State of the Bay Report 2010-Final - Anchor Environmental

State of the Bay 2010: 

Saldanha Bay and 

Langebaan Lagoon 

May 2011 

ANCHOR 

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

www.anchorenvironmental.co.za

State of the Bay 2010: 

Saldanha Bay and 


Prepared by: 

B.M. Clark, K. Tunley, A. Angel, K. Hutchings, 

N. Steffani and J. Turpie 

Cover picture: Pierre De Villers 

May 2011 

Prepared for:

TABLE OF CONTENTS 

Anchor Environmental 

TABLE OF CONTENTS 5 

LIST OF FIGURES 9 

LIST OF TABLES 18 

GLOSSARY 31 

1 INTRODUCTION 33 

2 STRUCTURE OF THIS REPORT 35 

3 BACKGROUND TO ENVIRONMENTAL MONITORING AND WATER QUALITY 

MANAGEMENT 36 

3.1 INTRODUCTION 36 

3.2 MECHANISMS FOR MONITORING CONTAMINANTS AND THEIR EFFECTS ON THE ENVIRONMENT36 

3.3 INDICATORS OF ENVIRONMENTAL HEALTH AND STATUS IN SALDANHA BAY AND LANGEBAAN 

LAGOON 38 

4 ACTIVITIES AND DISCHARGES AFFECTING THE HEALTH OF THE BAY 41 


4.2 URBAN AND INDUSTRIAL DEVELOPMENT 42 

4.3 DISCHARGES AND ACTIVITIES AFFECTING ENVIRONMENTAL HEALTH 50 

4.3.1 Dredging and port expansion 50 

4.3.2 Development of the Salamander Bay Boat yard 53 

4.3.3 Shoreline erosion in Saldanha Bay and Langebaan lagoon 54 

4.3.4 Shipping, ballast water discharges, and oil spills 61 

4.3.5 Reverse Osmosis Desalination Plant 65 

4.3.6 Sewage and associated waste waters 67 

4.3.7 Storm water 77 

4.3.8 Fish processing plants 79 

4.3.9 Mariculture 81 

4.3.10 Development of a Liquid Petroleum Gas Facility in Saldanha Bay 84 

5 WATER QUALITY 85 

5.1 WATER TEMPERATURE 85 

5.2 SALINITY 87 

5.3 DISSOLVED OXYGEN 88 

5.4 CURRENTS AND WAVES 91 

5.5 MICROBIOLOGICAL MONITORING 93 

5.6 TRACE METAL CONTAMINANTS IN THE WATER COLUMN 107 

5.7 SUMMARY OF WATER QUALITY IN SALDANHA BAY AND LANGEBAAN LAGOON 112 

State of the Bay 2010: Saldanha Bay and Langebaan Lagoon 5


6 SEDIMENTS 113 

6.1 SEDIMENT PARTICLE SIZE COMPOSITION 113 

6.1.1 Historical data 113 

6.1.2 Sediment Particle size results for 2010 115 

6.2 PARTICULATE ORGANIC CARBON (POC) AND NITROGEN (PON) 122 

6.3 TRACE METALS 127 

6.3.1 State of the Bay survey results for 2010 128 

6.3.2 Trends in sediment metal concentrations over time 135 

6.4 HYDROCARBONS 145 

6.5 SUMMARY OF SEDIMENT HEALTH STATUS OF SALDANHA BAY 147 

7 AQUATIC MACROPHYTES IN LANGEBAAN LAGOON 148 

7.1 LONG TERM CHANGES IN SEAGRASS IN LANGEBAAN LAGOON 149 

7.2 LONG TERM CHANGES IN SALTMARSHES IN LANGEBAAN LAGOON 151 

8 BENTHIC MACROFAUNA 152 

8.1 BACKGROUND 152 

8.2 HISTORIC DATA ON BENTHIC MACROFAUNA COMMUNITIES IN SALDANHA BAY 152 

8.3 APPROACH AND METHODS USED IN MONITORING BENTHIC MACROFAUNA IN 2010 154 

8.3.1 Sample collection 154 

8.3.2 Statistical Analysis 154 

8.4 BENTHIC MACROFAUNA SURVEY RESULTS 159 

8.4.1 Community Structure and Composition 159 

8.4.2 Abundance Biomass Indices 173 

8.4.3 Species Diversity Indices 177 

8.4.4 Linking Ecological Indices to Environmental Variables 180 

8.5 DISCUSSION 184 

8.6 SUMMARY OF BENTHIC MACROFAUNA FINDINGS 187 

9 INTERTIDAL INVERTEBRATES (ROCKY SHORES) 190 

9.1 BACKGROUND 190 

9.2 APPROACH AND METHODOLOGY 191 

9.2.1 Study Sites 191 

9.2.2 Survey Method 192 

9.2.3 Data Analysis 195 

9.3 RESULTS AND DISCUSSION 196 

9.3.1 2010 Survey 196 

9.4 TEMPORAL COMPARISON 205 

9.5 SUMMARY OF RESULTS 216 

10 FISH COMMUNITY COMPOSITION AND ABUNDANCE 218 



11 BIRDS 234 


10.2 METHODS 219 

10.2.1 Field sampling 219 

10.2.2 Data analysis 219 

10.3 RESULTS 221 

10.3.1 Description of inter annual trends in fish species diversity 221 

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

communities in Small Bay, Big Bay and Langebaan lagoon 226 

10.3.3 Status of fish populations at individual sites sampled during 2010 227 

10.3.4 Multivariate analysis of spatial and temporal trends in fish communities 229 

10.4 CONCLUSIONS 233 


11.2 BIRDS OF SALDANHA BAY AND THE ISLANDS 234 

11.2.1 National importance of Saldanha Bay and the islands for birds 234 

11.2.2 Ecology and status of the principle bird species 235 

11.3 BIRDS OF LANGEBAAN LAGOON 247 

11.3.1 National importance of Langebaan Lagoon for birds 247 

11.3.2 The main groups of birds and their use of habitats and food 247 

11.3.3 Inter-annual variability in bird numbers 249 

11.4 OVERALL STATUS OF BIRDS IN SALDANHA BAY AND LANGEBAAN LAGOON 250 

12 ALIEN INVASIVE SPECIES IN SALDANHA BAY-LANGEBAAN LAGOON 252 

12.1 THE OCCURRENCE AND SPREAD OF THE WESTERN PEA CRAB PINNIXA OCCIDENTALIS IN 

SALDANHA BAY 255 

13 MANAGEMENT AND MONITORING RECOMMENDATIONS 257 

13.1 ACTIVITIES AND DISCHARGES AFFECTING THE HEALTH OF THE BAY 257 

13.1.1 Human settlements, storm water and sewage 257 

13.1.2 Dredging 258 

13.1.3 Sewage 258 

13.1.4 Fish factories 258 

13.1.5 Mariculture 259 

13.1.6 Shipping, ballast water discharges and oil spills 259 

13.1.7 Other development in and around the Bay 259 

13.2 WATER QUALITY 260 

13.2.1 Temperature, Salinity and Dissolved Oxygen 260 

13.2.2 Chlorophyll a and Nutrients 260 

13.2.3 Currents and waves 260 

13.2.4 Trace metal concentrations in biota (MCM Mussel Watch Programme and Mariculture 

Operators) 260 

13.2.5 Microbiological monitoring (Faecal coliform) 261 

13.3 SEDIMENTS 261 



13.3.1 Particle size, Particulate Organic Carbon and Trace metals 261 

13.3.2 Hydrocarbons 261 

13.4 BENTHIC MACROFAUNA 262 

13.5 ROCKY INTERTIDAL 262 

13.6 FISH 262 

13.7 BIRDS 263 

13.8 SUMMARY OF ENVIRONMENTAL MONITORING REQUIREMENTS 263 

14 REFERENCES 266 


LIST OF FIGURES 


Figure 1.1. Regional map of Saldanha Bay and Langebaan Lagoon showing development (grey 

shading) and conservation areas. .............................................................................. 33 

Figure 3.1. 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)......................... 39 

Figure 4.1. Map of Saldanha Bay indicating anthropogenic developments established since 1973 

referred to in text. ..................................................................................................... 43 

Figure 4.2. 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. ....................... 44 


(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. ...................................................................................... 45 


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

settlements particularly around the town of Langebaan. ........................................... 46 

Figure 4.5. Aerial photograph of Langebaan showing absence of development setback zone 

between the town and the lagoon. ............................................................................ 48 

Figure 4.6. Satellite image of Saldanha (Small Bay) showing little or no setback zone between the 

town and the Bay. ..................................................................................................... 48 

Figure 4.7. Numbers of tourists visiting the West Coast National Park since 2005 (Data from Pierre 

Nel WCNP). ............................................................................................................... 49 

Figure 4.8. Location of the maintenance dredging site between Caissons 3 and 4 on the ore 

terminal. ................................................................................................................... 52 

Figure 4.9. 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. ........................................................................ 55 

Figure 4.10. Change in relative beach area, in thousands of m 2 , since 1960 to 2000 in Paradise and 

Spreeuwal beaches, based on aerial photographs (Figure courtesy of J. Gericke 2008). 

56 

Figure 4.11. Rock revetments constructed along the beach at Langebaan in an effort to protect 

coastal infrastructure. ............................................................................................... 58 

Figure 4.12. 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. ........................................................................................... 58 

Figure 4.13. State of the beach north of Groyne 2 in May 2010. Top: looking south from the middle 

of Leentjiesklip 1 beach towards the groyne, Middle: Looking north from the middle of 



the beach towards Leentjiesklip 1, Bottom: looking north towards Leentjieklip from 

the position where the sea still reaches right up to the rock revetment. .................... 59 

Figure 4.14. Coastal erosion at Paradise Beach near Clun Mykonos. ............................................. 60 

Figure 4.15. Number and types of vessels entering Saldanha Port from 1994-2010. (Sources: 

Marangoni 1998; Awad et al. 2003, Transnet-NPA). .................................................. 63 

Figure 4.16. Volumes of ballast water discharge in million tonnes by the different types of vessels 

entering Saldanha Port between 1994 and 2010. 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)............................................................................................. 63 

Figure 4.17. Location of waste water treatment works, sewage pump stations and conservancy 

tanks in Saldanha and Langebaan area ...................................................................... 69 

Figure 4.18. Monthly trends in the volume of (a) effluent released from the Saldanha WWTW, Apr 

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

(red line) (b) in the numbers of Faecal Coliforms, (c) and Total Suspended Solids, and 

(d) Chemical Oxygen Demand in effluent released from the Saldanha WWTW, April 

2003-February 2011. Allowable limits as specified in terms of a General Authorisation 

under the National Water Act 1998 for graphs b-d are represented by the dotted red 

line. 72 

Figure 4.19. Monthly trends in water quality parameters (a) Chemical Oxygen Demand, (b) 

Ammonia Nitrogen, (c) Nitrate Ammonia, (d) Orthophosphate and (e) Free Active 

Chlorine for effluent released from the Saldanha WWTW Apr 2003-February 2011, and 

general limits specific under the National Water Act 36 of 1998 (red line on each 

graph). 73 

Figure 4.20. Monthly trends in the volume of effluent discharged from the Langebaan WWTW in 

the period June 2009-February 2011, and allowable limits as specified in terms of a 

General Authorisation under the National Water Act 1998 (red line). ........................ 74 

Figure 4.21. Monthly trends in (a) the numbers of Faecal Coliforms, (b) Total Suspended Solids, and 

(c) Chemical Oxygen Demand in effluent released To from the Langebaan WWTW, 

June 2009-February 2011. Allowable limits as specified in terms of a General 

Authorisation under the National Water Act 1998 are represented by the red line. ... 75 

Figure 4.22. Monthly trends in the volume of Ammonia Nitrate, Ortho Phosphorus and Nitrate 

Nitrogen present in effluent from Langebaan WWTW, June 2009-February 2011. 

Allowable limits as specified in terms of a General Authorisation under the National 

Water Act 1998 (red line). ......................................................................................... 76 

Figure 4.23. 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 Note that runoff from the Port of Saldanha and ore 

terminal have been excluded as runoff from this site is now reportedly all diverted to 

storm water evaporation ponds. Material settling in these ponds is trucked to a 

landfill site. ............................................................................................................... 78 

Figure 4.24. Location of seawater intakes and discharges for seafood processing in Saldanha Bay 

together with location of current and proposed mariculture operations ................... 80 

Figure 4.25. Total monthly discharge of fresh fish processing effluent (FFP) disposed to sea by Sea 

Harvest 81 

Figure 4.26. Allocated mariculture concession areas in Saldanha Bay 2010 ................................... 82 



Figure 4.27. Overall annual mussel productivity (tons) in Saldanha Bay between 2000 and 2009 

(source: DAFF, 2010) ................................................................................................. 83 

Figure 5.1. Water temperature time series at the surface and at 10m depth for Big Bay and Small 

Bay, Saldanha Bay ..................................................................................................... 86 

Figure 5.2. Time series of salinity records for Saldanha Bay......................................................... 88 

Figure 5.3. Time series of chlorophyll and nitrate concentration measurements for Saldanha Bay. 

................................................................................................................................. 89 

Figure 5.4. Apparent oxygen utilization (AOU) time series Small Bay and Big Bay, Saldanha Bay. 

(Note: Positive values in red indicate an oxygen deficit). ........................................... 90 

Figure 5.5. 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 jetty (Present). (Adapted from Shannon and Stander 1977 and 

Weeks et al. 1991a) ................................................................................................... 92 

Figure 5.6. Faecal coliform and E. coli counts at 4 of the 10 sampling stations within Small Bay. 

(Feb 1999-Feb 2010). 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. .................................................................... 103 

Figure 5.7. Faecal coliform and E. coli counts at 3 of the 10 sampling stations within Small Bay. 

(Feb 1999-Feb 2010). A downward slope of the regression (solid red and blue lines) is 



Figure 5.8. Faecal coliform and E. coli counts at 4 sampling stations within Big Bay. (Feb 1999-Feb 

2010). 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. ........................................................................................ 105 

Figure 5.9. Faecal coliform and E. coli counts at 3 sampling stations within Langebaan Lagoon (Feb 

1999-Feb 2010). A Downward slope of the regression (solid red and blue lines) is 



Figure 5.10. 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 or 

internationally are shown as a dotted red line (see Table 5.10 for more details on this). 

110 

Figure 5.11. Concentrations of Cadmium, Lead and Mercury in mussels and oysters from four 

bivalve culture operations in Saldanha Bay covering the period 1993 to 2010. ........ 111 

Figure 6.1. Particle size composition of sediment at six locations in Saldanha Bay between 1977 

and 2010 ................................................................................................................. 118 

Figure 6.2. Particle size composition (percentage gravel, sand and mud) of sediment at five 

locations in Bay and one at the entrance to Langebaan Lagoon ............................... 119 

Figure 6.3. Particle size composition (percentage gravel, sand and mud) of sediment at five 

locations in Langebaan Lagoon in 2004, 2008 and 2009 ........................................... 120 

Figure 6.4. Variation in the percentage mud in sediments in Saldanha Bay and Langebaan Lagoon 

as indicated by the 2010 survey results. .................................................................. 121 



Figure 6.5. Average (± 95% confidence intervals) percentage mud occurring in Small Bay, Big Bay 

and Langebaan Lagoon sediments over time ........................................................... 121 

Figure 6.6. Variation in the % Organic Carbon in the sediments in Saldanha Bay and Langebaan 

Lagoon as indicated by the 2010 survey results ....................................................... 124 

Figure 6.7. Variation in the % Organic Nitrogen in the sediments in Saldanha Bay and Langebaan 

Lagoon as indicated by the 2010 survey results ....................................................... 124 

Figure 6.8. Particulate Organic Carbon (POC) percentage occurring in sediments of Saldanha Bay 

at six locations between 1974 and 2010 .................................................................. 125 

Figure 6.9. Particulate Organic Nitrogen (PON) percentage occurring in sediments of Saldanha Bay 

at six locations between 1999 and 2010 .................................................................. 126 

Figure 6.10. Percentage particulate organic carbon and nitrogen found in the sediments at two 

sites near Donkergat. .............................................................................................. 127 

Figure 6.11. Sediment sampling sites in Saldanha Bay and Langebaan Lagoon for 2010. Sites 

sampled from pre-1980 to 2010 are marked and labelled in red .............................. 129 

Figure 6.12. Variation in the concentration of Cadmium (Cd) in the sediments in Saldanha Bay and 

Langebaan Lagoon as indicated by the 2010 survey results...................................... 131 

Figure 6.13. Variation in the concentration of Copper (Cu) in the sediments in Saldanha Bay and 


Figure 6.14. Variation in the concentration of Lead (Pb) in the sediments in Saldanha Bay and 


Figure 6.15. Variation in the concentration of Nickel (Ni) in the sediments in Saldanha Bay and 


Figure 6.16. Metal:Al ratios for Copper, Lead, Cadmium and Nickel for sediments sampled in 2010 

from Saldanha Bay-Small Bay (SB), Big Bay (BB) and Langebaan Lagoon (LL) ............ 133 

Figure 6.17. Variation in the concentration of Iron (Fe) in the sediments in Saldanha Bay and 


Figure 6.18. Concentrations of Cadmium (Cd) in mg/kg recorded at six sites in Saldanha Bay 

between 1980 and 2009. Red lines indicate Effects Range Low values for sediments139 

Figure 6.19. Concentrations of Lead (Pb) in mg/kg recorded at six sites in Saldanha Bay between 

1980 and 2009. Red lines indicate Effects Range Low values for sediments ............. 140 

Figure 6.20. Concentrations of Copper (Cu) in mg/kg recorded at six sites in Saldanha Bay between 

1980 and 2009. Red lines indicate Effects Range Low values for sediments ............. 141 

Figure 6.21. Concentrations of Nickel (Ni) in mg/kg recorded at six sites in Saldanha Bay between 

1980 and 2009. Red lines indicate Effects Range Low values for sediments. ............ 142 

Figure 6.22. Trends in sediment Iron concentrations over time at sediment sampling sites in the 

vicinity of the bulk terminal Saldanha. ..................................................................... 143 

Figure 6.23. Variation of trace metal concentrations in sediments in the Donkergat area and Big 

Bay as indicated by the 2010 results. ....................................................................... 144 

Figure 7.1. Seagrass (black) and saltmarsh (green) near Bottelarey in Langebaan Lagoon. Source: 

Google Earth. .......................................................................................................... 148 

Figure 7.2. Width of the Zostera beds and density of Siphonia at Klein Oesterwal and Bottelary in 

Langebaan Lagoon, 1972-2006. ............................................................................... 150 



Figure 7.3. Change in saltmarsh area over time in Langebaan Lagoon. (Data from Gerricke 2008) 

............................................................................................................................... 151 

Figure 7.4. Change in the number of discrete saltmarsh patches over time in Langebaan Lagoon. 

