2009-2010 (~50% increase), yet the concentration of iron in 

the sediments at sites adjacent to the ore terminal remained fairly stable or decreased between 

2009 and 2010. This does suggest that the improved dust control methods implemented since 2007 

have been successful in reducing the input to the marine environment. Ongoing monitoring of 

sediment iron concentration will reveal if this reduction can be sustained at the anticipated higher 

volumes of ore handling in the near future. 

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Iron (mg/kg) 

Iron (mg/kg) 

Iron (mg/kg) 

Iron (mg/kg) 

Iron (mg/kg) 


Sediments 

14000 

12000 

10000 

8000 

6000 

4000 

2000 

0 

2004 2008 2009 2010 2011 

SB 14 

Iron (mg/kg) 

14000 

12000 

10000 

8000 

6000 

4000 

2000 

14000 

12000 

10000 

0 

2004 2008 2009 2010 2011 

BB 21 

8000 

6000 

4000 

2000 

0 

2004 2008 2009 2010 2011 

SB 15 

14000 

12000 

14000 

10000 

12000 

8000 

10000 

6000 

8000 

4000 

6000 

2000 

4000 

2000 

0 

2004 2008 2009 2010 2011 

0 

2004 2008 2009 2010 2011 

BB 22 

SB 16 

Figure 5.28. Concentrations of Iron (Fe) in mg/kg recorded at five sites in Saldanha Bay between 2004 and 2011. 

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Sediments 

5.4.3 Summary 

A multivariate analysis was conducted using PRIMER to determine the similarity (Euclidean distance) 

between sites based on the concentrations of the different trace metals in the sediments. The 

results are presented graphically in Figure 5.29 with different colour symbols indicating significant 

groupings of sites. These are organized based on the general relative concentrations of trace metals, 

with the red (A) indicating the highest concentrations and the blue (E) the lowest. The highest 

concentrations of all the trace metals measured were recorded at the Yacht Club Basin, the only 

exception being lead which was greater at the multi-purpose quay. This result correlates well with 

that of the particle size composition results which indicated that the Yacht Club Basin harboured the 

highest mud fraction. This suggests that a primary factor responsible for the high trace metal 

concentration is the poor flushing of fine sediments from this area. This is consistent with results 

observed since 2008. The grouping of most of the Small Bay sites into the category with the second 

highest concentrations of trace metals indicated that Small Bay had been subjected to a greater 

extent of contamination compared to Big Bay and Langebaan Lagoon. This is attributable to the 

poor circulation and flushing in Small Bay in combination with trace metal contamination by the 

surrounding industries and activities. The groups of sites with moderate to low concentrations of 

trace metals were not grouped spatially, but rather spread throughout Big Bay and Langebaan 

Lagoon. This indicates that the retention of trace metals varies spatially, most likely due to 

variations in depth and current strengths at different localities. Interestingly, Sites S1 and D1, 

positioned in Salamander Bay and Donkergat, respectively, grouped with the Yacht Club Basin and 

multi-purpose quay indicating that they are most similar based on the concentrations of trace 

metals. This indicates that these areas have been subject to high levels of trace metal 

contamination, most likely attributable to recent dredging activities in this part of the Bay. The low 

mud content at Donkergat and Salamander indicates that these areas are well flushed and it is 

probable, in the absence of further dredging, that trace metal concentrations will decline again over 

time. 

Elevated trace metal concentrations recorded in Saldanha Bay in 1999 were ascribed to an 

accumulation of these metals in the sediments of the Bay over the preceding 20 years, much of 

which was re-suspended as a result of dredging operations and had settled in the surface layers. 

Construction of the Marcus Island causeway and the ore terminal had contributed to this process by 

reducing wave action and modifying circulation patterns prevailing in the Bay. Subsequent 

monitoring has revealed a substantial overall decrease in the concentrations of metals in the Bay, 

suggesting that a disturbance, like dredging which remobilises the fine sediments and re-suspends 

metals, can severely affect the health of the Bay and that it takes between three to six years before 

the contaminated sediments are removed from the Bay by natural processes. It was also shown that 

metal concentrations were elevated near the Multi-purpose Quay as a result of lead and copper ore 

dust entering the environment during export activities. In addition, metal concentrations were high 

(often exceeding ERL values) in the Yacht Club Basin and this may be due to the fact that this area is 

a depositional zone for fine grained sediments and organic matter onto which metals adsorb. 

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Sediments 

Figure 5.29. Geographic representation of the results of a PRIMER analysis showing significant clustering of 

sites based on the similarity of trace metal concentrations. Group A generally had the highest 

concentrations for all metals and group E the lowest (SIMPER analysis) 

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Sediments 

5.5 Hydrocarbons 

Poly-aromatic hydrocarbons (PAH) (also known as polynuclear- or polycyclic-aromatic hydrocarbons) 

are present in significant amounts in fossil fuels (natural crude oil and coal deposits), tar and various 

edible oils. They are also formed through the incomplete combustion of carbon-containing fuels 

such as wood, fat and fossil fuels. PAHs are one of the most wide-spread organic pollutants and they 

are of particular concern as some of the compounds have been identified as carcinogenic for 

humans (Nikolaou et al. 2009). PAHs are introduced to the marine environment by anthropogenic 

means (combustion of fuels) and by natural means (oil welling up or products of biosynthesis) 

(Nikolaou et al. 2009). PAHs in the environment are found primarily in soil, sediment and oily 

substances, as opposed to in water or air, as they are lipophilic (mix more easily with oil than water) 

and the larger particles are less prone to evaporation. The highest values of PAHs recorded in the 

marine environment have been in estuaries and coastal areas, and in areas with intense vessel traffic 

and oil treatment (Nikolaou et al. 2009). 

Samples collected in Saldanha Bay in 1999 were analysed for the presence of hydrocarbons. 

No PAHs were detected in the samples, but low levels of contamination by aliphatic (straight chain) 

molecules, which pose the lowest ecological risk, were detected. This suggests that the main source 

of contamination is the spilling and combustion of lighter fuels from fishing boats and recreational 

craft (Monteiro et al. 1999). 

Sediment samples were collected at five sites in the vicinity of the ore quay and in April 2010 

and tested for hydrocarbon contamination. The total petroleum hydrocarbon contamination for all 

sites, with the exception of SB14, fell below the ERL value stipulated by the NOAA. The total 

petroleum hydrocarbon concentration at site SB14 was equal to the ERL value. Sediment samples 

from the same five sites were analysed by the CSIR for hydrocarbon content in 2011. No 

hydrocarbons were detected at a detection limit of 20 mg/kg. 

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Aquatic macrophytes 

6 AQUATIC MACROPHYTES IN LANGEBAAN LAGOON 

Three distinct intertidal habitats exist within Langebaan Lagoon: seagrass beds, such as those of the 

eelgrass Zostera capensis; salt marsh dominated by cordgrass Spartina maritime and Sarcocornia 

perennis; and unvegetated sandflats dominated by the sand prawn, Callianassa krausii and the 

mudprawn Upogebia capensis (Siebert and Branch 2005a,b). Sand and mud pawns are considered 

ecosystem engineers as their feeding and burrowing activities modify the local environmental 

conditions, which in turn modify the composition of the faunal communities (Rhoads and Young 

1970, Woodin 1976, Wynberg and Branch 1991). Seagrass beds and salt marshes perform an 

opposite and antagonistic engineering role to that of the sand and mud prawns as the root-rhizome 

networks of the seagrass and saltmarsh plants stabilize the sediments (Siebert and Branch 2005a). 

In addition, the three dimensional leaf canopies of the seagrass and saltmarsh plants reduce the 

local current velocities thereby trapping nutrients and increasing sediment accretion (Kikuchi and 

Peres 1977; Whitfield 1989, Hemmingra and Duarte 2000). The importance of seagrass and 

saltmarsh beds as ecosystem engineers has been widely recognized. The increased food abundance, 

sediment stability, protection from predation and habitat complexity offered by seagrass and 

saltmarsh beds provide nursery areas for many species of fish and invertebrates and support, in 

many cases a, higher species richness, diversity, abundance and biomass of invertebrate fauna 

compared to unvegetated areas (Kikuchi and Peres 1977, Whitfield 1989, Hemmingra and Duarte 

2000, Heck et al. 2003, Orth et al. 2006, Siebert and Branch 2007). Seagrass and saltmarsh beds are 

also important for waterbirds some of which feed directly on the shoots and rhizomes, forage 

amongst the leaves or use them as roosting areas at high tide (Baldwin & Lovvorn 1994, Ganter 

2000, Orth et al. 2006). 

Seagrass 

Saltmarsh 

Figure 6.1. 

Seagrass (black) and saltmarsh (green) near Bottelary in Langebaan Lagoon. Source: Google 

Earth. 

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6.1 Long term changes in seagrass in Langebaan Lagoon 

Seagrass beds are particularly sensitive to disturbance and are declining around the world at rates 

comparable to the loss of tropical rainforests, placing them amongst the most threatened 

ecosystems on the planet (Waycott et al. 2009). The loss of seagrass beds is attributed primarily to 

anthropogenic impacts such as coastal eutrophication, alterations to food webs caused by the 

overexploitation of predatory fish, and modified sediment dynamics associated with coastal and 

harbour development (Waycott et al. 2009). The loss of seagrass meadows has been shown to have 

profound implications for the biodiversity associated with them, including loss of invertebrate 

diversity, fish populations, that use the sheltered habitat as nurseries, and waterbirds, that use the 

seagrass meadows as foraging grounds during their non-breeding period (Hughes et al. 2002). 

Long-term changes in seagrass beds in Langebaan Lagoon have been investigated by Angel 

et al. 2006 and Pillay et al. (2010). Angel et al. (2006) focused on long term trends at Klein 

Oesterwal and Bottelary, and was able to show that the width of the Z. capensis bed changed 

substantially between 1972 and 2004, with three major declines evident in this period (Figure 6.2). 

The first occurred in the late 1970s, and was followed by a slow recovery in the early 1980’s, the 

second occurred between 1988 and 1993 and the third between 2002 and 2004 (Angel et al. 2006). 

Mirroring this decline were the striking fluctuations of the small endemic limpet Siphonaria 

compressa, which lives on the leaves of Z. capensis and is completely dependent on the seagrass for 

its survival. The densities of S. compressa collapsed twice in this period to the point of local 

extinction, corresponding with periods of reduced seagrass abundance (Figure 6.2). At Bottelary, the 

width of the seagrass bed and densities of S. compressa followed the same pattern as at Klein 

Oesterwal, with a dramatic collapse of the population between 2002 and 2004, followed by a rapid 

recovery in 2005 (Angel et al. 2006). The first decline in seagrass cover coincided with blasting and 

dredging operations in the adjacent Saldanha Bay, but there is no obvious explanation for the 

second decline (Angel et al. 2006). 

Pillay et al. (2010) documents changes in seagrass Zostera capensis abundance at four sites 

in the Lagoon – Klein Oesterwal, Oesterwal, Bottelary and the Centre banks using a series of aerial 

photographs covering the period 1960 to 2007. During this time the total loss of Z. capensis 

amounted to 38% or a total of 0.22 km 2 across all sites. The declines were most dramatic at Klein 

Oesterwal where close to 99% of the seagrass beds were lost during this period, but were equally 

concerning at Oesterwal (82% loss), Bottelary (45% loss) and Centre Bank (18% loss) (Pillay et al. 

2010). Corresponding changes were also observed in densities of benthic macrofauna at these sites, 

with species that were commonly associated with Zostera beds such as the starfish Parvulastra 

exigua and the limpets Siphoneria compressa and Fisurella mutabilis and general surface dwellers 

such as the gastropods Assiminea globules, Littorina saxatilis, and Hydrobia sp. declining in 

abundance, while those species that burrowed predominantly in unvegetated sand, such as 

amphopods Urothoe grimaldi and the polychaetes Scoloplos johnstonei and Orbinia angrapequensis 

increased in density. Pillay et al. (2010) was also able to show that the abundance of at least one 

species of wading bird Terek sandpiper which feeds exclusively in Zostera beds was linked to 

changes in the size of these beds, with population crashes in this species coinciding with periods of 

lowest seagrass abundance at Klein Oesterwal. By contrast, they were able to show that populations 

of wader species that do not feed in seagrass beds were more stable over time. 

While the precise reasons for the loss of Z. capensis beds remain speculative, the impact of 

human disturbance cannot be discounted, particularly at Klein Oesterwal where bait collection is 

common (Pillay et al. 2006). By 2007 the intertidal habitat at Klein Oesterwal had been transformed 

from a seagrass bed community to an unvegetated sand flat which was colonized by the burrowing 

sandprawn Callinassa kraussi and other sandflat species that cannot live in the stabilized sediments 

promoted by the seagrass (Pillay et al. 2010). The burrowing sandprawn turns over massive 

quantities of sediment and once established effectively prevents the re-colonization of seagrass and 

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the species associated with it (Siebert and Branch 2005, Angel et al. 2006). The long-term effects of 

the loss of seagrass at Klein Oesterwal, and to lesser degree at Bottelary and the Central banks, are 

not yet fully understood. However, studies suggest that the reduced seagrass bed coverage and the 

associated changes to macro-invertebrates may have cascading effects on higher trophic levels 

(Whitfield et al. 1989, Orth et al. 2006). Alterations to fish species diversity and abundance, and 

changes in the numbers of water birds that forage or are closely linked to seagrass beds may be seen 

in Langebaan Lagoon as a result of the loss of seagrass beds (Whitfield et al. 1989, Orth et al. 2006). 

The loss of seagrass beds from Langebaan Lagoon is a strong indicator that the ecosystem is 

undergoing a shift, most likely due to anthropogenic disturbances. It is critical that this habitat and 

the communities associated with it be monitored in future as further reductions are certain to have 

long term implications, not only for the invertebrate fauna but also for species of higher trophic 

levels. 

Figure 6.2. 

Width of the Zostera beds and density of Siphonia at Klein Oesterwal and Bottelary in 

Langebaan Lagoon, 1972-2006. 

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No. saltmarsh patches 

Saltmarsh area (million m 2 ) 



6.2 Long term changes in Saltmarshes in Langebaan Lagoon 

Saltmarshes in Langebaan are reportedly an important habitat and breeding ground for a range of 

fish, bird and invertebrate species (Christie 1981, Day 1981, Gerrike 2008). Langebaan Lagoon 

incorporates the second largest salt marsh area in South Africa, accounting for approximately 30% of 

this habitat type in the country, being second only to that in the Knysna estuary (Allanson et al. 

1999). 

Long term changes in salt marshes in Langebaan Lagoon were investigated by Gerrike (2008) 

using aerial photographs taken in 1960, 1968, 1977, 1988 and 2000. He found that overall saltmarsh 

area had shrunk by only a small amount between 1960 and 2000, losing on average 8 000 m 2 per 

annum. Total loss during this period was estimated at 325 000 m 2 , or 8% of the total (Figure 6.3,). 

Most of this loss has been from the smaller patches of salt marsh that existed on the seaward edge 

of the main marsh. This is clearly evident from the change in the number of saltmarsh patches in the 

lagoon over time, which has declined from between 20 and 30 in the 1960s and 70s to less than 10 

at present. Gerrike (2008) attributed the observed change over time to increases in sea level that 

would have drown the seaward edges of the marshes or possibly reduced sediment inputs from the 

terrestrial edge (i.e. reduced input of windblown sand due to stabilization by alien vegetation and 

development). 

20 

15 

10 

5 

0 

1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 

Figure 6.3. Change in saltmarsh area over time in Langebaan Lagoon. (Data from Gerricke 2008) 

30 

25 

20 

15 

10 

5 

0 

1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 

Figure 6.4. 

Change in the number of discrete saltmarsh patches over time in Langebaan Lagoon. (Data 

from Gerricke 2008) 

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7 BENTHIC MACROFAUNA 


It is important to monitor biological criteria in addition to physio-chemical and ecotoxicological 

variables as biological indicators provide a direct measure on the state of the ecosystem. Benthic 

macrofauna are the biotic component most frequently monitored to detect changes in the health of 

the marine environment. This is largely because these species are short lived and therefore their 

community composition responds noticeably to changes in environment quality over time (Warwick 

1993). Given that they are also relatively non-mobile (as compared with fish and birds) they tend to 

be directly affected by pollution and they are easy to sample quantitatively (Warwick 1993). 

Furthermore they are well-studied scientifically, compared with other sediment-dwelling 

components (e.g. meiofauna and microfauna) and taxonomic keys are available for most groups. In 

addition community response to a number of anthropogenic influences has been well documented. 

Organic matter is one of the most universal pollutants affecting marine life and it can lead to 

significant community disturbance, as is the case in Saldanha Bay. High organic loading typically 

leads to eutrophication, which may bring about a number of community responses. These include 

increased growth rates, disappearance of organisms due to anoxia, changes in community 

composition and reduction in the number of species following repeat hypoxia and even complete 

disappearance of benthic organisms in severely eutrophic and anoxic sediments (Warwick 1993). 

The community composition of benthic macrofauna is likely to be impacted by the increased level of 

trace metals and hydrocarbons found in the sediments. In addition the areas that are heavily 

dredged are likely to be inhabited by a greater proportion of opportunistic species. 

The main aim of monitoring the health of an area is to detect the effects of stress, as well as 

to monitor recovery after an environmental perturbation. There are numerous indices, based on 

benthic invertebrate fauna information, which can be used to reveal conditions and trends in the 

state of ecosystems. These indices include those based on community composition, diversity and 

species abundance and biomass. Given the complexity inherent in environmental assessment it is 

recommended that several indices be used (Salas et al. 2006). The community composition, 

diversity, and species abundance and biomass of soft bottom benthic macrofauna samples, collected 

in Saldanha Bay and Langebaan Lagoon in 2011, are considered in this report. 

7.2 Historic data on benthic macrofauna communities in Saldanha Bay 

The oldest records of benthic macrofauna species occurring in Saldanha Bay date back to the 1940’s, 

prior to the construction of the iron-ore terminal and Marcus Island causeway. Available data from 

this study is, however, not comparable with subsequent studies and as such cannot be used for 

establishing conditions in the environment prior to any of the major developments that occurred in 

the Bay. Moldan (1978) conducted a study in 1975 where the effects of dredging in Saldanha Bay on 

the benthic macrofauna were evaluated. Unfortunately, this study only provided benthic 

macrofauna data after the majority of Saldanha Bay (Small Bay and Big Bay) had been dredged. A 

similar study conducted by Christie and Moldan (1977) in 1975 examined the benthic macrofauna in 

Langebaan Lagoon, using a diver-operated suction sampler, and the results thereof provide a useful 

description of baseline conditions present in the Lagoon from this time. 

Several subsequent studies, conducted in the period 1975-1990, examined the benthic 

macrofauna communities of Saldanha Bay and/or Langebaan Lagoon, but are also, regrettably not 

comparable with any of the earlier or subsequent studies. Recent studies conducted by the CSIR in 

1999 (Bickerton 1999) and Anchor Environmental Consultants in 2004, 2008, 2009 and 2010 (Anchor 

Environmental Consultants 2004, 2009, 2010, 2011), do, however, provide comparative benthic 

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macrofauna data from Saldanha Bay and Langebaan Lagoon. In the intervening years between the 

1975 and 1999 studies, significant development took place in Saldanha Bay (previously described in 

this report) including ore export and dredging of Small Bay in 1997/98. The 1999 study was 

conducted approximately 12 months after dredging and is representative of a recovering benthic 

community. Direct comparisons between earlier studies are further complicated due to different 

equipment being used in 1975 than in 1999-2009. The study conducted in 1975 in Saldanha Bay 

(Moldan 1978) made use of a modified von Veen grab sampler weighted to 20 kg which sampled an 

area of 0.2 m 2 from the surface fraction of sediment whilst that of 1999-2009 made use of a diveroperated 

suction sampler which sampled an area of 0.24 m 2 to a depth of 30 cm. The former 

sampling technique (von Veen grab) would be expected to sample a smaller proportion of benthic 

macrofauna due to its limited ability to penetrate the sediment beyond the surface layers. The 

suction sampler effectively sampled to a depth of 30 cm, which is the range in which larger species, 

like prawns and crabs, are expected to occur. The study conducted in 1975 in Langebaan Lagoon 

(Christie and Moldan 1977) and those conducted by Anchor Environmental Consultants both made 

use of a diver-operated suction sampler which sampled an area of 0.24m 2 . However, in 1975 a 

depth of 60 cm was sampled while in surveys since 2004 a depth of only 30 cm was sampled. Thus, 

considering the differences in sampling techniques employed, it is likely that the changes reflected 

by the data between the 1975 and 1999-2008 in Saldanha Bay and Langebaan Lagoon are a function 

both of real changes that occurred in the Bay and an artefact of differences in sampling 

methodology. The exact location of sites sampled during 1975 and 1999-2008 studies also differed 

slightly (Figure 7.1), however, the broad distribution of sites throughout the sampling area ensures 

that the data collected are representative of Small Bay, Big Bay and Langebaan Lagoon and such can 

be compared with one another. 

7.3 Approach and methods used in monitoring benthic macrofauna in 2011 

7.3.1 Sampling 

A total of 30 sites were sampled for benthic macrofauna in 2011, ten of which were in Small Bay, 

seven in Big Bay, nine in Langebaan Lagoon, two in Salamander Bay and two in Donkergat (Figure 

7.1). The water depth ranged from 1.8 m to 21 m, with the shallowest sites being those in 

Langebaan Lagoon (Table 7.1). Samples were collected using a diver-operated suction sampler, 

which sampled an area of 0.08 m 2 to a depth of 30 cm and retained benthic fauna >1 mm in size in a 

muslin bag. Three suction samples were taken at each site and pooled, resulting in a total sampling 

surface area of 0.24 m 2 per site. These methods correspond exactly with those employed in 1999, 

2004 and 2008-2010 and thus facilitate comparisons between these sets of data. Samples were 

stored in plastic bottles and preserved with 5% formalin. 

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Figure 7.1. 

Sites sampled for benthic macrofauna between 1975 and 2011 in Saldanha Bay and Langebaan 

Lagoon. 

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Table 7.1. Depth at each of the sites sampled in 2011. 


Depth 

(m) Big Bay Depth (m) 

Langebaan 

Lagoon 

Depth (m) 

Salamander/ 

Donkergat 

SB1 10 BB20 20.9 LL31 5.5 D1 4.1 

SB2 7.8 BB21 10 LL32 4.4 D2 3.5 

SB3 5.2 BB22 11 LL33 3 S1 2.8 

SB8 10.9 BB25 10.3 LL34 4.1 S2 6.3 

SB9 14.7 BB26 15 LL37 3 

SB10 7.1 BB29 15 LL38 6.6 

SB14 15 BB30 3.4 LL39 5.7 

SB15 12 LL40 2.4 

SB16 16 LL41 0.8 

SB42 9.1 

Depth 

(m) 

In the laboratory, samples were rinsed of formalin, stained with Rose Bengal to aid in 

identification of biological material. All fauna were removed and preserved in 1% phenoxetol 

(Ethylene glycol monophenyl ether) solution. The macrofauna were then identified to species level 

where possible, but at least to family level in all instances. The biomass (blotted wet mass to four 

decimal places) and the abundance of species were recorded for each sample. 

7.3.2 Statistical Analysis 

The data collected from this survey were used for two purposes 1) to assess spatial variability in the 

benthic macrofauna community structure and composition between sites in 2011 and 2) to assess 

changes in benthic community structure over time (i.e. in relation to the 1999, 2004, 2008, 2009 and 

2010 surveys). Both the spatial and temporal assessments are necessary to provide a good 

indication of the state of the system. 

7.3.2.1 Community structure and composition 

Changes in benthic species composition can be the first indicator of disturbance, as certain species 

are more sensitive (i.e. likely to decrease in abundance in response to stress) while others are more 

tolerant of adverse conditions (and may increase in abundance in response to stress, taking up space 

or resources vacated by the more sensitive species). Monitoring the temporal variation in 

community composition also provides an indication of the rate of recovery of the ecosystem 

following disturbances in different areas of the system. This allows one to more accurately predict 

the impacts of proposed activities. “Recovery” following environmental disturbance is generally 

defined as the establishment of a successional community of species which progresses towards a 

community that is similar in species composition, density and biomass to that previously present (C- 

CORE 1996 and Newell 1998). The rate of recovery is thus dependent on the reference 

environmental conditions and the communities supported by such conditions. Given the spatial 

variability of environmental conditions (largely influenced by depth and exposure) as well as 

anthropogenic disturbances it is expected that recovery will vary spatially throughout the Saldanha 

Bay and Langebaan Lagoon system. 

Certain species are able to rapidly invade and colonise disturbed areas as they have high 

fecundity, rapid growth and rather short life-cycles (Newell 1998). These species are known as “rstrategists” 

or opportunistic species and their presence generally indicates unpredictable short-term 

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variations in environmental conditions which may result from either natural factors or 

anthropogenic activities. In stable environments the community composition is controlled 

predominantly by biological interactions rather than by fluctuations in environmental conditions. 

Species found in these conditions are known as “K-strategists” and are selected for their competitive 

ability. K-strategists are characterised by long-life spans, larger body sizes, delayed reproduction and 

low death rates. Intermediate communities with different relative proportions of opportunistic 

species and K-strategists are likely to exist between the extremes of stable and unstable 

environments. 

The statistical program PRIMER 6 (Clarke and Warwick 1993) was used to analyze the 

benthic macrofauna data. Data were root-root (fourth root) transformed and converted to a 

similarity matrix using the Bray-Curtis similarity coefficient. A cluster analysis was performed in order 

to find ‘natural groupings’ between samples (sites). The results of the cluster analysis are displayed 

on a dendrogram which graphically displays the similarity of sites by grouping the sites. Statistically 

significant clusters of sites are revealed using a SIMPROF analysis. These results were plotted 

geographically using ArcGIS to reveal any spatial trends in the sites grouped according community 

composition similarity. SIMPER analysis was used to identify species principally responsible for the 

clustering of sites. These results were used to characterise different regions of the system based on 

the communities present at the sites. It is important to remember that the community composition 

is a reflection of not only the physico-chemical health of the environment but also the ability of 

communities to recover from disturbances. 

7.3.2.2 Diversity Indices 

A number of indices (single numbers) can be used as measures of community structure; these 

include the total number of individuals (N), total number of species (S), the total biomass (B), and 

the species equability or evenness, which is a measure of how evenly individuals are distributed 

among different species. Diversity indices provide a measure of diversity, i.e. the way in which the 

total number of individuals is divided up among different species. Understanding changes in benthic 

diversity is important because increasing levels of environmental stress generally decrease diversity. 

Two different aspects of community structure contribute to community diversity, namely 

species richness and equability (evenness). Species richness refers to the total number of species 

present while equability or evenness expresses how evenly the individuals are distributed among 

different species. A sample with greater evenness is considered to be more diverse. It is important to 

note when interpreting diversity values that predation, competition and disturbance all play a role in 

shaping a community. For this reason it is important to consider physical parameters as well as other 

biotic indices when drawing a conclusion from a diversity index. 

The following measures of diversity were calculated for each sampling location using 

PRIMER V 6: 

The Shannon-Weiner diversity index (H’): H’ = - Σ i p i (log p i ) (1) 

Where pi is the proportion of the total count arising from the ith species. This is the most 

commonly used diversity measure and it incorporates both species richness and equability. 

The Pielou’s evenness index (J’): J’ = H’ observed / H’ max (2) 

Where H’max is the maximum possible diversity which would be achieved if all species were 

equally abundant (= log S). This is the most common expression of equability. 

The Margalef’s index (d) of species richness: D = (S-1)/ log N (3) 

Where S is the total number of species and N is the total number of individuals. 

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Species richness is often simply referred to as the total number of species (S), but this is very 

dependent on sample size. The Margalef’s index thus incorporates the total number of individuals 

(N) and is a measure of the total number of species present for a given number of individuals. 

The diversity (H’) value for each site was plotted geographically and this was used to 

interpolate vales for the entire system using ArcGIS in order to reveal any spatial patterns. The 

average diversity value was also then calculated for three pre-designated locations (Small Bay, Big 

Bay and Langebaan Lagoon) for 1999, 2004, 2008, 2009 and 2010. In order to test if the observed 

changes in diversity were statistically significant (p



in 2004, 2008, 2009 and 2010. SIMPER analysis revealed that a large suite of species (83 species) 

were responsible for much of the difference (90%) found between Langebaan Lagoon and Saldanha 

Bay in 2011. Opportunistic species such as the mud prawn (Upogebia capensis), the amphipod 

(Ampelisca spinimana) and the polychaete (Polydora) were found in higher abundance in Saldanha 

Bay compared to Langebaan Lagoon, while two Ostracod species and the amphipod, Ampelisca 

palmata were found in greater abundance in the Lagoon compared to Saldanha Bay. The 

polychaetes Notomastus latericeus and Marphysa depressa were found exclusively within the 

Lagoon. 

Figure 7.2. 

Dendrogram representing the similarity of sites (Bray Curtis Similarity) based on the benthic 

macrofaunal community composition sampled at Small Bay (SB), Big Bay (BB), Salamander Bay 

(S), Donkergat (D) and Langebaan Lagoon (LL) in 2011. The 30% level of similarity is indicated 

by the slice. Clusters of sites significantly similar are represented by the red dotted lines 

(SIMPROF). 

A further distinction of two groupings of sites within Saldanha Bay could be seen at the 30% level of 

similarity. The first grouping (A) included all Small Bay sites (with the exception of the Yacht Club 

basin and Multi-purpose Quay), all sites in Salamander Bay and Donkergat and sites along the Ore 

Terminal within Big Bay. These sites are all characterised by moderate to high levels of trace metal 

contamination and a relatively moderate to low mud component. The depth at these sites varies 

between 2.8 and 16 m. The second grouping (B) contained sites from the middle and southern 

sections of Big Bay. These sites were characterised by low trace metal concentrations and relatively 

moderate mud components. 

The cluster analysis also allowed us to identify sampling sites that are ‘outliers’, meaning 

that they have a very different species composition to other samples taken from the same area and 

thus do not fit into any groups. Species composition may differ at these sites due to anthropogenic 

impacts (such as pollution discharge) or certain environmental variables (e.g. a sudden increase in 

depth or change in the size of sediment particles). As was observed in all surveys since 2008, the site 

SB1 is an obvious outlier, most likely due to the fact that it had very low species abundance and 

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diversity (only 2 species in 2008, 4 species in 2009 and 2010, and 5 species 2011). As was evident in 

previous surveys, this site is characterized by very high levels of organic pollution and high trace 

metal concentrations. At the 30% level of similarity, the site at the Multi-purpose Quay (SB14) was a 

clear outlier. SB14 is dominated by two species, the deposit feeding bivalve Tellina gilchristi and the 

scavenging dog whelk Nassarius vinctus. Both are relatively small species and are likely to be 

opportunistic. 

Interestingly the site at the Multi-purpose Quay was most similar to the B grouping (central 

and southern Big Bay). The sediment analysis revealed that the Multi-purpose Quay had the second 

highest levels of trace metal contamination while the sites in the central and southern sections of 

the Bay had the lowest concentrations of trace metals (Figure 5.29). Figure 5.14, which shows the 

distribution of mud in the Bay, revealed that in 2011 the sites positioned centrally within Big Bay and 

at the Multi-purpose quay all had a relatively large mud fraction. The accumulation of mud at these 

sites is mostly likely due to the higher depth, while at the Multi-purpose quay it is most likely due to 

a combination of depth and shelter. This correlation suggests that the benthic macrofaunal 

communities in Saldanha Bay are more influenced by particle size composition than by the level of 

trace metal contamination. 

The cluster and SIMPROF analysis revealed 5 statistically similar groups of sites indicated by 

the red lines on the dendrogram (Figure 7.2). These groups were displayed geographically using GIS, 

which revealed a clear spatial pattern (Figure 7.5). Sites in the first group (A1 - orange) were all 

positioned in the northern reaches of Small Bay. This is the least disturbed area within Small Bay (as 

revealed by the levels of trace metal contamination and the distribution of mud) and the flushing of 

fine sediments and contaminants seems to be comparatively the best in this section of Small Bay. 

Sites in the second group (A2 - red) were all positioned around the Ore Terminal and in close 

proximity to the mussel farms. Historically these areas have shown a high level of disturbance due 

to a combination of dredging events, mariculture activities and reduced circulation. Sites from 

Donkergat and Salamander Bay comprised the third group (A3 - pink). This area had a similar 

particle size composition (Figure 5.14) and depth range to that found in the Lagoon (Table 7.1), 

however, the trace-metal contamination at this site was high (Figure 5.29). Sites from the central 

areas of Big Bay comprised the fourth group (B – green) and sites from the Lagoon comprised the 

fifth group (C - blue) (Figure 7.5). 

The benthic macrofaunal communities at all Small Bay, Salamander Bay and Donkergat sites 

(A1, 2 and 3) were characterised by the mud prawn Upogebia capensis and a polychaete species 

belonging to the genus Polydora (Table 7.2). Upogebia capensis, an opportunistic species, is typically 

found in sheltered bays where it creates burrows in fine muddy substrate. The mud prawn, which is 

common at most sites in Small Bay, has been dominant within Small Bay since the early nineties. 

Their initial increase in Small Bay was attributed to a reduction in water movement resulting from 

the construction of the iron ore terminal and the Marcus Island causeway (Jackson and McGibbon 

1991). The dominance of these species in these areas suggests that these sites are in the early 

phases of recovery or that the sites are subject to ongoing unpredictable environmental variations. 

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Figure 7.3 

Geographic representation of the results of a PRIMER analysis 

showing significant clustering of sites based on the similarity of 

trace metal concentrations (Euclidean Distance). Group A 

generally had the highest concentrations for all metals and group 

E the lowest (SIMPER analysis) 

Figure 7.4 

Variation in the percentage mud in sediments in Saldanha Bay 

and Langebaan Lagoon as indicated by the 2011 survey results. 

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The Small Bay sites (groups A1 and A2) were also characterised by the purple-lipped dog 

whelk Nassarius speciosus, the three legged crab (Thaumastoplax spiralis), the amphipod 

Hippomedon normalis and the tongue worm (Ochateostoma capense). The carnivorous purplelipped 

dog whelk N. speciosus is also an opportunistic species that can tolerate anoxic conditions, 

and has been known to occur in high abundance under the mussel rafts in Small Bay (Stenton-Dozey 

2001). The three legged crab is a small crab (8 mm) which is found in small temporary burrows or 

sharing the burrows of prawns. The northern Small Bay sites were distinguished from those around 

the Ore Terminal by the higher abundance of the polychaete Nephtys hombergii, an ostracod and 

two polychaete species. N. hombergii, is a burrowing predator that feeds on juvenile molluscs, 

crustaceans, other polychaetes, diatoms and detritus. N. hombergii prefers to live in fine grained 

sediments, and the abundance of this species generally increases as grain size decreases. This 

species is also known to tolerate a low oxygen concentration (Fauchald and Bellan 2009). 

The sites around the Ore Terminal and in close proximity to the mussel farms (A2) were 

distinguished from northern Small Bay sites by the relatively high abundances of amphipod species, 

most notably Ampelisca anomala, Ampelisca spinimana and Paramoera capensis. Ampelisca sp. are 

detritivores and are known to be abundant in dredged areas and on fine sand. It is thus not 

surprising that they had become dominant at sites in close proximity to the Ore Terminal in Small 

Bay and Big Bay given that this area has undergone periodic dredging. 

The Salamander Bay and Donkergat sites were distinguished from the Small Bay sites and 

Big Bay sites in close proximity to the Ore Terminal by the relatively high abundance of the 

opportunistic bivalve Tellina gilchristi, the polychaete Euclymene sp., the predatory crown crab 

Hymenosoma obiculare and the bivalve Venerupis corrugata. The small deposit feeding bivalve T. 

gilchristi was also a dominant species at the central Big Bay sites in 2011 and in previous surveys 

(Anchor Environmental Consultants 2010) and is likely to be an opportunistic species. The crown 

crab, which has previously dominated at most of the Small Bay sites (2010), lives in soft sediments, 

spending the day buried and coming out at night to feed on small crustaceans (Hill and Forbes 1979). 