(Data from Gerricke 2008) ....................................................................................... 151 

Figure 8.1. Benthic macrofauna sampling stations in 1975, 1999, 2004 and 2008. .................... 153 

Figure 8.2. Benthic macrofauna stations sampled within Saldanha Bay and Langebaan Lagoon in 

2010. ....................................................................................................................... 156 

Figure 8.3. Hypothetical ABC curves for species biomass and abundance showing undisturbed, 

moderately disturbed and grossly disturbed conditions (after Warwick 1993). ........ 157 

Figure 8.4. Dendrogram (a) and MDS ordination plot (b) showing similarities between sites based on 

the species composition for benthic macrofauna in Saldanha Bay, 2010. SB = Small 

Bay, BB = Big Bay, LL = Langebaan Lagoon. Brackets on the dendrogram show groups 

of samples at the 25% level of similarity. ................................................................. 161 

Figure 8.5. Overall trends in the biomass and abundance of benthic macrofauna in Small Bay as 

shown by taxonomic and functional groups. ............................................................ 164 

Figure 8.6. Trends in the biomass of dominant benthic macrofauna species at six sites in Small 

Bay. (important to note different scales used on graphs). ........................................ 165 

Figure 8.7. Trends in the abundance of dominant benthic macrofauna species at six sites in Small 

Bay. (important to note different scales used on graphs) ......................................... 166 

Figure 8.8. Overall trends in the biomass and abundance of benthic macrofauna in Big Bay as 

shown by taxonomic and functional groups. ............................................................ 169 

Figure 8.9. Trends in the biomass of dominant benthic macrofauna species at six sites in Small 


Figure 8.10. Trends in the abundance of dominant benthic macrofauna species at six sites in Small 


Figure 8.11. Overall trends in the abundance and biomass of benthic macrofauna in Langebaan 

Lagoon as shown by taxonomic and functional groups. ........................................... 172 

Figure 8.12. Variation in the W statistic calculated for the benthic macrofauna in Saldanha Bay and 

Langebaan Lagoon as indicated by the 2010 survey results. (1 = Undisturbed, 0 = 

moderately disturbed, -1 = disturbed) ..................................................................... 174 

Figure 8.13. Mean W statistic (± 0.95 confidence intervals) for all years sampled in Small Bay, Big 

Bay and Langebaan Lagoon (W = 1 indicates undisturbed, W = 0 indicates moderately 

disturbed, W = -1 indicates grossly disturbed) ......................................................... 175 

Figure 8.14. Mean (± 0.95 confidence intervals) Species diversity (H'), Species richness (d'), 

Evenness (J') and Total number of species (S) for benthic macrofauna samples 

collected from Small Bay (SB), Big Bay (BB) and Langebaan Lagoon (LL), Saldanha, 

2010. 178 

Figure 8.15: 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) ..................................................................................... 179 

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 and 2010. ........... 180 



Figure 8.17. MDS of Saldanha Bay and Langebaan Lagoon benthic macrofauna abundance (2010) 

with superimposed circles representing depth (Increasing circle size = deeper) ....... 181 

Figure 8.18. MDS of Saldanha Bay and Langebaan Lagoon benthic macrofauna abundance (2010) 

with superimposed circles representing abiotic factors: Particulate Organic Carbon 

(POC), Particulate Organic Nitrogen (PON), % Gravel and % Mud (Increasing circle size 

= larger measurement). ........................................................................................... 182 

Figure 8.19. MDS of Saldanha Bay benthic macrofauna abundance (2009) 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) ........................................................................................................ 183 

Figure 8.20. Two-dimensional PCA ordination of the environmental variables (metals, POC and 

PON; transformed and normalized) for Saldanha Bay 2010...................................... 183 

Figure 8.21. Benthic macrofauna species frequently found to occur in Saldanha Bay and Langebaan 

Lagoon, photographs by: Charles Griffiths. .............................................................. 188 

Figure 8.22. Benthic macrofauna species frequently found to occur in Saldanha Bay and Langebaan 

Lagoon, photographs by: Charles Griffiths. .............................................................. 189 

Figure 9.1. Positions of the eight rocky intertidal study sites in Saldanha Bay. ........................... 192 

Figure 9.2. The rocky shore study sites in 2009 from top right to left bottom: Dive School, Jetty, 

Schaapen Island East, and Schaapen Island West. .................................................... 193 

Figure 9.3. The rocky shore study sites in 2009 from top right to bottom left: Iron Ore Jetty, Lynch 

Point, North Bay, and Marcus Island. ....................................................................... 194 

Figure 9.4. Top left to bottom right: High shores at Dive School, Iron Ore Jetty, Schaapen West 

with blue green algal cover, and at Marcus Island. .................................................. 197 

Figure 9.5. From top right to bottom left: Mid shores at Jetty, Schaapen East showing rock 

depression with orange sponge and Ulva spp., Iron Ore Jetty with dense Balanus 

glandula cover (insert showing Afrolittorina knysnaensis nestling among barnacles), 

and Mytilus galloprovincialis, B. glandula and Ulva spp. partially growing on mussels 

recruits at Marcus Island. ........................................................................................ 198 

Figure 9.6. Low shore at the sheltered site Dive School dominated by the algae Gigartina 

polycarpa (top left), Ralfsia verrucosa and Ulva spp.(top right), the anemone 

Pseudoactinia flagellifera (bottom left), and the sea urchin Parechinus angulosus in 

rock pools with sparse cover of the indigenous mussels Aulacomya ater and 

Choromytilus meridionalis (bottom right). ............................................................... 199 

Figure 9.7. Top: Low shore at the semi-exposed/exposed site North Bay showing mussel band and 

emerging kelp Ecklonia maxima. Bottom: Low shore at the exposed site Marcus Island 

with the mussel bed overgrown by red algae and patches of ‘pink’ encrusting 

corallines in between. The limpet Scutellastra cochlear, which is associated with the 

encrusting corallines, is fringed by a narrow garden of fine red algae. ..................... 202 

Figure 9.8. The mean abundance (number/0.5 m 2 ) of the most important mobile species at the 

eight rocky shores in 2010. ...................................................................................... 202 

Figure 9.9. Dendrogram (top) and multi-dimensional scaling (MDS) plot (bottom) of the rocky 

shore communities at the eight study sites in 2010. The circles in the MDS plot 

indicate a 40% (black) and 50% (red) similarity level. See text for further explanation. 

............................................................................................................................... 203 



Figure 9.10. Contribution of the various functional groups to the biotic cover (%) at the eight rocky 

shore sites. The sites are sorted from left to right according to increase in wave 

exposure. ................................................................................................................ 205 

Figure 9.11. Box & whisker plots comparing species number (top) and percentage cover (bottom) 

among the years 2005, 2008, 2009 and 2010 at the eight study sites. The ovals 

encircle the sites with significant differences and different letters indicate which of the 

years differ (see text). ............................................................................................. 206 

Figure 9.12. Box & whisker plots comparing evenness (top) and Shannon-Wiener diversity indices 

(bottom) among the years 2005, 2008, 2009 and 2010 at the eight study sites. The 

ovals encircle the sites with significant differences and different letters indicate which 

of the years differ (see text). ................................................................................... 207 

Figure 9.13. Multi-dimensional scaling (MDS) plot of the rocky shore communities at the eight 

study sites in 2005 (red symbols), 2008 (green symbols), 2009 (blue symbols) and 2010 

(grey symbols). The line separates samples at a 40% similarity level, and the blue 

circles delineate the 50% similarity level.................................................................. 209 

Figure 9.14. The mean percentage cover of the various functional groups at the study sites in 2005, 

2008, 2009 and 2010. .............................................................................................. 212 

Figure 9.15. 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 and the bottom four graphs. 

214 

Figure 10.1. Sampling sites within Saldanha Bay and Langebaan lagoon where seine net hauls were 

conducted during 2005, 2007, 2008, 2009 and 2010 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: Bottelary, 14: Churchhaven, 15: Kraal aai 220 

Figure 10.2. 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. ...................................................................................................... 222 

Figure 10.3. Average abundance of fish species (number.m -2 ) recorded during annual beach seinenet 

surveys in Small Bay Saldanha. (Ave. = average, SE = standard error). Species not 

previously recorded are shown in bold font. ............................................................ 223 

Figure 10.4. Average fish abundance (all species) during five seine-net surveys conducted in 

Saldanha Bay and Langebaan lagoon. (Error bars show one Standard Error of the 

mean). 226 

Figure 10.5. Abundance of the most common fish species recorded in annual seine-net surveys 

within Saldanha Bay and Langebaan Lagoon (1986/87, 1994, 2005, 2007-2010) (Error 

bars show one standard error of the mean)............................................................. 227 

Figure 10.6. Average abundance of the four most common fish species at each of the sites sampled 

within Small Bay and Big Bay during the earlier surveys (1994, 2005, 2007-2009) and 

during the 2010 survey. Errors bars show plus 1 Standard error. Note the scale change 

on vertical axis shows a maximum of either 1 or 3 fish.m -2 . ..................................... 228 

Figure 10.7. Average abundance of the four most common fish species at each of the sites sampled 

within Langebaan lagoon during the earlier surveys (1994, 2005, 2007-2009) and 

during the 2010 survey. Errors bars show plus 1 Standard error. Note the scale 

change on vertical axis shows a maximum of between 1 and 80 fish.m -2 . ................ 229 



Figure 10.8. Multidimensional scaling plots showing similarities between the fish communities 

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

sampling events. Note that three replicate samples were collected at each site in each 

year. 230 


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

events. Note that three replicate samples were collected at each site in each year. 231 


sampled at six Lagoon sites during 1994, 2005, 2007, 2008, 2009 & 2010 sampling 

events. 232 

Figure 11.1. Trends in African Penguin populations at Malgas, Marcus, Jutten and Vondeling islands 

in Saldanha Bay (Data source: Rob Crawford, Oceans & Coasts, Department of 

Environmental Affairs)............................................................................................. 236 

Figure 11.2. Trends in breeding population of Kelp gulls at Malgas, Jutten, Schaapen, Vondeling 

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

Department of Environmental Affairs). ND = No data .............................................. 237 

Figure 11.3. Trends in breeding population of Hartlaub’s Gulls at Malgas, Marcus, Jutten, Schaapen 

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

Department of Environmental Affairs). .................................................................... 238 

Figure 11.4. Trends in breeding population of Swift Terns at Malgas, Marcus, Jutten and Schaapen 

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

Environmental Affairs)............................................................................................. 239 

Figure 11.5. Trends in breeding population of Cape Gannets at Malgas Island, Saldanha Bay ((Data 

source: Rob Crawford, Oceans & Coasts, Department of Environmental Affairs). ND = 

No data 240 

Figure 11.6. 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). ........................................................ 242 

Figure 11.7. 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). .................................................................... 243 

Figure 11.8. Trends in breeding population of White-breasted Cormorants at Marcus, Jutten, 

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

Oceans & Coasts, Department of Environmental Affairs). ........................................ 244 

Figure 11.9. Trends in breeding population of White-breasted Cormorants at Malgas, Marcus, 

Jutten, Schaapen, Vondeling and Meeuw islands in Saldanha Bay (Data source: Rob 

Crawford, Oceans & Coasts, Department of Environmental Affairs). ND = No data . 245 

Figure 11.10. Trend in breeding population of African Black Oystercatchers older than 1 year, on 

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

Oystercatcher Conservation Programme). ............................................................... 246 

Figure 11.11. Numerical composition of the birds on Langebaan Lagoon during summer and winter 

249 

Figure 11.12. Long term trends in the numbers of summer migratory waders on Langebaan Lagoon 

250 

Figure 11.13. Long term trends in the numbers of winter resident waders on Langebaan Lagoon . 250 



Figure 12.1. 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 and top number of 

individuals collected from these sites (bottom). ...................................................... 255 

Figure 12.2. Map showing changes in the distribution of the Western Pea crab Pinnixa occidentalis 

in Saldanha Bay and Langebaan lagoon in the period 2004-2010. ............................ 256 


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. .................................................... 40 

Table 4.1. Summary of major development in Saldanha Bay ...................................................... 45 

Table 4.2. Total human population and population growth rates for the towns of Saldanha and 

Langebaan from 1996 to 2004 (Saldanha Bay Municipality, 2005). ............................ 47 

Table 4.3. Projected total human population and population growth rates for the towns of 

Saldanha and Langebaan (Saldanha Bay Municipality, 2005). .................................... 47 

Table 4.4. 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). ................................................................................. 62 

Table 4.5. General standards as specified under the Water Act 54 (1956) and revised general 

limits specified under the National Water Act 36 of 1998. ......................................... 70 

Table 4.6. Monthly rainfall data (mm) for Saldanha Bay over the period 1895-1999 (source Visser 

et al. 2007). ............................................................................................................... 78 

Table 4.7. Typical concentrations of water quality constituents in storm water runoff (residential 

and Industrial) (from CSIR 2002) and South Africa Water Quality Guidelines for the 

Natural Environment (*) and Recreational Use (**). Values that exceed guideline 

limits are indicated in red. ......................................................................................... 79 

Table 4.8. Characterisation of effluent from Sea Harvest and Southern Seas Fishing factories in 

2001 and 1996/7, respectively (Data from Entech 1996 In CSIR 2002). ...................... 80 

Table 4.9. Details of marine aquaculture rights issued in Saldanha Bay (source: DAFF pers. comm. 

2011) ........................................................................................................................ 83 

Table 5.1. Maximum acceptable count of faecal coliforms (per 100 ml sample) for mariculture 

and recreational use .................................................................................................. 93 

Table 5.2. Percentage of samples in which the concentration of E. coli was above the 80 th 

percentile limit specified in South African Water Quality Guidelines for recreational 

use (100 organisms/ml) for 10 sites in Small Bay, 4 sites in Big Bay and 4 sites in 

Langebaan Lagoon. Blue shading indicates compliance with regulations, while pink 

shading indicates non-compliance. Dashes (-) with no shading indicate that no samples 

were collected in that year. (Source: Saldanha Bay Water Quality Forum Trust). ...... 95 


percentile limit specified in South African Water Quality Guidelines for recreational 

use (2 000 organisms/ml) for 10 sites in Small Bay, 4 sites in Big Bay and 4 sites in 

Langebaan Lagoon. Blue shading indicates compliance with regulations, while pink 

shading indicates non-compliance. Dashes (-) with no shading indicate that no samples 

were collected in that year. (Source: Saldanha Bay Water Quality Forum Trust). ...... 96 

Table 5.4. Percentage of samples in which the concentration of Faecal coliforms were above the 

80 th percentile limit specified in South African Water Quality Guidelines for 

recreational use (100 organisms/ml) for 10 sites in Small Bay, 4 sites in Big Bay and 4 

sites in Langebaan Lagoon. Blue shading indicates compliance with regulations, while 

pink shading indicates non-compliance. Dashes (-) with no shading indicate that no 



samples were collected in that year. (Source: Saldanha Bay Water Quality Forum 

Trust). ....................................................................................................................... 97 



recreational use (2 000 organisms/ml) for 10 sites in Small Bay, 4 sites in Big Bay and 4 




Trust). ....................................................................................................................... 98 


percentile limit specified in South African Water Quality Guidelines for mariculture use 

(20 organisms/ml) for 10 sites in Small Bay, 4 sites in Big Bay and 4 sites in Langebaan 

Lagoon. Blue shading indicates compliance with regulations, while pink shading 

indicates non-compliance. Dashes (-) with no shading indicate that no samples were 

collected in that year. (Source: Saldanha Bay Water Quality Forum Trust). ............... 99 


percentile limit specified in South African Water Quality Guidelines for mariculture use 

(60 organisms/ml) for 10 sites in Small Bay, 4 sites in Big Bay and 4 sites in Langebaan 

Lagoon. Blue shading indicates compliance with regulations, while pink shading 

indicates non-compliance. Dashes (-) with no shading indicate that no samples were 

collected in that year. (Source: Saldanha Bay Water Quality Forum Trust). ............. 100 



mariculture use (20 organisms/ml) for 10 sites in Small Bay, 4 sites in Big Bay and 4 




Trust). ..................................................................................................................... 101 



mariculture use (60 organisms/ml) for 10 sites in Small Bay, 4 sites in Big Bay and 4 




Trust). ..................................................................................................................... 102 

Table 5.10. Regulations relating to maximum levels for metals in molluscs in different countries 

109 

Table 6.1. Sediment Composition of samples collected from Small Bay (SB), Big Bay (BB) and 

Langebaan Lagoon (LL) in 2010; Particulate organic nitrogen (PON), particulate organic 

carbon (POC) and grain size composition (Sediment analyzed by Scientific Services) 116 

Table 6.2. Concentrations of metals (mg/kg) surface sediments collected from Small Bay (SB), Big 

Bay (BB) and Langebaan Lagoon in 2010 (Sediment analyzed by Scientific Services) 117 

Table 6.3. Summary of BCLME and NOAA metal concentrations in sediment quality guidelines128 

Table 6.4: Concentrations (mg/kg) of metals in sediments collected from Saldanha Bay in 2010. ... 130 

Table 6.5. Enrichment factors for Cadmium, Copper and Lead in sediments collected from 

Saldanha Bay in 2009 relative to sediments from 1980 ............................................ 134 



Table 6.6. Poly-aromatic hydrocarbons in sediment samples collected from Saldanha Bay and 

Langebaan Lagoon in April 2010. ............................................................................. 146 

Table 8.1. Depth at each of the sites sampled in 2010. ............................................................ 155 

Table 8.2. Five most dominant species within Small Bay, Big Bay and Langebaan Lagoon recorded 

in sampling conducted during 2010. ........................................................................ 160 

Table 8.3. W statistics at all stations sampled between 1999 and 2010 in Small Bay (1 = 

Undisturbed, 0 = moderately disturbed, -1 = Grossly disturbed) (Red indicates a 

decrease an green indicates an increase since the previous year) ............................ 176 

Table 8.4. W statistics at all stations sampled between 1999 and 2010 in Big Bay (1 = 

Undisturbed, 0 = moderately disturbed, -1 = Grossly disturbed)(Red indicates a 

decrease and green indicates an increase since the previous year). ......................... 176 

Table 8.5. W statistics at all stations sampled between 2004 and 2010 in Langebaan Lagoon (1 = 

Undisturbed, 0 = moderately disturbed, -1 = Grossly disturbed)(Red indicates a 

decrease an green indicates an increase since the previous year) ............................ 177 

Table 9.1. GPS positions (in WGS84), wave exposure, and topographical description of the eight 

rocky intertidal study sites in Saldanha Bay. ............................................................ 191 

Table 9.2. Total and average (±standard deviation) number of species, and average (±standard 

deviation) percentage cover, evenness (J’) and Shannon-Wiener diversity index (H’) for 

the intertidal communities at the eight study sites in Saldanha Bay in 2010. ........... 200 

Table 9.3. Results of one-way ANOVA’s analyzing differences in species number, percentage 

cover, evenness and Shannon-Wiener diversity index among the years 2005, 2008, 

2009 and 2010 at the eight study sites. Site name abbreviations used in the figure are 

provided in brackets behind the site name. df = 3,20 for all analyses; significant tests 

are highlighted in bold italic. ................................................................................... 208 

Table 9.4. PERMANOVA pairwise-testing results following significant main-tests. Only the 

relevant pairwise comparisons for the years 2005 versus 2008, 2008 versus 2009, and 

2009 versus 2010 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. ............................................... 210 

Table 9.5. Results from the SIMPER analysis listing the species that contribute >5% to the 

dissimilarity among the years at each site. The % cover data are averages across the 

six replicates per site, and are on the fourth-root transformed scale. ...................... 211 

Table 10.1. Average abundance of fish species (number.m -2 ) recorded during annual beach seinenet 

surveys in Big Bay Saldanha. Ave. = average, SE = standard error. Species not 

previously recorded are shown in bold font. ............................................................ 224 

Table 10.2. Average abundance of fish species (number.m -2 ) recorded during annual beach seinenet 

surveys in Langebaan Lagoon. Ave. = average, SE = standard error. .................. 225 

Table 11.1. Taxonomic composition of waterbirds in Langebaan Lagoon (excluding rare or vagrant 

species). .................................................................................................................. 248 

Table 12.1. 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. in prep. a & b) ........................................................... 252 


EXECUTIVE SUMMARY 


Regular, long-term environmental monitoring is essential to identify and to act pro-actively 

in minimising 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 to an area such as Saldanha 

Bay –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-decades) at sufficient frequency to enable identification of 

anthropogenic induced changes. 

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

interest largely owing to the conservation importance and it many unique features. The 

establishment of the Saldanha Bay Water Quality Forum Trust (SBWQFT) 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 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 

expanded considerably since this time 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. These report present data on parameters 

monitored directly by the SBWQFT as well as those monitored by other agency (government, private 

industry, academic institutes and NGOs). 

In this report, the 2010 State of the Bay report, available data on a variety of physical and 

biological parameters 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) are presented and 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 Saldanha Bay. 

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 

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. Major developments within the bay include the 

construction of the Marcus Island causeway and the iron ore jetty, 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/lagoon. 

Several dredge 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), 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 ore jetty 

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 

has been constructed at the Ore Terminal in Big Bay which is set to start discharging effluent into the 

Bay in the near future and the refurbishment and expansion of the small craft harbour at 

Salamander Bay in Langebaan Lagoon. The possibility of establishing of 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 jetty 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 is no longer operational but there is an 

indication that this factory may be brought back into commission soon. Sea Harvest discharges fresh 

fish processing effluent into the sea daily, with historical monthly discharges ranging between 50 

000 to 90 000 kl. Fish factory effluents contain large quantities of organic wastes, which accumulate 

in Small Bay and lead to significant degradation of the marine environment. There is currently one 

main mariculture operation in Small Bay (Blue Bay Aquafarm which farms mussels) and several areas 

have been earmarked for future mariculture developments. Elevated concentrations of organic 



matter in the vicinity of the mussel rafts have been attributed to biogenic waste. Problems 

associated with high concentrations of nutrients in fish factory waste and adjacent to mariculture 

farms include eutrophication, algal growth and anoxia. Organic matter is prone to accumulate in the 

sediments in Small Bay due to restricted water circulation, and this has led to a decline in the health 

of the marine environment and changes in marine species composition within Small Bay. 

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

order to stabilize the ship before and after cargo loading/offloading. Water from foreign ports is 

thus introduced to Saldanha Bay and is associated with several environmental risks such as transfer 

of alien species and the release of water containing high concentrations of contaminants. Volumes 

of ballast water discharge are greatest at the iron ore terminal and have increased steadily from 

2002 to 2010. 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 jetty and causeway. The water entering Small Bay appears to remain 

within the confines of the Bay for longer periods than was historically the case (i.e. an increased 

residence time). 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 

jetty). The wave exposure patterns in Small Bay and Big Bay has 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. 

Coastal waters in Small Bay have faecal coliform counts in excess of safety guidelines for 

both mariculture and recreational use the majority of the time. There have been noticeable 

improvements in water quality in Small bay from 2004 to 2010 in terms of recreational use; however 

faecal coliform counts are still well above guideline limits in some area. 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 appear to be getting worse. Considering the likely growth of mariculture and 

tourism industries on Saldanha Bay, it is imperative that further steps be taken to remedy this source 

of pollution into the Bay. Waste water from the Langebaan WWTW has historically always 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 

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 

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 are 

routinely monitored by the Department of Agriculture, Forestry and Fisheries (DAFF) and by the 

mariculture farm owners. The DAFF 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 supplied by the Mussel Watch Programme show that concentrations of 

Lead in mussels at the monitored sites are consistently are above guideline limits for foodstuffs for 

at least the last 10 years, while concentrations of Cadmium frequently exceed these limits, and those 

for Zinc do so occasionally. Concentrations of Copper are, 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, compared 

with those along the shore that filtering water that has been in the Bay for a longer period and may 

contain a greater quality of suspended sediment and associated contaminants. 

Sediments 

The distribution of mud, sand or 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 greater 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 surficial 

(surface) sediments has been observed following dredging events, however, with time (several 

years), significant proportions 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 (2004-2010) 

indicate that the sediment in the Bay is currently predominantly made up of sand and is not 

considered to contain high levels of contaminants, except in the most sheltered parts of the Bay (e.g. 

Yacht Club Basin and 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 

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 

2004 and 2009 indicate generally low organic matter concentrations occurring in Saldanha Bay, 

except at the Yacht Club basin and Mussel Farm sites. PON concentrations have increased notably at 

the Yacht Club basin and at the multipurpose quay from 1999 to 2009. 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 naturally 

occurring 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 (e.g. dredging). 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. At 

most sites contaminants have returned to natural or close to natural levels since this time, as fine 

sediments along with the associated contaminants have either been flushed out of the bay or have 

been reburied, but nonetheless are likely to become a serious risk again following any future 

dredging events. Key areas of concern regarding heavy metal pollution within Small Bay include the 

Yacht Club basin and the multipurpose terminal. Regular monitoring of trace metal concentrations is 

strongly recommended to provide an early warning of any future increases. 

Much concern was expressed over the possible contamination of the Bay and Lagoon by 

trace metals following the dredge event at Salamander Bay between 2009 and 2010. Data included 

in this report show that while concentrations of some trace metals (e.g. lead, copper and nickel) did 

increase in sediments in the area around the development site, these did not reach levels that could 

be considered to be of concern. 

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. The total petroleum 

hydrocarbon contamination for all sites, with the exception of one, 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 (seagrass and salt marshes) 

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, Calianassa krausii 

and the mudprawn Upogebia capensis. Seagrass 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. 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. Recent studies show that the aerial extent of seagrass beds in Langebaan Lagoon 

has decline by an estimated 38% since the 1960s, this being more dramatic in some areas than 

others (e.g. seagrass beds at Klein Oesterwal near the entrance to the lagoon have declined by 

almost 99% over this period). Corresponding changes have been observed in densities of benthic 

macrofauna at sites where seagrass cover has declined, with species that were commonly associated 

with seagrass having declining in abundance, while those species 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 has also been linked to changes in the size 

of these beds, with population crashes in this species coinciding with periods of lowest seagrass. By 

contrast, they were able to show that populations of wader species that do not feed in seagrass beds 

were more stable over time. 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. 

By contrast, little change has been reported in the extent of salt marshes 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 species abundance and biomass (the numbers 

and mass of species making up the benthic community) and species diversity (how many different 

species are present) from historical studies conducted prior to development of Saldanha Bay are 

compared to data from recent surveys (2005, 2008, 2009) in order to interpret the overall health of 

the marine environment. Pre-development benthic macrofauna surveys of Saldanha Bay and 

Langebaan Lagoon were conducted using slightly different methods to those of more recent studies 

which make accurate comparison between the data sets difficult. However, taking into 

consideration the differences in sampling techniques, it is evident that there have been significant 

changes in benthic communities within the Bay. The most dramatic change was observed 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 (number of species present) appears to have remained fairly consistent. The sea 

pen (Virgularia schultzei), a species highly sensitive to disturbance and pollution, disappeared from 

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

most likely deteriorated between 1999 and 2008, but has recently (2009 and 2010 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. Recent fluctuations 

in the health of these two areas seem to be closely linked to dredging activities which place severe 

stress on these areas, and from which it takes a significant period of time to recover. Conditions in 

Small Bay remain very much poorer than those in Big Bay or Langebaan Lagoon, however. The most 

severely impacted sites within Small Bay in 2010 remain the Yacht Club basin and the base of the ore 

jetty. 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 

(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 Lagoon, however, data collected in 2004, 2008, 2009 and 2010 indicate an almost 

complete dominance by crustaceans with a low diversity and abundance of polychaetes occurring in 

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 is not the case and are a concern for the Lagoon environment. 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 on by negative 

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

Saldanha Bay prior to 1980, at which time the alien, invasive Mediterranean mussel (Mytilus 

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

conducted in 1980 at Marcus Island compared to surveys conducted in 2001, clearly show strong 

links between the invasion of the Mediterranean mussel and changes in the intertidal rocky shore 

communities. The mid-to-low shore of the intertidal area is most impacted on by the invasive 

mussel, and local species like the black mussel and ribbed mussel have been displaced from the low 

shore by the highly competitive Mediterranean 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 were surveyed 

again in 2008, 2009, and 2010. Comparisons between these datasets shows that 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, having previously 

been confused with the native barnacle, and evidence shows that it has been present in South Africa 

since at least 1992. 

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 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. 

The 2010 sampling event recorded comparable data to earlier surveys in Big Bay and Small 

Bay with clear reductions in the abundance of some species. In Langebaan lagoon, the 2010 

sampling revealed the highest densities of white stumpnose and harder juveniles yet recorded in all 

the annual seine net sampling conducted to date. This reflects natural and human induced 

variations in 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 the stock. Although correlation should 

not be interpreted as cause and effect, it is notable that white stumpnose density recorded during 

2010 was higher than the long-term average at sites further away from anthropogenic disturbance 

(Lagoon and North Bay sites), whilst densities decreased at most Small Bay and Big bay sites. The 

presence and proposed expansion of heavy industrial activity, increased urbanization and associated 

pollutants entering the Bay system as well as future large scale dredging and port expansion plans 

undoubtedly places strain on the supporting environment and ecosystem, whilst increased human 

exploitation places direct pressure on fish stocks. 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. The diversity of birds utilising 

Saldanha Bay and the islands are considered low, however, this region supports substantial 

proportions of the total population of many of these species. Regular surveys of breeding 

populations of these birds have been conducted. 

Annual counts of breeding African Penguin pairs indicate that there has been an overall 

decrease in population size at all four islands in the Bay (Malgas, Marcus, Jutten and Vondeling). The 

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 2 049 breeding pairs in 1987 to 506 breeding pairs in 

2010, representing a 75% decrease in 24 years. This trend currently shows no sign of reversing, and 

immediate conservation action is required to prevent further declines. 

Populations of Kelp Gulls showed steady year-on-year increases in 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 species Mytilus galloprovincialus. 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 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 

three years. 



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

the West coast have been declining since the start of the eastward shift of the pelagic fish 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 pusilus 

pusillus) and the Great White Pelican (Pelecanus onocrotalus) on islands in Saldanha Bay are also of 

concern, having been responsible for a 25% reduction in the size of the colony at Malgas Island 

between 2001 and 2006. 

Bank Cormorant numbers have shown steady declines since 1991, which could be related to 

increasing numbers in other areas, however, the overall total population decline is of concern. 

Numbers of Crowned Cormorants are either stable or increasing. This species is not considered to 

be threatened in the region. 

White-breasted Cormorants are recent arrival in the Bay (first sighted in large numbers on 

Schaapen Island in 1995), but has since shown a steadily decline with only two breeding pairs being 

counted in 2004, and none since then. These birds are highly sensitive to disturbance and the 

observed decrease in numbers is likely to be as a result of increased human activity in the region. 

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 

fluctuate between 200 and 270, and between 100 and 160 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. Populations appear to have stabilised in the recent years, most likely due to the fact 

that the carrying capacity of the islands has probably 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 much as 98% of the waterbirds present in the Lagoon during summer months are 

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

Langebaan Lagoon has been identified as the most important wetland 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. Subsequent to 1980, data show a dramatic downward trend in the numbers of Palaearctic 

waders at the Lagoon with similar decreasing trends being echoed by resident waders. The likely 

cause of this decrease in both migrant and resident waders (the latter being of most concern) has 

been attributed to the siltation of the Lagoon reducing the amount of suitable feeding grounds and 

increasing levels of human disturbance. 

Introduced species 

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. Many of these are considered invasive, 

including the Mediterranean mussel Mytilus galloprovincialis, 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. 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. 


Summary 


In summary, it can be said that developments in Saldanha Bay and Langebaan Lagoon during 

the past thirty years have inevitably impacted on the environment. This State of the Bay Report 

aimed to examine long-term trends in available data sets to highlight long-term changes in 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 

resident waterbirds in Langebaan Lagoon and decreased numbers of White-breasted and Bank 

Cormorants are perhaps of greatest concern. However, the decreased numbers of birds may well be 

a reflection of poor fish, benthic macrofauna, 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. 


GLOSSARY 

Alien species An introduced species that has become naturalized. 


Articulated coralline algae Articulated corallines are branching, tree-like plants which are 

attached to the substratum by crustose or calcified, root-like 

holdfasts. 

Biodiversity 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. 

Biota All the plant and animal life of a particular region. 

Community structure 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 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. 

Corticated algae 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 (or encrusting) coralline algae Crustose corallines are typically slow growing crusts of 

varying thickness that can occur on rock, shells, or other algae. 

Ephemeral algae Opportunistic algae with a short life cycle that are usually the first 

settlers on a rocky shore. 

Fauna General term for all of the animals found in a particular location. 

Flora General term for all of the plant life found in a particular location. 

Foliose algae Leaf-like, broad and flat; having the texture or shape of a leaf. 

Filter-feeders Animals that feed by straining suspended matter and food particles 

from water. 