The central Big Bay sites were characterised by a high abundance of the cumacean, Iphinoe 

africana, which is a small detritivorous crustacean. These sites were also dominated by amphipods 

(Amphilisca spinimana and Photis longidactylus), polychaetes (Scolaricia dubia and Sabellides 

luderitzi), sandworms (Nephyts sphaerocirrata and N. hombergi), dog whelks (Nassarius vinctus and 

N. speciosus) and the deposit feeding bivalve T. gilchristi. The deposit feeding polychaete S. dubia 

has been found in soft bottom habitats with a fine grained sediment texture and a high percentage 

of organic matter (Jayaraj et al. 2008). Sea pens are colonial marine cnidarians which were 

historically found widely distributed in Saldanha Bay. These filter-feeding organisms are typical K- 

strategists and are thus good indicators of the state of recovery of an area. The sea pen Virgularia 

schultzei was found in high abundance at sites at the southern and central reaches of Big Bay (BB25, 

BB29 and BB30) in 1991, 2004 and 2009. It was not recorded at these sites in 1999 and 2008 and 

was found at a much lower abundance in 2010. The 2011 survey revealed that the abundance of sea 

pen had increased since 2010, but not yet to the levels seen in 2009. These three sites are the only 

sites within Saldanha Bay where the sea pen has been recorded since 1999. The distribution of the 

sea-pen does not correlate with the distribution of mud, but interestingly rather with the levels of 

trace metal contamination as all sites have very low levels of contamination. This suggests that this 

species has a low tolerance for trace metal contamination. The fluctuations in the numbers of sea 

pens at these sites in recent years is indicative of a very patchy distribution. The presence of sea 

pens certainly supports the notion that the sites in central Big Bay are at an advanced state of 

recovery. 

The macrofauna in Langebaan Lagoon was dominated by the amphipod Ampelisca palmata, 

two ostracod species, the crown crab (Hymenosoma obiculare), and a polychaete belonging to the 

genus Maldanidae. Maldanidae are deposit feeding polychaetes which burrow in soft sediment. 

Ostracods are small crustaceans (1-4 mm), commonly known as seed shrimps, that mostly crawl 

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through surface layers of sand or mud. They may be carnivores, filter feeders or scavengers (Branch 

and Griffiths 1994). 

Figure 7.5. 

Geographic representation of the results of a PRIMER analysis showing significant clustering of 

sites based on the similarity of benthic macrofaunal community composition (Bray-Curtis 

coefficient) 

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Top 10 species contributing to similarity 



Table 7.2. Top ten species characterising the benthic macrofaunal communities in Small Bay, Salamander Bay and Donkergat in 2011. 

Group 

(similarity) 

A1 (62%) 

North Small Bay 

A2 (55%) 

Ore Terminal and Mussel Farms 

A3 (56%) 

Salamander Bay and Donkergat 

Species Common name/group Species Common name/group Species Common name/group 

Upogebia capensis Mud prawn Upogebia capensis Mud prawn Upogebia capensis Mud prawn 

Thaumastoplax 

spiralis 

Polydora sp. 

Hippomedon 

normalis 

Heteromastus 

filiformis 

Ochaetostoma 

capense 

Nassarius 

speciosus 

Three-legged crab Polydora sp. Polychaete Polydora sp. Polychaete 

Polychaete 

Amphipod 

Polychaete 

Tongueworms 

Ochaetostoma 

capense 

Thaumastoplax 

spiralis 

Hippomedon 

normalis 

Ampelisca 

spinimana 

Tongueworms Euclymene sp. Polychaete 

Three-legged crab 

Hymenosoma 

orbiculare 

Crown crab 

Amphipod Nephtys hombergi Sand worm 

Amphipod Ostracoda Ostracod 

Purple-lipped dog whelk Eunoe nodulosa Polychaete Diopatra monroi Polychaete 

Ostracoda A (spiky) Ostracod Paramoera capensis Amphipod Glycera convoluta Polychaete 

Nephtys hombergi Sandworm Ampelisca anomala Amphipod Tellina gilchristi Gilchrist's tellin 

Glycera convoluta Polychaete Nassarius speciosus Purple-lipped dog whelk Venerupis corrugata Corrugated Venus (Bivalve) 

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Top 10 species contributing to similarity 



Table 7.3. Top ten species characterising the benthic macrofaunal communities in Central Big Bay and Langebaan Lagoon in 2011. 

Group (Similarity) B (55%) 

Big Bay central 

C (50%) 


Species Common name/group Species Common name/group 

Iphinoe africana Cumacean (Crustacean) Ampelisca palmata Amphipod 

Ampelisca spinimana Amphipod Ostracoda B (smooth) Ostracod 

Sabellides luderitzi Polychaete Hymenosoma orbiculare Crown crab 

Nassarius vinctus Dog whelk Ostracoda A (spiky) Ostracod 

Photis longidactylus Amphipod Maldanidae sp. A Polychaete 

Nephtys sphaerocirrata Sand worm Thaumastoplax spiralis Three-legged crab 

Scolaricia dubia Polychaete Anemone Anemone 

Nephtys hombergi Sand worm Notomastus latericeus Polychaete 

Nassarius speciosus Purple-lipped dog whelk Paraphoxus oculatus Amphipod 

Tellina gilchristi Gilchrist's tellin Orbinia angrapequensis Polychaete 

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7.4.1.2 Temporal Analysis 


The suspension feeding sea-pen communities, which were reported in Small Bay in 1975, have 

recovered. Filter feeders have remained a dominant functional group; however, this group is made 

up mostly of the opportunistic mud prawn (Upogebia capensis) and smaller amphipod species 

belonging to the Ampelisca genus. In all surveys since 1999 detritivores have also been a dominant 

functional group, even more so in some years than filter feeders. Most notably, the 2008 survey 

revealed a dramatic reduction in the proportion of filter feeders and increase in the proportion of 

detritivores. The dominant detritivores included tongue worms (Ochaetostoma capense) and 

polychaetes belonging to the genera Polydora and Euclymene. This dramatic shift to a detritivore 

dominated benthic ecosystem, seen in 2008, can be attributed to an increased deposition and 

accumulation of fine particles and organic matter between 2004 and 2008 (See §5.2.1 for more 

details on this). This in turn, can be attributed to the restricted flow, altered wave energy, 

deposition of fine sediments and increased organic matter, which resulted from harbour 

construction and fish factory, mussel farm and sewage effluents. In all years since 2008, filter 

feeders have been the dominant functional group both in terms of abundance and biomass. The 

2011 survey revealed a substantial increase in the numbers of detritivores. This was not matched in 

terms of biomass indicating an increase in small detritivorous species such as the polychaetes 

belonging to the genus Polydora. 

Crustaceans have dominated the benthic macrofauna in terms of biomass and abundance in 

all surveys conducted since 1999. The 2008 survey revealed that there had been a drastic reduction 

in the overall biomass and abundance of benthic macrofauna in Small Bay. This was most likely a 

result of the dredging activities conducted at the Mossgas quay and the Multi Purpose Quay in 

2007/08. Much of the reduction in biomass in 2008 could be accounted for by the reduced biomass 

of crustaceans, however the abundance of crustaceans did not decrease in the same manner. This 

indicates that many small crustaceans (most likely r-selective) dominated the benthic community 

following dredging. 

Since 2008 the average biomass in Small Bay has been increasing. This increase in biomass 

can be principally accounted for by the increased biomass of crustaceans and tongue worms 

(Echiuroidea) between 2008 and 2011. Interestingly, the abundance of crustaceans declined 

between 2008 and 2009, while the biomass increased. This suggests that the community had shifted 

from one composed primarily of small, opportunistic crustaceans to one composed of fewer, larger, 

(most likely K-selective) crustaceans in 2009. Small (low biomass) 1 polychaetes increased 

substantially in abundance between 2008 and 2009, then declined again in 2010. This suggests that 

the polychaetes were able to compete with small opportunistic crustaceans and colonise the 

recently disturbed benthic habitat between 2008 and 2009. It is likely that the polychaetes were 

then outcompeted between 2009 and 2010 by the growing populations of larger crustacean species. 

This is a possible indication of the succession in benthic macrofauna communities following the 

2007/08 dredging. Other signs of the recovery of the system evident from the 2010 and 2011 

surveys include the increase in the average biomass and abundance of gastropods and bivalves 

between 2008 and 2011. However, the 2011 survey revealed a substantial increase in the 

abundance of polychaetes. This increase was not reflected by the biomass results, indicating that 

once again the Small Bay sites had been colonised by small polychaete species. The reasons for this 

1 This is evident given that the overall biomass of polychaetes did not increase substantially while the abundance 

did. These are most likely small, fast growing r-selected species. 

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increase are not clear given that, based on the increases in other taxonomic groups, the ecosystem 

did not appear to have been negatively disturbed by anthropogenic or natural perturbations. The 

increase in small polychaete species (predominantly detritivores) is likely to be a result of biological 

interactions. 


Crustaceans and polychaetes have dominated the benthic macrofauna community in Big Bay in 

terms of abundance in all surveys conducted since 1999, while crustaceans and tongue worms 

(Echiuroidea) have dominated in terms of biomass. The overall biomass and abundance of benthic 

macrofauna in Big Bay increased between 1999 and 2004. This is an indication that benthic 

environment in Big Bay had been recovering since the dredging events of 1997/8. A dramatic 

decrease in both the abundance and biomass of benthic macrofauna in Big Bay was seen between 

2004 and 2008. It is likely that this was a response to the dredging events in Small Bay (maintenance 

dredging of the Multi Purpose Terminal) in 2007/8 and off north beach at the northern end of 

Langebaan Lagoon. Much of the reduction in biomass and abundance could be attributed to the loss 

of crustaceans. There was also a dramatic reduction in the density of polychaetes between 2004 

and 2008. 

There was a substantial increase in the abundance and biomass of benthic macrofauna in Big 

Bay between 2008 and 2009. Much of the increase in abundance was attributed to the increase in 

polychaetes. This was however not reflected in the biomass, indicating that the community had 

become dominated in terms of abundance by small polychaetes. The increase in the overall biomass 

of the benthic community between 2008 and 2009 was principally attributed to an increase in 

crustacean biomass. The results of the 2010 survey revealed that the abundance of benthic 

macrofauna had decreased while the biomass had increased. This indicates that fewer, larger 

organisms were dominating, and possibly leading to a reduction in the number of smaller organisms 

through predatory or competitive community interactions. This is a typical sign of the succession of 

a system following a disturbance. Interestingly, the abundance of polychaetes and crustaceans 

increased dramatically between 2010 and 2011. This result was not reflected in the biomass results 

indicating that small crustaceans and polychaetes had colonised the Big Bay area by 2011. The 

reason for the dramatic increase in the abundance of small polychaetes and crustaceans in Big Bay is 

not clear. A similar increase in the abundance of small polychaetes was also seen in Small Bay. It is 

likely that a natural Bay-wide fluctuation, possibly based on nutrient availability and productivity, 

may have occurred between 2010 and 2011, which supported an increase in the abundance of small 

polychaetes. The stability of other taxonomic groups and of the proportions of functional groups 

suggests that the system has not been subject to a negative disturbance and remains in a state of 

recovery following dredge events 

The biomass of the benthic community in Big Bay has been dominated by detritivores in all 

years except 2008 when scavengers became dominant. The increased proportion of scavengers was 

not reflected in terms of abundance suggesting that few, large scavenging species and many, small 

opportunistic detritivores colonised the benthic habitat following dredging. Since 2008, the benthic 

community has shifted back to one dominated by detritivores both in terms of abundance and 

biomass, indicating that larger detritivores had re-established. Filter feeding organisms are more 

abundant and make a greater contribution to the biomass of benthic macrofauna in Big Bay than in 

Small Bay. 


Langebaan Lagoon generally supports a much lower abundance and biomass of benthic macrofauna 

than Saldanha Bay. This may be due to the fast water movements and high levels of tidal variation 

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experienced in the Lagoon. The Lagoon is dominated in terms of abundance by polychaetes and 

crustaceans and in terms of biomass, by crustaceans. 

The overall biomass in Langebaan Lagoon declined sharply between 1975 and 2004. The 

reduction in biomass was linked to a reduction in the abundance of many of the taxa present in 1975 

(bivalves, polychaete worms, gastropods, echinoderms, and sea-pens). The overall abundance and 

biomass of macrofauna in Langebaan Lagoon declined sharply again between 2004 and 2008. The 

2008 survey also indicated that the proportion of filter feeders had been drastically reduced. 

The biomass then almost doubled between 2008 and 2009, principally owing to a marked 

increase in crustaceans. The abundance of macrofauna did not increase proportionately suggesting 

that larger-bodied crustaceans colonised the lagoon between 2008 and 2009. There were further 

increases in the abundance and biomass of benthic macrofauna between 2009 and 2010. The 

increase in the overall biomass in Langebaan Lagoon in 2010 was mainly due to increases in the 

biomass of polychaetes and echinoderms while the increased abundance of macrofauna was 

principally attributed to a marked increase in detritivorous crustaceans. The 2011 survey revealed 

that the abundance of small (low biomass) polychaetes had increased in the Lagoon, while the 

overall biomass of crustaceans had increased. In addition bivalve communities had increased both 

in terms of abundance and biomass. The overall biomass measured in 2010 and 2011 exceeded that 

measured in 1975, however the diversity of taxa has been reduced and crustaceans overwhelmingly 

dominate the benthic macrofauna biomass. This suggests that the Lagoon may have undergone an 

ecosystem shift. The 2011 survey results suggest that the Lagoon is in a relatively healthy state 

given the increases in biomass and abundance and relative stability of functional groups. However, 

similar to that seen in Saldanha Bay, there had been an increase in the abundance of small 

polychaetes. The results of the sediment survey in 2011 also revealed system-wide reduction in the 

mud content and increases in the concentrations of some trace metals. The sediment results 

coupled with the system wide trends seen in the benthic macrofaunal communities certainly suggest 

a system wide perturbation, the source or cause of which is unclear. 

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Average number of individuals per m² 

Proportion of total number of individuals 

Average wet mass per m² 

Proportion of total biomass 



3000 

2500 

2000 

1500 

1000 

1400 

1200 

1000 

800 

600 

400 

Polychaeta 

Crustacea 

Gastropoda 

Bivalvia 

Echinodermata 

500 

200 

Pennatulacea (sea pen) 

0 

1999 2004 2008 2009 2010 2011 


0 

1999 2004 2008 2009 2010 2011 


Echiuroidea (Tongue worm) 


100% 

90% 

80% 

70% 

60% 

50% 

40% 

30% 

20% 

10% 

0% 

1999 2004 2008 2009 2010 2011 

100% 

90% 

80% 

70% 

60% 

50% 

40% 

30% 

20% 

10% 

0% 

1999 2004 2008 2009 2010 2011 

SCAVENGER 

PREDATOR 

GRAZER 

FILTER FEEDER 

DETRITIVORE 



Figure 7.6. 

Overall trends in the biomass and abundance of benthic macrofauna in Small Bay as shown by taxonomic and functional groups. 

144 

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6000 

5000 

4000 

3000 

2000 

1000 

0 

1999 2004 2008 2009 2010 2011 


1000 

900 

800 

700 

600 

500 

400 

300 

200 

100 

0 

1999 2004 2008 2009 2010 2011 


Polychaeta 

Crustacea 

Gastropoda 

Bivalvia 

Echinodermata 




100% 

90% 

80% 

70% 

60% 

50% 

40% 

30% 

20% 

10% 

0% 

1999 2004 2008 2009 2010 2011 


100% 

90% 

80% 

70% 

60% 

50% 

40% 

30% 

20% 

10% 

0% 

1999 2004 2008 2009 2010 2011 


SCAVENGER 

PREDATOR 

GRAZER 

FILTER FEEDER 

DETRITIVORE 

Figure 7.7. 

Overall trends in the biomass and abundance of benthic macrofauna in Big Bay as shown by taxonomic and functional groups. 

145 

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3500 

400 

Polychaeta 

3000 

2500 

2000 

1500 

1000 

500 

0 

1999 2004 2008 2009 2010 2011 

350 

300 

250 

200 

150 

100 

50 

0 

1975 1999 2004 2008 2009 2010 2011 

Crustacea 

Gastropoda 

Bivalvia 

Echinodermata 






100% 

90% 

80% 

70% 

60% 

50% 

40% 

30% 

20% 

10% 

0% 

1999 2004 2008 2009 2010 2011 


100% 

90% 

80% 

70% 

60% 

50% 

40% 

30% 

20% 

10% 

0% 

1999 2004 2008 2009 2010 2011 


SCAVENGER 

PREDATOR 

GRAZER 

FILTER FEEDER 

DETRITIVORE 

Figure 7.8. 

Overall trends in the biomass and abundance of benthic macrofauna in Langebaan Lagoon as shown by taxonomic and functional groups. 

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7.4.2 Species Diversity Indices 

7.4.2.1 Spatial Analysis 

Trends in species diversity (represented by the Shannon Weiner Index, H’) for Saldanha Bay and 

Langebaan Lagoon in 2010 are presented in Figure 7.9. Small bay generally had the lowest species 

diversity of the three areas and Langebaan Lagoon the highest. Spatial patterns of diversity were 

patchy throughout the Lagoon and Big Bay. This result is consistent with previous surveys. 

The diversity of species in Small Bay is lowest at the Multi-purpose Quay (SB14). This is 

mostly likely due to the relatively frequent disturbances experienced at the site which would allow 

for few opportunistic species to colonize the area and prevent longer living K-strategist species from 

becoming established. The diversity at the remainder of sites in Small Bay was low to moderate. 

The area has been subject to permanent modifications to current patterns following the 

development of the causeway and ore terminal. This coupled with the range of ongoing activities in 

and around Small Bay, is likely to have changed the nature of the environment such that 

communities will never recover to their original pre-development state. However; the analysis of 

the community composition suggests that “recovery” to a healthy, albeit modified community state, 

is possible. The patchy diversity values as well as the spatial variations in community composition 

are in indicative of community recovery rates which vary over spatial scales and are dependent on 

both the nature of the environment (depth and exposure) and the frequency and type of 

anthropogenic disturbance. 

The diversity of benthic macrofauna in Big Bay was fairly low throughout, with the exception 

of BB26 and BB29 which had comparatively moderate diversities. The analysis of the sediment 

characteristics suggested that the central and southern areas of Big Bay were in a relatively healthy 

state compared to the rest of the system. It is likely that the communities at these sites are stable 

with low levels of environmental disturbance. The intermediate disturbance hypothesis suggests 

that at very low frequencies of disturbance most of the community will reach and remain at a climax 

state with competitive exclusion reducing the diversity to moderate levels. The sediment analysis 

results form 2011 suggest that the northern areas of Big Bay along the Ore Terminal have similar 

levels of contamination to that seen in Small Bay. The relatively low species diversity at these sites 

suggests that this area of Big Bay has been more recently or frequently disturbed than the central 

part of the Bay. Site BB30, which also showed a relatively low diversity, is a very shallow and 

exposed site. The communities at this site are thus subject to ongoing disturbance and are not likely 

to progress much beyond a pioneer phase with relatively low diversity values. Indeed site BB30 was 

dominated by a high abundance of small deposit feeding polychaetes belong to the Spionidae family. 

The diversity of benthic macrofauna recorded in 2010 in the Lagoon appeared patchy, with 

relatively high levels of diversity at most sites and low levels of diversity at sites LL32 (Kraalbaai) and 

LL41 (southern reaches of Lagoon). The Lagoon comprises a system of shallow sand bars and deeper 

channels which are subject to strong currents and tidal activities. This ongoing natural disturbance 

varies spatially and temporarily depending on sediment dynamics within the lagoon. The high 

diversity levels recorded at many of the sites may be a result of intermediate levels of disturbance 

which would allow for communities to pass the pioneering phase and increase in diversity but 

without reaching a stable state. The areas with low diversity may be a result of high levels of 

disturbance selecting for a few opportunistic species. 

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Figure 7.9. 

Variation in the diversity of the benthic macrofauna in Saldanha Bay and Langebaan Lagoon as 

indicated by the 2010 survey results. (H’ = 1.5 indicates low diversity, H’ = 3.5 indicates high 

diversity) 

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7.4.2.2 Temporal Analysis 

Species Diversity (H’) within Small Bay, decreased significantly between 1999 and 2008 (p



7.4.3 Linking Ecological Indices to Environmental Variables 

Environmental variables (Al, Fe, As Cd, Cr, Cu, Ni, Pb, Zn and organic carbon) were analyzed 

using principal component analysis, and the results are shown in Figure 7.11. The sediment sample 

SB1 and SB14 are clearly different from all others (characterized by a high pollution load), and this is 

also the case with the benthic macrofauna samples from this site. There is a very slight clustering of 

sites according to the groupings indicated by the SIMPROF analysis. This suggests that 

contamination levels did correlate with and potentially have an impact on community composition. 

However it is important to remember that trace metal contamination levels as well as benthic 

community composition are influenced by sediment particle size which in turn is affected by depth 

and exposure. The PCA only considers contamination levels and correlations seen between the PCA 

and benthic community clustering may in fact be related to particle size. The PCA may therefore 

exaggerate the extent of influence which trace metal contamination may be having on benthic 

community composition. It is thus important to view the various factors in isolation using the 

second method, bubble plots on the MDS graphs. 

Figure 7.11. Two-dimensional PCA ordination of the environmental variables (metals, POC and PON; 

transformed and normalized) for Saldanha Bay 2010. Sites are labelled according to significant 

groupings revealed by the SIMPROF analysis. 

As described earlier, MDS plots were generated from macrobenthic abundance data to 

identify if there were any similarities in community structure between samples drawn from different 

areas of the Bay and Lagoon. Environmental data was then superimposed on top of the MDS plots in 

the form of bubbles that are scaled in accordance with the magnitude/concentration of the 

parameter in question (i.e. larger bubbles represent higher concentrations of metals for example). 

The aim of superimposing bubble plots onto the macrobenthic MDS was to assess whether the 

spatial variability in the benthic community composition was linked to any specific contamination 

gradients or environmental variable(s). 

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Depth and the percentage mud appear to be the principle abiotic factors that correlate with, 

and most likely lead to distinctions in the benthic macrofauna community composition between 

Langebaan Lagoon and Saldanha Bay. Saldanha Bay is deeper and the sediments contain a higher 

percentage of mud compared to Langebaan Lagoon. This higher proportion of fine grained particles 

also correlated with trace metal content. This can clearly be seen at site SB1 and SB14, which had 

the highest mud content and the highest trace metal content. The benthic community compositions 

at these sites were clear outliers. Site SB1 represents an impoverished community with a very low 

abundance and diversity of benthic macrofauna (only 5 species and 6 individuals recorded in 2011). 

This site was also identified as impoverished in previous surveys, most likely owing to the high 

concentrations of organic matter and anoxic conditions within the sediments. Indeed, this site has 

elevated cadmium levels relative to all the other sites sampled. In addition it has relatively high 

concentrations of lead, copper, nickel, organic carbon (TOC) and mud. Site SB14 had a higher 

number of species (14) but was completely dominated by one species, the deposit feeding bivalve 

Tellina gilchristi. 

The concentrations of trace metals did correlate with the distinction in community 

composition seen between sites in Small Bay and adjacent to the Ore Terminal in Big Bay, and sites 

in the central and southern reaches of Big Bay. Any further distinction between the other sites 

sampled in Small Bay according to benthic macrofauna community composition does not clearly 

correlate with any of the other environmental variables measured. It is likely that natural 

community interactions and possibly other environmental variables not measured in this report are 

having an influence on the community composition in Small Bay. 

Figure 7.13, Figure 7.12 and Figure 7.14 indicate that Langebaan Lagoon is characterised by 

shallow water depths, and sediments with low mud, particulate organic carbon and very low to 

negligible concentrations of trace metals (with the exception of Ni). This suite of abiotic factors 

clearly correlates with the cluster of Langebaan sites that have been grouped according to benthic 

macrofauna community structure. This indicates that this particular suite of abiotic factors strongly 

influences the benthic macrofauna communities. More fine scale differences between the benthic 

communities within the lagoon are clearly not shaped by the abiotic variables considered here and it 

is likely that other factors such as water circulation patterns and community interactions influence 

the species composition within the lagoon. 

Figure 7.12. MDS of Saldanha Bay and Langebaan Lagoon benthic macrofauna abundance (2011) with 

superimposed circles representing depth (Increasing circle size = deeper) 

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Figure 7.13. MDS plot of Saldanha Bay and Langebaan Lagoon benthic macrofauna abundance (2011) with 

superimposed circles representing abiotic factors: Total Organic Carbon (TOC), and % Mud 

(Increasing circle size = larger measurement). 

Figure 7.14. MDS of Saldanha Bay benthic macrofauna abundance (2011) with superimposed circles 

representing concentrations of select metals: Cu, Cd, Pb and Ni. Circle size is proportional to 

magnitude of concentration (increasing circle size = larger concentration) 

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7.5 Discussion 

Macrobenthic community structure within Saldanha Bay has been the subject of several studies, 

most of which focus on anthropogenic impacts to benthic health. Kruger et al. (2005) studied the 

changes in epibenthos within Saldanha Bay between the 1960s and 2001, and found that there was 

a substantial change in benthic communities before and after harbour development. Severe 

declines in a number of species were reported, along with a change in the relative dominance of 

different trophic (feeding) groups, with a reduction in the number of suspension feeders and an 

increase in the numbers of opportunistic scavengers and predators (Kruger et al. 2005). Organisms 

that preferred sheltered habitats also became more common. These changes were attributed to the 

restricted flow, altered wave energy, deposition of fine sediments and increased organic matter, 

which resulted from harbour construction and fish factory and mussel farm effluents (Kruger et al. 

2005). 

Previous studies also indicate that the most significant changes in benthic faunal structure 

occurred directly after dredging and deepening of the harbour from 1974 to 1976. Up to 25 million 

cubic meters of sediment were dredged from the Bay, and the dredge spill was used to construct the 

new harbour wall (Moldan 1978). Dredging directly impacts benthic community structure for a 

variety of reasons: many organisms are either directly removed or buried, there is an increase in 

turbidity and suspended solids, organic matter and toxic pollutants are released and anoxia results 

from the decomposition of organic matter (Moldan 1978). Within Saldanha Bay, many species 

disappeared completely after dredging (most notably the sea-pen, Virgularia schultzei), only to be 

replaced by opportunistic species such as crabs and polychaetes (Moldan 1978). Harbours are 

known to be some of the most highly altered coastal areas that characteristically suffer poor water 

circulation, low oxygen concentrations and high concentrations of pollutants in the sediment 

(Guerra-Garcia and Garcia-Gomez 2004). Beckley (1981) found that the marine benthos near the 

iron-ore loading terminal in Saldanha Bay was dominated by pollution-tolerant, hardy polychaetes. 

This is not surprising since sediments below the ore terminal were found to be anoxic and high in 

hydrogen sulphide (characteristically foul smelling black sludge). 

7.6 Small Bay 

An assessment of the temporal variation in the composition, abundance, biomass and diversity of 

benthic macrofauna communities in Small Bay indicates two principle drivers influencing the benthic 

ecology in the area. The first and most obvious being the construction of the Ore Terminal and the 

Marcus Island causeway. These developments altered and reduced currents and wave energy in 

Small Bay. This permanent and ongoing impact has modified and reduced the capacity of the 

benthic environment to recover from large scale perturbations such as dredging. In addition, this 

has changed the nature of the environment and by doing so has changed the community structure 

and composition of species which can be supported by that environment. It is thus unlikely that 

benthic communities will ever recover to the pre-development state in Small Bay. However, this 

does not suggest the ecosystems in Small Bay cannot reach a “healthy” state. Indeed, increases in 

the abundance, biomass and diversity of benthic macrofaunal communities since 2008 do indicate 

the ongoing recovery of the area. Assessments of the community composition within Small Bay in 

2011 reveal spatial variations with sites in the northern reaches (further from dredged areas and Ore 

Terminal) having larger species and slightly higher diversity values. This suggests that impact 

intensity and recovery rates vary over spatial scales within Small Bay. 

The second principle driver of change with fairly wide-scale impacts in Small Bay is dredging. 

Dredge events have generally lead to an increase in mud content and trace mental contamination 

levels coupled with a reduction in macrofauna biomass, abundance and diversity. In the years 

immediately after dredge events the benthic communities have been dominated by fast growing 

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opportunistic species such as the shrimps Ampelisca spinimana and A. anomala. The most recent 

dredging event in Small Bay was the maintenance dredging at the Mossgas quay and the Multi 

Purpose Terminal. Dredging took place at these locations from the end of 2007 to March/April 2008 

with an estimated 50 000 m 3 of seabed material being removed from both terminals in order to 

deepen the berth. The 2008 survey of sediments revealed that there had been increases in the 

percentage mud, particulate organic carbon, cadmium, lead, copper and nickel at most of the Small 

Bay sites. The 2008 survey of the benthic macrofauna in Small Bay revealed that there had been 

drastic changes in the benthic macrofauna community. The average abundance and biomass of 

benthic macrofauna decreased and the diversity index (H’) decreased indicating that the proportion 

of fast growing opportunistic species in the community had increased. Indeed, the opportunistic 

shrimps Ampelisca spinimana and A. anomala had become dominant species in the Small Bay 

macrofauna community. Ampelisca sp. are detritivores and are abundant in dredging and on fine 

sand, and thus it is not surprising that they had become dominant at several sites in Small Bay. 

Data on physical parameters from 2009 and 2010 (percentage mud, particulate organic 

carbon and trace metal concentrations) indicated that the health of the Bay was improving. Signs of 

the succession of the benthic macrofaunal community were evident when assessing temporal 

variation in community composition between 2008 and 2010. The 2008 results indicated that the 

abundance of the dominant mud prawn, Upogebia capensis was greatly reduced following dredging. 

With the reduction of U. Capensis, smaller, pioneer species more tolerant of disturbed conditions 

(viz. increased fines, organic carbon and trace metals) increased in abundance and came to 

dominate the community in this area. In this case the opportunistic, tolerant species were the 

shrimps Ampelisca spinimana and A. anomala. A year later (2009), following improvements to the 

physical environment, it was clear that with the still slightly suppressed levels of U. capensis, but 

detrivorous and filter feeding polychaetes were able to colonise Small Bay and become dominant 

species while Ampelisca sp. populations had reduced. It is likely that the shrimps were being 

outcompeted by the polychaetes and U. capensis. Another year later (2010) and following further 

improvements to physical parameters in the bay, the abundance and biomass of polychaetes had 

reduced, while there had been further increases in the abundance and biomass of U. capensis. In 

addition there had been increases in the abundance of the detritivorous, bivalve Tellina gilchristi and 

the carnivorous, gastropod Nassarius speciosus. It is possible that U. capensis has become a climax 

species for the present day Small Bay system which has been drastically altered from its historical 

state by the development of the causeway and iron ore terminal. The 2011 survey results revealed 

two clear clusters of sites based on community composition, one cluster around the Ore Terminal 

and one in the northern reaches of Small Bay. Those around the Ore Terminal were distinguished 

from the northern sites by high abundances of the opportunistic species such Ampelisca sp. The 

sites around the Ore Terminal also had a slightly lower diversity than those to the north. This 

indicates that the intensity or frequency of impact at these sites was greater and that the 

community is at an earlier stage of succession than the sites in northern Small Bay. 

A variety of ongoing activities within Small Bay are also likely to compromise ecosystem 

health including the discharge of effluents from fish factories, mariculture operations, shipping 

traffic, port and boating activity, discharge of sewerage effluent (via the Bok River, which drains into 

Small Bay), seepage or overflow from sewerage pump stations and septic tanks, and residential and 

industrial storm-water runoff (CSIR 2002). Environmental perturbations caused by these activities 

are most likely exacerbated by the poor water circulation and reduced wave energy within Small 

Bay, which effectively reduces the flushing capacity of the Bay and results in the build-up of 

contaminants. 

Pollution tolerant species have previously been found in high abundance at sites adjacent to 

fish factory outfalls (Christie and Moldan 1977). Effluent discharged from the fish factories contains 

high levels of organic matter (mainly bloodwater, fish flesh and offal), that settles out at varying 

distances from the outlet. Once it settles on the bottom, the organic matter in the effluent is broken 

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down by detritivores, which ultimately leads to hypoxia or even anoxia. Anaerobic conditions thus 

often prevail close to fish factory outlets and this adversely effects macrobenthic diversity and 

abundance (Christie and Moldan 1977). While it was not possible to isolate the effects of the fish 

factory effluent in this study, earlier studies have found that benthic macrofaunal communities 

within Small Bay in the immediate vicinity of the outfalls from these factories were impoverished, 

and that diversity increased with distance from the fish factory (Christie and Moldan 1977; Jackson 

and McGibbon 1991). It is quite likely therefore that the effects of this continued discharge of waste 

to Small Bay contributed to the decline in overall health of the system between 1999 and 2008. 

Mariculture operations situated within Saldanha are dominated by mussel and oyster farms. 

A study conducted in 1993 revealed that raft-culture of mussels in Small Bay was adversely affecting 

benthic ecology, with disturbed communities occurring beneath 78% of the mussel rafts (Stenton- 

Dozey et al. 1999). This was attributed to the high organic loading beneath the raft, resulting from 

faeces produced by mussels and other fouling organisms such as the sea squirt Ciona intestinalis 

settling and decomposing on the bottom below the rafts. Benthic communities below the mussel 

rafts were characterised by deposit feeders and carnivores with a rapid turnover time, and hence 

labelled as unstable (Stenton-Dozey et al. 1999). Again, mussel rafts are likely to have contributed to 

the declines in benthic diversity and health observed in Small Bay between 1999 and 2008, but it has 

not been possible to isolate these effects in this study. 

7.7 Big Bay 

The community composition in Big Bay also varied spatially with two distinct clusters, one cluster 

comprising sites adjacent to the Ore Terminal and the other comprising sites in the central and 

southern reaches of Big Bay. The sites around the Ore Terminal in Big Bay clustered with those 

around the ore terminal in Small Bay indicating that activities around the Ore Terminal (dredging and 

shipping activities) are a primary influence to community composition in the northern section of Big 

Bay. The communities at these sites were dominated by opportunistic species, namely the mud 

prawn Upogebia capensis, the small polychaetes Polydora sp. and Ampelisca species, which suggests 

that the area is in an early stage of recovery or is an unstable area with ongoing disturbances. The 

sediment analysis results from 2011 suggest that the northern areas of Big Bay along the Ore 

Terminal have similar levels of contamination to that seen in Small Bay. The relatively low species 

diversity at these sites suggests that this area of Big Bay has been more recently or frequently 

disturbed than the central part of the Bay. 

The central Big Bay sites were characterised by a high abundance of the cumacean, Iphinoe 

africana, which is a small detritivorous crustacean. These sites were also dominated by amphipods, 

polychaetes, sandworms, dog whelks and the deposit feeding bivalve T. gilchristi. The analysis of the 

sediment characteristics suggested that the central and southern areas of Big Bay were in a relatively 

healthy state compared to the rest of the system. It is likely that the communities at these sites are 

stable with low levels of environmental disturbance. The suspension feeding sea pen, Virgularia 

schultzei, was also found in high abundance at sites at the southern and central reaches of Big Bay. 

These organisms are typical K-strategists and thus support the notion that the area is in a relatively 

stable state. The intermediate disturbance hypothesis suggests that at very low frequencies of 

disturbance most of the community will reach and remain at a climax state with competitive 

exclusion reducing the diversity to moderate levels. Site BB30, which showed a relatively low 

diversity is a very shallow and exposed site. The communities at this site are thus subject to ongoing 

disturbance and are not likely progress much beyond a pioneering phase with relatively low diversity 

values. Indeed site BB30 was dominated by a high abundance of small deposit feeding polychaetes 

belong to the Spionidae family. 

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Generally crustaceans and polychaetes have dominated the benthic macrofauna community 

in Big Bay in terms of abundance in all surveys conducted since 1999, while crustaceans and tongue 

worms (Echiuroidea) have dominated in terms of biomass. An overall increase in biomass, 

abundance and diversity of benthic macrofauna in Big Bay 1999 and 2004 suggested that the 

communities had been recovering since the dredging events of 1997/8. The dramatic decrease 

abundance, biomass and diversity of benthic macrofauna in Big Bay between 2004 and 2008 was 

likely to be a response to the dredging events in Small Bay (maintenance dredging of the Multi 

Purpose Terminal) in 2007/8 and off north beach at the northern end of Langebaan Lagoon. Much of 

the reduction in biomass and abundance could be attributed to the loss of crustaceans and 

polychaetes. 

There was an increase in the abundance of small, low biomass polychaetes and in the 

biomass of crustaceans between 2008 and 2009. The results of the 2010 survey revealed that the 

abundance of benthic macrofauna had decreased while the biomass had increased suggesting that 

fewer, larger organisms were dominating, and possibly leading to a reduction in the number of 

smaller organisms through predatory or competitive community interactions. This is a typical sign of 

the succession of a system following a disturbance. Interestingly the abundance of polychaetes and 

crustaceans increased dramatically between 2010 and 2011. This result was not reflected in the 

biomass results indicating that small crustaceans and polychaetes had colonised the Big Bay area by 

2011. The reason for the dramatic increase in the abundance of small polychaetes and crustaceans 

in Big Bay is not clear. A similar increase in the abundance of small polychaetes was also seen in 

Small Bay. It is likely that a natural Bay-wide fluctuation, possibly based on nutrient availability and 

productivity, may have occurred between 2010 and 2011, which supported an increase in the 

abundance of small polychaetes. The stability of other taxonomic groups and of the proportions of 

functional groups suggests that the system has not been subject to a negative disturbance and 

remains in a state of recovery following dredge events. It is likely that the slight reduction in 

diversity seen between 2010 and 2011 is a result of biological interactions within the community as 

the community recovery is progressing and not from external factors. 

7.8 Salamander Bay and Donkergat 

The depth of the sites sampled in Salamander Bay and Donkergat ranged between 2.8 m and 6.3 m, 

which is a similar depth range to sites sampled in the Lagoon, at the southern end of Big Bay and in 

the northern reaches of Small Bay. The results of the 2011 sediment analysis revealed that the 

sediments in the Donkergat and Salamander Bay areas had a relatively low mud content similar to 

that of the northern reaches of Small Bay, but greater than the Lagoon or southern reaches of Big 

Bay. This, in addition to the position of the sites within embayments and on the opposite site of Big 

Bay to the dominant swell direction, suggests that the Donkergat and Salamander areas are slightly 

more sheltered than the Lagoon and the eastern side of Big Bay. The percentage organic matter in 

the sediments was at a relatively moderate level also comparable to that of the northern parts of 


Interestingly, the trace metal concentrations greatly exceeded that found in the Lagoon, Big 

Bay or the northern reaches of Small Bay, and instead resembled that found in the most 

contaminated sites in Small Bay; namely the Yacht Club Basin and the Multi-purpose quay. 

Contaminants, such as metals, are predominantly associated with fine sediment particles (mud or 

cohesive sediments). This is due to the fact that fine grained particles have a larger surface area for 

the adsorption and binding of pollutants. Higher proportions of mud, relative to sand or gravel, can 

thus lead to high trace metal contamination. Based on the particle size composition, under pristine 

conditions in Donkergat and Salamander Bay trace metal concentrations would be expected to be 

less than or equal to, but certainly not exceeding the concentrations seen at sites in the northern 

reaches of Small Bay. The fact that concentrations of trace metals in Donkergat and Salamander Bay 

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exceeded that seen in Big Bay and the northern reaches of Small Bay suggests that the area had 

been subjected to disturbance. The dredging events that took place in 2009 and 2010 as part of the 

boat yard construction process re-suspended sediments and the associated trace metals. This 

activity was most likely the principle contributor to the contamination seen in Donkergat and 

Salamander Bay. Another contributor might include the unintentional releases of chemicals from 

boat cleaning processes and anti-foulants, although the extent to which this may have occurred is 

not known. 

No baseline information regarding the structure and composition of benthic macrofaunal 

communities in Donkergat and Salamander Bay was collected prior to dredging events in 2009/2010. 

Dredging occurred within Salamander Bay. Donkergat was sampled as a control station to represent 

reference conditions. The analyses of trace metal concentrations found in the sediments suggest 

that both Donkergat and Salamander Bay were impacted by dredging events. It is thus necessary to 

assess these areas in the context of the larger Saldanha Bay and Langebaan Lagoon system. 

However; there is no area within the Saldanha Bay and Langebaan Lagoon system where the benthic 

macrofaunal communities are easily comparable to the Salamander Bay and Donkergat areas. Small 

Bay has a history of much disturbance and is subject to several ongoing anthropogenic activities. Big 

Bay likewise has been subject to much disturbance in the northern reaches, is deep in the central 

areas and more exposed along the eastern banks, while Langebaan Lagoon is subject to strong 

currents and tidal activities. The spatial analysis of the Bray Curtis similarity results revealed that the 

benthic macrofauna communities in Salamander Bay and Donkergat were most similar to those in 

Small Bay. Indeed, this is likely to be due in part to the similar sediment particle sizes found in both 

areas. However, the dominance of several opportunistic species as well as the low diversity values 

calculated for both areas suggest that the either the communities were in an early stage of recovery 

or that environmental conditions were unstable. The diversity values were in fact lower than that 

found in the Lagoon, an area known to be subject to high levels of natural disturbance. As discussed 

above, the Donkergat and Salamander areas are likely to be less exposed and thus less prone to 

natural disturbances than the Lagoon. This suggests that benthic macrofaunal communities in both 

Salamander Bay and Donkergat had been impacted by the dredging event. This result indicates that 

continued monitoring of Salamander Bay and Donkergat must be assessed in the context of the 

whole system and not in isolation. 

7.9 Langebaan Lagoon 

The benthic macrofauna communities sampled in Langebaan Lagoon have been significantly 

different to those in Saldanha Bay in all surveys since 2004. This is most likely due to differences in 

the physical and biogeochemical processes predominating in the marine environment of Langebaan 

Lagoon compared with those in the Bay (CSIR 2002). The macrofauna in Langebaan Lagoon has been 

dominated by several small opportunistic species such as amphipods and polychaetes which 

suggests the system is relatively unstable and the benthic communities prone to high disturbance 

levels. Furthermore, the Lagoon generally supports a much lower abundance and biomass of 

benthic macrofauna than Saldanha Bay. The low stability of the environment in the Lagoon is most 

likely a result of the fast water movements and high levels of tidal variation rather than an 

anthropogenic disturbance. However, historically there is some evidence suggesting that 

anthropogenic activities had a negative impact on the benthic ecology. 

The overall biomass and species diversity in Langebaan Lagoon declined after 1975 following 

dredging. The reduction in biomass was linked to a loss in the abundance of many of the taxa 

present in 1975 (bivalves, polychaete worms, gastropods, echinoderms, and sea-pens). 

Changes in macrobenthos in Langebaan Lagoon may also be related to the recent invasion 

by the European mussel Mytilus galloprovincialis. During the mid-1990s an introduced alien invasive 

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mussel M. galloprovincialis began establishing dense intertidal beds on two intertidal sand flats close 

to the mouth of Langebaan Lagoon (Hanekom and Nel 2002). The mussel beds reached an 

estimated biomass of close to eight tons in 1999 raising concerns that the invasion could spread to 

the rest of the lagoon and other sandy substrata (Hanekom and Nel 2002). A comparative study 

between invaded and non-invaded areas showed a replacement of sandbank species communities 

by those typically found in rocky shores where the mussel provided the hard substratum suitable for 

their settlement (Robinson and Griffiths 2002). In early 2001, however, the mussels had started to 

die off and by mid-2001 only dead shells and anoxic sands remained. The precise causes of the die 

off have not been established but siltation and lowered food availability are suggested as possible 

reasons behind the declines (Hanekom and Nel 2002). In an effort to prevent the re-settlement of 

the mussel South African National Parks began to remove dead mussel shells in late 2001 (Robinson 

et al. 2007b). A study looking at the ecological impacts of the invasion and subsequent clearing of 

the dead shells was done comparing pristine non-invaded areas, invaded areas that had living 

mussel beds, un-cleared areas with no living mussels but a thick remnant mussel shell layer, and 

areas cleared of dead mussels (Robinson et al. 2007). The study found that community composition 

differed significantly between non-invaded and invaded areas where mussel created a multilayered 

complex habitat promoting the colonization of rocky-shore species. This significantly increased 

biomass but not species diversity, reflecting a replacement of the natural sandy ecosystem for a 

typical rocky-shore system (Robinson et al. 2007). After the die-off and subsequent clearing of the 

dead shell remains, some recovery was already evident between non-invaded and cleared areas 

after only 5 months. Although no significant differences were found between non-invaded and 

cleared areas, the absence of more than 50% of the species from the cleared areas shows that total 

recovery had still not been attained. The mussel invasion thus dramatically altered natural 

community composition which remained different from non-invaded areas even 5 months after the 

clearing, when the study ended. Fortunately this invasion was short lived. 

The overall abundance and biomass of macrofauna in Langebaan Lagoon declined sharply 

again between 2004 and 2008. The 2008 survey also indicated that the proportion of filter feeders 

had been drastically reduced. These results were possibly linked to the dredging that took place at 

the northern end of lagoon as part of the beach erosion mitigation. The biomass then almost 

doubled between 2008 and 2009, principally owing to a marked increase in crustaceans. The 

abundance of macrofauna did not increase proportionately suggesting that larger-bodied 

crustaceans colonised the lagoon between 2008 and 2009. There were further increases in the 

abundance and biomass of benthic macrofauna between 2009 and 2010. The 2011 survey revealed 

that the abundance of small (low biomass) polychaetes had increased in the Lagoon, while the 

overall biomass of crustaceans had increased. In addition bivalve communities had increased both in 

terms of abundance and biomass. The overall biomass measured in 2010 and 2011 exceeded that 

measured in 1975, however the diversity of taxa has been reduced and crustaceans overwhelmingly 

dominated the benthic macrofauna biomass. This suggests that the Lagoon may have undergone an 

ecosystem shift. The 2011 survey results suggest that the Lagoon is in a relatively healthy state 

given the increases in biomass and abundance and relative stability of functional groups. However, 

similar to that seen in Saldanha Bay, there had been an increase in the abundance of small 

polychaetes. The results of the sediment survey in 2011 also revealed system-wide reduction in the 

mud content and increases in the concentrations of some trace metals. The sediment results 

coupled with the system wide trends seen in the benthic macrofaunal communities certainly suggest 

a system wide perturbation, the source or cause of which is unclear. 

The average diversity of macrofauna in Langebaan Lagoon was relatively low in 2004, but 

increased between 2004 and 2008 and 2008 and 2009 such that the lagoon supported a moderate 

level of diversity. The 2010 survey revealed that there had been a very slight decrease in the 

diversity of macrofauna. By 2011 the average diversity of benthic macrofaunal communities in the 

Lagoon had increased to a fairly high level of diversity. The area is subject to natural disturbance 

(strong currents and tidal variation) and under such conditions the diversity of benthic communities 

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is expected to fluctuate slightly, be relatively patchy and remain moderate to high. The overall 

increase in diversity since 2004 certainly suggests that the communities have been in a state of 

recovery following one major perturbation. This recovery seems to vary spatially as diversity values 

are very patchy around the Lagoon. The Lagoon comprises a system of shallow sand bars and deeper 

channels which are subject to strong currents and tidal activities. This ongoing natural disturbance 

varies spatially and temporarily depending on sediment dynamics within the lagoon. The high 

diversity levels recorded at many of the sites may be a result of intermediate levels of disturbance 

which would allow for communities to pass the pioneering phase and increase in diversity but 

without reaching a stable state. The areas with low diversity may be a result of high levels of 

disturbance selecting for a few opportunistic species. 

7.10 Summary of benthic macrofauna findings 

A range of benthic community health indicators examined in this study over the period 1999 to 2011 

has revealed that benthic health most likely deteriorated in Small Bay from 1999 to 2008, but has 

recently (since 2009 survey) started to show signs of recovery. Benthic health within Big Bay 

improved marginally between 1999 and 2008 after which it decreased again to a state similar to that 

observed in 1999. There has been little change in benthic health within Langebaan Lagoon over the 

last decade. Small Bay and Big Bay have both suffered a significant reduction in species diversity 

over the last decade, although Small Bay, and in some cases Big Bay, is showing signs of recovery. 

Most notable is the return of the suspension feeding sea-pen Virgularia schultzei to Big Bay since 

2004 as well as an increase in the percentage biomass of large, long lived species such as the tongue 

worm Ochaetostoma capense, and several gastropods. The most severely impacted sites within 

Small Bay in 2011 remain the Yacht Club basin and the Multi-purpose Quay. These sites are prone to 

the accumulation of pollutants due to restricted water movement in these areas. Benthic fauna 

have been almost entirely eliminated from the Yacht Club basin in Small Bay, which is also the site 

registering the highest concentrations of metals and other contaminants. Although benthic health 

within Small Bay is showing signs of improvement, the health status of this site is still lower than that 

of Big Bay and Langebaan Lagoon. In order to ensure the continued improvement in the health of 

the Small Bay marine environment it is recommended that stringent controls are placed on the 

discharge of effluents into Small Bay to facilitate recovery of benthic communities in this extremely 

important area. 

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Paramoera capensis 

Nassarius 

vinctus 

Ampelisca 

brevicornis 

Glycera convoluta 

Hippomedon 

normalis 

Nephtys hombergi 

Orbinia angrapequensis 

Figure 7.15. Benthic macrofauna species frequently found to occur in Saldanha Bay and Langebaan Lagoon, 

photographs by: Nina Steffani. 

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Intertidal invertebrates 

Brittle star ( Ophiuroidea spp) 

Sea Cucumber ( Holothuroidea spp.) 

Sand Prawn ( Callianassa craussi ) 

Mud prawn ( Upogebia capensis ) 

Figure 7.16. Benthic macrofauna species frequently found to occur in Saldanha Bay and Langebaan 

Lagoon, photographs by: Charles Griffiths. 

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8 INTERTIDAL INVERTEBRATES (ROCKY SHORES) 


Despite the known changes that have taken place within the Saldanha Bay system over the last 

fifty years, almost no historical data exists on the state of rocky-shores in the area. Species 

presence/absence data was collected by undergraduate students of the University of Cape Town 

at Lynch Point Schaapen Island between 1965 and 1974 (Griffith pers. comm.). The accuracy and 

reliability of this data is, however, questionable and it is thus of limited value for monitoring 

changes in the health of the Bay ecosystems. Only a single historical study by Robinson et al. 

(2007) has examined the species composition of rocky intertidal communities Saldanha Bay in any 

level of detail. This study examined changes in community composition on the rocky-shores of 

Marcus Island between 1980 and 2001, focusing on the impact of the alien invasive 

Mediterranean mussel, Mytilus galloprovincialis 

Monitoring of rocky intertidal communities in the Bay was initiated as part of the State of 

the Bay monitoring programme in an effort to fill the gap in knowledge relating to rocky intertidal 

communities in the Bay. The first rocky shore survey for this programme was conducted in 2005, 

the results of which are presented in the first ‘State of the Bay’ report (Anchor Environmental 

Consultants 2006). Eight rocky shores spanning across a wave exposure gradient from very 

sheltered to exposed, were sampled in Small Bay, Big Bay and Outer Bay as part of this baseline. 

These surveys were repeated in 2008, 2009 and 2010 (Anchor Environmental Consultants 2009, 

2010, 2011). In agreement with results from the baseline survey, it was concluded that wave 

force is primarily responsible for shaping the intertidal rocky shore communities. More sheltered 

shores are dominated by seaweeds, while sites more exposed to higher wave energy are 

characterised by filter-feeders. It was suggested that the construction of the Marcus Island 

causeway and the Iron Ore Terminal had reduced the wave energy reaching rocky shores in Small 

Bay, having thus led to a change in community structure. As no historical data exist from these 

shores for confirmation, this remains speculative though. The results further indicated that the 

topography of the shore also influences community structure as sites consisting of rocky boulders 

had different biotic cover to shores with a flatter profile. Geographic location is also of 

importance, for example sampling stations on the bird breeding island Schaapen Island are 

situated in a transitional zone between the Saldanha Bay and the Langebaan Lagoon system. 

These same sites are also affected by high nutrient input through seabird guano that favours algal 

growth. Generally, the Saldanha Bay communities were healthy apart from the presence of two 

alien invasive species, the Mediterranean mussel Mytilus galloprovincialis and the North 

American barnacle Balanus glandula. 

2011. 

This chapter present results from the third annual monitoring survey conducted in May 

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8.2 Approach and Methodology 

8.2.1 Study Sites 

Spread along the shoreline of Saldanha Bay, eight rocky shore sampling sites were first visited 

during the baseline survey in 2005, and annually since 2008. The 2011 survey was conducted over 

the period 15-18 April 2011. Figure 8.1 depicts the location of the study sites. The sites Dive 

School and Terminal are situated along the northern shore in Small Bay. Marcus Island, Iron Ore 

Terminal and Lynch Point are in Big Bay, as are the sites Schaapen Island East and West, located 

on Schaapen Island in the entrance to Langebaan Lagoon. The site North Bay is situated in Outer 

Bay at the outlet of Saldanha Bay. 

0 km 

1 

Figure 8.1, 

Location of the eight rocky shore study sites in Saldanha Bay. 

The sampling sites have specifically been chosen to take into account the effects of 

differing degrees of wave exposure and topographical heterogeneity (type of rock surface and 

slope). Dive School (DS) and Jetty (J) are very sheltered sites with gentle slopes, consisting of 

boulders and rubble interspersed with sandy gravel (Figure 8.2). Schaapen Island East is situated 

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in a little baylet and is relatively sheltered and mostly flattish with some rougher rock sections 

(Figure 8.2). Schaapen Island West is slightly more exposed and flat with some parts of ragged 

topography (Figure 8.2). 

Dive School 

Very Sheltered 

Boulders and Rubble 

Jetty 

Very Sheltered 

Boulders and Rubble 

Schaapen Island East 

Sheltered to Semi-exposed 

Schaapen Island West 

Sheltered to Semi-exposed 

Flattish with some ragged sections 

Semi-steep with some ragged 

sections 

Figure 8.2. Rocky shore study sites in Saldanha Bay (top right to left bottom): Dive School, Jetty, 

Schaapen Island East, and Schaapen Island West. 

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Semi-exposed 

Very steep with large boulders 

Lynch Point 

Semi-exposed 

Flat with crevices 

North Bay 

Semi-exposed to exposed 

Flat mid and high shore with 

large boulders in the low shore 

Marcus Island 

Exposed 

Flat shore 

Figure 8.3. 

Rocky shore study sites in 2010 (top right to bottom left): Iron Ore Terminal, Lynch Point, 

North Bay, and Marcus Island. 

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The site at the Iron Ore Terminal (IO) is sheltered to semi-exposed with a very steep slope 

resulting in a very narrow total shore width (distance from low water to high water mark). The 

rocky surface of this site comprises of medium-sized broken boulders that are piled up to support 

a side arm of the iron ore terminal (Figure 8.3), which encircles a small area that was previously 

used for aquaculture purposes. The semi-exposed site Lynch Point (L) has a relatively smooth 

surface with occasionally deep crevices running across (Figure 8.3). North Bay (NB) is semiexposed 

to exposed with a relatively flat high and mid shore (Figure 8.3). The low shore consists 

of large unmovable square boulders separated by channels. The rocky intertidal site on Marcus 

Island (M) is very flat and openly exposed to the swell (Figure 8.3). 

8.2.2 Methods 

The unique physical environment of the rocky intertidal alternately exposes it to air and 

submerges it under water, creating a steep vertical environmental gradient for the biota that 

inhabits these shores. Rocky shores can thus be partitioned into different zones according to 

shore height level whereby each zone is distinguishable by their different biological communities 

(Menge & Branch 2001). At each study site, the rocky intertidal was divided into three shore 

height zones: the high, mid and low shore. In each of these zones, six 100°x°50-cm quadrats were 

randomly placed on the shore and the percentage cover of all visible species recorded as primary 

(occurring on the rock) and secondary (occurring on other benthic fauna or flora) cover, and 

individual mobile organisms counted to calculate densities within the quadrat area (0.5m 2 ). The 

quadrat was subdivided into smaller squares, to aid in the estimation of the percentage cover. 

Finally, the primary and secondary cover data for both mobile and sessile organisms were 

combined and down-scaled to 100%. This survey protocol is consistent with the previous survey 

protocols. 

A species list is provided in the Appendix. Sampling is non-destructive, i.e. the biota is not 

removed from the shore, and smaller infaunal species (e.g. polychaetes, amphipods, isopods) that 

live in the complex matrix of mussel beds or dense stands of algae are thus not recorded in this 

survey protocol. Additionally, some algae and invertebrates cannot be easily identified to generic 

or species level in the field and are thus recorded under a general heading only (e.g. crustose and 

articulate corallines, red turfs, sponge, colonial ascidian). For further analysis, intertidal species 

were categorized into ten functional groups: a) grazers, mostly limpet species, b) trappers, limpet 

species that specifically trap kelp fronds beneath their shells, c) filter-feeders, particularly sessile 

suspension feeders such as mussels and barnacles, d) mobile predators and scavengers, such as 

carnivorous whelks, e) anemones, f) crustose 2 and g) articulated coralline 3 algae, h) corticated 4 

and i) ephemeral foliose 5 seaweeds and j) kelps. 

2 Crustose (or encrusting) corallines - Crustose corallines are typically slow growing crusts of varying thickness that can 

occur on rock, shells, or other algae. 

3 Articulated corallines - Articulated corallines are branching, small tree-like plants, which are attached to the substratum 

by crustose or calcified, root-like holdfasts. 

4 Corticated algae - Algae that have secondarily formed outer cellular covering over part or all of an algal thallus. 

Usually relatively large and long-lived. 

5 Ephemeral algae - Opportunistic algae with a short life cycle that are usually the first settlers on a rocky shore. 

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8.2.3 Data Analysis 

The similarities or dissimilarities among the quadrats from the eight different study sites are 

analyzed with multivariate analyses techniques employing the software package PRIMER 6. These 

methods are useful for a graphical presentation of the results obtained from the typically large 

data sets collected during ecological sampling. The principle aim of these techniques is to discern 

the most conspicuous patterns in the community data. Comparisons between intertidal 

communities are based on the extent to which they share particular species at similar levels of 

occurrence. Patterns in the data are represented graphically through hierarchical clustering 

(dendrogram) and multi-dimensional scaling (MDS) ordination techniques. The former produces a 

dendrogram in which samples with the greatest similarity are fused into groups, and these are 

successively grouped into clusters as the similarity criteria defining the groups are gradually 

reduced. MDS techniques compliment hierarchical clustering methods by more accurately 

‘mapping’ the sample groupings two-dimensionally in such a way that the distances between 

samples represent their relative similarities or dissimilarities. 

Whether (a priori defined) groups of samples (e.g. sites, treatments, years) are statistically 

different is analysed by means of PERMANOVA. PERMANOVA is a routine for testing the 

simultaneous response of one or more variables to one or more factors in an analysis of variance 

(ANOVA) experimental design on the basis of any resemblance measure, using permutation 

methods (Anderson et al. 2008). In essence, the routine performs a partitioning of the total sum 

of squares according to the specified experimental design, including appropriate treatment of 

factors that are fixed or random, crossed or nested, and all interaction terms. A distance-based 

pseudo-F statistic is calculated in a fashion that is analogue to the construction of the F statistic 

for multi-factorial ANOVA models. P-values are subsequently obtained using an appropriate 

permutation procedure for each term. Following the main overall test, pair-wise comparisons are 

conducted. Significance level for the PERMANOVA routine is p



8.3 RESULTS AND DISCUSSION 

8.3.1 Species Diversity and Zonation 

The survey of the eight rocky shores yielded a total of 84 species/taxa, of which 50 taxa were 

invertebrates (59.5%) and 34 (40.5%) algae. The faunal component was represented by 16 

species of grazers, 3 trappers, 7 predators and scavengers, 6 anemones, and 18 filter-feeders. The 

algal component comprised 22 corticated (foliose) seaweeds, 6 ephemerals, 1 kelp, 4 crustose (or 

encrusting) corallines and 1 articulated coralline (it has to be pointed out that this is a gross 

underestimation of coralline taxa as most species are not identifiable in the field and are thus 

lumped into larger groups). 

The overall taxa count has remained relatively constant over the years with most taxa 

having also been recorded during one or more of the previous monitoring years (Anchor 

Environmental Consultants 2006, 2009, 2010, 2011). Furthermore many of the species are also 

listed by other studies conducted in the Saldanha Bay area (e.g. Simons 1977, Schils et al. 2001, 

Robinson et al. 2007). The species are generally common to the South African West Coast (e.g. 

Day 1974, Branch et al. 2010a), including the two alien invasive species, the Mediterranean 

mussel Mytilus galloprovincialis and the acorn barnacle, Balanus glandula. The former was 

introduced from Europe sometime in the 1970’s, but is now the dominant west coast mussel, 

forming a dense mid- to low shore band in wave-exposed areas (Hockey & van Erkom Schurink 

1992). The presence of B. glandula, originating from the Pacific coast of North America, has only 

been recognized more recently (Simon-Blecher et al. 2008), but it seems that the species has been 

in South Africa since at least the early 1990s and it is now the most abundant intertidal barnacle 

along the southern west coast (Laird & Griffiths 2008). The alien’s presence was overlooked for 

many years as it was mistaken for the indigenous species Chthamalus dentatus. Apparently as a 

result of the invasion by B. glandula, the formerly abundant C. dentatus is now very rare on South 

African west coast shores (Laird & Griffiths 2008). At the Saldanha Bay monitoring study sites, the 

alien barnacle was first confidently identified in 2008. It is, however, assumed that it had been 

present during the baseline survey in 2005 but was confused with the indigenous barnacle. 

Consequently, in all analyses involving the 2005 dataset, C. dentatus abundances are converted to 

B. glandula. 

The composition and distribution of the rocky intertidal biota is strongly influenced by the 

prevailing wave exposure at a shore as well as substratum topography. Within a site, however, 

shore height is the critical factor as the interface between air and water along with the action of 

tides and waves result in a vertical emersion gradient of increasing exposure to air from low shore 

to high shore. Clear, well studied, patterns of zonation of flora and fauna thus exist on rocky 

shores (Stephenson & Stephenson 1972). The effects of wave action are generally attenuated upshore 

and superseded by the uniformly severe desiccation stress experienced high on the shore. 

Consequently the high shores were relatively similar among the sites being mostly barren with 

few species. At the very sheltered boulder shores Dive School and Jetty, considerable amounts of 

sand and gravel had also accumulated amongst the boulders. Typical high shore species, 

particularly at the sheltered sites, included the winkle Oxystele variegata and towards the more 

exposed sites the small periwinkle Afrolittorina knysnaensis with average densities often 

exceeding 100 individuals per 0.5 m 2 (Figure 8.4). The alien B. glandula occurred at almost all high 

shores but with very low cover (on average 95% at most high 

shores. The exceptions were Schaapen East, which had occasional patches of blue-green algae, 

and Marcus Island were a dense low carpet of the ephemeral algae Ulva spp. with occasional tufts 

of another ephemeral, Porphyra capensis, covered >70% of the high shore (Figure 8.4). 

Ephemerals are opportunistic algae that have short life cycles and are usually the first settlers on 

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a rocky shore after a disturbance event. 

(Maneveldt et al. 2009). 

Their dominant presence is normally short-lived 

Oxystele variegata 

Blue-green algae 

Ulva spp. 

Porphyra capensis 

Figure 8.4. 

From top left clockwise: High shore at Dive School showing Oxystele variegata and 

sand/gravel accumulation among the boulders; high shore at North Bay showing the 

Afrolittorina knysnaensis on rock and accumulating in crevices; blue-green algae patch at 

Schaapen East high shore; and low growing Ulva carpet with Porphyra capensis tufts at the 

high shore at Marcus Island. See text for more information. 

O. variegata extended into the mid shore at the very sheltered sites Dive School and Jetty, 

but also occurred in low numbers at the other mid shores. The occasional limpet Cymbula 

granatina was also recorded. Algal cover was limited to the encrusting red algae Ralfsia verrucosa 

and some stands of Ulva spp. and Gigartina polycarpa. 

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Ulva band 

Balanus band 

Sand-worm mixture 

Mytilus patches 

Dense Balanus glandula cover 

Figure 8.5. 

From top left clockwise: Ulva-Balanus band at the mid shore at Schaapen Island East; the 

sand-tubeworm compact mixture at Schaapen Island West with Ulva; dense Balanus 

glandula cover at Iron Ore Terminal; and Mytilus patches interspersed with Balanus and 

Scutellastra granularis patches at Marcus Island. See text for more information. 

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At the Schaapen Island sites, the Dwarf cushion-star Parvulastra exigua was locally common in 

moist cracks and rock-depressions, as were the false limpets Siphonaria serrata and S. capensis. 

At Schaapen Island East, the upper mid-shore was characterized by distinct bands of Ulva and B. 

glandula (Figure 8.12). In contrast, alive barnacles were largely absent from the mid shore at 

Schaapen Island West although some empty shells still attached to the rock were encountered. 

Instead, at this site a tube-building polychaete was common. This tubeworm was deeply 

embedded in a compact matrix of sand, maybe cemented so compact by some secretion of the 

worm (Figure 8.12). This sand-worm mixture covered the mid shore in large patches, making up 

to 12% of the biotic cover there. 

With increasing wave force, the mid shore was dominated by filter feeders, specifically M. 

galloprovincialis and B. glandula (Figure 8.12). The latter was particularly abundant at the semiexposed 

site Iron Ore Terminal with 75% cover. Algal presence was generally low with some 

cover by the ephemerals Ulva spp. and Porphyra capensis, as well as the seaweeds Caulacanthus 

ustulatus and Nothogenia erinacea. Mobile animals included the limpets Scutellastra granularis, 

Siphonaria serrata, and the tiny periwinkle Afrolittorina knysnaensis nestling in amongst the 

barnacles. The scavenging whelk Burnupena spp. was encountered in low numbers at most sites. 

Differences in community structure were most pronounced at the low shore where the 

energy of waves is most effective. Generally, biotic cover within a shore increased towards the 

low shore, but cover also increased among the shores with intensifying wave force (from 28% at 

the low shore at Jetty to 84% at Marcus Island). At the very sheltered sites, faunal cover was very 

low with some mussel and mixed barnacle cover (B. glandula, Amphibalanus amphitrite and 

Notomegabalanus algicola). At Dive School, the two indigenous mytilids, Aulacomya ater and 

Choromytilus meridionalis, as well as the alien M. galloprovincialis co-occurred, albeit at very low 

densities. Algal cover was only slightly higher, consisting primarily of encrusting Ralfsia verrucosa, 

the foliose seaweeds Gigartina polycarpa, Nothogenia erinacea and the green ephemeral alga 

Ulva spp. Mobile animals included the limpet Cymbula granatina, the winkle Oxystele tigrina, 

Parvulastra exigua, and the sea urchin Parechinus angulosus, often found in groups in pools or 

crevices hidden under pieces of shell or gravel (Figure 8.6). Few large specimens of the false plum 

anemone Pseudoactinia flagellifera were also encountered there. 

At the sheltered Schaapen Island sites, the ground cover was dominated by a diverse 

array of up to 20 different algae species. Most common were ‘pink’ encrusting corallines (a 

variety of species), followed by foliose seaweeds such as Gigartina polycarpa, Aeodes orbitosa, 

Mazzaella capensis, Gymnogongrus glomeratus, Ulva sp., and a low growing turf-forming mixture 

of fine red algae (Figure 8.6). Particularly at Schaapen Island West, the mid-shore sand-worm 

mixture extended down into the low intertidal, often surrounding and intertwined with, algal 

stands. Occasionally, the sand had washed away and the thin stiff tubes of the polychaetes 

emerged (Figure 8.6). 

Burrowing in this sandy substrate were dense colonies of the red-chested sea cucumber 

Pseudocnella insolens, often numbering >350 individuals per 0.5m 2 (Figure 8.6). Sessile 

invertebrates were rare but mobile animals included the limpets Fissurella mutabilis and Cymbula 

granatina, the cushion star Parvulastra exigua, the winkle Oxystele tigrina and the scavenging 

whelk Burnupena spp. 

The semi-exposed site Iron Ore Terminal was still characterized by algae, in particular 

encrusting species, as well as Sarcothalia stiriata, Mazzaella capensis, Hypnea spicifera, 

Nothogenia erinacea, Plocamium spp., Ulva spp. and near the infratidal zone the kelp Laminaria 

pallida (Figure 8.6). Mussels and barnacles were present but with low cover, the latter primarily 

represented by the giant barnacle Austramegabalanus cylindricus (Figure 8.6). Very common was 

the pear-shaped limpet Scutellastra cochlear, followed by S. barbara and Cymbula granatina. 

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Pseudoactinia 

flagellifera 

Parechinus angulosus 

Polychaete tube 

emerging from sand 

Pseudocnella insolens 

Scutellastra cochlear 

surrounded by pink encrusting 

coralline 

Figure 8.6. 

From top to bottom right: Parechinus angulosus and Pseudoactinia flagellifera in the low 

shore pool at Dive School; overview of low shore at Schaapen Island East; close-up of 

tube-building polychaete emerging from sand; the sea cucumber Pseudocnella insolens 

embedded in sand; overview of low shore at Iron Ore Terminal; and close up of the giant 

barnacle Austromegabalanus cylindricus. See text for more information. 

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Scutellastra cochlear surrounded 

by encrusting coralline 

Mussel patches with secondary algae 

growth 

Aulacomya ater 

Figure 8.7. 

From top left clockwise: Scutellastra cochlear patch in association with ‘pink’ encrusting 

coralline algae on a low shore boulder at Lynch Point; overview of the low shore at North 

Bay showing kelp growing in the infratidal; Aulacomya ater patch at the low shore at 

Marcus Island; overview of the low shore at Marcus Island. 

With a further increase in wave action, the low intertidal became progressively 

dominated by sessile filter-feeders, particularly M. galloprovincialis with up to 40% cover at North 

Bay (Figure 8.7). At Marcus Island, the indigenous ribbed mussel Aulacomya ater occurred in 

patches and could locally be more dominant than M. galloprovincialis (Figure 8.7). This is in stark 

contrast to the mid shore, which is clearly dominated by the alien mussel and also to earlier years, 

where the alien mussel was the characterizing mussel species at this site (Robinson et al. 2007). 

Barnacle presence was largely restricted to secondary growth of Notomegabalanus algicola on 

mussel shells. Mobile fauna was characterized by dense patches of Scutellastra cochlear as well 

as S. barbara, S. granularis and the kelp-trapping S. argenvillei, Cymbula granatina, C. miniata and 

Fissurella mutabilis. The predatory whelks Burnupena spp. and Nucella cingulata were found 

hidden in the mussel matrix, feeding on mussels. Encrusting and, to a lesser degree, articulated 

corallines were the main algae species. Foliose seaweeds were represented by Champia 

lumbricalis and Plocamium spp., which are typical for wave swept shores, and minor cover of 

Sarcothalia stiriata, Ulva spp., red turf, and Laminaria pallida at the infratidal fringe (Figure 8.7). 

In S. cochlear patches, narrow gardens of fast-growing, fine red algae (e.g. Gelidium micropterum, 

G. pristiodes, Herposiphonia heringii) fringed larger individuals; the gardens serve as food source 

and are territorially defended and fertilized by the limpets (Figure 8.7). 

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8.3.2 Spatial Variation in Community Composition 

Figure 8.10 illustrates biotic cover, species number, evenness, and Shannon-Wiener diversity 

indices at the eight rocky shore sites (indices are calculated for the whole shore across all zones). 

Foremost it is apparent that the amount of rock surface covered by animals and seaweeds 

steadily increased with increasing wave exposure, with the exception of North Bay, where great 

parts of the very smooth rock surface was devoid of intertidal life. The two very sheltered 

boulder beaches in Small Bay were generally impoverished with little biotic cover and lowest 

species numbers, whereby Dive School had on average twice as many species as Jetty. There is a 

certain trend of increasing species richness with greater wave exposure with the highest species 

count at Marcus Island. In contrast, Dive School and Jetty had highest evenness. This indicates 

that the communities were not dominated by one or few species but rather all species were more 

or less equally abundant. Evenness reduced towards semi-exposed sites but increased again at 

greater exposure levels. A similar picture is evident for the Shannon-Wiener diversity index. 

Lowest evenness and diversity were found at Iron Ore Terminal. A low evenness means that the 

biota is dominated by one or few species, which at Iron Ore Terminal is clearly the invasive 

barnacle B. glandula. 

The abundances (as opposed to the space they occupy on the rock surface specified as 

percentage cover) of the most common mobile species per site are illustrated in Figure 8.9. Only 

few mobile species occurred at the high shore, the most prominent being the typical high shore 

species Oxystele variegata at the very sheltered sites and the periwinkle Afrolittorina knysnaensis. 

The mid shore had a greater array of common mobile species: O. variegata was still relatively 

common at very sheltered mid shores, as was O. tigrina. Whereas Siphonaria serrata and C. 

granatina were present at nearly all mid shores, Scutellastra granularis and A. knysnaensis were 

more abundant at semi-exposed to exposed sites. 

A. knysnaensis is normally abundant primarily in the upper intertidal where it congregates 

in crevices to escape the heat of the day, while emerging at night or on moist days to feed (Branch 

et al. 2010a). Particularly at Iron Ore Terminal, however, this snail was also abundant at the mid 

shore where it lives amongst the barnacle B. glandula (Figure 8.10). For a rocky shore in Table 

Bay, it has been shown that the abundance of A. knysnaensis is strongly positively correlated with 

that of B. glandula (M. Van Zyl, University of Cape Town, unpublished data 2009 cited in Griffiths 

et al. 2011). Laird & Griffiths (2008) also found a very noticeable difference between barnacle 

invaded and non-invaded areas reporting that A. knysnaensis were more abundant, and extended 

farther down the shore, in invaded areas where they nestled between dense colonies of B. 

glandula. The study demonstrated positive correlations for all shore heights. It is suggested that 

the barnacle cover increases habitat complexity and provides shelter for the periwinkles from 

strong wave action. 