Functional group A collection of organisms of specific morphological, physiological, 

and/or behavioral properties. 

Grazer An herbivore that feeds on plants/algae by abrasion from the 

surface. 

Indigenous Native to the country not introduced. 

Intertidal The shore area between the high- and the low-tide levels. 

Invertebrate Animals that do not have a backbone. Invertebrates either have an 

exoskeleton (e.g. crabs) or no skeleton at all (worms). 

Kelp A member of the order Laminariales, the more massive brown algae. 

Opportunistic Capable of rapidly occupying newly available space. 

Rocky shore community A group of interdependent organisms inhabiting the same rocky 

shore region and interacting with each other. 

Scavenger An animals that eats already dead or decaying animals. 



Shore height zone Zone on the intertidal shore recognizable by its community. 

Thallus General form of an alga that, unlike a plant, is not differentiated into 

stems, roots, or leaves. 

Topography The relief features or surface configuration of an area. 

Trappers Limpets that trap kelp fronds beneath their shells. 


1 INTRODUCTION 


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. 



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 this report (State of the Bay 2010), the fourth in the series. This (2010) report 

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 (2009), and includes information on 

trends in all of the parameters reported on in the previous reports (2006, 2008, and 2009). 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 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 

Chapter Two provides an outline of the structure of this report (this chapter). 

Chapter Three 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 Four 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 some impact on 

environmental health. 

Chapter Five 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 Six 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 Seven summarises available information on long-term trends in aquatic 

macrophytes (seagrasses and salt marshes) in Langebaan Lagoon 

Chapter Eight presents data on changes in benthic macrofauna in Saldanha Bay and 

Langebaan Lagoon from the 1970’s to the present day 

Chapter Nine 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 Ten 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 Eleven 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 Twelve 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 Thirteen 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. 



3 BACKGROUND TO ENVIRONMENTAL MONITORING AND 

WATER QUALITY MANAGEMENT 

3.1 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. 

3.2 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 

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). 



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 3.1). 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. 

3.3 Indicators of environmental health and status in Saldanha Bay and 


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 3.1 and Table 3.1). 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. 

(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 3.1. 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. 

Sediments: 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 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. 

Table 3.1. 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 

Good 

Fair 

Poor 

 

 

 

 

No or negligible modification from the 

natural state 

Minimal alteration to the physical 

environment, the biodiversity and 

integrity of the environment remains 

largely intact 

Significant change evident in the 

physical environment and associated 

biological communities; sensitive 

species may be lost, while tolerant or 

opportunistic species are beginning to 

dominate. 

Extensive changes evident in the 

physical environment and associated 

biological communities, majority of 

sensitive species lost, and tolerant or 

opportunistic species dominate. 

Relatively little human impact 

Some human-related 

disturbance, but ecosystems 

essentially in a good state, 

however, continued regular 

monitoring is strongly suggested 

Moderate human-related 

disturbance with good ability to 

recover. Regular ecosystem 

monitoring to be initiated to 

ensure no further deterioration 

takes place. 

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 

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). 



4 ACTIVITIES AND DISCHARGES AFFECTING THE HEALTH OF THE 

BAY 


Industrial development of Saldanha Bay dates back to the early 1900’s with the growth of a 

commercial fishing and rock lobster industry. 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 jetty. 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 jetty 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 



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. 

4.2 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 Oosterwal, 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). 


Fish factories 

Small craft 

harbour 

Mussel rafts 

Causeway 

Small Bay 

Marcus Island 

Big Bay 

Multipurpose terminal 

Langebaan 

Lagoon 

Iron ore jetty 


Figure 4.1. Map of Saldanha Bay indicating anthropogenic developments established since 1973 referred 

to in text. 

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 jetty. Between 1974 and 1976 extensive dredging was conducted to accommodate a deepwater 

port for use by large ore-carriers. The iron ore jetty 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 jetty essentially divided Saldanha Bay into two sections: a smaller area 

bounded by the causeway, the northern shore and the ore jetty (called Small Bay); and a larger , 

more exposed area adjacent called Big Bay, leading into Langebaan lagoon (Figure 4.1). A multipurpose 

terminal had been added to the jetty 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 (summarized 

in Table 4.1), dredging and submarine blasting has been necessary. Development of the causeway 



and iron-ore jetty 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 4.2. 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. 

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 4.2), 1989 (Figure 4.3) and in 2007 (Figure 4.4) 

clearly show the extent of development that has taken place within Saldanha By over the last 50 

years. 

Table 4.1. 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 jetty 

1980 Multi-purpose terminal added to Iron-ore jetty 

1984 Small craft harbour 

1998 Multi-purpose jetty extended 


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. 




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. 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 

Lagoon increased from 2 735 to 4 272 between 1996 and 2001, with a growth rate of 7.02%/yr 

(Table 4.2). 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 4.3.). 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 4.5 and Figure 4.6). Allowing an urban core to 

extend to the waters’ edge places the marine environment under considerable stress due to 

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 §4.3 for more detail on these issues). 

Table 4.2. Total human population and population growth rates for the towns of Saldanha and 

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

Location Total Population 

1996 

Total Population 

State of the Bay 2010: Saldanha Bay and Langebaan Lagoon 47 

2001 

Growth 1996-2001 

(%/yr) 

Saldanha 16 820 21 626 5.73 

Langebaan 2 735 4 272 7.02 

Table 4.3. 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 

Industrial 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 increasing tourism capacity 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) but no 

indication of growth in numbers in recent years since (Figure 4.7). 

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. An IDP was prepared for the Saldanha 

Municipality in 2006 and is due for revision in 2011 following the municipal elections. 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. The objective of an SDF is 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 SDF for the Saldanha Bay Municipality is currently under 

revision and a draft is available on the Saldanha Bay Municipality website for viewing and comment. 

The “Growth Potential of Towns” study conducted as part of the provincial SDF identifies Langebaan 

and Saldanha as having a high growth potential. It was estimated that, given the projected 

population figures, there would be a future residential demand of 7 200 units in Saldanha and 2 793 

units in Langebaan. The draft SDF proposes addressing these demands by increasing the residential 

density in specified nodes in both towns and by extending the urban edge of Saldanha towards 

Vredenberg, and that of Langebaan inland towards the east. Furthermore a feasibility study is 

currently underway to determine whether an industrial development zone can be established within 

the Saldanha Municipal Area.


Figure 4.5. Aerial photograph of Langebaan showing absence of development setback zone between the 

town and the lagoon. 

Figure 4.6. Satellite image of Saldanha (Small Bay) showing little or no setback zone between the town 

and the Bay. 



Figure 4.7. Numbers of tourists visiting the West Coast National Park since 2005 (Data from Pierre Nel 

WCNP). 

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 of the land 1km 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 100m inland of the high water mark; 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). 



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. 

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 objects of ICMA or coastal management objectives; 

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 

4.3 Discharges and activities affecting environmental health 

4.3.1 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 cubic meters 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 jetty 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 (§6.1) and benthic community structure (see §0). 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 

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 shelly material. 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 80’s and the depth has reduced from 

approximately 9m to 6m 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, shelly 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 000m 3 of sediments to be dredged at berth 201, 

approximately 300m 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). The impacts of 

the maintenance dredging are summarized above. 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 fill in navigation channels more rapidly 

(Schoonees et al. 1995). 

The third of these dredge events was undertaken in 2009/10 and completed in December 

2010, 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 ore jetty (Figure 4.8) (N. 

Jansen – Port of Saldanha pers. comm. 2011). The environmental impact assessment for the 

proposed dredge event was undertaken by Environmental Resources Management in April 2008. 

The purpose 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 bulkcarriers 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 (N. Jansen – Port of Saldanha pers. comm. 2011). 

Figure 4.8. Location of the maintenance dredging site between Caissons 3 and 4 on the ore terminal. 

Transnet has also proposed a Phase 2 Expansion of the Iron ore quay in order to increase its 

export capacity from, 45 million tonnes/annum to 90 million tonnes/annum. This will require 

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 expansion involves the 

development of two new berths on the southern side (Big Bay side) of the iron ore quay. 



Upgrades to the iron ore terminal that will impact the marine environment include: 

Deepening of shipping channels 

Disposal of dredged materials 

Possible reclamation into the bay using dredged materials 

Addition of 2 new shipping berths 

Addition of 3 stockpile areas 

Three alternatives are currently being considered for the addition of the stockpile areas 

(PDNA and SRK Consulting 2006), 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, but has since 

been put on hold and is currently in a pre-feasibility stage (N. Jansen – Port of Saldanha pers. comm. 

2011). 

4.3.2 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. 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. 

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 which assessed 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 

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 a result of the hard 

flat surfaces of the quay increasing 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). It was recommended that sites within Salamander Bay be 

monitored in future, possibly as part of the regular State of the Bay monitoring work. 

4.3.3 Shoreline erosion in Saldanha Bay and Langebaan lagoon 

Coastal zones contain diverse complex ecosystems including productive habitats important 

for human settlements, development and local subsistence. With more than half the world’s 

population living within 60 km of the shoreline, increased pressures of population growth, 

demographic shifts, economic development and global climate change pose unprecedented threats 

to sandy beach ecosystems worldwide (Schlacher et al. 2008). Coastal areas are also highly dynamic 

and subject to interacting marine and terrestrial processes that alter the deposition and movement 

of sediments along the coast in often unpredictable ways (Cooper and Pilkey 2004). The 

conservation of beaches as functional ecosystems therefore requires management interventions 

that not only mitigate threats to physical properties of sandy shores, but also their ecological value 

and ecosystem functioning. 

Beach erosion can occur as a result of human settlements and activities which alter the 

landscape and change the sedimentary processes leading to a net accumulation or erosion of 

sediments (Bird 1985). As much as 70% of the worlds sandy beaches are affected by erosion a 

problem which has been greatly exacerbated by development of human settlements in the coastal 

zone (Bird 1985). Climate change poses a further threat to coastal ecosystems, and beaches in 

particular. Beaches will experience the direct impact of sea level change, changes in storm and wave 

regimes as well as altered sediment budgets (Slott et al. 2006). Depending on the shape of the 

coastline, as storm and wave regiments change, there will be areas with greatly accelerated coastal 

erosion alternated by areas of shoreline accretion (Slott et al 2006). Globally, 70% of beaches are 

already receding, 20–30% are stable, while 10% or less are accreting (Schlacher et al. 2008). Under 

natural conditions, sea level rise would cause entire coastal system, including beach and dune 

systems, to retreat inland. In instances where coastal system 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, see (Figure 4.11, Feagin et al. 2005). Salt marshes are under immediate 

threat if the rate of sea level rise exceeds that of vertical accretion. 



Figure 4.9. 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 movement of beach sediment is a result of a process called “littoral drift” driven mainly 

by wave action. As the waves hit the shore they do so at an angle thereby displacing sediment along 

the shore. Beaches in areas prone to violent storms will have greater potential for sedimentary 

change, which will occur in single events rather than by long term trends. It is not clear whether 

storms in the Saldanha/Langebaan region will increase in frequency or intensity but it is a possible 

scenario, which coupled with long term changes in sea level and average wave height, would result 

in greater shifts in shoreline over less time. This may necessitate greater setback lines for 

development that those currently in place (Gericke 2008). 

4.3.3.1 Changes in beach and dune morphology in Saldanha Bay and Langebaan Lagoon 

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). 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 4.9). 

Gericke (2008) studied aerial photographs from Saldanha Bay between 1960 and 2000, to 

assess changes to beaches, coastal dunes and salt marshes, due to sedimentary forces, and the 

possible influence of anthropogenic factors. He focussed on two sites, Langebaan Beach (opposite 

the town of Langebaan) and Spreeuwalle (situated between Lynch point and the ore terminal). 

These two beaches fluctuated considerably in size over this 40 year period (Figure 4.10). The 

trajectory of change on the two beaches was initially similar, both beaches reached a low point in 

1972 (the lowest recorded in the case of Spreeuwalle) following which time they both increased in 

size until 1982 whereafter their paths diverged. Langebaan beach began declining precipitously in 

size at this point, a trend which continued until the end of the monitoring period (2000) where it 

reached the small size on record. By contrast, the beach at Spreeuwalle continued increasing slowly 

in size from 1983 until the end of the monitoring period. Nett change over the 40 year period was 

quite different for the two beaches, with Spreewalle having increased in area by 32,101 m 2 by the 

end of the period, while Langebaan beach had decreased in area by 179,322 m 2 . 


Relative Area (x 1 000 m 2 ) 

150 

100 

50 

0 

-50 

-100 

-150 

-200 

-250 


1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 

Figure 4.10. Change in relative beach area, in thousands of m 2 , since 1960 to 2000 in Paradise and 

Spreeuwal beaches, based on aerial photographs (Figure courtesy of J. Gericke 2008). 

His conclusion regarding these changes were as follows: 

The reason for the marked dip in the sediment area in 1977 is unexplained and could relate to 

the tide the day the picture was taken, which was not recorded, or transitory storm influence. 

The significant increase in sediment accumulation since 1977 to 1988 in Spreeuwal beach is 

attributed to the construction of the harbour wall between 1973 and 1976, and subsequent 

filling in of the wall with close to 250,000 m 2 of beach sand. After the construction, however, 

sediment has been trapped at Spreeuwal beach due to 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, however, the significant drop in sediment area of 

about 270,000 m 2 between 1988 and 2000 is, at least, partially related to sediment transport 

being cut off by the harbour wall. It would be expected that should the sands at Lentjiesklip 1, 2 

and 3 become depleted, Langebaan beach would lose sediment at a more rapid rate. 

In summary, 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 

northern corner of the beach, reducing the supply of sands to the beaches further south. He also 

pointed out that changes on the two beaches are at times out-of-sync from one another, with major 

accretion and erosion events on Langebaan beach lagging that at Spreeuwalle by as much as five 

years. These reasons advocated for this is that there are a number of beaches in between these two 

sites that act 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 


Year 

Langebaan Beach Spreeuwal Beach


(possibly linked to severe storm event in 2008), which poses a significant risk to houses in this area, 

does not bode well for what will happen to Langebaan beach in the future! 

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 little under 4 million m 2 in 2000. The reason behind the loss is alien 

vegetation encroachment by Port Jackson (Acacia saligna) and Rooikraans (Acacia cyclops). The 

consequences of this encroachment at Langebaan have not yet been studied, however. It is known 

though 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). 

4.3.3.2 Northern Langebaan beach erosion management measures 

In 1997 after severe storms resulted in the loss of property and houses 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 4.11), 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 the Department of Environmental Affairs and 

Tourism (DEAT) to contract Southern Oceaneering CC in 2003, to carry out a beach reclamation 

programme. This involved the deposition of large quantities of sand to extend the beach area. Two 

groynes were also constructed using sand filled bags, technically referred to as Geotextile Sand 

Containers (GSC’s), which were stacked in a linear formation for the construction of the groynes. 

Different sized bags (i.e. 2.5m³, 12m³ and 20m³) were filled with sand collected from two 

adjacent areas (Figure 4.12- 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 are 

then positioned with a crane in the water and with the assistance of a diver. The first 250 m groyne 

was completed in 2005 and the second 360m 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 4.12– Area C), and depositing sand north of the 2nd groyne up to the southern 

extent of Leentjiesklip No.1 (Figure 4.13). Approximately 380 000m³ of material was dredged until 

the end of the programme in November 2008. 



Figure 4.11. Rock revetments constructed along the beach at Langebaan in an effort to protect coastal 

infrastructure. 

Figure 4.12. 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. 



Prestedge Retief Dresner Wijnberg (PRDW) have been monitoring the state of the groynes 

and beach since dredging was completed in November 2008. Some structural damage became 

evident on the Northern Groyne (the second one constructed), with some of the bags suffering from 

wave damage (Anton Vonk, PRDW 2010 pers. comm.). These need to be repaired to ensure no 

further deterioration, and await budget from the municipality (Andrew McCarthy, PRDW 2011 pers. 

comm.). The southern end Groyne is reported to be working well and is retaining material. A 

bathymetric survey was conducted at the end of the project and a second bathymetric survey is 

pending. Once the necessary budget has been approved for the pending repair work and survey, a 

final report will be compiled which will mark the end of the monitoring period for this project 

(Andrew McCarthy, PRDW 2011 pers. comm.). 

Figure 4.13. State of the beach north of Groyne 2 in May 2010. Top: looking south from the middle of 

Leentjiesklip 1 beach towards the groyne, Middle: Looking north from the middle of the beach 

towards Leentjiesklip 1, Bottom: looking north towards Leentjieklip from the position where 

the sea still reaches right up to the rock revetment. 


4.3.3.3 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 4.14). 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 4.14. Coastal erosion at Paradise Beach near Clun 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 



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 begun during 2010 and is 

ongoing (J. Kotze – Langebaan Ratepayers Association, pers. comm. 2011). 

4.3.4 Shipping, ballast water discharges, and oil spills 

4.3.4.1 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 becomes 

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 4.1). 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 

1950’s 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 from ports of departure and discharged on arrival 

where new water can be taken on, depending on the cargo load. The conversion to ballast water set 

off a new wave of marine invasions, as species with a larval or planktonic phase in their life cycle 

where 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 nonindigenous 

species have the potential to establish themselves 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. in press). 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. 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 12 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 4.4). 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 § 5.6 for more on this) and in sediments in the Bay (see §127 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 

what side the ship is berthed (Figure 4.1). 

Table 4.4. 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). 

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 currently averages some 400 ships per year (Figure 4.15). As a result, the volume of ballast 

water discharged to the Bay has also increased by more than double since 2004, with close to 20 

million tons of ballast water being discharged each year (Figure 4.16). 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. 


Number and types of vessels entering 

Saldanha Port 

500 

450 

400 

350 

300 

250 

200 

150 

100 

50 

0 

Iron ore terminal 


Tanker vessels 

Other 

Total 


1994 

1995 

1996 

1997 

1998 

1999 

2000 

2001 

2002 

2003 

2004 

2005 

2006 

2007 

2008 

2009 

2010 

Figure 4.15. Number and types of vessels entering Saldanha Port from 1994-2010. (Sources: Marangoni 

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

Ballast water discharge in mt 

25,000,000 

20,000,000 

15,000,000 

10,000,000 

5,000,000 

0 

Iron ore terminal 


Tanker vessels 

Total 

1994 

1995 

1996 


Year 

1997 

1998 

1999 

2000 

2001 

2002 

Year 

2003 

2004 

2005 

2006 

2007 

2008 

2009 


Figure 4.16. Volumes of ballast water discharge in million tonnes by the different types of vessels entering 

Saldanha Port between 1994 and 2010. 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).


Associated with this increase in shipping traffic, is an increase in the incidence and risk of oil 

spills, the risk 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 

discharges to the Bay. Trace metals discharges thus probably pose possibly the greatest shippingassociated 

risk to the Bay at present. 

4.3.4.2 Oil spills 

In South Africa there have been a total of four mayor 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 

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). 

4.3.5 Reverse Osmosis Desalination Plant 

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 semipermeable 

membrane under high pressure, leaving the dissolved salts and other solutes behind on 

the surface of the membrane. Transnet have recently (within the last year) built 1 200m³/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 200m³/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 600m³/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 1200m³/day RO train, was awarded to VWS Envig in 2008. The installation of 

the plant commenced in 2010 and the plant was expected to be in operation in early 2011. 

4.3.5.1 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. Pretreatment 

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 Ml, for use (dust mitigation). 

The flocculant and non-oxidising biocide used during the pretreatment process as well as the 

antiscalant 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 comprises 6 boreholes located on the causeway, alongside the Multi-Purpose 

Terminal. The discharge pipeline is located at Caisson 3 and consists of a single port diffuser at -16 

to -18 m water depth. 


4.3.5.2 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: 

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 a 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. 

4.3.6 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: 

Ulva spp that thrive in high 

nutrient 

conditions 

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 

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 

O2/liter 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 µM 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 Gibbon 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 Jetty 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 (no longer in operation) 

Bongolethu Fishing Enterprises 

SA Lobster 

Cape Reef Products 

TNPA 

-Arcelor Mittal 

Namaqua Sands 

Abattoir 

Duferco 


o 

33 3’S 

o 

33 10’S 

Saldanha 

Bay 

0m 1500m 3000m 4500m 6000m 

o 

17 50’E 


Waste water treatment works 

Sewage pump stations 

Conservance tanks 

Bok River 


Oudepos 

Stofbergsfontein 

Club Mykonos 

Langebaan 

Langebaan 

Lagoon 

Oosterwal 


Figure 4.17. Location of waste water treatment works, sewage pump stations and conservancy 

tanks in Saldanha and Langebaan area 

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 Oosterwal, Stofbergsfontein and Oudepos (Figure 4.17). 

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 

Historically a number of these pump stations 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 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. Table 4 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. 

4.3.6.1 Water quality parameters associated with the Saldanha WWTW 

Trends over time for water quality parameters associated with effluent from the Saldanha 

WWTW are shown in Figure 4.18-Figure 4.19. Before 2005, the daily volume discharged never 

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. Numbers of faecal coliforms in the effluent from the WWTW exceeded allowable 

limits specified on 14 occasions since 2003 (15% of the time) (Figure 4.18). Allowable limits for Total 

Suspended Solids were exceeded on 12% of the occasions on which measurements were made, and 

measurements for Chemical Oxygen Demand (COD) exceeded allowable limits 28% of the time 

(Figure 4.18). Chemical Oxygen Demand is commonly used to indirectly measure the amount 

of organic compounds in water. 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. Nitrate Nitrogen limits were exceeded on 19% of the occasions (Figure 4.19). 

Table 4.5. 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 

GENERAL LIMIT FOR 

GENERAL AUTHORISATION 



(1956) UNDER THE NATIONAL 

WATER ACT (1998) 

Temperature 35oC - 

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 


Faecal coliforms (org/100 ml)) 

Flow (m 3 /day) 

Total Suspended Solids (mg/l) 

Chemical oxygen demand (mg/l) 

3000 

2500 

2000 

1500 

1000 

500 

0 

2500 

2000 

1500 

1000 

500 

0 

140 

120 

100 

80 

60 

40 

20 

0 

400 

350 

300 

250 

200 

150 

100 

50 

0 

Apr-03 

Apr-03 

Apr-03 

Apr-03 

Jul-03 

Jul-03 

Jul-03 

Jul-03 

Nov-03 

Nov-03 

Nov-03 

Nov-03 

Mar-04 

Mar-04 

Mar-04 

Mar-04 

Jul-04 

Jul-04 

Jul-04 

Jul-04 

Nov-04 

Nov-04 

Nov-04 

Nov-04 

Mar-05 

Mar-05 

Mar-05 

Mar-05 

Jul-05 

Jul-05 

Jul-05 

Jul-05 

Nov-05 

Nov-05 

Nov-05 

Nov-05 

Mar-06 

Mar-06 

Mar-06 

Mar-06 

Jul-06 

Jul-06 

Jul-06 

Jul-06 

Nov-06 

Nov-06 

Nov-06 

Nov-06 


Figure 4.18. Monthly trends in the volume of (a) effluent released from the Saldanha WWTW, Apr 2003- 

February 2011, and authorised total volume per year expressed as a daily limit (red line) (b) in 

the numbers of Faecal Coliforms, (c) and Total Suspended Solids, and (d) Chemical Oxygen 

Demand in effluent released from the Saldanha WWTW, April 2003-February 2011. Allowable 

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

graphs b-d are represented by the dotted red line. 


Mar-07 

Mar-07 

Mar-07 

Mar-07 

Jul-07 

Jul-07 

Jul-07 

Jul-07 

Nov-07 

Nov-07 

Nov-07 

Nov-07 

Mar-08 

Mar-08 

Mar-08 

Mar-08 

Jul-08 

Jul-08 

Jul-08 

Jul-08 

Oct-08 

Oct-08 

Oct-08 

Oct-08 

Feb-09 

Feb-09 

Feb-09 

Feb-09 

Jun-09 

Jun-09 

Jun-09 

Jun-09 

Oct-09 

Oct-09 

Oct-09 

Oct-09 

Feb-10 

Feb-10 

Feb-10 

Feb-10 

Jun-10 

Jun-10 

Jun-10 

Jun-10 

Oct-10 

Oct-10 

Oct-10 

Oct-10 

Feb-11 

Feb-11 

Feb-11 

Feb-11

Free ACtive Chlorine (mg/l) 

Amonia (mg/l as N) 

Nitrate (mg/l as N) 

Orthophosphorus (mg/l as P) 

70 

60 

50 

40 

30 

20 

10 

0 

60 

50 

40 

30 

20 

10 

0 

16 

14 

12 

10 

8 

6 

4 

2 

0 

5 

5 

4 

4 

3 

3 

2 

2 

1 

1 

0 

Apr-03 

Apr-03 

Apr-03 

Apr-03 

Jul-03 

Jul-03 

Jul-03 

Jul-03 

Nov-03 

Nov-03 

Nov-03 

Nov-03 

Mar-04 

Mar-04 

Mar-04 

Mar-04 

Jul-04 

Jul-04 

Jul-04 

Jul-04 

Nov-04 

Nov-04 

Nov-04 

Nov-04 

Mar-05 

Mar-05 

Mar-05 

Mar-05 

Jul-05 

Jul-05 

Jul-05 

Jul-05 

Nov-05 

Nov-05 

Nov-05 

Nov-05 

Mar-06 

Mar-06 

Mar-06 

Mar-06 

Jul-06 

Jul-06 

Jul-06 

Jul-06 

Nov-06 

Nov-06 

Nov-06 

Nov-06 


Figure 4.19. Monthly trends in water quality parameters (a) Chemical Oxygen Demand, (b) Ammonia 

Nitrogen, (c) Nitrate Ammonia, (d) Orthophosphate and (e) Free Active Chlorine for effluent 

released from the Saldanha WWTW Apr 2003-February 2011, and general limits specific under 

the National Water Act 36 of 1998 (red line on each graph). 


Mar-07 

Mar-07 

Mar-07 

Mar-07 

Jul-07 

Jul-07 

Jul-07 

Jul-07 

Nov-07 

Nov-07 

Nov-07 

Nov-07 

Mar-08 

Mar-08 

Mar-08 

Mar-08 

Jul-08 

Jul-08 

Jul-08 

Jul-08 

Oct-08 

Oct-08 

Oct-08 

Oct-08 

Feb-09 

Feb-09 

Feb-09 

Feb-09 

Jun-09 

Jun-09 

Jun-09 

Jun-09 

Oct-09 

Oct-09 

Oct-09 

Oct-09 

Feb-10 

Feb-10 

Feb-10 

Feb-10 

Jun-10 

Jun-10 

Jun-10 

Jun-10 

Oct-10 

Oct-10 

Oct-10 

Oct-10 

Feb-11 

Feb-11 

Feb-11 

Feb-11


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 below the allowable limit of 10mg/l (Figure 

20). 

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 Langebaan WWTW operates. The 

frequency of exeedence for this parameters since 2003 is 47.3% (i.e. nearly 50% of the readings are 

above the allowable limit). 

4.3.6.2 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 4.20-Figure 4.22). Faecal coliforms counts have exceeded 

the allowable limits specified on 4 occasions since 2009, which correspond to 19% of time (Figure 

4.21). Total Suspended Solids have only once exceeded the allowable limits, while measurements 

for Chemical Oxygen Demand exceeded allowable limits on 29% of the occasions (Figure 4.21). 

Flow (m 3 /day) 

7000 

6000 

5000 

4000 

3000 

2000 

1000 

0 

May-09 

Aug-09 

Dec-09 

Figure 4.20. Monthly trends in the volume of effluent discharged from the Langebaan WWTW in the period 

June 2009-February 2011, and allowable limits as specified in terms of a General Authorisation 

under the National Water Act 1998 (red line). 

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, while the levels of Ortho 

Phosphorus 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 limits (Figure 4.22). The levels of Nitrate 

Nitrogen have not exceeded allowable limits since measurements began in 2009, while levels of free 

active chlorine have exceeded allowable limits more than half (58%) of the time since monitoring 

commenced (Figure 4.21). 


Mar-10 

Jun-10 

Sep-10 

Jan-11

Faecal coliforms (org/100 ml) 

Chemical oxygen demand (mg/l) 

Total Suspended Solids (mg/l) 

1600 

1400 

1200 

1000 

800 

600 

400 

200 

0 

60 

50 

40 

30 

20 

10 

0 

180 

160 

140 

120 

100 

80 

60 

40 

20 

0 

May-09 

May-09 

May-09 

Aug-09 

Aug-09 

Aug-09 

Dec-09 

Dec-09 

Dec-09 


Figure 4.21. Monthly trends in (a) the numbers of Faecal Coliforms, (b) Total Suspended Solids, and (c) 

Chemical Oxygen Demand in effluent released To from the Langebaan WWTW, June 2009- 

February 2011. Allowable limits as specified in terms of a General Authorisation under the 

National Water Act 1998 are represented by the red line. 

4.3.6.3 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. Levels of chlorine in the 

effluent from both WWTWs is high, above the limits for a general authorisation around 50% of the 

time. 


Mar-10 

Mar-10 

Mar-10 

Jun-10 

Jun-10 

Jun-10 

Sep-10 

Sep-10 

Sep-10 

Jan-11 

Jan-11 

Jan-11

Amonia (mg/l as N) 

Nitrate(mg/l as N) 

Orthophosphorus (mg/l as P) 

Free Active Chlorine (mg/l) 

70 

60 

50 

40 

30 

20 

10 

0 

16 

14 

12 

10 

8 

6 

4 

2 

0 

16 

14 

12 

10 

8 

6 

4 

2 

0 

4 

3 

3 

2 

2 

1 

1 

0 

May-09 

May-09 

May-09 

May-09 

Aug-09 

Aug-09 

Aug-09 

Aug-09 

Dec-09 

Dec-09 

Dec-09 

Dec-09 


Figure 4.22. Monthly trends in the volume of Ammonia Nitrate, Ortho Phosphorus and Nitrate Nitrogen 

present in effluent from Langebaan WWTW, June 2009-February 2011. Allowable limits as 

specified in terms of a General Authorisation under the National Water Act 1998 (red line). 


Mar-10 

Mar-10 

Mar-10 

Mar-10 

Jun-10 

Jun-10 

Jun-10 

Jun-10 

Sep-10 

Sep-10 

Sep-10 

Sep-10 

Jan-11 

Jan-11 

Jan-11 

Jan-11

4.3.7 Storm water 


Storm water runoff, which occurs when rain flows over the impervious surfaces into 

waterways, is one of the major sources of non-point pollution in Saldanha (CSIR 2002). Sealed 

surfaces such as driveways, streets and pavements prevent rainwater from soaking into the ground 

and the runoff is typically directed 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 (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 can be divided into two categories, namely urban and rural runoff. 

Storm water runoff that could potentially impact the marine environment in Saldanha and 

Langebaan originates from the Saldanha Bay industrial area (36 ha), the Saldanha Bay residential 

area (398 ha), the Port of Saldanha and surrounding industrial sites (323 ha) and Langebaan to Club 

Mykonos (711 ha). 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 (Table 4.6 and Figure 4.23). 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. 



Figure 4.23. 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 Note that runoff from the Port of Saldanha and ore terminal have been excluded as runoff 

from this site is now reportedly all diverted to storm water evaporation ponds. Material 

settling in these ponds is trucked to a landfill site. 

Table 4.6. Monthly rainfall data (mm) for Saldanha Bay over the period 1895-1999 (source Visser et al. 

2007). 

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 

MAP = mean annual precipitation 

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 4.23). 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 4.7). 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 water quality guidelines for coastal and marine waters 

(marked in red). It is likely that introduction of contaminants via storm water runoff negatively 

impact the health of the marine environment, especially during the “first flush” period as winter 

rains arrive. 

Table 4.7. Typical concentrations of water quality constituents in storm water runoff (residential and 

Industrial) (from CSIR 2002) and South Africa 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** 

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. 

4.3.8 Fish processing plants 

Three fishing companies discharge wastewater into Saldanha Bay: Sea Harvest, SA Lobster 

Exporters (Marine Products), Live Fish Tanks (West Coast) – Lusithania (CSIR 2002). Southern Seas 

Fishing previously discharged wastewater into the Bay but closed its factories approximately 5 years 

ago. The locations of the fish factory intake and discharge points are shown in Figure 4.24. 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). 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). 


SA Lobster 

Live Fish Tanks 

Sea Harvest 

Current Mariculture Areas 

Proposed Mariculture Areas 

Blue Bay Aquafarm 


Figure 4.24. Location of seawater intakes and discharges for seafood processing in Saldanha Bay together 

with location of current and proposed mariculture operations 

Table 4.8. Characterisation of effluent from Sea Harvest and Southern Seas Fishing factories in 2001 and 

1996/7, respectively (Data from Entech 1996 In CSIR 2002). 

Sea Harvest Southern Sea 

Fishing 

Effluent volume (m 3 /month) 69 595 160 674 

Suspended solids(mg/l) 164 652 * 

Combustable solids (mg/l) 144 522 * 

Fat, Oil and grease(mg/l) 212 390 * 

SA WQ 

Guidelines 

Ammonia-N (mg/l) 164 137 0.020 mg/l 

KjeldahlNitrogen-N (mg/l) 83 317 

Phosphate-P (mg/l) 34 28 

Faecal coliform (CFU/100 ml) 751 - 

E. coli (CFU/100ml) 5 - † 

* 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 



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). Due to earlier uncertainties regarding the responsibilities of 

government departments, licenses under the National Water Act have not been issued to the 

seafood processing industries discharging effluent into Saldanha Bay (Ms W Kloppers, DWAF, pers. 

comm.). 

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 disposed of in the sea from 2004 to 2007 by Sea Harvest 

are shown in Figure 4.25. The volume of effluent disposed of to sea 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 kL. Regular monitoring of the volumes and quality of 

effluent produced has recently recommenced (2011, Paul Cloete, Environmental Officer, Sea Harvest 

Corporation (Pty) Ltd, pers. comm.). 