For the eight study sites in Saldanha Bay, such positive relationship is, however, not that 

conclusive when the data across all shore heights are included. Although the correlation is 

statistically significant, there are many situations in the high shore were B. glandula were absent 

but periwinkles plentiful (Figure 8.11). However, confining the analysis to the mid-shore, were 

the alien barnacle thrives particularly well and is densest, the positive relationship is evident 

(Figure 8.11). In the high shore where wave stress is minimal, the periwinkle is naturally 

abundant; in the mid-shore, however, wave stress increases and without shelter, the periwinkle 

normally declines in abundance. This would suggest that A. knysnaensis abundance is 

independent of the barnacle’s presence in the highest intertidal but lower down the shore, the 

barnacle matrix offers refuge and/or greater substrate complexity for the periwinkle to extend its 

range lower down the shore. 

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Cover% 

Shannon-Wiener 

100 

90 

80 

70 

60 

50 

40 

30 

20 

10 

0 

2.8 

2.6 

2.4 

2.2 

2.0 

1.8 

1.6 

Dive School 

Jetty 

Schaapen East 

Schaapen West 


Lynch Point 


Marcus Island 

Evenness 

36 

34 

32 

30 

28 

26 

24 

22 

20 

18 

16 

14 

12 

0.90 

Species Number 

0.85 

0.80 

Mean 

Mean±SE 

0.75 

Mean±SD 

0.70 

0.65 

0.60 

0.55 

0.50 

Dive School 

Jetty 

Schaapen East 

Schaapen West 


Lynch Point 


Marcus Island 

Mean 

Mean±SE 

Mean±SD 

1.4 

Dive School 

Jetty 

Schaapen East 

Schaapen West 


Lynch Point 


Marcus Island 

0.45 

Mean 

Mean±SE 

Mean±SD 

Dive School 

Jetty 

Schaapen East 

Schaapen West 


Lynch Point 


Marcus Island 

Mean 

Mean±SE 

Mean±SD 

Figure 8.8. 

Box & whisker plots of per cent cover, species number, evenness and Shannon-Wiener diversity at the eight rocky shore sites. Sites are sorted from left to right 

according to increasing wave exposure. 

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250 



Abundance (no/0.5m 2 ) 

0 20 40 60 80 100 120 140 

Dive School 

Jetty 

Schaapen East 

Schaapen West 


Lynch Point 


Marcus Island 

HIGH SHORE 

Scutellastra granularis 

Siphonaria serrata 

Afrolittorina knysnaensis 


Dive School 

Jetty 

Schaapen East 

Schaapen West 


Lynch Point 


Marcus Island 

0 10 20 30 40 50 

MID SHORE 


Cymbula granatina 


Fissurella mutabilis 

Afrolittorina knysnaensis 


Oxystele tigrina 

Burnupena spp. 

0 10 20 30 40 50 

Dive School 

Jetty 

Schaapen East 

Schaapen … 


Lynch Point 


Marcus Island 

LOW SHORE 


Scutellastra cochlear 

Cymbula granatina 


Fissurella mutabilis 


Oxystele tigrina 

Figure 8.9. 

Mean abundance (number/0.5 m 2 ) of the most common mobile species at the eight rocky 

shores in 2011. Sites are sorted from top to bottom according to increasing wave exposure. 

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Afrolittorina knysnaensis (no/0.5 m 2 ) 



Figure 8.10. The periwinkle Afrolittorina knysnaensis nestling in amongst the alien barnacle Balanus 

glandula at the mid shore at Iron Ore Terminal. 

600 

All Shore Heights 

Mid Shore 

500 

400 

300 

y = 2.4282x + 12.639 

R² = 0.3431 n = 144 p



Mobile animals in the low shore included O. tigrina, which was common at sheltered to semiexposed 

sites and Parvulastra exigua, frequently encountered in rock depressions and pools. C. 

granatina and Burnupena spp. occurred at all low shores at relatively equal densities, whereas S. 

cochlear was restricted to wave swept shores where it lives in patches of dense aggregations. 

It is understandable that the vertical gradient of emersion up the shore creates a stress gradient that 

has important ecological effects, creating the clear zonation patterns observed on rocky intertidal 

shores. Among shores, however, the structure of biotic communities is also affected by a horizontal 

gradient of exposure to wave action, from sheltered bays to exposed headlands. Viewing the 

distribution of the various functional groups shows obvious differences among the shores with 

regard to exposure (Figure 8.12). Very sheltered shores had generally low biotic cover consisting 

primarily of grazers and trappers (i.e. the limpet Cymbula granatina), with minor cover of sessile 

filter feeders and encrusting algae. The sheltered Schaapen Islands sites were dominated by algae 

(encrusting and foliose algae) but with further increase in wave force, filter feeders were clearly the 

most important group. At Marcus Island, ephemeral algae were also abundant. 

Figure 8.12. Contribution of the functional groups to the biotic cover (%) across the whole rocky shore at 

the eight study sites (sorted from left to right according to increasing wave exposure). 

Multivariate analysis (i.e. cluster analysis and multi-dimensional scaling) finally confirms the 

clear separation of the rocky shores with regard to wave exposure (Figure 8.13). At a 50% similarity 

level the sites group into three major groups: Group 1 contains the very sheltered shores Dive School 

and Jetty, Group 2 consists of the two sheltered Schaapen Island sites, whereas all other more 

exposed sites fall into Group 3. At a higher similarity level of 60%, most of the sites within the groups 

separate from each other, displaying a great within-site similarity. Only the three exposed sites 

Lynch Point, North Bay and Marcus Island still cluster together (Group 3A), signifying that the 

communities at these shores are relatively similar, while the steep Iron Ore Terminal shores splits off. 

178 

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Similarity 








Marcus Island 

Marcus Island 

Marcus Island 

Marcus Island 

Marcus Island 

Marcus Island 

Lynch Point 

Lynch Point 

Lynch Point 

Lynch Point 

Lynch Point 

Lynch Point 






Schaapen West 

Schaapen West 

Schaapen West 

Schaapen West 

Schaapen West 

Schaapen West 

Schaapen East 

Schaapen East 

Schaapen East 

Schaapen East 

Schaapen East 

Schaapen East 

Dive School 

Dive School 

Dive School 

Dive School 

Dive School 

Dive School 

Jetty 

Jetty 

Jetty 

Jetty 

Jetty 

Jetty 



20 

40 

60 

80 

100 

2D Stress: 0.12 

Group 1 

Site 

Dive School 

Jetty 

Schaapen East 

Schaapen West 


Lynch Point 


Marcus Island 

Similarity 

50 

60 

Group 3 

Group 3A 

Group 2 

Figure 8.13. Dendrogram (top) and multi-dimensional scaling (MDS) plot (bottom) of the rocky shore 

communities at the eight study sites in 2011. The circles in the MDS plot indicate a 50% (red) 

and 60% (blue) similarity level. See text for further explanation. 

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That exposure to wave action affects the distribution of organisms on a rocky shore is a well 

described phenomenon (e.g. Lewis 1964, McQuaid & Branch 1984, Raffaelli & Hawkins 1996, 

Bustamante et al. 1997, Menge & Branch 2001, Denny & Gaines 2007). Increasing exposure reduces 

siltation and increases the supply of dissolved oxygen and particulate food, favoring certain sessile, 

filter-feeding species, leading to an elevation of overall biomass (McQuaid & Branch 1985, 

Bustamante & Branch 1996, Bustamante et al. 1995, Steffani & Branch 2003a). A recent study has 

also shown that at the southern African west coast wave exposure has a positive effect on the 

recruitment of mussels and (to a lesser extent) barnacles (Pfaff et al. 2011). At the same time, 

increasing exposure carries an increased risk of dislodgement and physical damage, limiting the 

range of susceptible and physically fragile species. In contrast, sheltered shores are typically 

dominated by algae (McQuaid & Branch 1985) as species richness of most floral phyla and groups 

decrease with increasing exposure. However, it appears that the effect of wave exposure on plants 

varies with phyla and functional form group, as some forms can better withstand hydrodynamic 

forces than others (Denny & Gaylord 2002, Nishihara & Terada 2010). 

In contrast to the unidirectional nature of the vertical emersion gradient, the horizontal 

gradient is less well defined: some species do well on wave-exposed shores, some do best in shelter 

and others under intermediate conditions. Many species of intertidal animals and plants have 

evolved morphologies and behaviours specifically adapted to cope with wave-imposed forces. 

Despite these adaptations, hydrodynamic and impact forces can at times cause massive damage to 

rocky shore communities that fundamentally alters the structure and function of exposed rocky 

habitats, creating changes that can persist for many years. The magnitude of physical disturbance is 

less on protected shores, and as a result, the structure of protected communities is different from 

that of exposed assemblages. 

While wave force is clearly the main factor for differences among the shores, shore 

topography is also of importance. In the dendrogram and MDS plot, the very flat Schaapen Island 

sites drastically diverge from the two boulder shores Dive School and Jetty, and the steep semiexposed 

boulder shore Iron Ore Terminal separates from the more flattish smoother semi-exposed 

to exposed shores Lynch Point, North Bay and Marcus Island (Figure 8.13). The roughness of the 

substratum or generally termed habitat structure can be a crucial factor driving species richness, 

abundance and even body size (Kostylev et al. 2005). Habitat structure is generally thought to have 

two independent components: complexity, the physical architecture of a habitat; and heterogeneity, 

the relative abundance of different structural features such as boulders or crevices within a habitat 

(McCoy & Bell 1991). Effects of habitat structure on organism body size and abundance can be 

interrelated because the availability of microhabitat space within a habitat depends both on 

abundance and body size (Guarnieri et al. 2009). Smaller organisms can be more numerous than 

larger organisms in complex structure, because they have more useable space and require fewer 

resources per individual. Hence, habitat structure may shape the overall relationship between 

abundance and body size of an assemblage. For example, studies have shown that many mobile 

animals exhibit preferential movement from topographically simple locations (e.g. smooth surface) 

into those with more structural complexity (e.g. crevices, rugged surface) where they a more 

protected from hydrodynamic forces (McGuinness & Underwood 1986, Kostylev et al. 2005, 

O’Donnell & Denny 2008). This may not just apply to physical complexity but also microhabitats 

offered by biota. For example, it seems that A. knysnaensis uses the complex structure provided by 

barnacles to extend its range further down the shore (see text above). Mobile invertebrates can also 

respond to environmental extremes by moving between microhabitats to ameliorate thermal and 

desiccation stress (Meager et al. 2011), and again A. knysnaensis displays such behaviour. 

Distribution of sessile species, however, is driven by the longer-term processes of settlement, growth 

and mortality (Guarnieri et al. 2009). Substratum availability, microtopography and surface 

smoothness, can be limiting factors at local scale, and invertebrate larvae have developed complex 

behaviours and finely tuned discriminatory abilities to ensure successful settlement in the face of 

variations in substratum properties (Guarnieri et al. 2009). Topographic complexity influence the 

180 

ANCHOR 




settlement and persistence of benthic organisms, as planktonic larvae are more likely to be retained 

on rough surfaces while water movement may wash them off smooth surfaces (Eckman 1990, 

Guarnieri et al. 2009). This might explain the low sessile cover found on the very smooth rocks at 

North Bay (see Figure 8.12). 

Boulder shores also contain greater microhabitat diversity (e.g. upper and lower side of the 

boulders) than rocky platforms. Where boulders are large, the tops of these boulders stay immersed 

for a significantly longer period than smaller boulders (or flat platforms), with each single boulder 

essentially having its own shore height zonation. During low tide, the top layer of boulders provides 

the lower layers with shade, thus maintaining lower temperatures and higher moisture content 

(Takada 1999). Layers of boulders increase the surface area for attachment of organisms, but may 

reduce water movement thus accumulating detritus, which can lead to low oxygen conditions. Large 

boulders have been shown to considerably reduce the water flow velocity with invertebrate biomass 

decreasing significantly downstream of boulders (Guichard & Bourget 1998). Smaller boulders, on 

the other hand, may be unstable as they can turn over in heavy weather, and have often been found 

to have a more impoverished community than larger rocks (McGuinness 1987, Londoño-Cruz & 

Tokeshi 2007, McClintock et al. 2007). Boulder fields are thus are typically found to differ in their 

species assemblages to flatter shores (e.g. Sousa 1979, McGuinness 1984, McQuaid et al. 1985, 

McGuiness & Underwood 1986, Takada 1999, Cruz-Motta et al. 2003, Davidson et al. 2004, Hir & Hily 

2005). 

While shore topography is a likely factor controlling the difference in community structure 

between Dive School and Jetty, and the rocky shores on Schaapen Island, it may also be related to 

the fact that Schaapen Island lies in the transition zone between Saldanha Bay and Langebaan 

Lagoon. The water in the Lagoon is generally warmer with also slightly higher salinities compared to 

the Bay. This in turn translates into differences in their biological communities (Day 1959, Robinson 

et al. 2007). For example, there is a distinct separation in algal composition between communities 

from the Bay and the Lagoon, as the latter harbours a considerable number of South Coast seaweeds 

due to its warmer waters (Schils et al. 2001). Perlemoenpunt, located less than 1 km from Schaapen 

Island on the western site of the entrance to Langebaan Lagoon is described as the transition area 

between the Bay and the Lagoon, but with a marked Lagoon affinity (i.e. high similarity with the 

Lagoon sites) in its overall algal composition. Differences in community composition between the 

Bay and the Lagoon are also described for zooplankton, and rocky and sandy substrate assemblages 

(Day 1959, Grindley 1977, Anchor Environmental Consultants 2006, 2009, 2010, 2011). 

8.3.3 Temporal Analysis 

Temporal variation in biotic cover, species number, evenness, and species diversity at the 

eight rocky shores from 2005 to 2011 are depicted in Figure 8.14 and Figure 8.15. Cover and 

population indices at the very sheltered site Dive School varied only slightly, while at the second 

sheltered boulder beach Jetty there was a general increase in all population measures until 2010, 

decreasing again in 2011. Schaapen East displayed little variation in biotic cover but species number, 

evenness and diversity increased peaking in 2009, although reducing thereafter. Schaapen West, in 

contrast, experienced a drastic increase in percentage cover until 2010 due to abundant growth of 

ephemeral and blue-green algae, but these had almost vanished in 2011. This temporal dominance 

of ephemerals has probably led to the considerable decline in evenness and diversity observed from 

2005 to 2008, which are since then on the increase again. Biotic cover at Iron Ore Terminal, on the 

other, hand changed little with time, but species number and more pronounced evenness and 

diversity had a noticeable peak in 2010. Intertidal communities at Lynch Point and North Bay 

displayed minor temporal fluctuations in cover and species number, whereas evenness and diversity 

at Lynch Point peaked in 2009 and show a decreasing trend at North Bay. The most prominent 

181 

ANCHOR 




changes were recorded at Marcus Island where both percentage cover and species number steadily 

increased since 2005. Evenness and diversity, however, show no consistent trend. 

Temporal trends in rocky shore community patterns at the eight study sites are illustrated in 

Figure 8.16. Consistent for all years is the clustering according to wave exposure, with the three 

same main groups of Dive School and Jetty in Group 1, the Schaapen Island sites in Group 2, and the 

semi-exposed to exposed sites in Group 3. A certain inter-annual variability within each site is also 

evident, but this is more pronounced at some of the sites than at others. At Iron Ore Terminal, for 

example, the replicates from 2005 and 2010 separate from those from 2008 and 2011, while 2009 

samples are in between. Similar is apparent for Schaapen West and Marcus Island. The greatest 

within-site variability (or patchiness) occurs at the boulder beach Jetty where the replicates per year 

often disperse widely. 

PERMANOVA tests, conducted for each site over the years, confirm significant differences 

with regard to year (p = 0.001 for all tests). Further pair-wise testing reveals that for every site-byyear 

combination tested, interannual changes in community composition are significant (note that 

for the sake of brevity only combinations involving subsequent years are shown) (Table 8.1). 

However, the similarities among the rocky shore communities between the tested years are very 

high, especially for the last two years (from 54 to up to 70%). This suggests that for each site 

temporal changes in community structure, although statistically significant, are minor. 

The SIMPER test reveals which species are responsible for the observed differences in 

community structure among the years. Only species contributing >5% to the dissimilarity at any 

specific site are listed in Table 8.2. For brevity, only comparisons between 2010 and the current 

dataset are presented here. At most of the sites, only one or two species contributed significantly 

(>5%) to the differences in community structure between 2010 and 2011, and at Lynch Point and 

North Bay, no single species contributed >5%. Most contributing taxa were algae, mainly ephemeral 

blue-green algae (Cyanobacteria) that had decreased in abundance at all sites where they previously 

were common. This is particularly evident at Schaapen West where the disappearance of blue-green 

algae at the high shore contributed ~10% to the temporal dissimilarity. It is well described that bluegreen 

algae can cover great areas of open high shore rocks early on in the successional process 

temporarily, developing a thin ‘biofilm’ together with other microscopic algae (e.g. diatoms and 

spores of macroalgae) (Robles 1982, Cubit 1984, Maneveldt et al. 2009). Ephemeral blue-green algae 

may also be indicative of organic pollution (Pinedo et al. 2007). Both Schaapen Island and Marcus 

Island are closed to the general public and anthropogenic nutrient input into the high shore is 

unlikely, but the islands are important bird resting and breeding sites with a vast abundance of 

fertilizing guano. The arrival of blue-green algae at the high shores of Schaapen East, Schaapen West 

and Marcus Island were in the analysis of the 2010 survey data identified as the only noteworthy 

change in community structure since 2009 (Anchor Environmental Consultants 2011), and it was 

suggested that the plentiful nutrient supply from bird guano may have triggered the blue-green algae 

growth if washed into the intertidal after heavy rains (Bosman & Hockey 1986, 1988). 

182 

ANCHOR 


Lynch 

Point 



100 

90 

80 

70 

60 

Cover% 

50 

40 

30 

20 

10 

Species Number 

0 

36 

34 

32 

30 

28 

26 

24 

22 

20 

18 

16 

14 

12 

10 

8 

DS05 

DS08 

DS09 

DS10 

DS11 

J05 

J08 

J09 

J10 

J11 

SE05 

SE08 

SE09 

SE10 

SE11 

SW05 

SW08 

SW09 

SW10 

SW11 

IO05 

IO08 

IO09 

IO10 

IO11 

L05 

L08 

L09 

L10 

L11 

NB05 

NB08 

NB09 

NB10 

NB11 

M05 

M08 

M09 

M10 

M11 

DS05 

DS08 

DS09 

DS10 

DS11 

J05 

J08 

J09 

J10 

J11 

SE05 

SE08 

SE09 

SE10 

SE11 

SW05 

SW08 

SW09 

SW10 

SW11 

IO05 

IO08 

IO09 

IO10 

IO11 

L05 

L08 

L09 

L10 

L11 

NB05 

NB08 

NB09 

NB10 

NB11 

M05 

M08 

M09 

M10 

M11 

Mean 

Mean±SE 

Mean±SD 

Mean 

Mean±SE 

Mean±SD 

Figure 8.14. Temporal changes of % cover and species number (mean ± SE) from 2005 to 2011 at the eight 

rocky shore sites (DS = Dive School, J = Jetty, SE = Schaapen East, SW = Schaapen West, IO = 

Iron Ore Terminal, L = Lynch Point, NB = North Bay, M = Marcus Island). 

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ANCHOR 




0.9 

0.8 

0.7 

Evenness 

0.6 

0.5 

0.4 

0.3 

DS05 

DS08 

DS09 

DS10 

DS11 

J05 

J08 

J09 

J10 

J11 

SE05 

SE08 

SE09 

SE10 

SE11 

SW05 

SW08 

SW09 

SW10 

SW11 

IO05 

IO08 

IO09 

IO10 

IO11 

L05 

L08 

L09 

L10 

L11 

NB05 

NB08 

NB09 

NB10 

NB11 

M05 

M08 

M09 

M10 

M11 

Mean 

Mean±SE 

Mean±SD 

3.0 

2.8 

2.6 

2.4 

Shannon-Wiener 

2.2 

2.0 

1.8 

1.6 

1.4 

1.2 

1.0 

DS05 

DS08 

DS09 

DS10 

DS11 

J05 

J08 

J09 

J10 

J11 

SE05 

SE08 

SE09 

SE10 

SE11 

SW05 

SW08 

SW09 

SW10 

SW11 

IO05 

IO08 

IO09 

IO10 

IO11 

L05 

L08 

L09 

L10 

L11 

NB05 

NB08 

NB09 

NB10 

NB11 

M05 

M08 

M09 

M10 

M11 

Mean 

Mean±SE 

Mean±SD 

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ANCHOR 


Dive School 

Jetty 

Schaapen East 

Schaapen West 


Lynch Point 


Marcus Island 



Figure 8.15. Temporal changes of evenness and Shannon-Wiener diversity indices (mean ± SE) from 2005 to 

2011 at the eight rocky shore sites. (DS = Dive School, J = Jetty, SE = Schaapen East, SW = 

Schaapen West, IO = Iron Ore Terminal, L = Lynch Point, NB = North Bay, M = Marcus Island). 


2005 

2008 

2009 

2010 


Figure 8.16. Multi-dimensional scaling (MDS) plot of the rocky shore communities at the eight study sites 

from 2005 to 2011. The circles delineate a 40% similarity level. 

Another seaweed that had declined in abundance was Gigartina polycarpa at Dive School 

and Iron Ore Terminal, whereas Sarcothalia stiriata increased at the latter site. Changes in barnacle 

cover had also contributed to dissimilarities, specifically at the two very sheltered boulder beaches 

Dive School and Jetty, where B. glandula was absent in 2010 but present in 2011, while the striped 

barnacle Amphibalanus amphitrite occurred in 2010 at Jetty and Iron Ore Terminal but not in 2011. 

In general though, average dissimilarities between the years per site were low, indicating that 

temporal differences in rocky shore communities were small (Table 8.2). 

Temporal variations in abundance of functional groups at the eight study sites are illustrated 

in Figure 8.17. At the two sheltered boulder beaches Dive School and Jetty, filter feeders and 

ephemerals had slightly decreased while corticated algae and grazers had increased with time. In 

2011, however, algae other than encrusting were sparse. At Schaapen East, filter feeders depicted 

an increasing and ephemerals a decreasing trend, while encrusting corallines fluctuated strongly. At 

Schaapen West, biotic cover had steadily increased until 2010, especially encrusting corallines and 

ephemerals. The latter group had drastically declined by 2011, reducing the overall cover. Iron Ore 

Terminal and Lynch Point remained relatively constant over time, with only minor variations in 

encrusting coralline and ephemeral cover at Lynch Point. At North Bay, there was a drastic increase 

in filter feeders until 2010, remaining at the same level in 2011. Corallines and ephemerals again 

showed slight temporal fluctuations. At Marcus Island, ephemeral algae had greatly increased from 

2005 to 2009 while at the same time corticated algae and filter feeders declined. The substantial 

ephemeral cover resulted in an overall greater biotic cover in 2009. In 2010, ephemerals had 

somewhat reduced but returned again 2011. 

185 

ANCHOR 




Table 8.1. 

Figure 1: Groups 

PERMANOVA pairwise-testing results following significant main-tests. Only the relevant 

pairwise comparisons for the years 2005 vs 2008, 2008 vs 2009, 2009 vs 2010, and 2010 vs 2011 

per site are shown. Significant (p < 0.05) differences are highlighted in italic. Number of 

permutations are 462 for all pairwise comparisons. Percent similarity among the years tested 

are also provided. 

Figure 2: Pseudo-F 

Figure 3: Significance 

Level 

Figure 4: % Similarity 

Dive School 2005 vs 2008 2.5041 0.003 62.1 

Dive School 2008 vs 2009 2.9203 0.003 59.3 

Dive School 2009 vs 2010 1.5954 0.002 70.2 

Dive School 2010 vs 2011 2.1833 0.004 66.8 

Jetty 2005 vs 2008 2.8132 0.002 65.6 

Jetty 2008 vs 2009 3.4427 0.002 47.7 

Jetty 2009 vs 2010 2.2527 0.007 59.5 

Jetty 2010 vs 2011 2.8509 0.001 53.5 

Schaapen East 2005 vs 2008 3.4945 0.007 52.9 



Schaapen East 2010 vs 2011 2.0324 0.002 56.2 

Schaapen West 2005 vs 2008 3.465 0.003 48.0 



Schaapen West 2010 vs 2011 2.9673 0.002 58.7 

Iron Ore Terminal 2005 vs 2008 3.2623 0.002 50.2 



Iron Ore Terminal 2010 vs 2011 3.321 0.002 67.8 

Lynch Point 2005 vs 2008 2.4023 0.003 56.3 

Lynch Point 2008 vs 2009 2.6826 0.003 58.2 

Lynch Point 2009 vs 2010 2.6087 0.003 57.5 

Lynch Point 2010 vs 2011 1.9785 0.001 65.9 

North Bay 2005 vs 2008 1.9355 0.001 59.5 



North Bay 2010 vs 2011 1.9676 0.002 65.0 

Marcus Island 2005 vs 2008 3.559 0.002 56.8 



Marcus Island 2010 vs 2011 2.3449 0.003 68.7 

186 

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Table 8.2. 

Site 

SIMPER results listing the species that contribute >5% to the dissimilarity between 2010 and 

2011 at each site. The % cover data are averages across the six replicates per site, and are on 

the fourth-root transformed scale. 

Species 

2010 

%cover 


%cover 

Contribution 

% 

Average 

dissimilarity 

Dive School Balanus glandula 0.0 1.13 8.64 33.2 

Gigartina polycarpa 1.17 0.38 6.35 

Jetty Balanus glandula 0.0 1.39 11.78 46.5 

Amphibalanus amphitrite 1.26 0 10.70 

Ralfsia verrucosa 1.27 0.74 5.49 

Ulva spp. 1.03 0.51 5.42 

Schaapen East Blue green algae 1.76 0.86 6.30 43.8 

Schaapen West Blue green algae 1.85 0.0 9.45 41.3 

Iron Ore Terminal Amphibalanus amphitrite 1.24 0.0 8.62 32.2 

Gigartina polycarpa 0.92 0.0 6.42 

Sarcothalia stiriata 0 0.85 5.92 

Austromegabalanus 

cylindricus 

0.11 0.86 5.30 

Lynch Point Red turf 0 0.75 4.61* 34.1 

North Bay Laminaria pallida 0 0.77 4.75* 35.0 

Marcus Island Blue green algae 1.05 0.0 5.97 31.3 

* Note that at these sites none of the species contributed >5% to the dissimilarity. The species with the highest contribution 

is thus listed. 

From the temporal pattern displayed by the rocky shore communities, it is evident that at 

none of the sites there is a directional change in community composition that would indicate a 

persistent change, such as for example the arrival or loss of a species. Rather the communities show 

temporal fluctuations, reflecting for example dominance of ephemerals over one or more years (e.g. 

Schaapen West and Marcus Island). Ephemeral algae typically show strong temporal variation in 

their abundances (Griffin et al. 1999, Maneveldt et al. 2009). They generally have short life-cycles 

and dense populations are therefore only temporarily. Recruitment and survival success is also 

strongly related to environmental conditions that will vary from year to year. Ephemeral 

assemblages also vary in their species distribution and density according to the successional stage of 

the shore or patch on the shore. For example, limpet exclusion experiments on the south-western 

Cape resulted in an immediate recruitment of blue-green algae and Porphyra, which were after a 

couple of months replaced by Ulva spp. This green alga in turn, was then replaced by encrusting and 

corticated algae with time (1-2 years, Maneveldt et al. 2009). Changes in ephemeral algae cover over 

the years are thus likely to be a natural seasonal and interannual phenomenon, and there is no 

reason to assume anthropogenic influences. 

187 

ANCHOR 


Percentage 

cover 

Percentage 

cover 

Percentage 

cover 

Percentage 

cover 

Percentage cover 



80 

60 

40 

20 

0 

80 

60 

40 

20 

0 

80 

60 

Anemones 

Predators&Scavengers 

Trappers 

Grazers 

Filter-Feeders 

Articulated 

Encrusting 

Kelp 

Ephemeral 

Corticated 

40 

20 

0 

80 

60 

80 

40 

20 

0 

60 

40 

20 

0 

Figure 8.17. The mean percentage cover of the various functional groups at the study sites in 2005, 2008, 

2009, 2010, and 2011 (from top to bottom). 

188 

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High 05 

High 08 

High 09 

High 10 

High 11 

Mid 05 

Mid 08 

Mid 09 

Mid 10 

Mid 11 

Low 05 

Low 08 

Low 09 

Low 10 

Low 11 

High 05 

High 08 

High 09 

High 10 

High 11 

Mid 05 

Mid 08 

Mid 09 

Mid 10 

Mid 11 

Low 05 

Low 08 

Low 09 

Low 10 

Low 11 



20 

Dive 

School 

20 

Jetty 

0 

0 

30 

20 

10 

Schaapen 

East 

20 

10 

Schaapen 

West 

0 

0 

80 

60 

40 

20 

0 

Iron Ore 

Terminal 

80 

60 

40 

20 

0 

Lynch 

Point 

80 

60 

40 

20 

0 

North 

Bay 

80 

60 

40 

20 

0 

Marcus 

Island 

Figure 8.18. Mean percentage cover of the indigenous Aulacomya ater (green) and the aliens Mytilus 

galloprovincialis (red) and Balanus glandula (blue) at the eight study sites over the years. Note 

the difference in scale between the top four and bottom four graphs. 

189 

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Some of the sites experienced also temporal fluctuations in filter feeder abundance. 

Unquestionably, the two most prominent filter feeders along the southern west coast are the alien 

invasive B. glandula and M. galloprovincialis. A worldwide well known coastal invader, M. 

galloprovincialis has been described as the ecologically most important and numerically dominant 

marine alien species along the southern African coast (Robinson et al. 2005). It was first recorded in 

1979 in Saldanha Bay, and has now a distribution bridging three marine biogeographic provinces, 

covering over 2000 km of coastline (Robinson et al. 2005). The rate of increase and abundance of M. 

galloprovincialis is generally promoted by exposure to strong wave action (Branch et al. 2008). Along 

the west coast of South Africa, M. galloprovincialis dominates the rocky intertidal at the expense of 

various competitively inferior indigenous mussel and limpet species (Griffiths et al. 1992, Steffani & 

Branch 2003a, b, Branch & Steffani, 2004, Robinson et al. 2007, Branch et al. 2008, 2010b). In 

general, its competitive strength and impact on other elements of the fauna increases with wave 

exposure (Branch et al. 2008, 2010b). In comparison with the indigenous mussels Choromytilus 

meridionalis and Aulacomya ater, M. galloprovincialis has a faster growth rate, greater fecundity, and 

superior tolerance to desiccation (van Erkom Schurink & Griffiths 1991, 1993, Hockey & van Erkom 

Schurink 1992). This led to an upshore broadening of the width of intertidal mussel beds where this 

species has invaded (Hockey & van Erkom Schurink 1992). 

The time of arrival of the alien barnacle B. glandula is unknown, but it can be traced back to 

at least 1992 (Laird & Griffiths 2008). Similar to Mytilus, it is assumed that is has been introduced to 

South Africa in the ballast waters of ships (or attached to their hulls) that arrived in the port of 

Saldanha Bay (Griffiths et al. 2011). In 2008, its range extended from Cape Point 400 km northwards 

along the West Coast, but it is, at present at least, absent from the South Coast (Laird & Griffiths 

2008). It is now the most common barnacle along the cool-temperate west coast (Griffiths et al. 

2011). The high densities of intertidal B. glandula suggest that it has significant ecological impacts on 

the local biota; for example it is thought that it allows the indigenous periwinkle A. knysnaensis to 

extend its range further down the shore by providing increased habitat complexity and shelter from 

waves (Griffiths et al. 2011). 

Relative changes in percentage cover of the two alien invasives as well as the indigenous 

ribbed mussel Aulacomya ater, depict clear spatial and temporal patterns (Figure 8.18). As expected, 

both B. glandula and mussel cover is generally sparse at wave-protected shores. At Schaapen East, 

however, the barnacle invaded the mid shore in 2010 and had by April 2011 doubled its spread to 

cover 20% of the rock (see Figure 8.5). At semi-exposed sites, B. glandula is strongly represented in 

the mid shore where it is often the most dominant species, covering for example nearly 80% of the 

shore at Iron Ore Terminal. In contrast, the high and low shores of this site are almost barnacle free. 

Mussels are also restricted to the mid shore. At Lynch Point both B. glandula and Mytilus are 

common in the mid shore, whereby the relative dominance of one species over the other fluctuated 

over the years. In the low shore, however, B. glandula is typically rare and Mytilus the dominant 

filter feeder. With further increases in wave exposure, B. glandula cover in the mid shore reduces 

and Mytilus is the general dominant filter feeder (e.g. Marcus Island). 

The general picture thus emerges that B. glandula is most common at mid shores of semiexposed 

sites, but rarer at exposed sites and low shores; a similar shore-distribution pattern as 

described by Laird & Griffiths (2008). M. galloprovincialis, on the other hand, fares best at waveexposed 

sites and lower down the shore (see also Branch et al. 2008, 2010b). The distribution 

patterns of the two species suggest thus differences in their preferential habitats but it seems that 

there are areas of overlap. For example, at the mid shore of the semi-exposed to exposed site Lynch 

Point, mussel and barnacle cover fluctuated strongly, clearly showing that an increase of one taxa 

resulted in the decrease of the other. In other words, it could be that at this site, where the degree 

of wave action is suitable for both, the barnacle and mussel compete. Many studies of competition 

on intertidal rocky shores have shown that the resource most often competed for by sessile 

organisms is space and that upper and/or lower vertical distribution boundaries on the shores are 

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partly due to the relative ability of the species to compete for space (see review by Menge & Branch 

2001). The varying interannual success in competing for space might in turn be related to varying 

success in larval development, settlement and/or recruitment. For most benthic marine organisms, 

fluctuations in the arrival of broadly dispersing pelagic larvae are among the most important factors 

driving population dynamics (Roughgarden et al. 1988, Menge et al. 1997, Menge & Branch 2001). 

Because dispersal and supply of larvae to suitable settlement habitats are highly dependent upon 

coastal water movements during larval development, large variability in recruitment can occur over 

various spatial and temporal scales and may be greatly influenced by the effects of topography and 

season on oceanographic processes. A recent study on settlement and recruitment dynamics of 

mussels and barnacles (mostly M. galloprovincialis and B. glandula by virtue of their dominance) in 

the southern Benguela upwelling region (Pfaff et al. 2011), found that recruitment of both mussels 

and barnacles was strongly seasonal, with peaks in austral summer (November to January) and spring 

(August to October), respectively. There was further a strong spatial variation, which was on a 

regional scale related to differences in upwelling strength (upwelling centre at headlands versus 

downstream bays), and on a local scale due to differences of wave exposure, whereby recruitment 

rates were consistently higher in wave-exposed than in protected habitats. Inter-annual variability in 

recruitment intensity at a particular site was for both taxa, however, only moderate but still 

observable, and may thus result in temporal variability of adult populations. Without more research 

and particularly experimental work, however, it cannot be ascertained whether there is indeed 

competitive interaction between Mytilus and Balanus, and whether the barnacle’s zonation pattern 

is determined by the mussel. 

The only indigenous filter feeder of any importance at the study sites was the ribbed mussel 

Aulacomya ater. Present only with very low cover at the low shores of most shores, A. ater had at 

the low shore of Marcus Island increased in abundance from 2005 to 2009, almost disappeared in 

2010 only to return again in 2011 with an average of 17% cover. An earlier study by Robinson and 

co-workers (2007) investigated the impacts and implications of the invasion of the intertidal zone at 

Marcus Island by Mytilus. A single data set taken in 1980 prior to the invasion was compared to a 

survey conducted in 2001, using the same technique as the original sampling. Before the invasion, 

dense stands of mussels, primarily Aulacomya ater, were restricted to the low shore, whereas scarce 

cover of Choromytilus meridionalis was recorded in the mid and low shore. In 2001, Mytilus had 

heavily invaded all zones except the very high shore, and replaced the indigenous mussels in the low 

shore. The mid shore, previously a patchy environment, comprising mainly bare rock interspersed 

with patches of algae and large limpets, was transformed to a less patchy but structurally more 

complex mussel matrix with increased invertebrate densities and species richness. The authors 

concluded that the invasion had its greatest impact in the mid-to-low shore, and is clearly displacing 

A. ater from the rock surface. Experimental manipulations conducted on the West Coast of South 

Africa confirm a negative impact of Mytilus presence on A. ater abundance (Branch et al. 2010b). 

Although a direct comparison between the 2001 survey at Marcus Island and the current surveys is 

not possible (Robinson et al. 2007 reported density not percentage cover) it seems likely that up until 

2008, Mytilus cover had even further increased and A. ater reduced. The strong decline of Mytilus 

cover in 2009 may has temporarily released the local mussel from the competitive pressure, but with 

the return of the alien mussels, it all but disappeared again. In 2011, however, Mytilus cover had 

again drastically declined while A. ater gained in cover. Such short cycles in relative dominance 

especially for the relatively slower growing indigenous mussel (van Erkom Schurink & Griffiths 1993) 

is somewhat surprising. When undistributed, the Mytilus matrix at Marcus Island’s low shore is very 

dense and multilayered (Robinson et al. 2007, pers. obs.). Surveying of the shore is done by nondestructive 

methods (see Method section) and any biota hidden in the deepest layer of the tight 

matrix cannot be seen without removing the top layer. A. ater can often been found burrowed in the 

Mytilus matrix (Griffiths et al. 1992, Steffani & Branch 2003b), and it is thus possible that deep in the 

lowest depth of the mussel bed, A. ater is always present, but is only exposed when the top Mytilus 

layer is removed by, for example, storm waves that often impact the exposed shore of Marcus Island. 