Volume of Effluent (kL) 

450000 

400000 

350000 

300000 

250000 

200000 

150000 

100000 

50000 

0 

2001 

2004 

2005 

2006 

2007 

Jan-01 

Feb-01 

Mar-01 

Apr-01 

May-01 

Jun-01 

Jul-01 

Aug-01 

Sep-01 

Oct-01 

Nov-01 

Dec-01 

May-04 

Jun-04 

Jul-04 

Aug-04 

Sep-04 

Nov-04 

Dec-04 

Jan-05 

Feb-05 

Mar-05 

Apr-05 

May-05 

Jun-05 

Jul-05 

Aug-05 

Sep-05 

Oct-05 

Nov-05 

Dec-05 

Jan-06 

Feb-06 

Mar-06 

Apr-06 

May-06 

Jun-06 

Jul-06 

Aug-06 

Sep-06 

Oct-06 

Nov-06 

Dec-06 

Jan-07 

Feb-07 

Mar-07 

Figure 4.25. Total monthly discharge of fresh fish processing effluent (FFP) disposed to sea by Sea Harvest 

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 000m 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). 

4.3.9 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 4.9 and Figure 4.26). 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 


Date


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. 

Blue Sapphire Pearls 

West Coast Oyster Growers 

West Coast Seaweeds 

± 0 0.5 1 2 km 

West Coast Aquaculture 

Blue Bay Aqua Farm 

Figure 4.26. Allocated mariculture concession areas in Saldanha Bay 2010 

Striker Fishing 

West Coast Seaweeds 

West Coast 

Oyster Growers 

The 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 4.27). There was a 

decrease in productivity by 54 tons between 2008 and 2009. In 2009 the mussel sub-sector (based 

in Saldanha Bay) was the second highest contributor to the overall mariculture productivity for the 

country (DAFF 2010). 



Table 4.9. Details of marine aquaculture rights issued in Saldanha Bay (source: DAFF pers. comm. 2011) 

Company 

Mussels 

Products 

Oysters 

Abalone 


Scallops 

Red Bait 

Seaweed 

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 

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 

A study was conducted between 1997 and 1998 which 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). 

Figure 4.27. Overall annual mussel productivity (tons) in Saldanha Bay between 2000 and 2009 (source: 

DAFF, 2010)

4.3.10 Development of a Liquid Petroleum Gas Facility in Saldanha Bay 


Sunrise Energy has proposed to build an import facility for Liquid Petroleum Gas (LPG) in 

Saldanha Bay to supplement current LPG refineries in the Western Cape and ensure that industries 

dependant on LPG can remain in operation. The LPG facility could also aid in replacing electricity in 

heating applications, supporting the diversification of energy sources in the automotive sector, 

reducing South Africa’s carbon footprint through replacement of coal, wood and fuel oil burning and 

replacing wood and cardboard burning for domestic heating in the Cape Flats. The information 

presented below is based upon the information contained in the Licence 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 involves: 

(i) An offshore marine component for the off-loading of LPG; 

(ii) Onshore storage facility comprising six (6m in diameter and 60m long) mild steel storage 

bullets lying horizontally alongside each other in a mounded (buried) storage area; 

(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. 

An Environmental Impact Assessment (EIA) process in terms of section 24 of the National 

Environmental Management Act (Act No 107 of 1998) (NEMA) has been initiated and is expected to 

be completed by July 2011. Three alternative marine off-loading options are being investigated in 

the EIA process, namely; jetty off-loading, single point mooring and a conventional buoy mooring 

(preferred option) (ERM 2010). None of the off-loading options will require dredging. Potential sites 

being considered for the off-loading facility are in the vicinity of the ore jetty in both Big Bay and 

Small Bay. The preferred site is to the east of the Ore Jetty in Big Bay. Potential impacts to the 

marine environment, being investigated through the EIA process, include changes in water quality, 

change in sediment dynamics, impacts to benthic fauna, visual and landscape impacts, noise, socioeconomic 

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. 


5 WATER QUALITY 


The temperature, salinity (salt content) and dissolved oxygen concentration 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. Long-term data series of these three variables exist for Saldanha Bay and these are 

discussed in some detail below. Other measurable physical and chemical variables such as nutrient 

levels (specifically dissolved nitrate – a limiting nutrient for phytoplankton growth), chlorophyll 

concentration (a measure of primary production), current strengths and circulation patterns have 

been reported on in various studies and the key findings or trends are also summarised in this 

chapter. 

5.1 Water temperature 

Water temperature records for Saldanha Bay and Langebaan Lagoon were first collected 

during 1974-75 as part of a detailed survey by the then Sea Fisheries Branch, Department of 

Industries (now Marine and Coastal Management, Department of Environmental Affairs and 

Tourism). The survey was initiated to collect baseline data of the physical and chemical water 

characteristics prior to the development of the Bay as an industrial port. The findings of this survey 

were published in a paper by Shannon and Stander (1977). Surface water temperatures prior to the 

construction of the iron ore/oil jetty and Marcus Island causeway varied from 16-18.5 ° C during 

summer (January 1975) and 14.5-16 ° C during winter (July 1975). During both periods, higher 

temperatures were measured in what is now the northern part of Small Bay and within Langebaan 

Lagoon, whilst cooler temperatures were measured at sampling stations in Outer Bay and Big Bay. 

The water column was found to be fairly uniform in temperature during winter and spring (i.e. 

temperature did not change dramatically with depth) and the absence of a thermocline (a clear 

boundary layer separating warm and cool water) was interpreted as evidence of wind driven vertical 

mixing of the shallow waters in the Bay. A clear shallow thermocline was observed at about 5 m 

depth, during the summer and autumn months at some deeper stations and was thought to be the 

result of warm lagoon water flowing over cooler sea water. The absence of a thermocline at other 

shallow sampling stations was once again considered evidence of strong wind driven vertical mixing. 

Shannon and Stander (1977) suggested that there was little interchange between the relatively sunwarmed 

Saldanha Bay water and the cooler coastal water through the mouth of the Bay, but rather 

a “slopping backwards and forwards tidal motion”. 

The Sea Fisheries Research Institute continued regular monitoring (quarterly) of water 

temperature (and other variables) in Saldanha Bay until October 1982. These data were presented 

and discussed in papers by Monteiro et al. (1990) and Monteiro and Brundrit (1990). The 

temperature time series for Small Bay and Big Bay is shown in Figure 5.1. This expanded data series 

allowed for a better understanding of the oceanography of Saldanha Bay. The temperature of the 

surface waters was observed to fluctuate seasonally with surface sun warming in summer and 

cooling in winter, whilst the temperature of deeper (10 m depth) water shows a smaller magnitude, 

non-seasonal variation, with summer and winter temperatures being similar (Figure 5.1). In most 

years, a strong thermocline separating the sun warmed surface layer from the cooler deeper water 

was present during the summer months at between 5-10 m depth. During the winter months, the 

thermocline breaks down due to surface cooling and increased turbulent mixing, and the water 

column becomes nearly isothermal (surface and deeper water similar in temperature) (Figure 5.1). 

Unusually warm, deeper water was observed during December 1974 and December 1976 and was 

attributed to the unusual influx of warm oceanic water during these months (Figure 5.1). 


Temperature (C) 

Temperature (C) 

22 

20 

18 

16 

14 

12 

10 

8 

22 

20 

18 

16 

14 

12 

10 

8 

Oct-79 

Jul-79 

Apr-79 

Jan-79 

Sep-78 

Jun-78 

Mar-78 

Dec-77 

Oct-77 

Aug-77 

Jun-77 

Mar-77 

Dec-76 

Sep-76 

Jun-76 

Mar-76 

Jan-76 

Oct-75 

Jul-75 

Apr-75 

Mar-75 

Feb-75 

Jan-75 

Dec-74 

Oct-74 

Sep-74 

Aug-74 

Jul-74 

May-74 

Apr-74 

Oct-79 

Jul-79 

Apr-79 

Jan-79 

Sep-78 

Jun-78 

Mar-78 

Dec-77 

Oct-77 

Aug-77 

Jun-77 

Mar-77 

Dec-76 

Sep-76 

Jun-76 

Mar-76 

Jan-76 

Oct-75 

Jul-75 

Apr-75 

Mar-75 

Feb-75 

Jan-75 

Dec-74 

Oct-74 

Sep-74 

Aug-74 

Jul-74 

May-74 

Apr-74 

1 m 10 m 

Big Bay water temperature 

1 m 10 m 

Small Bay water temperature 


Figure 5.1. Water temperature time series at the surface and at 10m depth for Big Bay and Small Bay, 

Saldanha Bay 

Warm oceanic water is typically more saline and nutrient-deficient than the cool upwelled 

water that usually occurs below the thermocline in Saldanha Bay. This was reflected in the high 

salinity (Figure 5.2), and low nitrate and chlorophyll concentration (a measure of phytoplankton 

production) measurements taken at the same time (Monteiro and Brundrit 1990). Monteiro et al. 

(1990) suggested that the construction of the Marcus Island causeway and the iron ore/oil jetty in 

1975 had physically impeded water movement into and out of Small Bay, thus increasing the 

residence time and leading to systematically increasing surface water temperatures when compared 

with Big Bay. There appears to be little support for this in the long-term temperature time series 

(Figure 5.1) and although the pre-construction data record is limited to only one year, Shannon and 


Oct-82 

Jul-82 

Apr-82 

Jan-82 

Oct-81 

Jul-81 

Apr-81 

Jan-81 

Apr 94 

Oct-82 

Jul-82 

Apr-82 

Jan-82 

Oct-81 

Jul-81 

Apr-81 

Jan-81 

Feb 97 

Feb-00 

Jan-00 

Dec-99 

Nov-99 

Oct-99 

Sep-99 

Aug-99 

Jul-99 

Jun-99 

May-99 

Apr-99 

Mar-99 

Apr 94 

Feb 97


Stander (1977) show Small Bay surface water being 2 ° C warmer than that in Big Bay during summer, 

prior to any harbour development. It is likely that the predominant southerly winds during summer 

concentrate sun warmed surface water in Small Bay, whilst much of the warm surface layer is driven 

out of Big Bay into the outer Bay by these same winds. 

More detailed continuous monitoring of temperature throughout the water column at 

various sites in Outer Bay, Small Bay and Big Bay during a two week period in February-March 1997, 

also allowed better understanding of the mechanisms causing the observed differences in the 

temperature layering of the water column. The summer thermocline is not a long-term feature, but 

has a 6-8 day cycle. Cold water, being denser than warmer water, will flow into Saldanha Bay from 

the adjacent coast when wind driven upwelling brings this cold water near to the surface. The 

inflow of cold, upwelled water into the Bay results in a thermocline, which is then broken down 

when the cooler bottom water flows out the Bay again. This density driven exchange flow between 

Saldanha Bay and coastal waters is estimated to be capable of flushing the bay within 6-8 days, 

substantially less than the approximately 20 day flushing time calculated based on tidal exchange 

alone by Shannon and Stander (1977). The influx of nutrient rich upwelled water into Saldanha Bay 

is critical in sustaining primary productivity within the Bay, with implications for human activities 

such as fishing and mariculture. The fact that the thermocline is seldom shallower than 5 m depth 

means that the shallower parts of Saldanha Bay, particularly Langebaan Lagoon, are not exposed to 

the nutrient (mainly nitrate) import from the Benguela upwelling system. As a result these shallow 

water areas do not support large plankton blooms and are usually clear. 

The most recent monitoring of water temperature in Saldanha Bay was conducted by the 

CSIR (Monteiro et al. 2000) over the period March 1999-February 2000. This was the most intensive 

long-term temperature record to date, with continuous measurements (every 30 minutes) taken at 1 

m depth intervals over the 11 m depth range of the water column where the monitoring station was 

situated in Small Bay. The average monthly temperature at the surface (1m) and bottom (10 m) for 

this period is shown in Figure 5.1. These data confirmed the pattern evident in earlier data, showing 

a stratified (layered) water column for spring-summer caused by wind driven upwelling, with the 

water column being more or less isothermal (of equal temperatures) during the winter (Figure 5.1). 

The continuous monitoring of temperature also identified a 3 week break in the usual upwelling 

cycle during December 1999, with a consequent gradual warming of the bottom water. Once again, 

this “warm water” event (although the water column remained stratified indicating that the 

magnitude of this event was not as great as those observed during December 1974 and 1976 events) 

was associated with a decrease in phytoplankton production (due to reduced import of nitrate) 

which, in turn, impacted negatively on local mussel mariculture yields (Monteiro et al. 2000). 

5.2 Salinity 

The salinity data time series covers much of the same period as that for water temperature 

and salinity data was extracted from the studies of Shannon and Stander (1977), Monteiro and 

Brundrit 1990, Monteiro et al. (1990) and Monteiro et al. (2000) (Figure 5.2). There was little 

variation in the salinity with depth in the water column and the values recorded at 10 m depth are 

presented in Figure 5.2. Under summer conditions when the water column is stratified, surface 

salinities may be slightly elevated due to evaporation and therefore salinity measurements from the 

deeper water more accurately reflect those of the source water. Salinities of the inshore waters 

along the west coast typically vary between 34.6-34.9 parts-per-thousand (ppt), or grams of salt per 

kilogram of sea water) (Shannon 1966), and the salinity values recorded for Saldanha Bay usually fall 

within this range. During summer months when wind driven coastal upwelling within the Benguela 

region brings cooler South Atlantic Central Water to the surface, salinities are usually lower than 



during the winter months when the upwelling front breaks down and South Atlantic surface waters 

move against the coast (warm surface waters are more saline due to evaporation). 

Salinity (PSU) 

35.3 

35.2 

35.1 

35 

34.9 

34.8 

34.7 

34.6 

34.5 

Oct-79 

Jul-79 

Apr-79 

Jan-79 

Sep-78 

Jun-78 

Mar-78 

Dec-77 

Oct-77 

Aug-77 

Jun-77 

Mar-77 

Dec-76 

Sep-76 

Jun-76 

Mar-76 

Jan-76 

Oct-75 

Jul-75 

Apr-75 

Mar-75 

Feb-75 

Jan-75 

Dec-74 

Oct-74 

Sep-74 

Aug-74 

Jul-74 

May-74 

Apr-74 

Figure 5.2. Time series of salinity records for Saldanha Bay 

The salinity time series shows salinity peaks in December 1974 and 1976 which reflects the 

warm water inflows that occurred at this time (Figure 5.2). Higher than normal salinity values were 

also recorded in August 1977 and July 1979 and although this was not reflected in the temperature 

time series (probably due to rapid heat loss and mixing during winter), the salinity peaks do indicate 

periodic inflows of surface oceanic water into Saldanha Bay. 

Oceanic surface waters tend to be low in nutrients and therefore limit primary production 

(phytoplankton growth). These oceanic water intrusions into Saldanha Bay, that were identified 

from the temperature and salinity measurements, corresponded to low levels of nitrate and 

chlorophyll concentrations measured at the same time as salinity and temperature peaks (Monteiro 

and Brundrit 1990) (Figure 5.3). This highlights the impacts of the changes in physical oceanography 

(water temperature and salinity) in the immediate area on the biological processes (nitrate and 

chlorophyll) occurring within Saldanha Bay (Monteiro and Brundrit 1990). Data concerning these 

parameters cover a short period only (1974-1979) and as such are little use in examining effects of 

human development on the Bay. 

5.3 Dissolved oxygen 

Sufficient dissolved oxygen in sea water is essential for the survival of nearly all marine 

organisms. Low oxygen (or anoxic conditions) can be caused by excessive discharge of organic 

effluents (for example, from fish factory waste or municipal sewage) and microbial breakdown of 

this excessive organic matter depletes the oxygen in the water. The well known “black tides” and 

associated mass mortality of numerous marine species, which occasionally occur along the west 


Oct-82 

Jul-82 

Apr-82 

Jan-82 

Oct-81 

Jul-81 

Apr-81 

Jan-81 

Apr 94 

Feb-00 

Jan-00 

Dec-99 

Nov-99 

Oct-99 

Sep-99


coast, result from the decay of large plankton blooms under calm conditions. Once all the oxygen in 

the water is depleted, anaerobic bacteria (not requiring oxygen) continue the decay process, causing 

the characteristic sulphurous smell. Apparent oxygen utilization (AOU - a measure of the potential 

available oxygen in the water that has been used by biological processes) values for Small and Big 

Bay over the period April 1974 - October 1982 and July 1988 are given in Monteiro et al. (1990). 

AOU is defined as the difference between the saturated oxygen concentration (the highest oxygen 

concentration that could occur at a given water temperature e.g. 5 ml/l) and the measured value 

(e.g. 1 ml/l) – hence positive AOU (5 ml/l – 1 ml/l = 4 ml/l) values indicate an oxygen deficit 

(indicated in red in Figure 5.4). More recent data on oxygen concentration in Small Bay (covering 

the period September 1999-February 2000) were provided by Monteiro et al. (2000). During this 

study, oxygen concentration at 10 m depth was recorded hourly by an instrument moored in Small 

Bay, these values were converted to AOU and the monthly average plotted in Figure 5.3. 