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This would explain why firstly Mytilus cover reduced, i.e. removed by wave action, and secondly A. 

ater cover is recorded, i.e. only now visible and recordable with non-destructive methods. 

Invasive alien species have been identified as one of the major threats to the maintenance of 

biodiversity in the marine environment (Carlton & Geller 1993, Carlton 1999, Ruiz et al. 1999, IUCN 

2009), particularly in the context of global climate change (Occhipinti-Ambrogi 2007, Occhipinti- 

Ambrogi & Galil 2010). To date, 22 confirmed extant marine aliens, plus 18 cryptogenic species, have 

been recorded from South African waters, with one additional species found in on-land mariculture 

facilities (Griffiths et al. 2009). The true number of introduced species may well exceed these 

estimates by several times. The major means of introduction is international shipping, i.e. via ballast 

water and as attachment to the hulls of ships, followed by aquaculture (Galil et al. 2008). Saldanha 

Bay is a deepwater harbour receiving vessels from all over the world and it thus likely that one of the 

greatest perils to the intertidal (and in fact all other) communities in Saldanha Bay is the introduction 

of alien species, and their potential to become invasive. 

8.4 SUMMARY OF FINDINGS 

A total of 84 taxa were recorded from the eight study sites, most of which had also been found in the 

previous survey years. The faunal component was represented by 16 species of grazers, 3 trappers, 7 

predators and scavengers, 6 anemones, and 18 filter-feeders. The algal component comprised 22 

corticated (foliose) seaweeds, 6 ephemerals, 1 kelp, 4 crustose (or encrusting) corallines and 1 

articulated coralline. The species are generally common to the South African West Coast and many 

are listed by other studies conducted in the Saldanha Bay area including the two alien invasive 

species, the Mediterranean mussel Mytilus galloprovincialis and the North American acorn barnacle 

Balanus glandula. 

Within a site, the vertical emersion gradient of increasing exposure to air leads to a clear 

zonation of flora and fauna from low shore to high shore. Differences among the rocky shores, 

however, are strongly influenced by the prevailing wave exposure at a shore as well as substratum 

topography. Very sheltered shores had generally low biotic cover consisting primarily of grazers and 

trappers, with minor cover of sessile filter feeders and encrusting algae. With increasing wave force, 

filter feeders were clearly the most important group. The two very sheltered boulder beaches in 

Small Bay separate from the flat Schaapen Island sites, which may also be related to geographic 

location as Schaapen Island lies in a transitional zone between the Bay and the Lagoon, and to the 

nutrient input through seabird guano that favours algal growth on Schaapen Island. Similarly, the 

steep boulder beach Iron Ore Terminal separates from the other more flattish semi-exposed to 

exposed sites. 

From the temporal pattern displayed by the rocky shore communities, it is evident that at 

none of the sites there is a directional change in community composition that would indicate a 

persistent change, such as for example the arrival or loss of a species. Rather the communities show 

temporal fluctuations, reflecting the temporary dominance of short-lived ephemeral species and/or 

interannual variation in larval supply or recruitment success. In general, rocky shore communities 

were relatively stable with only minor changes over the years. 

The two most important filter feeders, being also the characteristic species at most shores 

and zones, are the aliens M. galloprovincialis and B. glandula. The latter is most abundant at mid 

shores of semi-exposed sites, but rarer at exposed sites and low shores. M. galloprovincialis, on the 

other hand, fares best at wave-exposed sites and lower down the shore. It is likely that one of the 

greatest threats to rocky shore communities in Saldanha Bay is the introduction of alien species via 

shipping, and their potential to become invasive. 

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9 FISH COMMUNITY COMPOSITION AND ABUNDANCE 


The waters of Saldanha Bay and Langebaan Lagoon support an abundant and diverse fish fauna. 

Commercial exploitation of the fish within the Bay and lagoon began in the 1600’s by which time the 

Dutch colonists had established beach-seine fishing operations in the region (Poggenpoel 1996). 

These fishers’ targeted harders Liza richardsonii and other shoaling species such as white steenbras 

Lithognathus lithognathus and white stumpnose Rhabdosargus globiceps, with much of the catch 

dried and salted for supply to the Dutch East India Company boats, troops and slaves at the Castle in 

Cape Town (Griffiths et al. 2004). Commercial netfishing continues in the area today, and although 

beach-seines are no longer used, gill-net permits holders targeting harders landed an estimated 590 

tons valued at approximately R1.8 million during 1998-1999 (Hutchings and Lamberth 2002a). 

Species such as white stumpnose, white steenbras, silver kob Argyrosomus inodorus, elf Pomatomus 

saltatrix, steentjie Spodyliosoma emarginatum, yellowtail Seriola lalandi and smoothhound shark 

Mustelus mustelus support large shore angling, recreational and commercial boat line-fisheries which 

contribute significantly to the tourism appeal and regional economy of Saldanha Bay and Langebaan. 

In addition to the importance of the area for commercial and recreational fisheries, the sheltered, 

nutrient rich and sun warmed waters of the Bay provide a refuge from the cold, rough seas of the 

adjacent coast and constitute an important nursery area for the juveniles of many fish species that 

are integral to ecosystem functioning. 

The importance and long history of fisheries in the Bay and Lagoon, has led to an increasing 

number of scientific data on the fish resources and fisheries in the area. Early studies studies, mostly 

by students and staff of the University of Cape Town investigated fish remains in archaeological 

middens surrounding Langebaan Lagoon (Poggenpoel 1996), whilst many UCT Zoology Department 

field camps sampled fish within the lagoon (Unpublished data). Gill net sampling with the aim of 

quantifying bycatch in the commercial and illegal gill net fishery was undertaken during 1998-99 

(Hutchings and Lamberth 2002b). A once of survey for small cryptic species utilizing rotenone, a fish 

specific, biodegradable toxin that prevents the uptake oxygen by small fish, was conducted by 

Anchor Environmental Consultants (AEC) during April 2001 (Awad et al. 2003). The data from the 

earlier gill netting and rotenone sampling survey was presented in the “State of the Bay 2006” report 

(AEC 2006). Seine-net sampling of near-shore, sandy beach fish assemblages was conducted over 

short periods during 1986-1987 (UCT Zoology Department, unpublished data), in 1994 (Clark 1997), 

and 2007 (AEC, UCT Zoology Department). Monthly seine-net hauls at a number of sites throughout 

Saldanha Bay-Langebaan over the period November 2007-November 2008 were also conducted by 

UCT M.Sc. student Clement Arendse who was investigating white stumpnose recruitment. These 

data were reported on in the “State of the Bay 2008” report (AEC 2009). 

Other recent research on the fish fauna of the area includes acoustic tracking and research 

on the biology of white stumpnose within Langebaan lagoon and Saldanha Bay, monitoring of 

recreational shore and boat angler catches and research on the taxonomy and life history of 

steentjies and sand sharks and (Kerwath et al. 2009, Næsje et al. 2008, Tunley et al. 2009, Attwood et 

al. 2010). Key findings of these studies include evidence that the Langebaan lagoon MPA effectively 

protects white stumpnose during the summer months that coincides with both peak spawning and 

peak recreational fishing effort (Kerwath et al. 2009). White stumpnose within the Saldanha- 

Langebaan system grow more rapidly and mature earlier than populations elsewhere on the South 

African south coast (Attwood et al. 2010). Male white stumpnose in Saldanha Bay reach maturity in 

their second year at around 19 cm fork length (FL) and females in their third year at around 22 cm FL 

(Attwood et al. 2010). Similar differences in growth rate and the onset of maturity for steentjies 

between Saldanha Bay and south coast populations were reported by Tunley et al. (2009). These life 

history strategies (relatively rapid growth and early maturity) are probably part of the reason that 

stocks of these species have to date been resilient to rapidly increasing recreational fishing pressure 

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Fish 

in Saldanha and Langebaan. Results from angler surveys indicate that approximately 92 tons of 

white stumpnose is landed by anglers each year (Næsje et al. 2008). Further details of the results of 

these studies were reported on in the State of the Bay 2008 report (AEC 2009). The research on sand 

sharks suggests that the common sand shark species in bay and lagoon is actually Rhinobatos blockii, 

not R. annulatus as previously thought (Dunn & Schultz UCT Zoology Department personal 

communication). New information on the life history of this species has been collected and will be 

published in the near future. 

The Saldanha Bay Water Quality Forum Trust (SBWQFT) commissioned AEC to undertake 

experimental seine-net sampling of near shore fish assemblages at a number of sites throughout the 

Saldanha-Langebaan system during 2005, 2008, 2009, 2010 and 2011 as part of the monitoring of 

ecosystem health “State of the Bay” programme. In the 2006 report it was noted that the existing 

seine-net survey data was the most suitable for comparative analyses over time and it was 

recommended that future seine-net surveys were conducted during late summer - early autumn, as 

this was the timing of peak recruitment of juveniles to the near-shore environment, as well as the 

timing of most of the earlier surveys. Since 2008, seine-net surveys have therefore been conducted 

during March-April of each year. These studies have made a valuable contribution to the 

understanding of the fish and fisheries of the region. 

This report presents and summarizes the data for the 2011 seine-net survey and investigates 

trends in the fish communities by comparing this with data from previous seine-net surveys 

(1986/87, 1994, 2005, 2007, 2008, 2009 & 2010) in the Saldanha- Langebaan system. Recent data on 

the commercial and recreational catch-per-unit-effort of white stumpnose (the principal target 

species in the Bay) are also presented and compared to the results of the experimental seine net 

surveys. 

9.2 Methods 

9.2.1.1 Field sampling 

Experimental seine netting for all surveys covered in this report was conducted using a beach-seine 

net, 30 m long, 2 m deep, with a stretched mesh size of 12 mm. Replicate hauls (3-5) were 

conducted approximately 50 m apart at each site during daylight hours. The net was usually 

deployed from a small rowing dinghy 30-50 m from the shore. Areas swept by the net were 

calculated as the distance offshore multiplied by the mean width of the haul. Sampling during 1986- 

87 was only conducted within the lagoon where 30 hauls were made, whilst 39 and 33 replicate hauls 

were made at 8 and 11 different sites during 1994 and 2005 surveys respectively in the Bays and 

Lagoon. During 2007, 21 hauls were made at seven sites in the both Bays and Lagoon and for the last 

four years, 2-3 hauls have been made at each of 15 standard sites every April (2008-2011) (Figure 

9.1). Large hauls were sub-sampled at the site, the size of the sub-sample estimated visually and the 

remainder of the catch released alive. 

9.2.1.2 Data analysis 

Numbers and mass of fish caught were corrected for any sub-sampling prior to data analyses. All fish 

captured were identified to species level where possible and abundance calculated as the number of 

fish per square meter sampled. During the six most recent seine-net surveys (2005, 2007, 2008, 

2009, 2010 & 2011) the total of each species caught was weighed to the nearest gram. The weight of 

any fish released alive was calculated from published length-weight relationships (Mann 2000). For 

the purposes of this report, abundance data were used for analysis of spatial and temporal patterns. 

The number of species caught, average abundance and associated variance of fish (all species 

combined) during each survey were calculated and graphed. The average abundance of the most 

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Fish 

common fish species caught in the three main areas of the system, namely Small Bay, Big Bay and 

Langebaan lagoon during each survey, were similarly calculated and presented graphically. The 

average abundance of the four-five most ubiquitous species in the system over all survey years was 

calculated and plotted for each sampling site. 

In order to investigate changes in the entire fish community composition between years, 

multivariate statistical analysis were conducted using the PRIMER software. Fish density data were 

fourth-root transformed and the Bay-Curtis similarity index was used to create similarity matrices. 

Relationships between years were represented using multidimensional scaling and these were 

statistically tested using two way mixed model PERMANOVA tests with years as a fixed effect and 

sites as a random effect (this takes into account the variability between sampled sites when 

comparing samples between years). The principal species contributing to dissimilarities between 

years were identified using the SIMPER routine. 

The status of the most significant commercial and recreational fishery in the Saldanha Bay 

system (that for white stumpnose), i.e. the health of the adult stock as opposed to the juvenile 

recruitment that is assessed by the experimental seine net fishery, was investigating using data from 

three different sources: 

1. Commercial catch returns from traditional line fish permit holders active throughout the 

Saldanha Bay – Langebaan area over the period January 2006 – December 2011. These data 

were obtained from the Department of Agriculture, Forestry and Fisheries (DAFF). 

2. Roving creel surveys of shore anglers and slipway boat inspections conducted by the 

SANParks Coastcare programme with the assistance of Prof CG Attwood (UCT) over the 

period January 2006- January 2009. These data were obtained from Prof. Attwood. 

3. Boat landing site inspections by scientific fishery observers acting on behalf of the DAFF over 

the period September 2007 to September 2010. These data were obtained from the DAFF. 

These data include information on the number of fishers (crew or shore anglers in the 

group), the hours fished and the catch of each species. The commercial permit holder is legally 

required to complete the daily catch return, but these are not frequently validated (i.e. are reliant on 

the honesty of the permit holder). Slipway inspections by trained monitors are a method of 

validating commercial catch returns, but include data from both the commercial and recreational 

boat fishing sectors. All these data are fisheries dependent – i.e. not an independent scientific survey 

(such as the seine net survey) and therefore reflect the behaviour of the fishery (targeting, gear and 

catch restrictions etc) as well as the relative abundance (or availability to the fishery) of the adult 

stock. Assessing trends in white stumpnose catch rates from all three different sectors , commercial 

boat, recreational boat and shore anglers using data collected or reported by different groups does 

increase the robustness of the analysis and confidence in the results (should they be in general 

agreement!) Catch-per-unit-effort (CPUE) was used as an estimate of relative abundance of adult 

(above the minimum size limit) white stumpnose in the Saldanha-Langebaan system. The rational is 

that the more abundant the species is in the fished area, the more will be caught per unit fishing 

time. This was simply calculated as the number or weight of white stumpnose caught per angler-hour 

fished (total catch or weight divided by the number of anglers/crew multiplied by the hours fished). 

The average monthly CPUE for each data set was plotted to investigate any trends in the relative 

abundance over time. The average annual catch rate, calculated from July to June in order to 

encompass the summer fishing season, was also graphically compared to the average annual catch of 

juvenile white stumpnose in the seine net surveys. 

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Fish 

Figure 9.1. 

Sampling sites within Saldanha Bay and Langebaan lagoon where seine net hauls were 

conducted during 2005, 2007, 2008, 2009 ,2010 and 2011 sampling events, 1: North Bay west, 

2: North Bay east, 3:Small craft harbour, 4: Hoedtjiesbaai, 5: Caravan site, 6: Blue water Bay, 7: 

Sea farm dam, 8: Spreeuwalle, 9: Lynch point, 10: Strandloper, 11: Schaapen Island, 12: Klein 

Oesterwal, 13: Botelary, 14: Churchaven, 15: Kraalbaai. 

9.3 Results 

9.3.1 Description of inter annual trends in fish species diversity 

For the first time, the 2011 annual survey recorded Cape Stumpnose in Big Bay and Langebaan 

lagoon samples. This species is rare on the west coast and typically inhabits south and east coast 

estuary nursery habitats. Although Cape Stumpnose had not been sampled during any of the earlier 

annual seine net surveys, this species was caught in the monthly surveys conducted during 2007- 

2008 by Clement Arendse. The total species count remains at thirty-seven fish species taking into 

account the three different species of goby of the genus Caffrogobius, namely: C. nudiceps, C. 

gilchristi and C. caffer that have been identified in the Bay. Due to the uncertainty surrounding 

identification of these species in earlier surveys, they have been grouped at the generic level for data 

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Number of species 


Fish 

presented reports since 2008. The species list and abundance of each species caught in Small Bay, 

Big Bay and the Lagoon during each of the different surveys are shown in Table 9.1, Table 9.2 & 

Table 9.3 respectively. Considering data from all surveys conducted to date, a greater diversity of 

species have been captured in Big Bay (27) , slightly fewer in Small Bay (25) with the fewest found in 

the Lagoon (19) (Table 9.1, Table 9.2 & 

Table 9.3). Species richness was usually highest in Small Bay and varied little over time, although in 

2009 & 2010 there was a slight reduction in the number of species caught in Small Bay, this increased 

again in 2011 (Figure 9.2). Slightly more variation in the number of species caught over the period of 

sampling is apparent for Langebaan lagoon and Big Bay samples with the second most diverse 

samples collected from these areas during 2011 (Figure 9.2). 

18 

1986 1994 2005 2007 2008 2009 2010 2011 

16 

14 

12 

10 

8 

6 

2250m 2 

7200m 2 

3750m 2 

5600m 2 

4950m 2 

4275m 2 

5525m 2 

5400m 2 

6250m 2 

10500m 2 

5850 m 2 

7500m 2 

4950m 2 

1800m 2 

7125m 2 

7200m 2 

6000m 2 

11325m 2 3150 m 2 

9000m 2 

6150m 2 

2925m 2 

4 

2 

0 

Figure 9.2. 

Small Bay Big Bay Lagoon 

Fish species richness during seven seine-net surveys in Saldanha Bay and Langebaan lagoon 

conducted over the period 1986-2010. The total area netted in each area and survey is shown. 

The actual species composition in the different areas between the surveys does change 

substantially between years, but the same ubiquitous species occur in nearly all surveys in the three 

areas (Table 9.1, Table 9.2 & 

Table 9.3). Within Small Bay, eight species have occurred in all surveys to date, with gurnard 

not captured for the first time in 2011, and pipefish only absent in the 2005 sample. Five of the 27 

species recorded in Big Bay occurred in all surveys with three more, silversides False Bay klipvis and 

elf only absent in one survey each (2007, 1994 and 2009 respectively). Similarly, six of the 19 species 

found in the lagoon occurred in all surveys. It appears that Small Bay has the highest proportion of 

“resident” species that occur there consistently, whilst a larger proportion of the Big Bay and 

Langebaan Lagoon ichthyofauna occur seasonally or sporadically in these areas. Short term 

fluctuations in diversity and abundance of near shore sandy beach fish communities with changes in 

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Fish 

oceanographic conditions are the norm rather than the exception (see for e.g. Clark 1994). In the 

earlier surveys (1994-2008), average species richness and abundance (all species combined) was 

highest in Small Bay and lowest in Big Bay (Figure 9.2, Figure 9.3). Although this pattern still holds for 

abundance in the 2011 survey (this was however, the result of very large harder catches in Small 

Bay), this was not the case for diversity with more species captured in Big Bay during the past two 

annual sampling events. This is simply an indication of the high variability in surf zone fish densities 

that will be recorded when shoaling species are part of the fish assemblage rather than an indication 

in fundamental changes in the fish communities. 

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Fish 

Table 9.1 

Average abundance of fish species (number.m -2 ) recorded during annual beach seine-net surveys in Small Bay Saldanha. (Ave. = average, SE = standard 

error). Species not previously recorded are shown in bold font. 

Year Apr-94 Oct-05 Apr-07 Apr-08 Apr-09 Apr-10 Apr-11 

Species Common name Ave SE Ave SE Ave SE Ave SE Ave SE Ave SE Ave SE 

Atherina breviceps silverside 1.3084 0.4004 0.0410 0.0136 0.9690 0.1802 1.6505 0.6931 0.109 0.052 0.3397 0.1121 0.6420 0.2777 

Caffrogobius sp. goby 0.0160 0.0035 0.1294 0.0983 1.0888 0.5198 0.0162 0.0122 0.019 0.009 0.0039 0.0024 0.0307 0.0272 

Cheilidonichthys capensis gurnard 0.0022 0.0010 0.0082 0.0023 0.0003 0.0003 0.0004 0.0004 0.0006 0.0003 0.0007 0.0007 

Clinus latipennis False Bay Klipvis 0.0004 0.0004 0.0006 0.0006 

Clinus sp. larvae Klipvis larvae 0.0004 0.0004 

Clinus superciliosus super klipvis 0.0080 0.0018 0.0028 0.0016 0.0090 0.0044 0.0142 0.0049 0.0030 0.0022 0.0017 0.0007 0.0250 0.0104 

Diplodus sargus capensis black tail 0.0022 0.0017 0.0178 0.0086 0.0532 0.0202 0.4437 0.2204 0.062 0.043 0.0011 0.0011 0.0007 0.0007 

Etrumeus terres red eye sardine 0.0009 0.0009 

Gilchristella aestuaria estuarine round herring 0.0026 0.0020 

Gonorhynchus gonorhynchus beaked sand eel 0.0001 0.0001 0.0004 0.0004 

Haploblepherus 

pictus dark Shy Shark 0.0002 0.0002 0.0019 0.0019 

Heteromycteris capensis Cape sole 0.0049 0.0018 0.0017 0.0011 0.0162 0.0074 0.0022 0.0013 0.026 0.009 0.0108 0.0037 0.0185 0.0097 

Lithognathus sp steenbras sp. 0.0079 0.0037 

Liza richardsonii harder 0.6951 0.4400 0.5847 0.3283 2.1429 0.8870 0.8742 0.4165 0.4181 0.1867 1.1895 0.2816 38.4739 25.3006 

Mustelus mustelus smoothhound shark 0.0027 0.0022 0.0009 0.0007 

Myliobatis aquila eagle ray 0.0013 0.0005 0.0004 0.0003 0.0079 0.0074 0.0004 0.0004 

Pomatomus saltatrix elf 0.0009 0.0009 0.0013 0.0013 0.0003 0.0003 0.0007 0.0007 

Poroderma africana striped catshark 0.0009 0.0005 

Psammogobius knysnaensis Knysna sand gobi 0.0028 0.0026 

Raja clavata thornback skate 0.0011 0.0007 

Rhabdosargus globiceps white stumpnose 0.0618 0.0259 0.0079 0.0031 5.0564 1.1656 0.4191 0.1487 0.0562 0.0179 0.0822 0.0328 0.0244 0.0122 

Rhinobatos blockii bluntnose guitar fish 0.0009 0.0005 0.0013 0.0005 0.0153 0.0092 0.0007 0.0004 0.0010 0.0006 0.0008 0.0008 0.0006 0.0006 

Spondyliosoma emarginatum steentjie 0.0013 0.0009 0.0092 0.0072 0.0003 0.0003 0.0237 0.0237 

Syngnathus temminckii pipe fish 0.0022 0.0012 0.0037 0.0019 0.0257 0.0125 0.0004 0.0002 0.0035 0.0021 0.0033 0.0018 

Trachurus trachurus horse mackerel 0.0094 0.0094 

Total 2.11 0.51 0.81 0.32 9.37 2.30 3.46 1.17 0.70 0.21 1.64 0.26 39.25 25.21 

Number of species 24 16 14 14 15 12 12 13 

Number of hauls 59 5 12 6 12 12 12 12 

Total area sampled(m 2 ) 28025 2250 7200 3750 5600 4950 4275 3150 

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Table 9.2 

Average abundance of fish species (number.m -2 ) recorded during annual beach seine-net surveys in Big Bay Saldanha SE = standard error. 

Year Apr-94 Oct-05 Apr-07 Apr-08 Apr-09 Apr-2010 Apr-11 

Species Common name Ave SE Ave SE Ave SE Ave SE Ave SE Ave SE Ave SE 

Atherina breviceps silverside 0.0003 0.0002 0.0025 0.0012 0.1257 0.0624 0.0946 0.0687 0.0289 0.0133 0.1679 0.0769 

Blennophis blenny sp. 0.0001 0.0001 0.0001 0.0001 

Caffrogobius sp. goby 0.0002 0.0002 0.0031 0.0020 0.0005 0.0005 

Callorhinchus capensis St Joseph 0.0017 0.001 

Cancelloxus longior Snake eel 0.0001 0.0001 0.0003 0.0003 0.0004 0.0003 

Cheilidonichthys capensis gurnard 0.0021 0.0012 0.0079 0.0043 0.0005 0.0003 0.0054 0.0023 0.0022 0.0010 0.0001 0.0001 0.0063 0.0039 

Chorisochismus sp suckerfish sp. 0.0001 0.0001 

Clinus latipennis False Bay Klipvis 0.0017 0.0006 0.0003 0.0002 0.0007 0.0003 0.0007 0.0004 0.0002 0.0002 0.0002 0.0002 

Clinus superciliosus super klipvis 0.0037 0.001 0.0017 0.0008 0.0006 0.0006 0.0002 0.0001 

Dasyatis chrysonota Blue Stingray 0.0004 0.0004 0.0001 0.0001 

Diplodus sargus capensis black tail 0.0004 0.0004 0.0009 0.0004 

Engraulis japonicus anchovy 0.0002 0.0002 

Gonorhynchus gonorhynchus beaked sand eel 0.0005 0.0003 

Haploblepherus pictus Dark Shy Shark 0.0002 0.0002 


Liza richardsonii harder 0.3877 0.1218 0.2098 0.0595 1.4077 0.7576 0.1805 0.0450 0.1201 0.0365 0.2153 0.0777 0.9968 0.4905 

Mustelus mustelus smoothhound shark 0.0013 0.0006 0.0001 0.0001 

Myliobatis aquila eagle ray 0.0049 0.0027 0.0003 0.0003 

Parablennius cornutus blenny 0.0002 0.0002 

Pomatomus saltatrix elf 0.0005 0.0003 0.0001 0.0001 0.0159 0.0157 0.0430 0.0265 0.0068 0.0031 0.0217 0.0096 

Psammogobius knysnaensis Knysna sand gobi 0.0006 0.0004 0.0006 0.0004 

Rhabdosargus globiceps white stumpnose 0.003 0.0012 0.0207 0.0177 0.3358 0.1098 0.2012 0.0523 0.0501 0.0266 0.051 0.023 0.1341 0.1204 

Rhabdosargus holubi Cape stumpnose 0.0007 0.0007 

Rhinobatos blockii bluntnose guitar fish 0.0066 0.0022 0.0022 0.0017 0.0029 0.0017 0.0019 0.0013 0.0001 0.0001 0.0009 0.0008 0.0009 0.0008 

Spondyliosoma emarginatum steentjie 0.0004 0.0004 0.0002 0.0003 0.0002 

Syngnathus temminckii pipe fish 0.0002 0.0002 0.0004 0.0003 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 


Total 0.48 0.12 0.25 0.06 1.85 0.77 0.61 0.14 0.29 0.09 0.31 0.08 1.34 0.61 

Number of species 27 14 12 10 17 12 13 14 

Number of hauls 104 14 12 6 18 18 18 18 

Total area sampled(m 2 ) 45975 5525 5400 6250 10500 5850 7500 4950 

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Table 9.3. 

Average abundance of fish species (number.m -2 ) recorded during annual beach seine-net surveys in Langebaan Lagoon. SE = standard error. 

Species Apr&Jun Apr-94 Oct-05 Apr-07 Apr-08 Apr-09 Apr-10 Apr-11 

Common name 1986-87 SE Ave SE Ave SE Ave SE Ave SE Ave SE Ave SE Ave SE 

Atherina breviceps silverside 1.1916 0.2595 1.1865 0.3068 0.0524 0.0246 0.0786 0.0335 0.1416 0.0492 0.0654 0.0267 0.1206 0.0377 0.2857 0.11 

Blennophis blenny sp. 0.0001 0.0001 

Caffrogobius sp. goby 0.0888 0.0530 0.0608 0.0184 0.1776 0.1267 0.3072 0.1262 0.0626 0.0150 0.0748 0.0335 0.0973 0.0318 0.3764 0.14 

Cheilidonichthys capensis gurnard 0.0020 0.0010 0.0038 0.0019 0.0001 0.0001 

Clinus latipennis False Bay Klipvis 0.0163 0.0085 0.0001 0.0001 0.0002 0.0002 

Clinus superciliosus super klipvis 0.0698 0.0369 0.0063 0.0038 0.0006 0.0005 0.0031 0.0029 

Diplodus sargus capensis black tail 0.0120 0.0111 0.0003 0.0002 


Lichia amia leervis 0.0002 0.0002 

Liza richardsonii harder 0.2452 0.0971 0.7182 0.1941 0.3452 0.1453 3.8468 3.3679 0.1548 0.1066 0.3750 0.0980 9.5032 7.4567 1.572 0.54 

Parablennius cornutus blenny 0.0002 0.0002 

Pomatomus saltatrix elf 0.0001 0.0001 0.0002 0.0002 0.0013 0.001 

Poroderma africana striped catshark 0.001 0.001 

Psammogobius knysnaensis Knysna sand gobi 0.0958 0.0455 0.4916 0.1487 0.1411 0.0457 0.6768 0.2501 0.2237 0.0700 0.2736 0.0661 0.1691 0.0336 0.1176 0.08 

Rhabdosargus globiceps white stumpnose 0.0009 0.0008 0.0055 0.0025 0.0001 0.0001 0.2016 0.2170 0.0354 0.0293 0.0263 0.0167 0.2445 0.1582 0.0959 0.04 

Rhabdosargus holubi Cape stumpnose 0.0114 0.01 

Rhinobatos blockii bluntnose guitar fish 0.0176 0.0100 0.0011 0.0006 0.0008 0.0004 0.0065 0.0032 0.0005 0.0005 

Solea bleekeri blackhand sole 0.0006 0.0003 0.0004 0.0003 0.0003 0.0002 0.0001 0.0001 0.0003 0.0003 

Spondyliosoma emarginatum steentjie 0.0001 0.0001 0.0009 0.0009 0.0001 0.0001 0.0006 0.0006 

Syngnathus temminckii pipe fish 0.0063 0.0025 0.0007 0.0004 


Total 1.71 0.30 2.49 0.431 0.69 0.18 5.12 3.20 0.65 0.16 0.84 0.13 10.15 7.44 2.4658 0.52 

Number of species 21 9 14 11 8 11 11 9 12 

Number of hauls 128 30 20 12 9 15 13 15 14 

Total area sampled(m 2 ) 67725 18000 7125 7200 6000 9000 6150 11325 2925 

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9.3.2 Description of inter-annual trends in fish abundance and current status of fish 

communities in Small Bay, Big Bay and Langebaan lagoon 

Within the Saldanha-Langebaan system, harders, silversides and gobies numerically dominated the 

catches for all surveys. Overall the catches made during the 2011 survey were the largest on record 

within Small Bay (exclusively due to the very big catches of harders made at the three sites along the 

northern shore) and well above average for the Big Bay (second highest on record after the 2007 

survey) and Langebaan lagoon sites (3 rd highest on record) (Figure 9.3). Estimated white stumpnose, 

nude goby and blacktail abundance, that was above average in Small Bay during the 2007 and 2008 

surveys has remained below historical levels in this region since 2009 (Figure 9.4). Within Big Bay 

and Langebaan Lagoon however, higher than average fish density was again observed during the 

2011 sampling. During the 2009 survey, the densities of all the more common fish species in Small 

and Big Bay were lower than the preceding two years and in some cases the lowest recorded during 

sampling thus far. The 2011 survey saw a recovery in the density of harders, white stumpnose, elf 

and silverside in Big Bay, whilst within Langebaan lagoon, abundance of harders, Caffrogobius sp. 

and white stumpnose was well above the average recorded in earlier surveys (Figure 9.4). With the 

exception of harders, the opposite trend was observed in Small Bay i.e. a decrease in abundance of 

the common species (Figure 9.4). 

It appears that the unfavourable environmental conditions that reduced the spawning 

success of adults and caused high mortality rates of eggs, larval and juveniles of several species 

during the 2008-2009 periods have passed and the results of better than average recruitment are 

seen in the 2010 and 2011 data for Big bay and Langebaan Lagoon. The observed density of white 

stumpnose and harders in Langebaan lagoon recorded during the 2010 and 2011 sampling remains 

higher than that recorded during most of the earlier surveys, suggesting good recruitment in this 

area and possibly reflecting the demonstrated benefits of the Langebaan Lagoon marine protected 

area for exploited fish species (Figure 9.4). Naturally high variability in recruitment strength is 

frequently observed for marine fish species and it is likely that natural environmental fluctuations 

rather than anthropogenic factors that caused the poor recruitment in 2009. The fact that Small Bay 

showed the opposite trend in recruitment strength compared to the Big Bay and Lagoon sites during 

2011, is however, cause for concern. The better than average recruitment recorded at the latter 

sites suggests that it was not a “poor” year for egg, larval and juvenile survival within the Bay as a 

whole. Either the environmental conditions were not conducive for the dispersal of eggs and larvae 

into the Small Bay area (i.e. they didn’t get there), or it was not good for their survival (i.e. they got 

there but survival was poor). Both are plausible explanations, but if the environment was not 

conducive to survival of juveniles during the summer of 2010/2011 this could have been a result of 

anthropogenic factors. 

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Fish abundance (No.m -2 ) 


Fish 

70 

1986 1994 2005 2007 2008 2009 2010 2011 

60 

50 

40 

30 

20 

10 

0 

Figure 9.3. 

Small Bay Big Bay Lagoon 

Average fish abundance (all species combined) during eight seine-net surveys conducted in 

Saldanha Bay and Langebaan lagoon. (Error bars show one Standard Error of the mean). 

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Fish 

7 

6 

5 

4 

3 

2 

1 

0 

Fish abundance-Small Bay 

1994 2005 2007 2008 

2009 2010 2011 

W stump silverside nude goby black tail 

2.4 

2.0 

1.6 

1.2 

0.8 

0.4 

0.0 

Fish abundance-Big Bay 

1994 

2005 

2007 

2008 

2009 

2010 


harder silverside W stump Cape sole elf 

70 

Harders -Small Bay 

60 

50 

40 

30 

20 

10 

10.0 

9.0 

8.0 

7.0 

6.0 

5.0 

4.0 

3.0 

2.0 

1.0 

Fish abundance-Langebaan Lagoon 

1986-87 

1994 

2005 

2007 

2008 

2009 

2010 


0 

1994 2005 2007 2008 2009 2010 2011 

0.0 

harder 

Caffrogobius Knysna gobi silverside W stump 

sp. 

Figure 9.4. 

Abundance (no. m -2 ) of the most common fish species recorded in annual seine-net surveys 

within Saldanha Bay and Langebaan Lagoon (1986/87, 1994, 2005, 2007, 2010 & 2011) (Error 

bars show one standard error of the mean). 

9.3.3 Status of fish populations at individual sites sampled during 2011 

The average abundance of the four most abundant species in catches made during all earlier surveys 

and the most recent 2011 survey at each of the sites sampled is shown in Figure 9.5 , Figure 9.6 & 

Figure 9.7. The fish species include two commercially important species, (white stumpnose, 

harders), benthic gobies of the genus Caffrogobius and the ubiquitous shoaling silverside (an 

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Fish 

important forage fish species). During earlier surveys, the generally higher abundance of these 

species within Small Bay compared to Big Bay is clear, but during the 2011 survey, abundance of 

these species at both the Seafarm dam and Strandloper sites were similar to the historical Small Bay 

average (Figure 9.5). Within each of the three main areas, there are also some differences in the fish 

communities between sites, with sites on the northern shore of Small Bay having consistently higher 

densities of these four species than the small craft harbour site on the western shore of Small Bay or 

the exposed Spreeuwalle and Lynch Point sites within Big Bay (Figure 9.5 & Figure 9.6). Although the 

average densities of these more common species are highly variable between years, it is clear that at 

the time of the 2011 sampling (with the exception of harders) the average abundance of the other 

species within Small Bay had decreased but within Big Bay and Langebaan Lagoon, they had 

increased (Figure 9.5 , Figure 9.6 & Figure 9.7). 

150 

3.5 

3.0 

2.5 

2.0 

1.5 

1.0 

0.5 

0.0 

Campsite 

Silverside Goby sp. Harder W Stump 

4.0 

3.5 

3.0 

2.5 

2.0 

1.5 

1.0 

0.5 

0.0 

Bluewater Bay 


4.0 

3.5 

3.0 

2.5 

Hoedtjies Baai 

Previous surveys average 

2011 average 

4 

5 6 

2.0 

1.5 

1.0 

0.5 

0.0 


3 

1.0 

0.9 

0.8 

0.7 

0.6 

0.5 

0.4 

0.3 

0.2 

0.1 

0.0 

Small craft harbour 


Figure 9.5. 

Average abundance of the four most common fish species at each of the sites sampled within 

Small Bay during the earlier surveys (1994, 2005, 2007-2010) and during the 2011 survey. 

Errors bars show plus 1 Standard error. Note the scale change on vertical axis shows a 

maximum of either 1, 4 or 150 fish.m -2 . 

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Fish 

4.0 

3.5 

Seafarm dam 

3.0 

7 

2.5 

2.0 

8 

1.5 

1.0 

0.5 

0.0 

9 


1.0 

Spreeuwalle 

10 

0.8 

0.6 

0.4 

0.2 

0.0 


4.0 

3.5 

3.0 

2.5 

2.0 

1.5 

1.0 

0.5 

0.0 

Strandloper 

Previous surveys 

average 



1.0 

0.8 

0.6 

0.4 

0.2 

0.0 

Lynch Point 


Figure 9.6. 


Big Bay during the earlier surveys (1994, 2005, 2007-2010) and during the 2011 survey. Errors 

bars show plus 1 Standard error. Note the scale change on vertical axis shows a maximum of 

either 1, 4 or 150 fish.m -2 . 

In the earlier surveys, most sites within the Lagoon had lower estimated fish abundance 

than that recorded in Small Bay and had similar fish densities to those found at the Big Bay sites 

(Figure 9.5 , Figure 9.6 & Figure 9.7). However, the 2011 densities of all four species at lagoon sites 

were higher than average, and comparable to those recorded at sites in Small Bay and Big Bay. 

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Fish 

9.0 

8.0 

7.0 

6.0 

5.0 

4.0 

3.0 

2.0 

1.0 

0.0 

Schaapen island 


2.0 

1.5 

1.0 

Klein oestewal 

0.5 

11 

0.0 


15 

12 

13 

3 

2.5 

2 

1.5 

Botlery 

1 

14 

0.5 

0 


2.0 

1.5 

Kraal Baai 

3.0 

2.5 

2.0 

Churchaven 

Previous surveys 

average 

1.0 

1.5 


0.5 

1.0 

0.5 

0.0 

0.0 



Figure 9.7. 


Langebaan lagoon during the earlier surveys (1994, 2005, 2007-2010) and during the 2011 

survey. Errors bars show plus 1 standard error. Note the scale change on vertical axis shows a 

maximum of between 1 and 9 fish.m -2 . 

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9.3.4 Multivariate analysis of spatial and temporal trends in fish communities 

The use of multivariate statistical techniques allows for the analysis of any patterns in the complete 

fish community, taking account of both the community species composition, and the abundance of 

each species. In the 2009 State of the Bay report, multivariate analyses showed that on average, the 

fish communities from each of the three areas (Small Bay, Big Bay and Langebaan Lagoon) are 

significantly different from each other. This was related to environmental differences between the 

three areas. It was concluded that although the whole Saldanha Bay- Langebaan Lagoon system is 

connected, the near-shore environment in one area (i.e. Small Bay, Big Bay or the Lagoon) on 

average, appears more suitable to the juveniles of particular species than the other areas. 

The statistically significant differences in the fish communities found in the three main areas 

(Small Bay, Big Bay and Langebaan Lagoon), as well as the similarities between sites within each of 

these areas, supported the analysis of temporal trends (which provide information on changes in the 

health of the marine environment) on an area specific basis. The 2010 State of the Bay report also 

reported on the separation of the different sites within each area, based on dissimilarities in the fish 

community between sites. This separation is similar to the overall trend in fish communities 

throughout the bay and lagoon, a pattern relating to the degree of exposure of each site was 

evident, from the most exposed sites through to the most sheltered samples. In this report, analysis 

focussed on detecting any differences between years, taking account of the established inter-site 

variability by using a two factor (sites and years as factors) PERMANOVA design. The MDS plot for 

Small Bay shows that samples from most years grouped centrally, suggesting little change in the fish 

community over time (Figure 9.8). Fish samples taken at some sites during 2005 and 2011 are 

however outliers, indicating that these are dissimilar to the majority of other years. 

Transform: Fourth root 

Resemblance: S17 Bray Curtis similarity 


year 

94 

2005 

2007 

2008 

2009 

2010 


Figure 9.8. 

Multidimensional scaling plots showing similarities between the fish communities sampled at 

four sites within Small Bay during 1994, 2005, 2007, 2008, 2009, 2010 and 2011 sampling 

events. 

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A two way PERMANOVA indicated significant differences in the fish community between 

sample years (Pseudo F = 2.7, P< 0.0001) and between sites (Pseudo F = 9.2, P< 0.0001) and a 

significant interaction effect (Pseudo F = 2.9, P< 0.0001). Pairwise tests indicate that there are 

significant differences between all years sampled and at least two of the other annual sampling 

events (Table 9.4). This is indicative of the high natural variability in the surfzone fish community 

inhabiting Small Bay. We suspect, given the orientation of Small Bay facing into the prevailing 

southerly wind, that short term meteorological changes, (such as a wind change to a northerly or 

westerly) that are common during April and strongly influence the nature of the surfzone, are the 

primary drivers of this observed variability. The only way to account for this natural variability is to 

sample more intensively, by replicating the survey within years, sampling the same sites on different 

days within each survey and repeating it over several weeks. This is unfortunately not logistically 

possible, but trends in the ecological health of the Bay (for fish at least) can still be inferred from any 

long term consistent trends over time. It is clear from the MDS plot that only some of the 2005 and 

2011 samples collected in Small Bay were the most dissimilar from the other annual samples and 

there is no consistent trend that may be indicative of increasing or decreasing ecosystem health 

(Figure 9.8). It must be noted that as with the 2005 samples, there is also high inter-sample 

variability (spread of data in the MDS plot) within the 2011 samples. (Some samples group with 

those from other survey periods, some are outliers). The 2011 sites that are outliers include the 

small craft harbour (typically different from the other Small Bay sites) and the Campsite sites (where 

very high catches of harders were made during 2011 sampling), and this variability does not 

necessarily represent declining ecosystem health at these sites. 

Although the 2011 Small Bay samples were not significantly different from the 2010 

samples, the fish community overall was significantly different from that sampled during 1994, 2007 

and 2009. SIMPER analyses identified higher abundance of harders, and decreased average 

abundance of silversides, white stumpnose, Cape sole, blacktail and gobies in the 2011 samples as 

the dominant causes (>80%) of dissimilarity between the 2011 samples and the significantly 

different 1994, 2007 and 2009 samples. Although none of these species had disappeared from 

catches in Small Bay during 2011, they were on average substantially less abundant than in nearly all 

of the earlier surveys and this is somewhat concerning. 

Table 9.4. 

Results of the multivariate PERMANOVA pairwise tests between Small Bay fish samples 

collected in different years. NS: not significant, *: P < 0/05, **: P < 0.01 

1994 2005 2007 2008 2009 2010 

1994 

2005 * 

2007 ** NS 

2008 NS * NS 

2009 ** NS NS * 

2010 NS * NS * * 

2011 * NS * NS * NS 

Within Big Bay too, little grouping of sampling years in the MDS plot is evident with the 2008 

and 2005 outliers representing a few of Plankiesbaai and North Bay samples (Figure 9.9). All of the 

2011 samples are distributed well within the range of samples collected in earlier years, indicating 

no substantial changes in the Big Bay fish communities overall at sampled sites. The mixed model 

PERMANOVA test did however, indicate significant differences between sites (Pseudo F = 7.6, P< 

0.001), between sampling events (Pseudo F = 14.9, P< 0.05) and a significant interaction effect 

(Pseudo F = 4.1, P< 0.001). Pairwise testing showed that only the Big Bay fish samples collected 

during 1994 were significantly different from those collected during 2007 and 2009. Big Bay fish 

209 

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Fish 

samples collected during all other years were statistically similar, indicating no consistent change in 

the Big Bay surf zone fish community over time. 




year 

1994 

2005 

2007 

2008 

2009 

2010 


Figure 9.9. 

Multidimensional scaling plot showing similarities between the fish communities sampled at 

seven Big Bay sites during 1994, 2005, 2007, 2008, 2009, 2010 and 2011 sampling events. 

An MDS plot of Langebaan Lagoon fish samples shows some evidence of separation between 

sampling years with samples collected during 1994, 2007, 2010 and 2011 mostly grouping on the 

bottom and right of the MDS plot (Figure 9.10). The mixed model PERMANOVA test did indicate 

significant differences between sites (Pseudo F = 17.9, P< 0.001), between sampling events (Pseudo 

F = 4.2, P< 0.001) and a significant interaction effect (Pseudo F = 3.1, P< 0.001). Pairwise testing 

showed that fish samples collected during 1994, 2008 and 2011 were significantly different to those 

sampled during other years, but these were not consistent (Table 9.5). The 2011 lagoon samples 

were significantly different from four (all except 2007 and 2010 samples) of the previous six annual 

sampling events. 

SIMPER identified the high densities of harders, white stumpnose and Caffrogobius sp (goby 

species) and relatively lower densities of Psammogobius sp in the lagoon samples collected during 

2011 as been the primary contributors (~80%) to the dissimilarity in samples between the 2011 and 

the significantly different 1994, 2005, 2008 and 2009 samples. The 2011 samples were most similar 

to the 2007 and 2010 samples when higher than average overall fish abundance was recorded, and 

as the dissimilarity to the other years is largely a result of increased abundance of the common 

species (as opposed to decreases or the absence of species) it appears that the near shore fish 

community within the lagoon is in an overall healthy state. 

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Fish 




year 

1994 

2005 

2007 

2008 

2009 

2010 


Figure 9.10. Multidimensional scaling plots showing similarities between the fish communities sampled at 

six Lagoon sites during 1994, 2005, 2007, 2008, 2009, 2010 and 2011 sampling events. 

Table 9.5. 

Results of the multivariate PERMANOVA pairwise tests between Langebaan lagoon fish 

samples collected in different years. NS: not significant, *: P < 0/05, **: P < 0.01 

1994 2005 2007 2008 2009 2010 

1994 

2005 * 

2007 NS NS 

2008 NS NS * 

2009 NS NS NS * 

2010 * NS NS * NS 

2011 ** * NS ** * NS 

9.3.5 Status of the commercial and recreational white stumpnose fishery 

White stumpnose are the most important and recreational and commercial fish species landed 

within the Saldanha Bay- Langebaan lagoon system. Recreational boat and shore based angling for 

this species is arguably one of the largest draw cards for visitors and residents of Langebaan, whilst 

white stumpnose are a mainstay of the small commercial handline fishery that operates within the 

Bay. Data from access point (at slipways and harbours) and roving creel (along the shore line) 

surveys conducted over the period 2006- 2007 provided a valuable snapshot of this fishery (Naesje 

et al. 2008) and the results were reported on in the 2008 State of the Bay report. 

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CPUE (fish.angler -1 .hour -1 ) 

Jan 06 

Feb 06 

Mar 06 

Apr 06 

May 06 

Jul 06 

Aug 06 

Sep 06 

Oct 06 

Nov 06 

Dec 06 

Jan 07 

Feb 07 

Mar 07 

Apr 07 

May 07 

Jun 07 

Jul 07 

Aug 07 

Sep 07 

Oct 07 

Nov 07 

Dec 07 

Jan 08 

Feb 08 

Mar 08 

Apr 08 

May 08 

Jun 08 

Jul 08 

Aug 08 

Sep 08 

Oct 08 

Nov 08 

Dec 08 

Jan 09 


Fish 

This study confirmed that white stumpnose dominated the catches of shore and boat 

anglers, contributing 85-90% of the catch numerically. Boat fishing effort peaked over the months of 

December to April (average of 15-27 boats per day), whilst high levels of shore angling effort was 

observed over a longer period (September- April). Using the average crew size and catch rate for 

each type of fisher, the researchers calculated a total annual white stumpnose catch in the area as 

147 000 fish or 92 tons. The researchers note that human population in the area is growing at ~6 % 

per year, much of this population growth (and associated economic development) is driven by 

people who wish to fish in Langebaan Lagoon and Saldanha Bay and they expressed concern over 

whether the stocks can sustain these increasing levels of exploitation. 

These roving creel and access point surveys continued until January 2009 under the 

management of SAN Parks (shore angler and boat angler data), whilst an access point survey at 

slipways was initiated on behalf of DAFF in September 2007 and continued until 2010 (boat anglers 

only). These data, along with commercial line fish catch return data covering the period January 

2006 - December 2011, were analysed to provide updated CPUE trends in the regionally important 

white stumpnose fishery. 

Estimated CPUE for shore anglers interviewed by roving creel monitors was highly variable, 

and clearly showed the seasonal increase in catch rate between Spring and autumn each year 

(typically increasing in August and decreasing in May each year) (Figure 9.11). The average CPUE for 

the three year time series is 0.26 fish per angler per hour, i.e. on average a shore angler catches a 

white stumpnose for every four hours of fishing. A linear trend line suggests there may have been a 

slight decrease in shore angler CPUE over the three year period, but given the variability in the data, 

this is not statistically significant (R 2 = 0.25). The 2006-2007 fishing season was clearly the best for 

shore anglers over the three year period for which data exists, with catch rates about double the 

average for the monitored period. The 2007 seine net survey also recorded the highest white 

stumpnose recruitment density (average of all 45 sites sampled throughout Saldanha-Langebaan) on 

the monitoring record. 

2 

1.8 

1.6 

1.4 

1.2 

1 

0.8 

0.6 

0.4 

0.2 

0 

Jan 06 - May 06 Jul 06 - Jun 07 Jul 07 - Jun 08 Jul 08 - Jan 09 

Figure 9.11. White stumpnose catch-per-unit-effort (CPUE) for shore based anglers in the Saldanha 

Langebaan area over the period January 1996 - January 2009. 

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Fish 

Boat inspection data representing a combination of commercial and recreational vessels 

(mostly recreational) fishing in Langebaan Lagoon and Saldanha Bay show the same variable catch 

rates and seasonal peaks as the recreational shore angler data (Figure 9.12). In contrast to the shore 

angler data, boat CPUE shows a slight positive trend, but once again this is not statistically significant 

(R 2 = 0.01). The shore angler CPUE data series unfortunately ended in mid January 2009, whilst the 

boat angler CPUE showed a clear and strong peak over the 2008-2009 summer indicating that 

relative white stumpnose abundance was high during this period (Figure 9.12). The 2006-2007 and 

the 2009-2010 summer seasons also had above average boat angler CPUE. 

1.8 

1.6 

1.4 

CPUE fish.angler -1 .hour -1 

1.2 

1 

0.8 

0.6 

0.4 

0.2 

0 

1 3 5 8 10 12 2 4 6 8 10 12 2 4 6 8 10 12 2 4 6 8 10 12 2 4 6 8 

2006 2006 2007 2007 2008 2008 2009 2009 2010 2010 

Jan 06 - 

May 06 

Jul 06 - Jun 07 Jul 07 - Jun 08 Jul 08 - Jun 09 Jul 09 - Jun 10 Jul 10 

- Sep 

10 

Figure 9.12. White stumpnose catch-per-unit-effort (CPUE) for boat based anglers in the Saldanha 

Langebaan area over the period January 1996 – September 2010. 

Far fewer commercial linefish vessels (~10) target white stumpnose in Saldanha Bay and 

Langebaan lagoon, but all permit holders submit compulsory daily catch return data to the 

Department of Agriculture, Forestry and Fisheries. These data show strong congruence with the 

observer recorded boat inspection data, providing some validation of both fishery monitoring 

methods (Figure 9.12). The very strong peak in white stumpnose CPUE observed in the boat 

inspection data (mostly recreational) during 2008-09 is however, not sustained throughout the 

fishing season in the commercial data, with the commercial boat catch rate declining out of synch 

with the mostly recreational catch rate over the period January-May 2009. The reasons for this are 

not clear, but may well reflect a shift in targeting by commercial fishers. Another clear peak in 

commercial white stumpnose CPUE is evident in the Spring of 2001 (August-October). Overall, the 

available data on white stumpnose catch rates from three different fisheries sectors active in the 

Saldanha-Langebaan reveal high inter- and intra annual variability, but do not show any consistent 

trends. This suggests that for the time been that the white stumpnose fishery is sustainable at the 

effort levels operating over this time period. 

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CPUE (fish.angler -1 .hour -1 ) 

CPUE (kg.crew -1 .hour -1 ) 


Fish 

Boat inspections 

Commercial catch returns 

1.8 

4.5 

1.6 

4 

1.4 

3.5 

1.2 

3 

1 

2.5 

0.8 

2 

0.6 

1.5 

0.4 

1 

0.2 

0.5 

0 

0 

Nov-11 

Sep-11 

Jul-11 

May-11 

Mar-11 

Jan-11 

Nov-10 

Sep-10 

Jul-10 

May-10 

Mar-10 

Jan-10 

Nov-09 

Sep-09 

Jul-09 

May-09 

Mar-09 

Jan-09 

Nov-08 

Sep-08 

Jul-08 

May-08 

Mar-08 

Jan-08 

Nov-07 

Sep-07 

Jul-07 

May-07 

Mar-07 

Jan-07 

Nov-06 

Sep-06 

Jul-06 

May-06 

Mar-06 

Jan-06 

Figure 9.13. White stumpnose catch-per-unit-effort (CPUE) for commercial and recreational boat based 

anglers and commercial linefish permit holders catch returns in the Saldanha Langebaan area 

over the period January 2006 – December 2011. 

9.3.6 Comparisons of white stumpnose catch rates with the seine net survey data 

Tagging studies have shown adult white stumpnose to be largely resident within the Saldanha Bay, 

Langebaan system (Kerwath et al. 2009). Links between the spawner biomass and juvenile 

abundance in the indentified surfzone nursery habitats can therefore be expected. The high shore 

angler CPUE recorded in 2007 is indicative of relatively high white stumpnose abundance and it is 

possible that this gave rise to the strong juvenile recruitment seen in seine net surveys that year. 

Relationships between spawner biomass (the mass of adults) and juvenile recruitment are however 

notoriously difficult to show empirically. Indeed, some fisheries scientists go as far as to state there 

is no relationship other than in the absence of spawning adults, recruitment will fail. This is due to 

two main factors- one is the very high fecundity of most broadcast spawning marine fish (like white 

stumpnose) where a single female can spawn hundreds of thousands of eggs ever few weeks 

throughout the spawning season; and the other is the extremely high mortality that occurs during 

the egg and larval phases. This means that few adult females can produce strong recruitment under 

favourable environmental conditions that enhance egg and larval survival; or that a large female 

spawner biomass can produce very poor recruitment due to unfavourable environmental conditions. 

The commercial and recreational boat CPUE does not show a peak in January-February 2007. In fact, 

the boat catch rate declined sharply during this period, suggesting an increase in availability of white 

stumpnose to shore anglers and a decrease in availability to boat anglers, possibly indicating a 

movement into shallower water during this period (Figure 9.11, Figure 9.12). During the early 2006- 

2007 summer season, boat CPUE was above average and this does suggest that white stumpnose 

abundance was relatively high during this period. For the reasons given above, however, we are 

hesitant however to infer that this was the cause of the strong juvenile recruitment observed during 

April 2007. 

By the time juvenile white stumpnose are sampled in the annual April seine net surveys, 

however, the high mortality egg, larval and very early juvenile life history phases are completed and 

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Fish 

although juvenile mortality is still high, a significant portion of these juvenile should survive to 

recruit into the fisheries (approximately 2 years). The signal will unfortunately be confounded by the 

fact that at least four different year classes of recruits will contribute to making up the bulk of the 

catch in any fishing season (ages 2-6 dominate in the fisheries). Very strong juvenile recruitment 

can, however, be expected to leave a signal in the fishery CPUE. These recruits would only be 

available to the fishery at the legal minimum size two years later i.e. the 2007 juvenile recruitment 

measured in the surfzone should be reflected in the angler catches from the 2008-2009 fishing 

season onwards. This is based on the estimated growth rate of white stumpnose that attain 25 cm 

Total Length in their third year (age 2 +) (Attwood et al. 2010). These recruits would contribute to 

the fishery throughout their life spans, with the majority of the catch reported as 4-6 year old fish in 

2006 (Naesje et al. 2008). The relationship between the average juvenile white stumpnose density 

recorded in annual seine net surveys and the observed boat CPUE with a two year lag, is shown in 

Figure 9.14. The high density of juveniles recorded in the April 2007 seine net survey corresponds to 

a strong peak in the average annual (July 2008-June 2009) boat angler CPUE. It can be expected that 

this strong recruitment would have sustained elevated catches for several years. The following year, 

however, average boat angler CPUE again declined significantly – although not to below the average 

catch rate. Unfortunately the overlap in both data series is too short to interpret signals with much 

confidence. The commercial catch return data provide a longer period of overlap and the elevated 

catch do appear to be sustained in response to the strong 2007 juvenile recruitment, despite 

declining surf zone density estimates. This analysis has shown that there does appear to be a link 

between the estimates of juvenile white stumpnose utilizing the surfzone nursery habitats and the 

catch rate made by fisheries in the area. The potential to use the annual seine net surveys as a 

predictor of future fishery productivity and thereby enabling adaptive management to be 

implemented should be further investigated. The value of this will only be improved with ongoing 

monitoring that will allow for better understanding of the relationship between juvenile recruitment 

and fishery catches. 

215 

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Density (no.m -2 ) 

Density (no.m -2 ) 

CPUE (fish.angler-hour -1 ) 

CPUE (kg.crew-hour -1 ) 


Fish 

White stumpnose abundance and Boat CPUE 

2.0 

1 

1.5 

Average density seine survey 

Average CPUE boats (+ 2 years) 

0.9 

0.8 

0.7 

0.6 

1.0 

0.5 

0.4 

0.5 

0.3 

0.2 

0.1 

0.0 

2005 (2006_7) 2006 (2007_8) 2007 (2008_9) 2008 

(2009_10) 

2009(2010_11) 2010(2011_12) 2011(2012_13) 

0 

Year 

White stumpnose abundance and Commercial boat CPUE 

2.0 

1.4 

1.5 

Average density seine survey 

Average CPUE commercial boats 

1.2 

1 

1.0 

0.8 

0.6 

0.5 

0.4 

0.2 

0.0 

2005 (2006_7) 2006 (2007_8) 2007 (2008_9) 2008 (2009_10) 2009(2010_11) 2010(2011_12) 2011(2012_13) 

0 

Year 

Figure 9.14. Comparison between the average annual juvenile white stumpnose abundance as estimated 

from seine net surveys and the observed boat (inspections) and commercial (catch returns) 

catch-per-unit-effort two years later 

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Fish 

9.4 Conclusion 

The current status of fish and fisheries within Saldanha Bay-Langebaan appears satisfactory. 

Long term monitoring by means of experimental seine-netting has revealed statistically significant 

differences in fish community structure between different sampling sites within years and between 

sampling years. A consistent long-term negative trend, since fish sampling began in 1986-87 has 

however, not been detected. In fact fish abundance of key species at sites within or in close 

proximity to the Marine Protected Area appears to be increasing. This reflects natural and human 

induced impacts on the adult population size, recruitment success and use of the near shore habitat 

by fish species; but may also be a result of the benefits of protection from exploitation and reduced 

disturbance at some sites due to the presence of the Langebaan MPA. Certainly, the study by 

Kerwath et al. (2009) demonstrated the benefits of the MPA for white stumpnose, and the 

protection of harders from net fishing in the MPA undoubtedly benefits this stock in the larger Bay 

area. 

The 2011 sampling event recorded remarkably good harder recruitment throughout the 

Saldanha Bay-Langebaan system, whilst the estimated abundance of other key species such as white 

stumpnose, gobies and silversides within Big Bay and Langebaan Lagoon compare favourably with 

data from earlier surveys. In Small Bay, however, there were clear reductions in the abundance of 

key species (with the exception of harders), with the lowest yet recorded black tail density and the 

second lowest white stumpnose density to date. This follows the trend observed in the 2010 report 

and it is somewhat concerning that the estimated abundance of some key species is decreasing in 

the areas of maximum anthropogenic disturbance within Small Bay, whilst they are increasing in 

other less disturbed areas of Big Bay and Langebaan lagoon. 

In the data set collected to date, the average density of commercially important fish such as 

white stumpnose was much higher at Small Bay sites compared to Big Bay and Lagoon sites 

(although the opposite trend was observed in 2011). Indeed the average white stumpnose density 

calculated from all seine net surveys to date is 0.8 fish.m -2 in Small Bay, compared with 0.1 fish.m -2 in 

Big Bay and 0.05 fish.m -2 in Langebaan lagoon. The juveniles of other species were similarly more 

abundant in Small Bay. This gives an indication of the importance of Small Bay as a nursery habitat 

for the fish species that support the large and growing fisheries throughout the Bay. The monetary 

value of the recreational fishery in Saldanha-Langebaan should not be regarded as regionally 

insignificant as a lot of the expenditure associated with recreational angling is taking place within 

Langebaan and Saldanha itself. Furthermore the popular white stumpnose fishery is undoubtedly a 

major draw card to the area and has probably contributed significantly to the residential property 

market growth the region has experienced. The value of Small Bay as a fish nursery and the 

economic value of the resultant fisheries should not be disregarded when considering the 

environmental impacts of the proposed future industrial developments within Small Bay. The 

monitoring record from the annual seine net surveys will prove increasingly valuable in assessing 

and mitigating the impacts of future developments on the regions ichthyofauna. Extending the seine 

net monitoring record would also facilitate analysis of the relationship between recruitment to the 

surfzone nursery habitat and future catches in the fisheries. Should this relationship prove robust 

and quantifiable, this will allow for adaptive management of the fisheries in the future as fishing 

effort continues to increase and at some point fishing mortality will need to be contained, if the 

fisheries are to remain sustainable. 

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Birds 

10 BIRDS 


Together with the five islands within the Bay and Vondeling Island slightly to the South, Saldanha 

Bay and Langebaan Lagoon provide extensive and varied habitat for waterbirds. This includes 

sheltered deepwater marine habitats associated with Saldanha Bay itself, sheltered beaches in the 

Bay, islands that serve as breeding refuges for seabirds, rocky shoreline surrounding the islands and 

at the mouth of the Bay, and the extensive intertidal salt marshes, mud- and sandflats of the 

sheltered Langebaan Lagoon. Langebaan Lagoon has 1 750 ha of intertidal mud- and sandflats and 

600 ha of salt marshes (Summers 1977). Sea grass Zostera capensis beds are more extensive at the 

southern end of the lagoon. Beds of the red seaweed Gracilaria verrucosa are mainly found at the 

mouth and patchily distributed over the sandflats. There are also small saltpans and drainage 

channels which add habitat diversity around the lagoon. Most of the plant communities bordering 

the lagoon belong to the West Coast Strandveld, a vegetation type which is seriously threatened by 

agricultural activities and urban development. Twelve percent of this vegetation type is conserved 

within the park (Boucher and Jarman 1977, Jarman 1986). Although there is no river flowing into the 

Lagoon, it has some estuarine characteristics due to the input of fresh groundwater in the southern 

portion of the lagoon. 

Saldanha Bay and Langebaan Lagoon are not only extensive in area but provide much of the 

sheltered habitat along the otherwise very exposed West Coast of South Africa. There are only four 

other large estuarine systems which provide sheltered habitat comparable to Langebaan Lagoon for 

birds along the West Coast – the Orange, Olifants and Berg and Rietvlei/Diep. There are no 

comparable sheltered bays and relatively few offshore islands. Indeed, these habitats are even of 

significance at a national scale. While South Africa’s coastline has numerous estuaries (about 290), it 

has few very large sheltered coastal habitats such as bays, lagoons or estuaries. Indeed, the 

Langebaan-Saldanha area is comparable in its conservation value to systems such as Kosi, St Lucia 

and the Knysna estuary. 

Saldanha Bay, and particularly Langebaan Lagoon, are thus of tremendous importance in 

terms of the diversity and abundance of waterbird populations supported. A total of 283 species of 

birds have been recorded within the boundaries of the West Coast National Park, of which 11 are 

seabirds, known to breed on the islands within the Bay (Birdlife International 2011). 

10.2 Birds of Saldanha Bay and the Islands 

10.2.1 National importance of Saldanha Bay and the islands for birds 

Saldanha Bay and the islands are important not so much for the diversity of birds they support, but 

for the sheer numbers of birds of a few species in particular. 

The islands of, Vondeling (21 ha), Schaapen (29 ha), Malgas (18 ha) and Jutten (43 ha), 

Meeuw (7 ha) and Marcus (17 ha), support important seabird breeding colonies and forms one of 

only a few such breeding areas along the West Coast of South Africa. They support nationallyimportant 

breeding populations of African Penguin (recently up-listed to Endangered under IUCN’s 

red data list criteria), Cape Gannet (Vulnerable), Cape Cormorant (Near-threatened), White-breasted 

Cormorant, Crowned Cormorant (Near Threatened), and Bank Cormorant (Vulnerable), Kelp and 

Hartlaub’s gulls and Swift Tern. 

In addition to seabird breeding colonies, the islands also support important populations of 

the rare and endemic African Black Oystercatcher (Near-threatened). These birds are resident on 

218 

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Birds 

the islands, but are thought to form a source population for mainland coastal populations through 

dispersal of young birds. 

10.2.2 Ecology and status of the principle bird species 

The African Penguin Spheniscus demersus is endemic to 

southern Africa, and breeds in three regions: central to 

southern Namibia, Western Cape and Eastern Cape in 

South Africa (Whittington et al. 2005a). The species has 

recently been up-listed to Endangered, under IUCN’s ‘red 

data list’ due to recent data revealing rapid population 

declines as a result of competition with commercial 

fisheries for food and shifts in prey populations (Birdlife 

International 2011; Pichegru et al. 2009). The Namibian 

population collapsed in tandem with the collapse of its 

main prey species, the sardine (Sardinops sagax; Ludynia 

2010). In South Africa the penguins breed mainly on 

offshore islands in the Western and Eastern Cape with 

strongly downward trends at all major colonies 

(Whittington et al. 2005b). 

The changes in population sizes at islands in Saldanha is believed to be partially linked to 

patterns of immigration and emigration by young birds recruiting to colonies other than where they 

fledged, with birds tending to move to Robben and Dassen Islands in recent years (Whittington et al. 

2005b). However, once they start breeding at an island, they will not breed anywhere else. Penguin 

survival and breeding success is closely tied to the availability of pelagic sardines S. sagax and 

anchovies Engraulis encrasicolus within 20– 30 km of their breeding sites (Pichegru et al. 2009). Diet 

samples taken from penguins at Marcus and Jutten Islands showed that the diet of African penguins 

in the Southern Benguela from 1984 to 1993 was dominated by anchovy (Laugksch and Adams 

1993). During periods when anchovy are dominant, food is more consistently available to penguins 

on the western Agulhas Bank than at other times (older anchovy remain there throughout the year 

and sardines are available in the region in the early part of the year). Penguin colonies closest to the 

Agulhas Bank would benefit during periods of anchovy dominance while those colonies between 

Lüderitz and Table Bay (including Saldanha Bay) would be faced with a diminished food supply as the 

anchovy population contracts to the north off Namibia and the south off South Africa (Whittington 

et al. 2005b). The reduced abundance of anchovy may explain the decrease in the African penguin 

population evident from 1987 to 1993 clearly reflected in Saldanha (Figure 10.1). Furthermore, both 

prey species are exploited by purse-seine fisheries which together with the eastward displacement 

of the pelagic fish off the South African coast between 1997 and 2005, further reduced food 

availability for the penguins. 

The number of African penguins breeding in the Western Cape decreased from some 92 000 

pairs in 1956, to 18 000 pairs in 1996, there was a slight recovery to a maximum of 38 000 pairs in 

2004, before another dramatic collapse to 11 000 pairs in 2009, equating to a total decline of 60.5% 

in 28 years (Crawford et al. 2008a, b, R. Crawford unpubl. data). In Saldanha Bay the population has 

decreased from 2 049 breeding pairs in 1987 to 614 breeding pairs in 2011, representing a 75% 

decrease in 24 years (Figure 10.1). Although penguin numbers in Saldanha Bay in 2011 are slightly 

up on that in 2010 (614 vs. 506 pairs), the overall downward trend currently shows no sign of 

reversing, and immediate conservation action is required to prevent further declines. 

219 

ANCHOR 


Number of breeding pairs 


Birds 

2500 

African Penguin 

2000 

Total 

Malgas 

1500 

1000 

Marcus 

Jutten 

Vondeling 

500 

0 

Figure 10.1. Trends in African Penguin populations at Malgas, Marcus, Jutten and Vondeling islands in 

Saldanha Bay (Data source: Rob Crawford, DEA: Oceans & Coasts). 

Year 

There is considerable uncertainty around the cause of the decreases, however. One of the 

measures currently being employed to curb these declines is the use of no-take zones for purseseine 

fishing. This strategy, recently tested at St Croix Island in the Eastern Cape, was effective in 

decreasing breeding penguins’ foraging efforts by 30% within three months of closing a 20 km zone 

to purse-seine fisheries (Pichegru et al. 2010). In this case the use of small no-take zones has 

represented immediate benefits for a top predator dependent on pelagic prey, with minimum cost 

to the fishing industry, while protecting ecosystems within these habitats and important species. 

However, research at Dassen and Robben Islands has not delivered such positive results. 

The reduction in colony sizes at most of the islands in Saldanha Bay will have had severe 

negative consequences for penguins. When Penguins breed in large colonies, packed close to one 

another, they are better able to defend themselves against egg and chick predation by Kelp gulls. 

Also, these losses are trivial at the colony level. However, the fragmented colonies and the massive 

rise in gull numbers associated with the rapidly expanding human settlements in the area, means 

that gull predation is increasingly problematic. Similarly, predation by seals (on land and around 

colonies) is having an increasingly negative impact on these dwindling colonies (Makhado et al. 

2009). Additional stress, such as turbidity and increased vessel traffic, will not only impact penguins 

directly, but is likely to influence the location of schooling fish that the penguins are targeting and 

their ability to locate these schools. There are also concerns that toxin loads influence individual 

birds’ health, reducing their breeding success and/or longevity (Game et al. 2009). 

In summary, the initial collapse of the penguin colonies in the area is probably related to 

food availability around breeding islands and in areas where birds not engaged in breeding are 

foraging. However, now that colonies have shrunk so dramatically, the net effect of local conditions 

at Saldanha Bay are believed to be an increasingly important factor in the continued demise of 

African penguin colonies at the islands. 

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Birds 

The Kelp Gull Larus dominicanus breeds 

exclusively on offshore islands, apart from one 

mainland site. The Islands in Saldanha Bay support 

a significant proportion of South Africa’s breeding 

population. Within this area, the majority breed on 

Schaapen, Meeuw and Jutten Islands, with 

additional small but consistent breeding 

populations on Vondeling and Malgas islands. 

Small numbers of breeding kelp gulls were 

recorded on Marcus Island in 1978, 1985 and 1990- 

92, but breeding has since ceased, probably due to 

the causeway connecting the island to the mainland 

allowing access to mammal predators (Hockey et al. 2005). Overall, the number of Kelp gulls on the 

islands increased until 2000 (Figure 10.2), probably due to the increase in availability of food as a 

result of the introduction and spread of the invasive alien mussel species Mytilus galloprovincialis. 

This was not particularly good news, however, as Kelp Gulls are known to eat the eggs of several 

other bird species (e.g. Cape Cormorants and Hartlaub's Gulls). However, since 2000, the 

populations on the islands have been steadily decreasing following large-scale predation by Great 

White Pelicans Pelecanus onocrotalus that was first observed in the mid-1990s (Crawford et al. 

1997). During 2005 and 2006 pelicans caused total breeding failure of Kelp Gulls at Jutten and 

Schaapen Islands (de Ponte Machado 2007) the effects of which are still apparent (Figure 10.2). 

Numbers are now well below those at the start of the comprehensive counting period. 

14000 

12000 

10000 

8000 

6000 

Kelp Gull 

Total 

Malgas 

Marcus 

Jutten 

Vondeling 

Schaapen 

Meeuw 

Caspian Is. 

4000 

2000 

0 

Figure 10.2. Trends in breeding population of Kelp gulls at Malgas, Jutten, Schaapen, Vondeling and 

Meeuw Islands in Saldanha Bay (Data source: Rob Crawford, DEA: Oceans & Coasts). 

Year 

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1987 

1988 

1989 

1990 

1991 

1992 

1993 

1994 

1995 

1996 

1997 

1998 

1999 

2000 

2001 

2002 

2003 

2004 

2005 

2006 

2007 

2008 

2009 

2010 



Birds 

Hartlaub's Gull, Larus hartlaubii, is about the 10th 

rarest of the world's roughly 50 gull species. It is endemic to 

southern Africa, occurring along the West Coast from 

Swakopmund to Cape Agulhas. It breeds mainly on 

protected islands but has also been found to breed in 

sheltered inland waters. Hartlaub’s Gulls are relatively 

nomadic, and can alter breeding localities from one year to 

the next (Crawford et al. 2003). 

The numbers breeding on the different islands are 

highly erratic, as are the total numbers in the Bay. The 

highest and most consistent numbers of breeding birds are 

found on Malgas, Jutten and Schaapen islands, with a few birds breeding Vondeling Island between 

1991 and 1999. They have also been recorded breeding on Meeuw Island in 1996 and from 2002 to 

2004. There are substantial inter-annual fluctuations in numbers of birds breeding, suggesting that in 

some years an appreciable proportion of the adults do not breed (Crawford et al. 2003). Natural 

predators of this gull are the Kelp Gull, African Sacred Ibis and Cattle Egret, which eat eggs, chicks 

and occasionally adults (Williams et al. 1990). In Saldanha Bay there is no discernable upward or 

downward trend over time, but there is some concern in that breeding has ceased at Schaapen 

Island and overall numbers have remained very low for the past four years (Figure 10.3). 