Chlorophyll concentration (ug/l ) 

Nitrate concentration ( uM ) 

34 

32 

30 

28 

26 

24 

22 

20 

18 

16 

14 

12 

10 

8 

6 

4 

2 

0 

34 

32 

30 

28 

26 

24 

22 

20 

18 

16 

14 

12 

10 

8 

6 

4 

2 

0 

Apr-74 

Aug-74 

Jun-74 

Oct-74 

Oct-74 

Aug-74 

Jun-74 

Apr-74 

Feb-75 

Dec-74 

Feb-75 

Dec-74 

Apr-75 

Jun-75 

Jun-75 

Apr-75 

Oct-75 

Aug-75 

Dec-75 

Feb-76 

Dec-75 

Oct-75 

Aug-75 

Apr-76 

Feb-76 

Jun-76 

Apr-76 

Aug-76 

Jun-76 

Oct-76 

Aug-76 

Oct-76 

Feb-77 

Dec-76 

Feb-77 

Dec-76 


Apr-77 

Jun-77 

Oct-77 

Aug-77 

Jun-77 

Apr-77 

Aug-77 

Feb-78 

Dec-77 

Dec-77 

Oct-77 

Jun-78 

Apr-78 

Apr-78 

Feb-78 

Aug-78 

Jun-78 

Feb-79 

Dec-78 

Oct-78 

Aug-78 

Oct-78 

Jun-79 

Apr-79 

Feb-79 

Dec-78 

Apr-79 

Oct-79 

Aug-79 

Figure 5.3. Time series of chlorophyll and nitrate concentration measurements for Saldanha Bay.

AOU (ml/l) 

AOU (ml/l) 

5 

4 

3 

2 

1 

0 

-1 

-2 

-3 

-4 

2 

1.5 

1 

0.5 

0 

-0.5 

-1 

-1.5 

-2 

-2.5 

-3 

-3.5 

Increasing 

oxygen deficit 

Oct-79 

Jul-79 

Apr-79 

Jan-79 

Sep-78 

Jun-78 

Mar-78 

Dec-77 

Oct-77 

Aug-77 

Jun-77 

Mar-77 

Dec-76 

Sep-76 

Jun-76 

Mar-76 

Jan-76 

Oct-75 

Jul-75 

Apr-75 

Mar-75 

Feb-75 

Jan-75 

Dec-74 

Oct-74 

Sep-74 

Aug-74 

Jul-74 

May-74 

Apr-74 

Oct-79 

Jul-79 

Apr-79 

Jan-79 

Sep-78 

Jun-78 

Mar-78 

Dec-77 

Oct-77 

Aug-77 

Jun-77 

Mar-77 

Dec-76 

Sep-76 

Jun-76 

Mar-76 

Jan-76 

Oct-75 

Jul-75 

Apr-75 

Mar-75 

Feb-75 

Jan-75 

Dec-74 

Oct-74 

Sep-74 

Aug-74 

Jul-74 

May- 

Apr-74 




Figure 5.4. Apparent oxygen utilization (AOU) time series Small Bay and Big Bay, Saldanha Bay. (Note: 

Positive values in red indicate an oxygen deficit). 

There is no clear trend evident in the AOU time series, low oxygen concentrations (high AOU 

values) occur during both winter and summer months (Figure 5.4). Small Bay does experience a 

fairly regular oxygen deficit during the winter months, whilst Big Bay experiences less frequent and 

lower magnitude oxygen deficits. Monteiro et al. (1990) attributed the oxygen deficit in Small Bay 

largely to anthropogenic causes, namely reduced flushing rates (due to the causeway and ore jetty 

construction) and discharges of organic rich effluents. The most recent data (September 1999- 

February 2000) indicate a persistent and increasing oxygen deficit as summer progresses (Figure 

5.4). It is clear that oxygen levels within Small Bay are very low during the late summer months, 


Oct-82 

Jul-82 

Apr-82 

Jan-82 

Oct-81 

Jul-81 

Apr-81 

Jan-81 

Oct-82 

Jul-82 

Apr-82 

Jan-82 

Oct-81 

Jul-81 

Apr-81 

Jan-81 

Jul 88 

Feb-00 

Jan-00 

Dec-99 

Nov-99 

Oct-99 

Sep-99 

Jul 88


likely as a result of naturally occurring conditions, however, the ecological functioning of the system 

could be further compromised by organic pollutants entering the Bay. There is evidence of anoxia in 

localised areas of Small Bay (e.g. under the mussel rafts, within the yacht basin) that is caused by 

excessive organic inputs. Monteiro et al. (1997) identified the effluent from a pelagic fish processing 

factory as the source of nitrogen that resulted in an Ulva seaweed bloom in Small Bay. 

5.4 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 5.5A). 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 5.5A). 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 5.5A). 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. 

The currents and circulation of Saldanha Bay subsequent to the construction of the Marcus 

Island causeway and the iron ore/oil jetty 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 jetty (Figure 5.5B). 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 jetty 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. 


) 

A 

) 


Figure 5.5. 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 jetty (Present). (Adapted from Shannon and Stander 1977 and Weeks et al. 1991a) 


B


Construction of the iron ore jetty 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 5.5A). The iron ore jetty 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). 

5.5 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 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). Target limits, based on the faecal coliform count, for 

recreational water use, are provided in the Water Quality Guidelines for Use in South African Coastal 

Marine Waters (Department of Water Affairs and Forestry 1995a, b) and are indicated below (Table 

5.1). 

Table 5.1. Maximum acceptable count of faecal coliforms (per 100 ml sample) for mariculture and 

recreational use 

Purpose/Use Guideline value 

Mariculture 20 faecal coliforms in 80 % of samples 

60 faecal coliforms in 95% of samples 

Recreational 100 faecal coliforms in 80 % of samples 

(full water contact) 2 000 faecal coliforms in 95% of samples 

In 1998 the council for Scientific and Industrial research (CSIR) were contracted by the 

Saldanha Bay Water Quality Forum Trust 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). 

Regular monitoring of microbiological indicators within Saldanha Bay has continued to the 

present day, now undertaken by the SBWQFT, and the available data now covers the period 

February 1999 to December 2010 for 18 stations (10 in Small Bay, 4 in Big Bay and 4 in Langebaan 

Lagoon). This updated data set is summarized in this report to assess and highlight changes in faecal 



pollution within Saldanha Bay over the past 12 years. Data during this period has, for the most part, 

been collected on a bimonthly basis (twice per month) since 1999 at 14 stations within Small and Big 

Bay in Saldanha, with the exception of Station 11 (Seafarm - TNPA) where no data was collected 

during 2003-2004 and 2008 (Table 5.2 – Table 5.9, and Figure 5.6 - Figure 5.9). At three stations 

within Big Bay regular data collection only started in 2001. 

In general the data from the microbial monitoring programme suggest that nearshore 

coastal waters in Saldanha Bay can be classed as fair, with some sites coming out as good but an 

equal number of sites coming out as poor. Levels of E. coli and faecal coliforms were similar for 

most sites. Only four sites in the Bay (all in Small Bay) did not meet the 80% guideline limit for 

recreational use in 2010, while only one site (Site 8 opposite the municipal caravan park in Small 

Bay) did not meet the 95% guideline limit for faecal coliforms. (All sites with compliant with the 95% 

limit for E. coli). The most contaminated site in 2010 was the site in front of the Hoedjiesbaai Hotel 

(Site 7) which exceeds the 80% guideline limit by 16 and 30%, respectively in 2010. Overall levels of 

compliance are similar to that observed in 2009 but not as good as results achieved in 2006 and 

2007. 

As far as the guideline limits for mariculture are concerned, which are much stricter than 

those are recreational use, levels of compliance were predictably much lower than for the 

recreational guidelines. A total of 11 sites (out of a total of 17) were not compliant in respect of the 

80% limits for E. coli, while 9 were not compliant in respect of the 95% limits in 2010. Many of the 

non-compliant sites exceeded the limit by quite a large margin (up to 71 over in the case of the 80% 

limit and up to 40% in the case of the 95% limit). The worst sites were all located in Small Bay (Sites 

5-9, Hoedjiesbaai to the Bok River mouth). The problem was not as bad in respect of faecal coliform 

counts, with 5 and only 1 out of 17 sites registering non-compliance in 2010 for the 80 and 95% 

limits, respectively. Sites showing the highest exeedence were also all in Small Bay (Hoedjiesbaai 

and Bluewater Bay). Overall levels of compliance are similar to that observed in previous years. 

Time series plots and linear regression analysis of the faecal coliform and E. coli counts were 

carried out for selected sites within Small Bay (Figure 5.6 and Figure 5.7), Big Bay (Figure 5.8) and 

Langebaan (Figure 5.9). Most stations within Small Bay show a statistically significant decrease, in 

faecal coliform and E. coli concentrations, over the last ten years. Stations 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 5.6 and Figure 5.7). Overall health rankings for small bay have not changed since 2009, 

with the exception of Hoedjies Bay which ranks Poor with no trend either way. 

Time series plots for the four most frequently sampled sites in Big Bay are shown in Figure 

5.8. 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 two of the sites, Seafarm at TNPA 

and Paradise Beach. No significant trend was recorded at Mykonos Harbour and overall health 

ranking remains good. Station 16 (Leentjiesklip) shows a significant improvement over the past 10 

years, although there are sampling gaps in the data, and its overall health ranking is that of Fair 

tending to Good. 

Langebaan North shows no significant change over time with its overall health remains Good 

(Figure 5.9). Langebaan main beach, however, shows significant improvement over time, with 

overall health ranking going from Fair to Good. This year we have included sampling records at 

Langebaan Yacht club that show significant improvement in water quality since sampling began in 

2005, although the 80 th percentile for mariculture is still regularly exceeded. The overall health 

ranking for this site is Fair tending to Good. The trend at the remaining sites in Langebaan Lagoon 

indicated conditions are improving over time, which is encouraging. 



Table 5.2. Percentage of samples in which the concentration of E. coli was above the 80 th percentile limit specified in South African Water Quality Guidelines for 

recreational use (100 organisms/ml) for 10 sites in Small Bay, 4 sites in Big Bay and 4 sites in Langebaan Lagoon. Blue shading indicates compliance with 

regulations, while pink shading indicates non-compliance. Dashes (-) with no shading indicate that no samples were collected in that year. (Source: 

Saldanha Bay Water Quality Forum Trust). 

Year 

1. Beach at mussel rafts 

2. Small Craft Harbour 

3. Small Quay - Sea Harvest 

4. Saldanha Yacht Club 

5. Pepper Bay - Big Quay 

Small Bay Big Bay Langebaan 

6. Pepper Bay- "Cape Reef" 

7. Hoedjies Bay Hotel - Beach 

8. Beach at caravan park 

9. Beach - Bok River Mouth 

1999 25% 10% 27% 57% 43% 32% 32% 9% 39% 0% 0% 0% 10% - 0% - - - 

2000 0% 0% 20% 20% 20% 0% 0% 0% 20% 0% 0% 0% 0% - 0% - - - 

2001 0% 9% 17% 59% 63% 40% 41% 27% 69% 0% 0% 0% 0% 29% 33% 38% - - 

2002 14% 0% 19% 50% 27% 13% 32% 22% 54% 0% 0% 0% 20% - 8% 18% - - 

2003 0% 0% 29% 32% 53% 19% 24% 7% 71% 0% - 0% 20% - 11% 7% - - 

2004 0% 14% 18% 63% 30% 14% 27% 23% 52% 0% - 0% 0% - 17% 8% 25% 0% 

2005 0% 33% 11% 33% 24% 10% 38% 20% 37% 33% 33% 0% 0% 0% 0% 0% 20% 0% 

2006 0% 0% 14% 9% 25% 8% 19% 13% 8% 0% 0% 0% 17% 0% 0% 0% 17% 0% 

2007 0% 0% 0% 0% 8% 11% 29% 18% 17% 0% 0% 0% 20% 0% 0% 0% 13% 13% 

2008 0% 0% 0% 0% 10% 17% 7% 27% 21% 0% - 0% 0% 0% 0% 0% 0% 0% 

2009 0% 0% 21% 0% 8% 10% 33% 20% 43% 0% 0% 0% 15% 15% 0% 7% 7% 11% 

2010 0% 0% 0% 0% 9% 26% 36% 32% 25% 0% - 0% 17% 0% 0% 0% 11% 0% 


10. General Cargo Quay - TNPA 

11. Seafarm - TNPA 

12. Mykonos - Paradise Beach 

13. Mykonos - harbour 

16. Leentjiesklip 

14. Langebaan North - Leentjiesklip 

15. Langebaan Main Beach 

17. Langebaan Yacht Club 

18. Tooth Rock



recreational use (2 000 organisms/ml) for 10 sites in Small Bay, 4 sites in Big Bay and 4 sites in Langebaan Lagoon. Blue shading indicates compliance with 



Year 










1999 0% 0% 0% 5% 0% 5% 0% 0% 0% 0% 0% 0% 0% - 0% - - - 

2000 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% - 0% - - - 

2001 0% 0% 0% 12% 31% 7% 12% 0% 13% 0% 0% 0% 0% 0% 0% 0% - - 

2002 0% 0% 0% 0% 0% 0% 4% 11% 15% 0% 0% 0% 0% - 0% 5% - - 

2003 0% 0% 0% 0% 0% 0% 0% 0% 0% - 0% 0% 0% - 0% - - - 

2004 0% 0% 0% 5% 5% 0% 0% 8% 0% 0% - 0% 0% - 0% 0% 0% 0% 

2005 0% 0% 0% 0% 6% 0% 0% 10% 5% 0% 0% 0% 0% 0% 0% 0% 0% 0% 

2006 0% 0% 0% 0% 17% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 

2007 0% 0% 0% 0% 0% 0% 6% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 

2008 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% - 0% 0% 0% 0% 0% 0% 0% 

2009 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 

2010 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% - 0% 0% 0% 0% 0% 0% 0% 










18. Tooth Rock


Table 5.4. Percentage of samples in which the concentration of Faecal coliforms were above the 80 th percentile limit specified in South African Water Quality 

Guidelines for recreational use (100 organisms/ml) for 10 sites in Small Bay, 4 sites in Big Bay and 4 sites in Langebaan Lagoon. Blue shading indicates 

compliance with regulations, while pink shading indicates non-compliance. Dashes (-) with no shading indicate that no samples were collected in that 

year. (Source: Saldanha Bay Water Quality Forum Trust). 

Year 











1999 32% 23% 64% 68% 77% 64% 55% 23% 48% 0% 0% 0% 9% - 0% - - - 

2000 0% 0% 20% 40% 40% 20% 20% 0% 40% 0% 0% 0% 0% - 0% - - - 

2001 0% 9% 17% 65% 63% 47% 41% 27% 69% 0% 0% 0% 0% 29% 33% 38% - - 

2002 14% 0% 19% 50% 32% 13% 32% 22% 54% 0% 0% 0% 20% - 8% 18% - - 

2003 0% 0% 25% 37% 53% 19% 24% 7% 71% 0% - 0% 20% - 11% 7% - - 

2004 0% 13% 18% 68% 38% 21% 27% 23% 57% 0% - 0% 0% 0% 17% 8% 25% 0% 

2005 0% 33% 11% 33% 24% 10% 38% 20% 42% 33% 33% 0% 0% 0% 0% 0% 20% 0% 

2006 0% 0% 14% 9% 31% 8% 19% 14% 8% 0% 0% 0% 17% 0% 0% 0% 20% 0% 

2007 0% 0% 0% 0% 8% 11% 29% 18% 17% 0% 0% 0% 20% 0% 0% 0% 13% 13% 

2008 0% 0% 0% 0% 20% 17% 13% 25% 37% 0% - 0% 0% 0% 0% 0% 0% 11% 

2009 0% 13% 19% 0% 7% 8% 44% 19% 50% 0% 0% 0% 14% 31% 22% 7% 19% 10% 

2010 33% 0% 0% 0% 8% 32% 50% 37% 24% 0% - 0% 10% 0% 0% 0% 18% 0% 










18. Tooth Rock



Guidelines for recreational use (2 000 organisms/ml) for 10 sites in Small Bay, 4 sites in Big Bay and 4 sites in Langebaan Lagoon. Blue shading indicates 



Year 











1999 0% 0% 9% 9% 14% 14% 5% 5% 9% 0% 0% 0% 5% - 0% - - - 

2000 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% - 0% - - - 

2001 0% 0% 0% 18% 31% 7% 12% 0% 13% 0% 0% 0% 0% 0% 0% 0% - - 

2002 0% 0% 0% 0% 0% 0% 4% 11% 15% 0% 0% 0% 0% - 0% 5% - - 

2003 0% 0% 0% 0% 0% 0% 0% 0% 10% 0% - 0% 0% - 0% 0% - - 

2004 0% 0% 0% 5% 5% 0% 0% 8% 0% 0% - 0% 0% 0% 0% 0% 0% 0% 

2005 0% 0% 0% 0% 6% 0% 0% 10% 5% 0% 0% 0% 0% 0% 0% 0% 0% 0% 

2006 0% 0% 0% 0% 15% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 

2007 0% 0% 0% 0% 0% 0% 6% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 

2008 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% - 0% 0% 0% 0% 0% 0% 0% 

2009 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 

2010 0% 0% 0% 0% 0% 0% 0% 5% 0% 0% - 0% 0% 0% 0% 0% 0% 0% 










18. Tooth Rock



mariculture use (20 organisms/ml) for 10 sites in Small Bay, 4 sites in Big Bay and 4 sites in Langebaan Lagoon. Blue shading indicates compliance with 