3500 

3000 

2500 

2000 

1500 

Hartlaub's Gull 

total 

Vondeling 

Malgas 

Jutten 

Marcus 

Schaapen 

Meeuw 

Caspian Is. 

1000 

500 

0 

Figure 10.3. Trends in breeding population of Hartlaub’s Gulls at Malgas, Marcus, Jutten, Schaapen and 

Vondeling Islands in Saldanha Bay (Data source: Rob Crawford, DEA: Oceans & Coasts). 

Year 

The Swift Tern, Sterna bergii, is a widespread species that occurs as a common resident in 

southern Africa. Swift Terns breed synchronously in colonies, usually on protected islands, and often 

in association with Hartlaub’s Gulls. Sensitive to human disturbance, their nests easily fall prey to Kelp 

Gulls, Hartlaub’s Gulls and Sacred Ibis (Le Roux 2002). During the breeding season, fish form 86% of 

all prey items taken, particularly pelagic shoaling fish, of which the Cape Anchovy (Engraulis 

encrasicolus) is the most important prey species. Since 2001 there has been an increase in the Swift 

Tern population number in South Africa. This increase coincided with a greater abundance of two of 

222 

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Birds 

their main prey species, sardines and anchovies. 

However, since 2005, the population in the Western 

Cape has shifted south and eastward, coinciding with a 

similar shift of their prey species (Crawford 2009). In 

southern Africa, Swift Terns show low fidelity to 

breeding localities, unlike the African Penguin, Cape 

Gannet and Cape Cormorant, which enables them to 

rapidly adjust to changes in prey availability (Crawford 

2009). 

In Saldanha Bay, Jutten Island has been the 

most important island for breeding Swift Terns over the past 30 or more years, but breeding numbers 

are erratic at all the islands. The breeding population shifted to Schaapen Island in 2007, and since 

then no breeding has been recorded on any of the islands, which is a major cause for concern (Figure 

10.4). 

4000 

3500 

3000 

2500 

2000 

1500 

Swift Tern 

Total 

Vondeling 

Malgas 

Jutten 

Marcus 

Schaapen 

Meeuw 

Caspian Is. 

1000 

500 

0 

Figure 10.4. Trends in breeding population of Swift Terns at Malgas, Marcus, Jutten and Schaapen islands 

in Saldanha Bay (Data source: Rob Crawford, DEA: Oceans & Coasts). 

Year 

Cape Gannets Morus capensis are restricted 

to the coast of Africa, from the Western Sahara, 

around Cape Agulhas to the Kenyan coast. In 

southern Africa they breed on six offshore islands, 

three off the Namibian coast, and two off the west 

coast of South Africa (Bird Island in Lambert's Bay 

and Malgas Island in Saldanha Bay), and one (Bird 

Island) at Port Elizabeth. The Cape Gannet is listed as 

Vulnerable on the IUCN’s global Red Data List, due to 

its restricted range and population declines (Birdlife 

International 2011). 

Cape Gannets breed on islands which afford 

them protection from predators. They feed out at sea and will often forage more than a hundred 

223 

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1980 

1981 

1982 

1983 

1984 

1985 

1986 

1987 

1988 

1989 

1990 

1991 

1992 

1993 

1994 

1995 

1996 

1997 

1998 

1999 

2000 

2001 

2002 

2003 

2004 

2005 

2006 

2007 

2008 

2009 

2010 



Birds 

kilometres away from their nesting sites (Adams and Navarro 2005). This means that only a small 

proportion of foraging takes place within Saldanha Bay. The quality of water in Saldanha Bay should 

therefore not have a significant effect on the Cape Gannet population. 

The bird colony at Malgas Island has shown population fluctuation since the early 1990’s and 

a steady decline since 1996 (Figure 10.5). This contrasts with population figures for Bird Island, off 

Port Elizabeth, where numbers have increased. A recent study suggested that Cape Gannet 

population trends are driven by food availability during their breeding season (Lewis et al. 2006). 

Pichegru et al. (2007) showed that Cape Gannets on the west coast have been declining since the 

start of the eastward shift of the pelagic fish in the late 1990s. This has resulted in west coast 

gannets having to increase their foraging efforts, during the breeding season, forage in areas with 

very low abundance of their preferred prey, and feed primarily on low-energy fishery discards (93% 

of total prey intake; Crawford et al. 2006, Pichegru et al. 2007). A bioenergetics model showed that 

enhanced availability of low-energy fishery discards does not seem to compensate for the absence 

of natural prey (Pichegru et al. 2007). In addition to the above, and of more concern at a local level, 

is the recent increase in predation by Cape fur seals Arctocephalus pusilus pusillus and the Great 

White Pelican Pelecanus onocrotalus (Makhado et al. 2006; Pichegru et al. 2007). Predation by seals 

caused a 25% reduction in the size of the colony at Malgas Island between 2001 and 2006 (Makhado 

et al. 2006). These added threats weigh heavily on an already vulnerable species. 

60000 

Cape Gannet 

50000 

40000 

30000 

20000 

10000 

0 

Figure 10.5. Trends in breeding population of Cape Gannets at Malgas Island, Saldanha Bay. Open data 

points are interpolated (no data). (Data source: Rob Crawford, DEA: Oceans & Coasts). 

Year 

These recent findings have changed the overall health of the Gannet population on Malgas 

Island from Good to Fair based on the increase in predation by fur seals and recently observed 

predation by the Great White Pelican (Pichegru et al. 2007). Management measures were 

implemented between 1993 and 2001 and 153 fur seals seen to kill Gannets, were shot (Makhado et 

al. 2006). This practice has continued in an effort to improve breeding success (Makhado et al. 

2009). The effects of this may be manifest in the slight recovery in Gannet numbers between 2006 

and 2009, but numbers have declined since then. 

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Birds 

Cape Cormorants Phalacrocorax capensis are endemic to 

southern Africa, where they are abundant on the west coast but 

less common on the east coast, occurring as far as Seal Island in 

Algoa Bay. They breed between Ilha dos Tigres, Angola, and Seal 

Island in Algoa Bay, South Africa. They generally feed within 10-15 

km of the shore, preying on pelagic goby Sufflogobius bibarbatus, 

Cape anchovy Engraulis capensis, pilchard Sardinops occelatus and 

Cape horse mackerel Trachurus trachurus (du Toit 2004). 

The Cape Cormorant is regarded as Near Threatened owing 

to a decrease in the breeding population during the late 1970s 

(Cooper et al. 1982). Numbers decreased again during the early 

1990s following an outbreak of avian cholera, predation by Cape fur 

seals and White Pelicans as well as the eastward displacement of 

sardines off South Africa (Crawford et al. 2007). As a result there 

are large inter-annual fluctuations in breeding numbers due to breeding failure, nest desertion and 

mass mortality related to the abundance of prey, for which they compete with commercial fisheries. 

This makes it difficult to accurately determine population trends. In addition, during outbreaks of 

avian cholera, tens of thousands of birds die. Cape Cormorants are also vulnerable to oiling, and are 

difficult to catch and clean. Discarded fishing gear and marine debris also entangles and kills many 

birds. Kelp Gulls prey on Cape Cormorant eggs and chicks and this is exacerbated by human 

disturbance, especially during the early stages of breeding, as well as the increase in gull numbers 

(du Toit, 2004). 

The Saldanha Bay population has been relatively stable since 1988, though with a fair 

amount of interannual fluctuation (Figure 10.6). Numbers have generally been highest on Jutten 

Island. Although no long term trends are discernable the population has not recovered to its 1993 

level of over 23 000 breeding pairs. 

30000 

25000 

20000 

15000 

Cape Cormorant 

Total 

Vondeling 

Malgas 

Jutten 

Marcus 

Schaapen 

Meeuw 

10000 

5000 

0 

Figure 10.6. Trends in breeding population of Cape Cormorants at Malgas, Jutten, Schaapen, Vondeling and 

Meeuw islands in Saldanha Bay (Data source: Rob Crawford, Oceans & Coasts, Department of 

Environmental Affairs). 

Year 

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Birds 

Bank Cormorants Phalacrocorax 

neglectus are endemic to the Benguela 

upwelling region of southern Africa, breeding 

from Hollamsbird Island, Namibia, to Quoin 

Rock, South Africa. They seldom range farther 

than 10 km offshore. Their distribution roughly 

matches that of kelp Ecklonia maxima beds. 

They prey on various fish, crustaceans and 

cephalopods, feeding mainly amongst kelp 

where they catch West Coast rock lobster, Jasus 

lalandii and pelagic goby Sufflogobius 

bibarbatus (du Toit 2004). The total population 

decreased from about 9000 breeding pairs in 

1975 to less than 5000 pairs in 1991-1997 to 

2800 by 2006 (Kemper et al. 2007). One of the main contributing factors to the decrease in the 

North and Western Cape colonies was a major shift in the availability of the West Coast rock 

lobster from the West Coast to the more southern regions, observed between the late 1980s and 

early 1990s to the turn of the century (Cockcroft et al. 2008). The abundance of lobsters was further 

severely affected by an increase in the number and severity of mass lobster strandings (walkouts) 

during the 1990s (Cockcroft et al. 2008). Ongoing population declines led to the Bank Cormorant’s 

status being changed from Vulnerable to Endangered (Birdlife International 2011). 

Count data from the Saldanha Bay area shows the dramatic decrease in the population at 

Malgas Island, which was previously the most important island for this species. This was 

accompanied by a slight increase in numbers on Marcus and Jutten islands but there has been no 

recovery to peak numbers breeding in 1991 (Figure 10.7). 

300 

250 

200 

150 

Bank Cormorant 

Total 

Vondeling 

Malgas 

Jutten 

Marcus 

Schaapen 

Meeuw 

100 

50 

0 

Figure 10.7. Trends in breeding population of Bank Cormorants at Malgas, Marcus, Jutten and Vondeling 

islands in Saldanha Bay (Data source: Rob Crawford, Oceans & Coasts, Department of 

Environmental Affairs). 

Year 

226 

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Birds 

In Saldanha Bay the declines are mainly attributed to scarcity of their main prey, the rock 

lobster which in turn has reduced recruitment to the colonies (Crawford 2007; Crawford et al. 

2008c). Bank Cormorants are also very susceptible to human disturbance and eggs and chicks are 

taken by Kelp Gulls and Great White Pelicans. Increased predation has been attributed to the loss of 

four colonies in other parts of South Africa and Namibia (Hockey et al. 2005). Smaller breeding 

colonies are more vulnerable to predation which would further accelerate their decline. Birds are 

also known to occasionally drown in rock-lobster traps, and nests are often lost to rough seas. 

local water quality (Hockey et al. 2005). 

The White-breasted Cormorant 

Phalacrocorax carbo lucidus, also known as 

Great Cormorant, occurs along the entire 

southern African coastline, and is common in 

the eastern and southern interior, but occurs 

only along major river systems and wetlands in 

the arid western interior. The coastal 

population breeds from Ilha dos Tigres in 

southern Angola, to Morgan Bay in the Eastern 

Cape. Along the coast, White-breasted 

Cormorants forage offshore, mainly within 10 

km of the coast, and often near reefs. Whitebreasted 

Cormorants that forage in the marine 

environment feed on bottom-living, mid-water 

and surface-dwelling prey, such as sparid fishes 

(e.g. Steentjies and White stumpnose, du Toit 

2004). This species forages in Saldanha Bay and 

Langebaan Lagoon, making it susceptible to 

Within Saldanha Bay, breeding effort has occasionally shifted between islands. Whitebreasted 

Cormorant bred on Malgas Island in the 1920’s, and low numbers of breeding pairs were 

counted on Marcus and Jutten Islands intermittently between 1973 and 1987 when they stopped 

breeding there and colonized Schaapen, Meeuw and Vondeling islands (Crawford et al. 1994). Most 

of the breeding population was on Meeuw in the early 1990s, but shifted to Schaapen in about 1995. 

By 2000, the breeding numbers at Schaapen had started to decline and the breeding population had 

shifted entirely back to Meeuw by 2004, where it has remained since (Figure 10.8). Overall numbers 

have increased recently and there is no long term declining trend. 

Human disturbance poses a threat at breeding sites. These cormorants are more susceptible 

to disturbance than the other marine cormorants, and leave their nests for extended periods if 

disturbed, exposing eggs and chicks to Kelp Gull predation. Other mortality factors include Avian 

Cholera, oil pollution, discarded fishing line and hunting inland (du Toit 2004). Due to Schaapen 

Islands’ close proximity to the town of Langebaan, the high boating, kite-boarding and other 

recreational use of the area may pose a threat to these birds. 

227 

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Birds 

180 

160 

140 

120 

100 

80 

Whitebreasted Cormorant 

Total 

Vondeling 

Malgas 

Jutten 

Marcus 

Schaapen 

Meeuw 

Caspian Is. 

60 

40 

20 

0 

Figure 10.8. Trends in breeding population of White-breasted Cormorants on the islands in Saldanha Bay 

(Data source: Rob Crawford, DEA: Oceans & Coasts). 

Year 

The Crowned Cormorant Phalacrocorax 

coronatus is endemic to Namibia and South Africa, 

occurring between the Bird Rock Guano Platform in 

southern Namibia and Quoin Rock, South Africa. It is 

listed as Near Threatened on the IUCN’s Red Data List 

due to its small and range restricted population, making 

it very vulnerable to threats at their breeding colonies 

(Birdlife International 2011). This species is highly 

susceptible to human disturbance and predation by fur 

seals, particularly of fledglings. Crowned Cormorants 

generally occur within 10 km from the coastline and 

occasionally in estuaries and sewage works up to 500 m 

from the sea. They feed on slow-moving benthic fish 

and invertebrates, which they forage for in shallow 

coastal waters and among kelp beds (du Toit 2004). 

Populations of this species have been comprehensively counted since 1991. Since then, 

numbers have been relatively stable in terms of overall trend, with considerable interannual 

variability. Populations on Malgas and Jutten Islands have been more stable than the larger 

populations on Schaapen and Meeuw Islands (Figure 10.9). In general the Crowned Cormorant 

population does not seem threatened by lack of food or predation in the Saldanha Bay area. 

228 

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Birds 

900 

800 

700 

600 

500 

400 

300 

Crowned Cormorant 

Total 

Vondeling 

Malgas 

Jutten 

Marcus 

Schaapen 

Meeuw 

Caspian Is. 

200 

100 

0 

Figure 10.9. Trends in breeding population of Crowned Cormorants on the islands in Saldanha Bay (Data 

source: Rob Crawford, DEA: Oceans & Coasts). 

Year 

The African Black Oystercatcher 

Haematopus moquini is endemic to southern 

Africa. It is listed as Near Threatened in the 

IUCN’s a Red Data List, owing to its small 

population and limited range (Birdlife 

International 2011). It breeds in rocky intertidal 

and sandy beach areas from Namibia to the 

southern KwaZulu-Natal coast. The islands in 

Saldanha Bay support an important number of 

these birds. They are most numerous on Marcus, 

Malgas and Jutten Islands, where their 

populations currently fluctuate between 200 and 270, and between 100 and 160 birds, respectively. 

Their numbers have increased dramatically over the past 25 years. In the last 35 years (since 1980) 

the population has grown by 100 breeding pairs on the three main breeding islands in Saldanha Bay 

(Figure 10.10). This steady increase in Oystercatcher numbers over the past two decades is due 

primarily to the introduction and proliferation of the alien mussel Mytilus galloprovincialis, as well as 

due to the enhanced protection of this species throughout much of its range. 

African Black Oystercatchers are resident on the islands, feeding in the rocky intertidal. 

While the invasive alien mussels proliferated and became important in the diet between the late 

1980s and the early 1990s, the effects on population only began to show much later because of the 

age at first breeding and slow breeding rate of these birds (Hockey 1983). The population has 

stabilised in the recent years, suggesting that carrying capacity of the islands has been reached 

(Loewenthal in prep.). Oystercatchers are unlikely to be affected by water quality in Saldanha Bay 

except in as much as it affects intertidal invertebrate abundance. Like most of the birds described 

above, they are, however, vulnerable to catastrophic events such as oil spills. 

229 

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1976 

1977 

1978 

1979 

1980 

1981 

1982 

1983 

1984 

1985 

1986 

1987 

1988 

1989 

1990 

1991 

1992 

1993 

1994 

1995 

1996 

1997 

1998 

1999 

2000 

2001 

2002 

2003 

2004 

2005 

2006 

2007 

2008 

2009 

2010 



Birds 

600 

500 

400 

Total 

Malgas 

Jutten 

Marcus 

African Black Oystercatcher (3 Islands only) 

300 

200 

100 

0 

Figure 10.10. Trend in breeding population of African Black Oystercatchers older than 1 year, on Marcus, 

Malgas and Jutten Islands. (Data source: Douglas Loewenthal, Oystercatcher Conservation 

Programme). 

Year 

10.3 Birds of Langebaan Lagoon 

10.3.1 National importance of Langebaan Lagoon for birds 

Langebaan Lagoon supports an average of about 50 000 waterbirds during summer and about 

18 000 during winter. Fifty-five species of waterbirds are regularly recorded at Langebaan Lagoon. 

About two thirds of the waterbird species are waders, of which 18 species are regular migrants from 

the Palaearctic region of Eurasia; these make up 87% of the summer wader population by numbers. 

Important non-waders which utilise the system are Kelp and Hartlaub's Gulls, Greater Flamingo, 

Sacred Ibis and Common Tern. Resident waterbird species which utilise the rocky and sandy 

coastlines include the African Black Oystercatcher and the White-fronted Plover, both of which 

breed in the area. 

The thousands of migratory waders visit Langebaan Lagoon during the austral summer 

making it the most important ‘wintering’ area for these birds in South Africa (Underhill 1987). Since 

Langebaan Lagoon regularly supports over 20 000 waders it is recognised as an internationally 

important site under the Ramsar Convention on Wetlands of International Importance, to which 

South Africa is a signatory. With regard to density and biomass of waders, Langebaan Lagoon 

compares favourably to other internationally important coastal wetlands in West Africa and Europe. 

The true importance of Langebaan Lagoon for waders cannot be assessed without recourse 

to a comparison with wader populations at other wetlands in southern Africa. During the summer of 

1976 to 1977, the wader populations at all coastal wetlands in the south-western Cape were 

counted (Siegfried 1977). The total population was estimated at 119 000 birds of which 37 000 

occurred at Langebaan. Only one other coastal wetland, the Berg River estuary, contained more 

than 10 000 waders. Thus, Langebaan Lagoon held approximately one third of all the waders in the 

south-western Cape (Siegfried 1977). Studies were extended to Namibia (then South West Africa) in 

the summer of 1976-77. Walvis Bay Lagoon contained up to 29 000 waders and Sandvis had 

approximately 12 000 waders. Therefore, it was determined that Langebaan Lagoon was the most 

230 

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Birds 

important wetland for waders on the west coast of southern Africa (Siegfried, 1977). Taking species 

rarity and abundance into account, Langebaan Lagoon has been ranked fourth of all South African 

coastal lagoons and estuaries in terms of its conservation importance for waterbirds (Turpie 1995). 

In 1985, Langebaan Lagoon was declared a National Park, and recreational activities such as 

boating, angling and swimming have since been controlled within the Lagoon through zonation. 

10.3.2 The main groups of birds and their use of habitats and food 

The waterbirds of Langebaan Lagoon can be divided into nine different taxonomic orders (Table 

10.1), the most species-rich being the Charadriiformes, which include the waders, gulls and terns. 

Table 10.1 also shows the more commonly used groupings of waterbirds, each of which is described 

in more detail below. Their relative contribution to the bird numbers on the estuary differs 

substantially in summer and winter, due to the prevalence of migratory birds in summer (Figure 

10.11). Waders account for about 88% of the birds on Langebaan Lagoon during summer, nearly all 

of these being migratory. In winter, resident wader numbers increase slightly, and numbers of 

flamingos increase substantially. 

Table 10.1. 

Common groupings 

Waterfowl 

Cormorants, darters, 

pelicans 

Wading birds 

Taxonomic composition of waterbirds in Langebaan Lagoon (excluding rare or vagrant species). 

Order 

Podicipediformes (Grebes) 1 

Anseriformes (Ducks, geese) 9 

Gruiformes (Rails, crakes, gallinules, coots) 7 

Pelecaniformes (Cormorants, darters, pelicans) 7 

Ciconiiformes (Herons, egrets, ibises, spoonbill, etc.) 14 

Phoenicopteriformes (Flamingos) 2 

Birds of prey Falconiformes (Birds of prey) 4 

SA 

Resident 

Waders Charadriiformes: Waders 8 18 

Gulls Gulls 2 

Terns Terns 3 4 

Kingfishers Alcediniformes (Kingfishers) 2 

Total 59 22 

Migrant 

Waders are the most important group of birds on Langebaan Lagoon in terms of numbers. 

The influx of waders into the area during summer accounts for most of the seasonal change in 

community composition. Most of the Palaearctic migrants depart quite synchronously around early 

April, but the immature birds of many of these species remain behind and do not don the breeding 

plumage of the rest of the flock. The resident species take advantage of relief in competition for 

resources and use this period to breed. The migrants return more gradually in spring, with birds 

beginning to trickle in from August, and numbers rising rapidly during September to November. 

Waders feed on invertebrates that mainly live in intertidal areas, at low tide, both by day 

and night (Turpie and Hockey 1995). They feed on a whole range of crustaceans, polychaete worms 

and gastropods, and adapting their foraging techniques to suit the type of prey available. Among 

231 

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Birds 

the waders, plovers stand apart from the rest in that they have insensitive, robust bills and rely on 

their large eyes for locating prey visually. Oystercatchers have similar characteristics, using their 

strong bills to prise open shellfish. Most other waders have soft, highly sensitive bills and can locate 

prey by touch as well as visually. Those feeding by sight tend to defend feeding territories, whereas 

tactile foragers often forage in dense flocks. 

Flamingos 

2% 

Cormorants 

1% 

Pelicans 

0% 

Herons, 

egrets, ibises 

1% 

Gulls, terns 

8% 

Resident 

waders 

1% 

Gulls, terns 

15% 

Herons, 

egrets, ibises 

7% 

Resident 

waders 

7% Migratory 

waders 

30% 

Waterfowl 

1% 

Waterfowl 

0% 

Summer 

Migratory 

waders 

87% 

Flamingos 

37% 

Winter 

Pelicans 

1% 

Cormorants 

2% 

Figure 10.11. Average numerical composition of the birds on Langebaan Lagoon during summer and winter. 

Waders require undisturbed sandflats in order to feed at low tide and undisturbed roosting 

sites at high tide. In the 1970’s it was determined that the most important sandflats, in terms of the 

density of waders they support, were in Rietbaai, in the upper section of Langebaan Lagoon, and at 

the mouth, near Oesterwal. The important roosting sites were the salt marshes, particularly 

between Bottelary and Geelbek (Summers 1977). 

Gulls and terns are common throughout the area. Although their diversity is relatively low, 

they make up for this in overall biomass, and form an important group. Both Kelp Gulls and 

Hartlaub’s Gulls occur commonly in the lagoon. 

Cormorants, darters and pelicans are common as a group, but are dominated by the marine 

cormorants which breed on the Saldanha Bay islands. Great White Pelicans visit the bay and lagoon 

to feed, but they breed beyond the area at Dassen Island. African Darters Anhinga rufa are 

uncommon, and are more typical of lower salinities and habitats with emergent vegetation which is 

relatively uncommon in the study area. 

Waterfowl occur in fairly large numbers because of the sheer size of the study area, but they 

are not as dense as they might be in freshwater wetland habitats or nearby areas such as the Berg 

River floodplain. 

Other birds that commonly occur on the lagoon include birds of prey such as African Fish- 

Eagle Haliaeetus vocifer, Osprey Pandion haliaetus and African Marsh-Harrier Circus ranivorus, and 

species such as Pied Kingfisher Ceryle rudis and Cape Wagtail Motacilla capensis. 

10.3.3 Inter-annual variability in bird numbers 

Irregular waterbird surveys were conducted at Langebaan Lagoon from 1934, but, due to the 

large size of the lagoon, these early counts were confined to small areas. It was not until 1975 that 

annual summer (January or February) and winter (June or July) surveys of the total population of 

waders at high tide, when waders congregate to roost on saltmarshes and sand spits, were 

232 

ANCHOR 


Number of birds 

1976 

1977 

1978 

1979 

1980 

1981 

1982 

1983 

1984 

1985 

1986 

1987 

1988 

1989 

1990 

1991 

1992 

1993 

1994 

1995 

1996 

1997 

1999 

2000 

2001 

2002 

2003 

2004 

2005 

2006 

2007 

2008 

2009 



Birds 

conducted by members of the Western Cape Water Study Group (WCWSG) (Underhill, 1987). An 

analysis of the numbers of waders over the period 1975 to 1980 showed stable summer populations, 

but large year to year variations in the number of Palearctic migrants that over-wintered (Robertson, 

1981). The Western Cape Water Study Group monitored Langebaan continuously up to 1991, and 

since 1992, the Lagoon has been monitored bi-annually by the Co-ordinated Waterbird Counts 

(CWAC), organised by the Avian Demography Unity at the University of Cape Town. 

The above data sets provide the opportunity to examine the long term trends in bird 

numbers at Langebaan Lagoon up to the present day. This reveals a dramatic downward trend in 

the numbers of Palearctic waders at the Lagoon, especially since 2008 (Figure 10.12). Much of the 

reduction in numbers in the 2011 summer count was due to very low numbers of Curlew Sandpiper 

on the lagoon. 

The reasons for these declines are diverse and poorly understood, but seem to be a 

combination of loss and degradation of their breeding sites as well as of their over-wintering 

grounds during their non-breeding period (Dias et al. 2006). However, while the downward trend 

may echo global trends in certain wader populations, what is of more concern is that the trend 

appears to be echoed by resident waders, although in recent years populations numbers seem to be 

stabilizing (Figure 10.13). This does suggests that conditions at Langebaan Lagoon are at least 

partially to blame. The most likely problems are that of siltation of the system reducing the area of 

suitable (e.g. muddy) intertidal foraging habitat, loss of seagrass beds with their associated 

invertebrate fauna (Pillay et al. 2011; see §1) and human disturbance, which has been shown to 

have a dramatic impact on bird numbers in other estuaries (Turpie and Love 2000). 

45000 

40000 

35000 

30000 

25000 

20000 

15000 

10000 

5000 

0 

Figure 10.12. Long term trends in the numbers of summer migratory waders on Langebaan Lagoon 

233 

ANCHOR 


Number of birds 

1976 

1977 

1978 

1979 

1980 

1981 

1982 

1983 

1984 

1985 

1986 

1987 

1988 

1989 

1990 

1991 

1992 

1993 

1994 

1995 

1996 

1997 

1999 

2000 

2001 

2002 

2003 

2004 

2005 

2006 

2007 

2008 

2009 



Birds 

1200 

1000 

800 

600 

400 

200 

0 

Figure 10.13. Long term trends in the numbers of winter resident waders on Langebaan Lagoon 

Year 

10.4 Overall status of birds in Saldanha Bay and Langebaan Lagoon 

Populations of two cormorant species, namely Bank Cormorants and White-breasted Cormorants, 

that utilise islands within the Saldanha Bay region for shelter and breeding, have decreased since 

early to mid-1990. This has been attributed to the construction of the causeway linking Marcus 

Island to the mainland, and to increased human disturbance. The Cape Gannet population on 

Malgas Island has also undergone increased decline due mainly to predation by Cape fur seals and 

more recently by Great White Pelicans. Predation by the seals was responsible for a 25% reduction 

in the size of the colony at Malgas Island, between 2001 and 2006. Management measures have 

been put in place, through selective culling of seals, which has improved conditions for the gannets 

at Malgas Island. The African Penguin populations are also under considerable pressure, partially 

due to causes unrelated to conditions on the island such as the eastward shift of the sardines, one of 

their main prey species. However, because populations are so depressed, conditions at the islands 

in Saldanha have now become an additional factor in driving current population decreases. Direct 

amelioration actions to decrease these impacts at the islands are difficult to find, however, support 

for conservation activities that improve penguin conservation, as a means to offset these impacts, 

should be considered. All other species of seabirds investigated in this study in the Saldanha Bay 

region appear to have healthy populations with either stable numbers or increasing numbers. 

Decreasing numbers of migrant waders utilising Langebaan Lagoon reflects a global trend of 

this nature, largely due to increasing disturbance to breeding grounds of many species. The 

decreasing populations of resident waterbirds present in Langebaan Lagoon, a concern in itself, 

suggests that local conditions may be partly to blame for the decrease in migratory birds. This longterm 

trend is most likely due to unfavourable conditions persisting in Langebaan Lagoon as a result 

of anthropogenic impacts. It is highly recommended that the status of key species be monitored and 

used as an indication of environmental conditions in the area. 

234 

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Birds 

11 ALIEN INVASIVE SPECIES IN SALDANHA BAY-LANGEBAAN 

LAGOON 

To date, an estimated 85 marine species have been recorded as introduced to South African waters 

mostly though shipping activities or mariculture (Mead et al. in prep). At least 62 of these are 

thought to occur in Saldanha Bay-Langebaan Lagoon (Table 11.1). Many of these are considered 

invasive, including the Mediterranean mussel Mytilus galloprovincialis, the European green crab 

Carcinus maenas (Griffiths et al. 1992; Robinson et al. 2005), the barnacle Balanus glandula (Laird 

and Griffiths, in press), and the Pacific South American mussel Semimytilus algosus (C.L. Griffiths, 

UCT, pers. comm.). An additional twenty five species are currently regarded as cryptogenic (of 

unknown origin – i.e. potentially introduced) but very likely introduced. Comprehensive genetic 

analyses are required to determine their definite status, however (Griffiths et al. 2008). 

Most of the introduced species in this country have been found in sheltered areas such as 

harbours, and are believed to have been introduced through shipping activities, mostly ballast 

water. Because ballast water tends to be loaded in sheltered harbours the species that are 

transported originate from these habitats and have a difficult time adapting to South Africa’s 

exposed coast. This might explain the low number of introduced species that have become invasive 

along the coast (Griffiths et al. 2008). 

Future surveys in the Bay will be used to confirm the presence of all listed species and will be 

used to ascertain if any additional or newly arrived introduced species are present. Information on 

this nature for several key alien species in Saldanha Bay, some of which were identified through the 

State of the Bay monitoring programme, are presented below 

Table 11.1. 

Taxon 

PROTOCTISTA 

List of introduced and cryptogenic species from Saldanha Bay-Langebaan Lagoon. Occurrence 

is listed as confirmed or likely (not confirmed from the Bay but inferred from their distribution 

in the region). Region of origin and likely vector for introduction (SB = ship boring, SF = ship 

fouling, BW = ballast water, BS = solid ballast, OR = oil rigs, M = mariculture, F = Fisheries 

activities, I = intentional release) are also listed. (Data from Mead et al. 2011 a & b) 

Occurrence in Saldanha 

Bay Origin Vector 

Mirofolliculina limnoriae Likely Unknown SB 

Zoothamnium sp. Likely Unknown SF 

DINOFLAGELLATA 

Alexandrium tamarense-complex: Likely N Atlantic/N Pacific BW 

Alexandrium minutum Likely Europe BW 

Dinophysis acuminata Likely Europe BW 

PORIFERA 

Suberites tylobtusa Likely Red Sea F 

CNIDARIA 

Anthozoa 

Sagartia ornata Confirmed Europe SF/BW 

Metridium senile Likely N Atlantic/N Pacific SF/OR 

Hydrozoa 

Pachycordyle navis Likely Europe SF/BW 

Coryne eximia Likely N Atlantic/N Pacific SF/BW 

Pinauay larynx Likely North Atlantic SF/BW 

235 

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Birds 

Taxon 



Pinauay ralphi Likely North Atlantic SF/BW 

Laomedea calceolifera Likely North Atlantic SF/BW 

Gonothyraea loveni Likely North Atlantic SF/BW 

Obelia bidentata Confirmed Unknown SF/BW 

Obelia dichotoma Confirmed Unknown SF/BW 

Obelia geniculata Confirmed Unknown SF/BW 

ANNELIDA 

Polychaeta 

Boccardia proboscidea* Likely Eastern Pacific SF/BW 

Capitella sp. / spp. complex Likely Unknown SF/BW 

Polydora hoplura Confirmed Europe SF/BW 

Dodecaceria fewkesi Likely North American Pacific SF/BW 

Hydroides elegans Likely Indo-Pacific SF/BW 

Neodexiospira brasiliensis Likely Indo-Pacific SF/BW 

Janua pagenstecheri Likely Europe SF/BW 

Simplicaria pseudomilitaris Likely Unknown SF/BW 

CRUSTACEA 

Cirripedia 

Balanus glandula Confirmed North American Pacific SF/BW 

Isopoda 

Dynamene bidentata Likely Europe SF/BW 

Paracerceis sculpta Likely Northeast Pacific SF/BW 

Synidotea hirtipes Confirmed Indian Ocean SF/BW 

Synidotea variegata Confirmed Indo-Pacific SF/BW 

Ligia exotica Confirmed Unknown SB 

Limnoria quadripunctata Confirmed Unknown SB 

Limnoria tripunctata Confirmed Unknown SB 

Amphipoda 

Chelura terebrans Confirmed Pacific Ocean SF/SB 

Ischyrocerus anguipes Confirmed North Atlantic SF/BW 

Erichthonius brasiliensis Confirmed North Atlantic SF/BW 

Cymadusa filosa Likely Unknown BS 

Caprella equilibra Confirmed Unknown SF/BW 

Caprella penantis Confirmed Unknown SF/BW 

Paracaprella pusilla Confirmed Unknown SF/BW 

Jassa marmorata Likely North Atlantic SF/BW 

Jassa slatteryi Confirmed North Pacific SF/BW 

Orchestia gammarella Confirmed Europe BS 

North American 

Cerapus tubularis 

Confirmed 

Atlantic 

BS 

Decapoda 

Carcinus maenas Confirmed Europe 

INSECTA 

SF/BW/O 

R 

236 

ANCHOR 



Birds 

Taxon 

Coleoptera 



Cafius xantholoma Likely Europe BS 

MOLLUSCA 

Gastropoda 

Littorina saxatilis Confirmed Europe BS 

Catriona columbiana Likely North Pacific SF/BW 

Tritonia nilsodhneri Likely Europe SF/BW 

Kaloplocamus ramosus Likely Unknown SF/BW 

Thecacera pennigera Likely Unknown SF/BW 

Anteaeolidiella indica Confirmed Unknown SF/BW 

Bivalvia 

Mytilus galloprovincialis Confirmed Europe SF/BW 

Ostrea edulis Confirmed Europe m 

Teredo navalis Likely Europe SB 

Lyrodus pedicellatus Likely Unknown SB 

Bankia carinata Likely Unknown SB 

Bankia martensi Likely Unknown SB 

Dicyathifer manni Likely Unknown SB 

Teredo somersi Likely Unknown SB 

BRACHIOPODA 

Discinisca tenuis Confirmed Namibia M 

BRYOZOA 

Watersipora subtorquata Confirmed Caribbean SF 

Bugula neritina Confirmed Unknown SF 

Bugula flabellata Confirmed Unknown SF 

Conopeum seurati Confirmed Europe SF 

Cryptosula pallasiana Confirmed Europe SF 

CHORDATA 

Ascidiacea 

Ascidia sydneiensis Likely Pacific Ocean SF 

Ascidiella aspersa Likely Europe SF 

Botryllus schlosseri Confirmed Unknown SF 

Ciona intestinalis Confirmed Unknown SF 

Clavelina lepadiformis Confirmed Europe SF 

Cnemidocarpa humilis Likely Unknown SF 

Corella eumyota Confirmed Unknown SF 

Diplosoma listerianum Confirmed Europe SF 

Microcosmus squamiger Likely Australia SF 

Tridemnun cerebriforme Confirmed Unknown SF 

RHODOPHYTA 

Schimmelmannia elegans Likely Tristan da Cunha BW 

Antithamnionella ternifolia Likely Australia SF/BW 

Antithamnionella spirographidis Confirmed North Pacific SF/BW 

237 

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Birds 

Taxon 



CHLOROPHYTA 

Codium fragile fragile (tomentosoides 

strain) Confirmed Japan SF/BW 

VASCULAR PLANTS 

Ammophila arenaria Confirmed Europe I 

Spartina maritima Confirmed Europe BS 

11.1 The occurrence and spread of the marine alien species in Saldanha Bay 

11.1.1 European mussel Mytilus galloprovincialis 

Mytilus galloprovincialis was first detected in South Africa (in Saldanha Bay in fact) in 1979 (Mead et 

al. 2011a) but was only confirmed in 1984 (Grant et al. 1984, Grant & Cherry 1985). At this stage the 

population was already widespread in the country, being the most abundant mussel species on 

rocky shores between Cape Point and 

Luderitz. This species has subsequently 

extended is distribution range as far as 

East London (Robinson et al. 2005). It is 

suspected that Mytilus was most likely 

first introduced to the country between 

the late 1970s and early 1980s (Griffiths 

et al. 1992) and that the reason for its 

late detection is that it is easily confused 

with the indigenous black mussel, 

Choromytilus meridionalis. Mytilus is, 

however, easily distinguished by the 

trained eye, being fatter, and having a 

pitted resilial ridge, and differs in habitat 

- occurring higher on the shore and away 

Figure 11.1 

European mussel Mytilus galloprovincialis. 

Photo: C.L. Griffiths. 

from sand-inundated sites – than Choromytilus. This species is commercially cultured in Saldanha 

Bay and elsewhere and is widely exploited by recreational and subsistence fishers (Robinson et al. 

2005; 2007). 

In its native countries in Europe, M. galloprovincialis is known to form dense subtidal beds 

directly on sandy bottoms (Ceccherelli and Rossi 1984) which stands in stark contrast to the sorts of 

areas it typically inhabits in southern Africa (viz. exposed rocky shores). Historically, Mytilus 

galloprovincialis has rarely if ever been found in heavily silted areas, which remain dominated by the 

indigenous Choromytilus meridionalis (Hockey and Van Erkom Schurink 1992). That said, Mytilus 

began establishing dense intertidal beds on the sandy centre banks of Langebaan Lagoon in the mid- 

1990s (Hanekom and Nel 2002, Robinson and Griffiths 2002, Robinson et al. 2007). The biomass on 

the banks peaked at an estimated 8 t in 1998 (Robinson and Griffiths 2002), but subsequently 

crashed, decreasing in size by ~88% by early 2001 (Hanekom and Nel 2002) and had died off 

completely by mid-2001, leaving only empty shells and anoxic sand (Robinson et al. 2007). The 

reason for the die off is still not clear, and impacts on the macrobenthic infauna in the banks was 

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Birds 

evident for at least 6 month after most of the dead mussel shells had been removed by SANParks in 

late 2001. 

11.1.2 European shore crab Carcinus maenas 

Carcinus maenas is a native European crab species that has been introduced on both the Atlantic 

and Pacific coasts of North America, in 

Australia, Argentina, Japan and South Africa 

(Carlton & Cohen 2003). It is typically is 

restricted to sheltered, coastal sites and 

appears thus far to have been unable to 

establish on the open wave-swept coastline 

in South Africa (Hampton and Griffiths 2007) 

and elsewhere. In South Africa it was first 

collected from Table Bay Docks in 1983 and 

later in Hout Bay Harbour. It has established 

dense populations in both harbours where it 

has reportedly decimated shellfish 

Figure 11.2 

European shore crab Carcinus maenas. 

Photo: C.L. Griffiths. 

populations (Robinson et al. 2005). Surveys in Saldanha Bay has not turned up any live specimens of 

this species to date, but a single dead specimen was picked up by Robinson et al. (2004) in Small Bay 

(the Small Craft Harbour). It is not clear whether there is in fact and extant population in the Bay at 

present or not. 

11.1.3 Shell worm Boccardia proboscidea 

Boccardia proboscidea is a small (20 mm long) tube-dwelling worm found in shallow sand-lined 

burrows on the surfaces of oysters, abalone and other shellfish. It occurs naturally on the Pacific 

coast of North America and Japan (Simon et al. 2009, Picker & Griffiths 2011). In South Africa it is 

known to occur on a number of oyster and abalone farms and has also recently been recorded in 

Saldanha Bay outside aquaculture facilities (Haupt et al. 2010). 

11.1.4 Pacific South American mussel Semimytilus algosus 

The Pacific South American mussel Semimytilus algosus is a small (up to 50 mm) elongated, 

relatively flat and smooth brown mussel, with a shell tinged with green. This species has been long 

known from Namibia (since the 1930s, Kensley & Penrith 1970) but was only recently (2010) found 

in South Africa. It reportedly occurs in huge densities of thousands of individuals per square metre 

low on the shore, along most of the West Coast of South Africa. It is likely that it was transported 

southwards from Namibia either by shipping or under its own steam. This species show a strong 

preference for wave exposed shores (C.L. Griffiths pers. comm.) and thus is unlikely it reach high 

densities in Saldanha Bay. It has, however, been observed on ropes in the mussel farms in Saldanha 

Bay. 

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Birds 

11.1.5 Acorn barnacle Balanus glandula 

The presence of B. glandula, which originates from the Pacific coast of North America, has only 

recently been recognized (Simon-Blecher 

et al. 2008). It seems, however, that this 

species has been in South Africa since at 

least the early 1990s. It is now the most 

abundant intertidal barnacle along the 

southern west coast (Laird & Griffiths 

2008) and in Saldanha Bay (see Chapter 8 

above). The fact that it looks very similar 

to the indigenous species Chthamalus 

dentatus accounts for the fact that it went 

undetected for so long. B. glandula has 

reportedly displaced populations of the 

Figure 11.3 Acorn barnacle Balanus glandula. Photo: 

indigenous and formerly abundant C. 

C.L. Griffiths. 

dentatus species which is now reportedly 

very rare on South African west coast shores (Laird & Griffiths 2008). B. glandula was first 

confidently identified in the State of the Bay surveys in Saldanha Bay in 2008 but it is assumed, 

however, that it had been present during the baseline survey in 2005 but was confused with the 

indigenous barnacle. 

11.1.6 Disc lamp shell Discinisca tenuis 

The disc lamp shell Discinisca tenuis is a 

small (20 mm diameter) disc shaped 

brachiopod with a semi-transparent, 

hairy, fringed shell. It was first recorded 

clinging on oysters grown in suspended 

culture in Saldanha Bay in 2008 (Haupt 

et al. 2010). More recently (2011) it has 

been reported as living freely outside of 

the oyster culture operation on 

Schaapen Island (Prof. G.M. Branch, 

pers. Comm.). This species is endemic 

to Namibia and is through to have been 

introduced to South Africa with cultured 

oyster imports from this country (Haupt 

Figure 11.4 Disc lamp shell Discinisca tenuis. Photo: 

C.L. Griffiths. 

et al. 2010). This species reportedly reaches very high densities in it home range and could become 

a significant fouling species in Saldanha Bay in the foreseeable future, although no previous history 

of invasion exists for this brachiopod. 

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Birds 

11.1.7 Lagoon snail Littorina saxatilis 

Littorina saxatilis was first recorded in South Africa in 1974 (Day 1974), and the only known 

population are those in Langebaan and Knysna lagoons (Hughes 1979, Robison et al. 2004, Picker & 

Griffiths 2011). In it home range in the North Atlantic this species occurs in crevices on rocky shores 

(Gibson et al. 2001), but in South Africa it is restricted to sheltered salt marshes and lagoons, where 

it occurs on the stems of the cord grass Spartina maritima (Hughes 1979). It occurs only in the upper 

reaches of Langebaan Lagoon, between Bottelary and Churchhaven, and has not spread further 

afield than this in at least 20 years (Robison et al. 2004). It is not considered to be a major threat to 

the Lagoon or Bay ecosystems. 

11.1.8 Brooding anemone Sagartia ornata 

The only known records of the brooding anemone Sagartia ornata in South Africa are from 

Langebaan lagoon where it occurs in relatively high densities (hundreds per square meter) 

intertidally in beds of the spiky cord grass Spartina maritima and attached to rocks covered by sand 

(Acuña et al. 2004, Robinson et al. 2004, Picker & Griffiths 2011. Its presence in South Africa was 

first detected in 2002 (Acuña et al. 2004). Its home range extends throughout Western Europe, 

Britain and the Mediterranean (Manuel 1981), where it occur in crevices on rocky shores and on kelp 

holdfasts (Gibson et al. 2001). As such, it has the potential to spread more widely into Saldanha Bay 

and along the South African west coast, where conditions and habitats are similar to that in its home 

range, although it has not done so as yet. Impacts on local fauna are probably minimal and 

presumably restricted to small prey species. 

11.1.9 Hitchhiker amphipod Jassa slatteri 

Jassa slatteri is a small (9 mm) inconspicuous amphipod that constructs tubes of soft mud or crawls 

around on seaweeds, hydroids and other marine growth (Picker & Griffiths 2011, Colan 1990). It is 

common on piers, buoys and other structures in Saldanha Bay. It is suspected that it was introduced 

directly from its native habitat in Pacific North America or another infected temperate harbour 

where they are common. It is small and occurs in high densities and is probably a valuable food 

source for fish and other predators. 

11.1.10 Dentate moss animal Bugula dentata 

Bugula dentate is a bryzoan (lace animal) that forms colonies up to 50 mm tall and looks superficially 

like seaweed. It attaches to hard surfaces such as ships hulls, wharfs and rocks, hanging vertically in 

the water. It was introduced to South Africa from the Indo-Pacific region, very early on in our history 

(first report in 1852). It is common and a minor nuisance as a fouling species and occurs along much 

of the South African coast (Florence et al. 2007, Picker & Griffiths 2011). 

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Birds 

11.1.11 Vase tunicate Ciona intestinalis 

Ciona intestinalis is a tall (15 cm), cylindrical yellowish solitary ascidian with a soft floppy, 

transparent test. It forms large aggregations on submerged structures in harbours and lagoon from 

Saldanha Bay to Durban. It was originally introduced from North Atlantic prior to 1955. It is an 

important pest as it quickly coasts hard marine surfaces. It is known to smother and kill mussels on 

aquaculture facilities, especially mussel ropes. 

11.1.12 Jelly crust tunicate Diplosoma listerianum 

Diplosoma listerianum is a colonial sea squirt that forms thin, fragile, yellow to dark grey jelly-like 

sheets up to 50 cm in diameter that grow over all types of substrata on sheltered shores between 

Alexander Bay and Durban (Monniot et al. 2001, Picker & Griffiths 2011). It is believed to have been 

accidentally introduced from Europe prior to the 1949, probably as a fouling organism. 

11.1.13 Dirty sea squirt Ascidiella aspersa 

Ascidiella aspersa is a medium sized (10 cm), solitary sea squirt that occurs on the west coast 

between Saldanha Bay and Table Bay (Monniot et al. 2001, Picker & Griffiths 2011). It was 

introduced from Europe and is normally found attached to ropes and floating pontoons in harbours. 

This species can form aggregations with others of the same species or other fouling species. 

11.1.14 Western pea crab Pinnixa occidentalis in Saldanha Bay 

The Western Pea crab Pinnixa occidentalis was 

originally described from California by M. J. 

Rathbun in 1893, but is presently reported to occur 

along the whole west coast of North America from 

Alaska to Mexico (Ocean Biogeographic 

Information System 2011). The depth range 

distribution for this species is reported to range 

from 11-319 m. This species was recently (in the 

latter part of 2010) identified in the collections 

from the Saldanha Bay: State of the Bay surveys 

(Clark et al. 2011), previously being listed as 

unidentified owing to it not having been previously 

Figure 11.5 Western pea crab Pinnixa 

occidentalis. Photo: C.L. Griffiths. 

reported from South Africa waters. It appears to have established itself in the Bay in the period 

between 1999 (at which time no specimens were recorded in a comprehensive set of samples from 

the Bay) and 2004 when it was recorded at four of the 30 sampling sites in the Bay. Subsequent to 

this, both the abundance and range occupied by this species expanded fairly rapidly (increasing from 

4 sites and 10.1 individuals m -2 ) to a maximum of 8 sites and 37.2 individuals m -2 in 2009 and 2010, 

respectively (Figure 11.6). The initial distribution (2004) took the form of a narrow swathe extending 

right across Saldanha Bay from Hoedjiesbaai to the Lagoon entrance, which filled out a little in 2008, 

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No. sites 

Abundance (no. ind. m -2 ) 


Birds 

and then extended through into the upper reaches of Langebaan lagoon in 2009 (Figure 11.6). The 

distribution in 2010 and 2011 was similar to that in 2008 and 2009 but did not include any sites in 

the lagoon which suggests that the habitat here may not be entirely suited to the species which 

favours deeper water (>10 m) in its native area (Ocean Biogeographic Information System 2011). 

10 

8 

6 

4 

2 

0 

1999 2004 2008 2009 2010 2011 

40 

30 

20 

10 

0 

1999 2004 2008 2009 2010 2011 

Figure 11.6 

No of sites (top) at which the Western Pea crab Pinnixa occidentalis has been recorded in 

Saldanha Bay and Langebaan lagoon in the period 2004-2011 and trend in abundance (bottom) 

of this organism in the Bay . 

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Birds 

Figure 11.7. Map showing changes in the distribution of the Western Pea crab Pinnixa occidentalis in 

Saldanha Bay and Langebaan lagoon in the period 2004-2010. 

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Recommendations 

12 MANAGEMENT AND MONITORING RECOMMENDATIONS 

Monitoring of aquatic health and activities and discharges potentially affecting health of Saldanha 

Bay and Langebaan Lagoon has escalated considerably in recent years owing to concerns over 

declining health in the Bay. This section provides a summary of the state of health of Saldanha Bay 

and Langebaan Lagoon as reflected by the various environmental parameters reported on in this 

study. It also briefly describes current monitoring efforts and provides recommendations as to 

management actions that need to be implemented in order to mitigate some of the threats that 

have been detected. It also provides recommendations on how existing monitoring activities may 

need to be modified in the future to accommodate changes in the state of the Bay. 

12.1 Activities and discharges affecting the health of the Bay 

12.1.1 Human settlements, storm water and sewage 

Human settlements surrounding Saldanha Bay and Langebaan Lagoon have expanded tremendously 

in recent years. This is brought home very strongly by population growth rates of over 9% per 

annum in Langebaan and nearly 7% in Saldanha over the period 2002 to 2004. This translates to a 

doubling in the population size every 8 years in the former case and every 10 years in the latter. 

Numbers of tourists visiting the area every year are increasing a similarly rapid rate. This rapid rate 

in development translates to an equally rapid increase in the amounts of waste and waste water 

that is produced and has to be treated. Expansion and upgrades of treatment facilities have for the 

most part not been able to cope with such a rapid rate of expansion, with the result that much of the 

effluent produced is discharged to the environment without adequate treatment. The amount of 

hardened (as opposed to naturally vegetated) surfaces surround the Bay and Lagoon have also 

expanded at break-neck speed in recent years, with concomitant increases in volumes of 

contaminated storm water running off into the Bay. The contaminant loads in waste water running 

off into the Bay is not adequately monitored (e.g. there is no monitoring of storm water quality or 

run off from Saldanha or Langebaan, trace metals in ballast water have not been assessed since 

1996, trace metals in bivalves assessed through the mussel watch programme was last available in 

2007), nor is it adequately controlled at present (e.g. the Saldanha and Langebaan waste water 

treatments works still operate off an exemption issued under the old Water Act of 1956 in spite of 

the fact that the new National Water Act with attendant water quality guidelines came into force in 

1998). The contribution to trace metal and organic loading in the Bay from these sources is thus 

largely unknown, but is of concern. 

Provision has not been made for adequate buffers zones around the Lagoon and Bay with 

the result that development encroaches right up to the waters’ edge and is now widely threatened 

by coastal erosion. Disturbance from increasing numbers of people recreating in the Bay and lagoon 

of is taking its toll of sensitive habitats and species, especially seagrass, water birds and fish in 


Urgent management intervention is required to limit further degradation of the 

environment from these pressures, and should focus on the following issues in particular: 

 

 

Ensuring that all discharges to the Bay are properly licensed and adequate monitored (both 

volume and water quality) and that the quality of the effluent is compliant with existing 

South African Water Quality Guidelines for the Coast Zone and any other legislative 

requirements; 

Development setback lines are established around the perimeter of the Bay and Lagoon that 

are compliant with new national legislation (specifically the Integrated Coast Management 

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Act, 2009) and allow for adequate protection of the environment and infrastructure arising 

from current and future (i.e. climate change) pressures; and 

Sensitive habitats and fauna and flora in the Bay are assigned levels of protection that 

ensure minimal disturbance to these areas/populations. 

12.1.2 Dredging 

Dredging interventions in the Bay in the past, particularly those associated with the Iron Ore 

Terminal have been shown to have devastating impacts on the ecology of the Bay. Effects of the 

most recent major dredging event are still discernable in the sediments and faunal communities in 

the Bay more than one decade after their occurrence. Likely ecological impacts arising from any 

future proposed dredging programmes need to be carefully considered and these need to be 

weighed up very carefully against social and economic benefits that may be derived from such 

programmes or projects. Where such impacts are unavoidable, mitigation measures applied must 

follow international best practice and seek to minimize and impacts to the ecology of the Bay. Even 

relative small dredging operations, such as those undertaken as part of the upgrade of the naval 

boatyard at Salamander Bay, can have very wide reaching impacts on the Bay and Lagoon. 

12.1.3 Sewage 

Effluent from two waste water treatment works (Saldanha and Langebaan) finds way into the Bay at 

present. The Saldanha WWTW operates on an exemption issued by the Department of Water 

Affairs (DWAF) in terms of the Water Act of 1956 which authorises the release of a total volume of 

958 000 m 3 into the Bok river (and ultimately Saldanha Bay) per year. Until recently the Langebaan 

WWTW did not discharge any effluent into the sea as all of it was used it to irrigate the local golf 

course. However, increasing volumes of effluent received by this plant is yielding more water than is 

required for irrigation and some of this is now discharged into the Bay. There are also nine sewage 

pump stations in Saldanha Bay and two conservancy tanks, all of which are situated close to the 

coast. There are eighteen sewage pump stations in Langebaan situated throughout the town, many 

of which are near the edge of the lagoon, and three conservancy tanks spread around the edge of 

the lagoon at Oostewal, Stofbergsfontein and Oudepos. Historically a number of these 

pumpstations used to overflow from time to time directly into the Bay when the pumps 

malfunctioned. This has now a rare event, however, as much of the associated infrastructure has 

been upgraded recently and is now regularly maintained. The effluent released by these two 

WWTW is compliant with regulations in respect of some but not all contaminants. 

12.1.4 Fish factories 

Data on effluent discharged from fish factory effluent discharged in to Saldanha Bay is patchy and 

not considered very reliable, particularly that available in recent years. Data on effluent quality is 

even scarcer, being restricted to data collected from two processing plants over a period of one year 

in 1996 and 2002, respectively. Data available for one of the principal processing factories in the Bay 

indicate that effluent volumes have, until recently at least, been increasing steadily each year. Given 

the high organic loading of these effluents, as indicated by the historic water quality data, these 

discharges have presumably contributed significantly to organic loading in the Bay, particularly in 


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Although the available data do not show this, it is quite likely that effluent discharge to the 

Bay from this source has tailed off sharply, owing mostly to the fact that pelagic fish stocks (sardine 

and anchovy) have moved beyond the reach of fishing vessels stationed in Saldanha Bay (now 

centered off Gansbaai). One of the two major fish processing establishments (Premier fishing) shut 

down their operations in Saldanha a few years ago but is set to recommence in the near future 

again. In spite of this likely reduction in effluent discharge volumes it is strongly recommended that 

both the volume and quality of all effluent discharged from fish processing facilities in Saldanha be 

monitored, and that the quality of the effluent be made compliant with existing South African 

Water Quality Guidelines for the Coast Zone. All of the existing establishments still operate off 

exemptions issued under the old 1956 Water Act and need to be made compliant with the new 1998 

National Water Act. 

12.1.5 Mariculture 

Saldanha Bay is the only natural sheltered embayment in South Africa and as a result it is regarded 

as the major area for mariculture. A total area of approximately 145 ha has been allocated to seven 

mariculture operators within Saldanha Bay. All operators farm mussels and six of the operators also 

farm oysters. Abalone, scallops, red bait and seaweed are each cultured on one of the farms. These 

farms have been shown to cause organic enrichment and anoxia in sediments under the rafts owing 

to contamination by the farmed animals themselves, faeces, and fouling species. 

12.1.6 Shipping, ballast water discharges and oil spills 

Shipping traffic and ballast water discharges to the Bay are currently monitored by the Port of 

Saldanha. Data indicate a steady growth in the numbers of vessels visiting the Bay and a 

concomitant increase in the volume of ballast water discharged to the Bay, especially since 2002 (up 

by about 75%). Associated with this increase in shipping traffic, is an increase in the incidence and 

risk of oil spills, an increased risk of introducing alien species to the Bay, increased volume of trace 

metals entering the Bay, and direct disturbance of marine life and sediment in the Bay. Of particular 

concern is the potential input of trace metals to the Bay from this source. Trace metal 

concentrations in ballast water discharged to Saldanha Bay have in the past (1996), been shown to 

exceed South Africa Water Guidelines. Whether this is still the case or not is unknown, given that 

the concentrations of these contaminants in ballast water discharges has not been assessed in 

recent years. It may well be that measures introduced to minimise risk from alien species’ 

introduction (such as open ocean ballast water exchange) have gone a long way towards addressing 

water quality issues as well. 

It is strongly recommended that shipping traffic and ballast water discharges continue to be 

monitored in the future and that this be accompanied by a contaminant monitoring programme. 

12.1.7 Other development in and around the Bay 

There are a range of other development that are planned (e.g. oil and gas terminals), commissioned 

and/or are under construction (e.g. reverse osmosis desalination plants) in and around the Bay that 

will add pressure on the ecological function and integrity of the system. Potential impacts from 

these activities need to be carefully considered and monitored especially in light of the existing 

pressures on the Bay which have already caused severe degradation in some areas. 

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12.2 Water Quality 

12.2.1 Temperature, Salinity and Dissolved Oxygen 

From a water quality perspective, key physico-chemical changes that have resulted from 

anthropogenic impacts on the Bay include modification in circulation patterns and wave exposure 

gradients in the Bay, leading to a reduction in water movement and exchange between the Bay and 

the adjacent marine environment. 

There is currently no continuous monitoring of physico-chemical parameters (temperature, 

salinity and dissolved oxygen) taking place in Saldanha Bay whereby the data are readily accessible 

to the Saldanha Bay Water Quality Trust. It is strongly recommended that continuous (at least 

hourly) monitoring of temperature and (if possible) oxygen be implemented at a minimum of three 

locations in the Bay, including two stations in Small Bay (one specifically in the Yacht Club Basin), and 

one station in Big Bay using similar methodology and station locations to that employed by the CSIR 

(1999). It should be possible to download this data remotely and it should be analysed on a regular 

basis. Furthermore, it would be beneficial to obtain such data from both surface and bottom waters 

(i.e. 1 m and 10 m) to enable ongoing comparisons with historical data. 

12.2.2 Chlorophyll a and Nutrients 

There is currently no regular monitoring of chlorophyll a or nutrient concentrations (specifically 

nitrogen and ammonia) taking place in Saldanha Bay. It is strongly recommended that monthly 

monitoring of these parameters be implemented at a minimum of the same two stations identified 

for temperature, salinity and oxygen monitoring. This may require manual samples to be collected 

on a monthly basis and sent for laboratory analysis. Ongoing data analysis and interpretation should 

form a part of such monitoring programs. These data would be invaluable in calibrating existing 

hydrodynamic and biological production models that have been developed for the Bay. 

12.2.3 Currents and waves 

Long term changes in the patterns of current flow and wave energy should be quantified through a 

formal dedicated study to be conducted approximately every five years. 

12.2.4 Trace metal concentrations in biota (DEA Mussel Watch Programme and 

Mariculture Operators) 

The concentrations of metals in the flesh of mussels are currently monitored by the Mussel Watch 

Programme, which is conducted by the Department of Agriculture, Forestry, and Fisheries. Data are 

available for the period between 1997-2001 and 2005-2007 but not since this time apparently due to 

a backlog in processing of samples. The mussel samples collected from the shore are analysed for 

the metals cadmium (Cd), copper (Cu), lead (Pb), zinc (Zn), iron (Fe) and manganese (Mn), 

hydrocarbons and pesticides. No long term trends are evident in the data but it is clear that 

concentrations of trace metals in the mussels from some sites in the Bay are way in excess of 

guideline limits for foodstuffs for human consumption and are cause for considerable concern. 

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Data on trace metals concentrations in shellfish from the mariculture farms in the Bay were 

also obtained from DAFF (courtesy of the farm operators). These results show that trace metal 

concentrations away from the shore are much lower than those in nearshore water and mostly meet 

guidelines for foodstuffs for human consumption. 

In the light of the fact that large qualities of shellfish are harvested and consumed by 

recreational and subsistence fishers from the shore of the Bay, it is imperative that this Mussel 

Watch Program is continued and possibly extended to cover other species as well (e.g. fish). 

12.2.5 Microbiological monitoring (Faecal coliform) 

Water samples are currently analysed fortnightly for faecal coliform and E. coli concentrations from 

20 stations in Saldanha Bay and Langebaan Lagoon. Faecal coliform counts in Small Bay regularly 

exceed water quality guidelines for recreational and mariculture use. Despite guideline values being 

exceeded in Small Bay, there has been a general improvement in water quality over the last decade 

but these gains seems to be dropping off again now. Water quality (bacterial counts) for Big Bay fall 

mostly below guideline limits, however there has been a notable decline in water quality within Big 

Bay over time and this is of some concern. There appear to be limited bacterial contamination 

within Langebaan Lagoon, but levels are clearly increasing with time, and unmitigated erosion of 

Langebaan beach may increase the risk of sewage pollution via broken or leaking sewage holding 

tanks. It is imperative that management steps are taken to improve water quality within Small Bay, 

especially in the vicinity of the Bok River mouth (sewage outlet). The upgrading of sewage 

treatment and storm water facilities needs to match the rate of development in order to prevent 

any further degradation of water quality within the Bay. The current level of monitoring should 

continue as such with regular analysis and interpretation of data taking place. 

The older DWAF water quality guidelines for recreational use have recently been revised 

following an international review of guidelines for coastal waters, which highlighted several 

shortcomings in those developed by South Africa. The revised guidelines (RSADEA 2011) are based 

on counts of intestinal Enterococci and E. coli, and require that both types of bacteria be 

enumerated at least every two weeks. It is highly recommended that enumeration of Enterococci be 

included in the Saldanha water sampling programme in place of faecal coliforms as several studies 

have shown faecal coliforms and E.coli to be relatively poor indicators of health risks in marine 

waters. These organisms are also less resilient than Enterococci (and other pathogenic bacteria) so if 

analysis is focussed on coliforms, risk can be underestimated due to mortality occurring in the time 

taken between collection and analysis. Guidelines state that samples should be collected 15-30 cm 

below the surface, on the seaward side of a recently broken wave. Samples to be tested for E. coli 

counts should be analysed within 6-8 hours of collection, and those to be tested for intestinal 

Enterococci, within 24 hours. Analyses should be completed by an accredited laboratory, preferably 

one with ISO 17025 accreditation. 

12.3 Sediments 

12.3.1 Particle size, Particulate Organic Carbon and Trace metals 

Sediment monitoring in the Bay has revealed that key heavy metal contaminants (Cd, Pb, Cu, and Ni) 

are increasing at a number of sites in the Bay, particularly in Small Bay, to the extent that they are 

almost certainly impacting on benthic fauna and possibly other faunal groups in the Bay. These 

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contaminants are typically associated with the finer sediment fraction and are highest in the most 

quiescent areas of the Bay (i.e. In the Yacht basin and adjacent of the Multipurpose terminal). 

Sediment monitoring (particle size, particulate organic carbon and trace metals) should 

continue to be conducted annually at the same suite of stations that have been monitored since 

1999 along with additional stations added since this time (e.g. those in Langebaan Lagoon). 

Dredging in the Bay should be avoided if at all possible, and appropriate precautions need to be 

taken when dredging become necessary to ensure that suspended trace metals do not reach 

cultured organisms in the Bay. 

12.3.2 Hydrocarbons 

Poly-cyclic, poly-nuclear compounds and pesticides were considered to pose no threat during 

analysis conducted in 1999. This has been confirmed through more recent studies (2010). It is 

recommended, however, that these pollutants should be monitored approximately every five years. 

12.4 Benthic macrofauna 

A range of benthic community health indicators examined in this study over the period 1999 to 2011 

has revealed that benthic health most likely deteriorated in Small Bay from 1999 to 2008, but has 

recently (2009-2011 surveys) started to show signs of recovery. Benthic health within Big Bay 

improved marginally between 1999 and 2008 after which it decreased again to a state similar to that 

observed in 1999. There has been little change in benthic health within Langebaan Lagoon over the 

last decade. Small Bay and Big Bay have both suffered a significant reduction in species diversity 

over the last decade, although Small Bay, and in some cases Big Bay, is showing signs of recovery. 

Most notable is the return of the suspension feeding sea-pen Virgularia schultzei to Big Bay since 

2004 as well as an increase in the percentage biomass of large, long lived species such as the tongue 

worm Ochaetostoma capense, and several gastropods. Although benthic health within Small Bay is 

showing signs of improvement, the health status of this site is still lower than that of Big Bay and 

Langebaan Lagoon. In order to ensure the continued improvement in the health of the Small Bay 

marine environment it is recommended that stringent controls are placed on the discharge of 

effluents into Small Bay to facilitate recovery of benthic communities in this extremely important 

area. 

The most impoverished site was situated in the Yacht Club harbour, where benthic species 

were virtually absent and the concentration of certain contaminants was highest. The Yacht Club 

harbour should thus be targeted as a key area of concern more stringent management procedures 

should be implemented to reduce the discharge and contamination of contaminants at this site. 

This regularity (annually) and intensity of benthic macrofauna monitoring should continue at all of 

the current stations. 

12.5 Rocky intertidal 

Key changes in the rocky intertidal ecosystem reflect the regional invasion by the Mediterranean 

mussel Mytilus galloprovincialis and the North American barnacle Balanus glandula which compete 

for space on most of the rocky intertidal substrata in the bay at the expense of the native species. 

Their spread throughout the Bay has significantly altered natural community structure in the mid 

and lower intertidal, particularly in wave exposed areas. 

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The intertidal transects (and the quadrats along those transects) that were established in the 

survey initiated in 2005 should continue to be monitored annually for another year but could then 

be reduced in frequency to once every five years thereafter. 

12.6 Fish 

The current status of fish and fisheries within Saldanha Bay-Langebaan appears satisfactory. Long 

term monitoring by means of experimental seine-netting has revealed no statistically significant, 

negative trends since fish sampling began in 1986-87. It is likely that the major changes reflected in 

the macrobenthos and concurrent reduction in the extent of eelgrass (Zostera capensis) in 

Langebaan lagoon since the 1970’s (see §1 for more details on this) did have a dramatic impact on 

the ichthyofauna. These changes would have caused ecosystem wide effects that included changes 

in both the physical habitat (extent of eel grass, sediment structure etc) and food sources 

(reductions in bivalves and polychaetes and increases in sand prawns) available to fish. This would 

have likely favoured some fish species and had a negative impact on others. The abundance of two 

species that tend to favour aquatic macrophyte habitats namely pipefish and super klipvis, does 

appear to have declined in Langebaan lagoon since the 1986/87 sampling. However, the major 

changes that probably occurred in the system would have taken place at the same time that the 

changes in benthos and eelgrass took place (i.e. 1970s-1980s), and as no fish sampling took place 

over this period, these are not reflected in the available data which only exists from the late 1980’s. 

Fish sampling surveys should be conducted annually at the same sites selected during the 

2005 study for the next two years but could then be reduced in frequency to once every five years 

thereafter. This sampling should be confined to the same seasonal period each year for comparative 

purposes. Additional data on daily catch records from anglers (West Coast National Park and fishing 

clubs) is now being collected by Marine and Coastal Management. This initiative should be strongly 

supported as it will provide invaluable information that will contribute to an improved 

understanding of the overall health of fish populations in the Bay. 

12.7 Birds 

An alarming decrease in the abundance of both resident and migrant waders utilising Langebaan 

Lagoon is evident over the past decade and is believed to be a function of increased human 

utilisation of the area and possible reduction in available food. Similar declines are evident in some 

bird species breeding on the offshore islands in the Bay. This is believed to be a function of 

reductions in their food supply (largely pelagic fish e.g. pilchard) outside of the Bay and human 

disturbance within the Bay. Encouraging increases in numbers of African Black Oystercatchers have 

been observed on some of the islands in the Bay and is believed to be related to the proliferation of 

alien mussels on rocky shores in the area, which constitute an important food source for these birds. 

Populations of key bird species are currently monitored annually on the offshore islands 

within the Saldanha Bay area, whilst bird populations in Langebaan Lagoon are monitored twice per 

annum. These bird counts are conducted as part of an ongoing monitoring programme, managed by 

the Avian Demography Unit of the University of Cape Town and Oceans and Coasts (Department of 

Environmental Affairs). The data from these surveys should be regularly obtained from these 

organisations and examined on an annual basis. 

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12.8 Summary of environmental monitoring requirements 

In summary, the environmental monitoring currently implemented in Saldanha Bay and Langebaan 

Lagoon (e.g. sediment, benthic macrofauna and birds) should continue with some small adjustments 

or additions, however, monitoring of other environmental parameters that are not currently 

assessed on a regular basis (e.g. temperature, oxygen, rocky intertidal and fish populations) require 

structured, maintained monitoring to be implemented. 

Table 11.1. Tabulated summary of Environmental parameters reported on in the State of the Bay: Saldanha 

Bay and Langebaan Lagoon. 

Parameter monitored Time period Anthropogenic induced impact 

Water Quality 

Physical 

aspects 1974-2000 No clear change attributable to development 

(temperature, salinity, 

dissolved oxygen, nutrients 

and chlorophyll) 

Current circulation patterns 

and current strengths 

1977 vs. 1991 Reduced wave energy, and impaired circulation 

and rate of exchange in Small Bay 

Increased current strength alongside obstructions 

(e.g. ore terminal) 

Microbiological (faecal 1999-2011 Faecal coliform counts in Small Bay frequently 

coliform) 

exceed safety levels. 

Big Bay and Langebaan Lagoon mostly remain 

within safety levels for faecal coliform pollution 

Heavy metal contaminants 

in water 

1997-2008 Concentrations of cadmium, copper, lead, zinc, 

iron and manganese in mussel flesh currently well 

below required safety levels, but this may change 

following any future dredging events owing to 

elevated metal concentration in sediments. 

SEDIMENTS 

Particle 

(mud/sand/gravel) 

size 

Particulate Organic Carbon 

(POC) 

Particulate Organic Nitrogen 

(PON) 

Trace metal contaminants 

in sediments 

1977-2011 Mud component of sediments has increased as a 

result of reduced water movement and dredging 

(negative impact) but has recovered somewhat 

since the last major dredging events (1999 and 

2007). 

1974-2011 Elevated levels of POC evident at Yacht Club basin 

and Mussel Farm (negative impacts). POC 

increased in 2008-2009 at Multi-Purpose Terminal 

and Yacht Club basin. 

1974-2010 PON concentrations have increased steadily over 

time in Yacht Club basin and at multipurpose quay. 

PON concentrations remain low in Big Bay. 

1980-2011 Cadmium, lead, copper and nickel are currently 

elevated considerably above historic levels. 

Concentrations were highest in 1999 following 

major dredge event. Pb, Cu, Ni elevated in 2008- 

2010 at Yacht Club and multipurpose terminal, 

which may be related to maintenance dredging 

that occurred at end 2007/beginning 2008. 

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Parameter monitored Time period Anthropogenic induced impact 

BENTHIC MACROFAUNA 

Species biomass 1975-2011 Increased biomass of benthic macrofauna in Small 

Bay and Big Bay. 

Decreased biomass of benthic macrofauna in 


Significant decrease in benthic health in Small Bay, 

and slight improvement in Big Bay from 2008-2011 

Species diversity 1975-2011 Significant decreased species diversity at all Small 

Bay sites, increased species diversity in Big Bay, no 

significant changes in Langebaan Lagoon. 

ROCKY INTERTIDAL 

Impact of alien mussel and 

barnacle introductions 

FISH 

Community composition 

and abundance 

BIRDS 

Population numbers of key 

species in Saldanha Bay and 

islands 

Population numbers of key 

species in Langebaan 

Lagoon 

1980-2011 Displacement of local mussel and other native 

species from the lower shore leading to decreased 

species diversity (negative). 

1986-2011 Baseline conditions established against which to 

measure future changes. 

Causes of changes in fish communities not clearly 

discernable from natural variability, but some 

concern due to mounting anthropogenic pressures 

on fish stocks and the supporting environment. 

1977-2011 Decreasing populations of Cape, Bank and Whitebreasted 

Cormorants are attributed to 

construction of causeway and increasing human 

disturbance. 

1976-2011 Some recovery of resident populations of waders 

in Langebaan Lagoon. Continued decrease in 

migrant waders utilising Langebaan Lagoon, 

attributed to diminishing feeding grounds and 

human disturbance. 

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