Year 











1999 38% 29% 68% 71% 76% 79% 73% 18% 74% 0% 0% 0% 10% - 13% - - - 

2000 0% 0% 40% 60% 40% 25% 80% 0% 60% 0% 50% 0% 0% - 0% - - - 

2001 0% 27% 33% 76% 94% 93% 76% 67% 94% 20% 33% 0% 0% 71% 50% 62% - - 

2002 14% 27% 62% 65% 77% 50% 84% 50% 88% 33% 0% 100% 50% - 42% 68% - - 

2003 33% 36% 64% 74% 84% 44% 76% 47% 90% 0% - 0% 20% - 33% 27% - - 

2004 0% 57% 41% 79% 70% 64% 68% 62% 91% 0% - 20% 40% - 67% 38% 50% 50% 

2005 0% 33% 44% 60% 59% 50% 77% 70% 84% 33% 67% 57% 0% 0% 33% 38% 40% 33% 

2006 0% 33% 43% 18% 50% 17% 50% 25% 75% 33% 50% 50% 67% 0% 0% 20% 33% 20% 

2007 20% 0% 27% 42% 54% 44% 47% 55% 83% 33% 33% 0% 30% 100% 14% 44% 50% 25% 

2008 0% 0% 0% 40% 50% 50% 53% 64% 58% 0% - 0% 33% 0% 17% 14% 50% 33% 

2009 20% 67% 43% 20% 38% 30% 61% 60% 62% 50% 0% 29% 46% 46% 0% 27% 21% 22% 

2010 50% 25% 13% 0% 64% 53% 91% 63% 63% 0% - 33% 17% 20% 0% 18% 22% 33% 










18. Tooth Rock



mariculture use (60 organisms/ml) for 10 sites in Small Bay, 4 sites in Big Bay and 4 sites in Langebaan Lagoon. Blue shading indicates compliance with 



Year 











1999 25% 14% 50% 62% 52% 47% 45% 18% 52% 0% 0% 0% 10% - 6% - - - 

2000 0% 0% 20% 20% 20% 0% 0% 0% 40% 0% 0% 0% 0% - 0% - - - 

2001 0% 9% 25% 65% 69% 67% 41% 27% 75% 0% 0% 0% 0% 57% 50% 46% - - 

2002 14% 0% 33% 60% 45% 19% 40% 33% 69% 0% 0% 0% 30% - 17% 41% - - 

2003 0% 9% 50% 42% 79% 31% 38% 27% 76% 0% - 0% 20% - 11% 20% - - 

2004 0% 14% 35% 68% 55% 50% 32% 31% 65% 0% - 0% 20% - 33% 23% 25% 0% 

2005 0% 33% 11% 47% 29% 30% 46% 50% 53% 33% 33% 14% 0% 0% 0% 13% 20% 0% 

2006 0% 0% 14% 9% 42% 8% 25% 25% 33% 0% 50% 0% 33% 0% 0% 0% 17% 0% 

2007 20% 0% 9% 0% 15% 22% 29% 18% 50% 0% 0% 0% 20% 0% 0% 11% 13% 13% 

2008 0% 0% 0% 20% 20% 17% 13% 45% 26% 0% - 0% 0% 0% 0% 0% 0% 0% 

2009 0% 17% 21% 20% 8% 20% 44% 47% 52% 50% 0% 0% 15% 31% 0% 13% 7% 11% 

2010 0% 0% 0% 0% 18% 32% 55% 37% 25% 0% - 0% 17% 10% 0% 0% 11% 17% 










18. Tooth Rock



Guidelines for mariculture use (20 organisms/ml) for 10 sites in Small Bay, 4 sites in Big Bay and 4 sites in Langebaan Lagoon. Blue shading indicates 



Year 











1999 0% 0% 60% 100% 80% 80% 80% 40% 100% 0% 25% 0% 20% - 0% - - - 

2000 0% 27% 33% 76% 94% 93% 76% 73% 94% 20% 33% 0% 0% 71% 50% 62% - - 

2001 14% 27% 67% 75% 86% 56% 84% 56% 88% 25% 0% 100% 50% - 42% 68% - - 

2002 33% 36% 56% 74% 84% 50% 76% 47% 90% 0% - 0% 20% - 33% 27% - - 

2003 0% 50% 47% 79% 67% 64% 73% 62% 91% 0% - 20% 40% 0% 67% 38% 50% 50% 

2004 0% 33% 44% 60% 59% 60% 77% 70% 84% 33% 67% 57% 0% 0% 33% 38% 40% 33% 

2005 0% 33% 43% 18% 54% 25% 50% 29% 67% 25% 50% 50% 67% 0% 0% 18% 40% 20% 

2006 20% 0% 27% 42% 54% 44% 47% 55% 83% 33% 33% 0% 30% 100% 14% 40% 50% 25% 

2007 0% 33% 17% 40% 50% 50% 53% 58% 74% 50% - 0% 43% 0% 14% 14% 50% 44% 

2008 17% 50% 38% 31% 33% 33% 72% 69% 64% 33% 0% 20% 43% 46% 22% 27% 38% 20% 

2009 67% 25% 10% 0% 58% 53% 91% 68% 76% 0% - 33% 20% 20% 0% 15% 36% 33% 

2010 33% 0% 0% 0% 8% 32% 50% 37% 24% 0% - 0% 10% 0% 0% 0% 18% 0% 










18. Tooth Rock



Guidelines for mariculture use (60 organisms/ml) for 10 sites in Small Bay, 4 sites in Big Bay and 4 sites in Langebaan Lagoon. Blue shading indicates 



Year 











1999 0% 0% 20% 60% 40% 20% 60% 0% 40% 0% 0% 0% 0% - 0% - - - 

2000 0% 9% 25% 71% 75% 73% 41% 27% 75% 0% 0% 0% 0% 57% 50% 46% - - 

2001 14% 0% 33% 65% 45% 19% 40% 33% 73% 0% 0% 0% 30% - 25% 45% - - 

2002 0% 9% 44% 53% 79% 31% 43% 27% 76% 0% - 0% 20% - 11% 20% - - 

2003 0% 13% 35% 68% 52% 50% 32% 31% 65% 0% - 0% 20% 0% 33% 23% 25% 0% 

2004 0% 33% 11% 47% 29% 30% 54% 50% 58% 33% 33% 14% 0% 0% 0% 13% 20% 0% 

2005 0% 0% 14% 9% 46% 8% 25% 29% 25% 0% 50% 0% 33% 0% 0% 0% 20% 0% 

2006 20% 0% 9% 0% 15% 22% 35% 18% 50% 0% 0% 0% 20% 0% 0% 10% 13% 13% 

2007 0% 0% 0% 20% 20% 17% 20% 42% 42% 50% - 0% 0% 0% 0% 0% 0% 11% 

2008 0% 25% 19% 15% 7% 17% 50% 56% 55% 33% 0% 0% 21% 38% 22% 13% 19% 10% 

2009 33% 25% 0% 0% 25% 47% 73% 42% 29% 0% - 0% 10% 10% 0% 0% 18% 17% 

2010 0% 0% 0% 0% 0% 0% 0% 5% 0% 0% - 0% 0% 0% 0% 0% 0% 0% 










18. Tooth Rock

Counts per 100ml of sample 



10000 

1000 

100 

10 

1 

0.1 

10000 

1000 

100 

10 

1 

0.1 

10000 

1000 

100 

20-Jan-99 

24-May-99 

25-Sep-99 

27-Jan-00 

10 

1 

0 

Faecal Coliform 

y = 1E+14e -0.0007x 

R 2 = 0.2058 p0.05 

30-May-00 

1-Oct-00 

2-Feb-01 

6-Jun-01 

8-Oct-01 

9-Feb-02 

14-Jun-02 

16-Oct-02 

17-Feb-03 

21-Jun-03 

23-Oct-03 

24-Feb-04 

27-Jun-04 

29-Oct-04 

2-Mar-05 

4-Jul-05 

7 



4 

3 

5 

6 

2 

8 

Hoedjies Bay Hotel - Beach 

1 

9 

6-Nov-05 

10-Mar-06 

12-Jul-06 

10 


E. coli 

Expon. (E. coli) 

Expon. (Faecal Coliform) 

E. coli 

y = 1109.2e -8E-05x 

R 2 = 0.0043 p>0.05 

13-Nov-06 

17-Mar-07 

19-Jul-07 

20-Nov-07 

23-Mar-08 

25-Jul-08 

26-Nov-08 

31-Mar-09 

2-Aug-09 

4-Dec-09 

7-Apr-10 

9-Aug-10 

11-Dec-10 

Trend shown 

Trend not shown 

Figure 5.6. Faecal coliform and E. coli counts at 4 of the 10 sampling stations within Small Bay. (Feb 1999-Feb 2010). 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.

7 

4 

3 

5 

6 

2 

95 th Percentile recreational 80 th Percentile recreational 95 th Percentile mariculture 

8 

1 

9 

10 

Trend shown 

Trend not shown 




10000 

1000 

100 

10 

0.1 


y = 0.1308e 0.0001x 

R 2 = 0.0119 p>0.05 

E. coli 

y = 0.0017e 0.0003x 



1 

10000 

1000 

100 

0.1 

20-Jan-99 

24-May-99 

25-Sep-99 

27-Jan-00 

10 

1 

10000 

1000 

100 

20-Jan-99 

24-May-99 

25-Sep-99 

27-Jan-00 

10 

1 

0.1 

20-Jan-99 

24-May-99 

25-Sep-99 

27-Jan-00 

30-May-00 

1-Oct-00 

2-Feb-01 

6-Jun-01 

8-Oct-01 

9-Feb-02 

14-Jun-02 

16-Oct-02 

17-Feb-03 

21-Jun-03 

23-Oct-03 

24-Feb-04 

27-Jun-04 

29-Oct-04 

2-Mar-05 

4-Jul-05 


y = 1E+07e -0.0003x 

R 2 = 0.0439 p


10000 

1000 

100 

10 

1 

0 


y = 0.0004e 0.0003x 

20-Jan-99 

24-May-99 

25-Sep-99 

27-Jan-00 

R 2 = 0.0841 p>0.05 

30-May-00 

1-Oct-00 

2-Feb-01 

6-Jun-01 

8-Oct-01 

9-Feb-02 

14-Jun-02 

16-Oct-02 

17-Feb-03 

21-Jun-03 

23-Oct-03 

24-Feb-04 

27-Jun-04 

29-Oct-04 

2-Mar-05 

4-Jul-05 


Seafarm - Portnet 

6-Nov-05 

10-Mar-06 

12-Jul-06 

11 


E. Coli 

Expon. (E. Coli) 


E. coli 

y = 8E-05e 0.0003x 

R 2 = 0.1086 p0.05 

Myconos - Harbour 

30-May-00 

1-Oct-00 

2-Feb-01 

6-Jun-01 

8-Oct-01 

9-Feb-02 

14-Jun-02 

16-Oct-02 

17-Feb-03 

21-Jun-03 

23-Oct-03 

24-Feb-04 

27-Jun-04 

29-Oct-04 

2-Mar-05 

4-Jul-05 

Lientjies Klip 

6-Nov-05 

10-Mar-06 

12-Jul-06 

6-Nov-05 

10-Mar-06 

12-Jul-06 

6-Nov-05 

10-Mar-06 

12-Jul-06 


E. Coli 



E. coli 

y = 3E-07e 0.0004x 

R 2 = 0.3285 p0.05 

13-Nov-06 

17-Mar-07 

19-Jul-07 

20-Nov-07 

23-Mar-08 

25-Jul-08 

26-Nov-08 

31-Mar-09 

2-Aug-09 

4-Dec-09 

7-Apr-10 

9-Aug-10 

11-Dec-10 


E. Coli 



E. coli 

y = 1E+07e -0.0003x 

R 2 = 0.0712 p>0.05 

13-Nov-06 

17-Mar-07 

19-Jul-07 

20-Nov-07 

23-Mar-08 

25-Jul-08 

26-Nov-08 

31-Mar-09 

2-Aug-09 

4-Dec-09 

7-Apr-10 

9-Aug-10 

11-Dec-10


10000 

1000 

100 

10 

1 

0 

20-Jan-99 

24-May-99 

25-Sep-99 

27-Jan-00 


y = 0.0222e 0.0002x 

R 2 = 0.0198 p>0.05 

30-May-00 

1-Oct-00 

2-Feb-01 

6-Jun-01 

8-Oct-01 

9-Feb-02 

14 

15 

17 

14-Jun-02 

16-Oct-02 

17-Feb-03 

21-Jun-03 


23-Oct-03 

24-Feb-04 

27-Jun-04 

29-Oct-04 

2-Mar-05 

4-Jul-05 

6-Nov-05 

10-Mar-06 

12-Jul-06 

Langebaan North - Windsurf centre 

18 

13-Nov-06 

17-Mar-07 

19-Jul-07 


E. Coli 



E. coli 

y = 0.862e 6E-05x 

R 2 = 0.0031 p>0.05 

20-Nov-07 

23-Mar-08 

25-Jul-08 

26-Nov-08 

31-Mar-09 

2-Aug-09 

4-Dec-09 

7-Apr-10 

9-Aug-10 

11-Dec-10 


10000 

1000 


Figure 5.9. Faecal coliform and E. coli counts at 3 sampling stations within Langebaan Lagoon (Feb 1999-Feb 2010). 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. 



100 

10 

1 

0 


y = 1E+09e -0.0005x 

R 2 = 0.1224 p0.05 

14-Jun-02 

16-Oct-02 

30-May-00 

1-Oct-00 

2-Feb-01 

6-Jun-01 

8-Oct-01 

9-Feb-02 

17-Feb-03 

21-Jun-03 

14-Jun-02 

16-Oct-02 

23-Oct-03 

24-Feb-04 

27-Jun-04 

29-Oct-04 

2-Mar-05 

4-Jul-05 

6-Nov-05 

10-Mar-06 

12-Jul-06 

Langebaan main beach - Pearly's 

17-Feb-03 

21-Jun-03 

23-Oct-03 

24-Feb-04 

27-Jun-04 

29-Oct-04 

13-Nov-06 

17-Mar-07 

19-Jul-07 

2-Mar-05 

4-Jul-05 

6-Nov-05 

10-Mar-06 

12-Jul-06 

Langebaan Yacht club 


E. Coli 



E. coli 

y = 8E+08e -0.0005x 

R 2 = 0.1142 p0.05 

20-Nov-07 

23-Mar-08 

25-Jul-08 

26-Nov-08 

31-Mar-09 

2-Aug-09 

4-Dec-09 

7-Apr-10 

9-Aug-10 

11-Dec-10

5.6 Trace Metal Contaminants in the water column 

State of the Bay 2010: Saldanha Bay and Langebaan Lagoon 


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 1995). 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 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 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 2010 period. 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, and should ensure that such problems do not 

recur in the future (Watling 1981; G. Kiviet pers. comm.). Data from the mussel watch programme 

are represented in Figure 5.10 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 guideline have not been specified in national legislation those adopted 

by other countries have been used (Table 5.10). 

Data supplied by the Mussel Watch Programme (Figure 5.10) show that concentrations of 

Lead in mussels at the monitored sites are consistently are above guideline limits for foodstuffs for 

at least the last 10 years, 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 5.10). No clear trends over time are evident for any of the trace metals, although recent data 

(post 2007) are lacking. 

Concentrations of Lead in mussel from Saldanha Bay tend 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 5.10). 

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 5.11). Data from these farms suggest that the situation in the 

deeper parts of the Bay where the farms are located are less of a problem than is the case with the 

nearshore coastal water where the samples for the Mussel Watch programme 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 (



Table 5.10. 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 

European Union 4 

Japan 5 

Switzerland 2 

Russia 6 

South Korea 2 

2.0 

1.5 

10.0 

1.0 

10.0 

0.3 

USA 7, 8 1.7 4.0 

China 9 

Brazil 10 

Israel 10 

2.0 0.5 

1.0 0.5 

2.0 0.2 

0.6 0.5 

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. 

2.0 

2.0 

0.5 

1.0

Concentrations (ppm) 












14 

12 

10 

8 

6 

4 

2 

0 

12 

10 

8 

6 

4 

2 

0 

300 

250 

200 

150 

100 

50 

0 

450 

400 

350 

300 

250 

200 

150 

100 

50 

0 

250 

200 

150 

100 

50 

0 

14 

12 

10 

14 

12 

10 

8 

6 

4 

2 

0 

12 

10 

8 

6 

4 

2 

0 

300 

250 

200 

150 

100 

50 

0 

450 

400 

350 

300 

250 

200 

150 

100 

50 

0 

8 

6 

4 

2 

0 

250 

200 

150 

100 

50 

0 

10 

9 

8 

7 

6 

5 

4 

3 

2 

1 

0 

May- 

97 

Oct- 

97 

May- Oct- 

97 97 

May- 

97 

May- 

97 

May- 

98 

May- 

99 

Oct- 

99 

May- 

00 

Recommended limit = 70 ppm 

May- 

98 

May- Oct- 

99 99 

Recommended limit = 0.5 ppm 

Oct- 

97 

Oct- 

97 

May- Oct- 

97 97 

May- Oct- 

97 97 

May- 

97 

Oct- 

97 

May- Oct- 

97 97 

May- 

97 

May- 

97 

May- May- 

98 99 

May- May- 

98 99 

Cadmium 

Oct- 

00 

Copper 

May- Oct- 

00 00 

Lead 

Oct- May- 

99 00 

Oct- May- 

99 00 

Fish factory 

May- Oct- Oct- Apr- Oct- Apr- 

01 01 05 06 06 07 


01 01 05 06 06 07 

Oct- May- Oct- Oct- Apr- Oct- Apr- 

00 01 01 05 06 06 07 

Zinc 

Iron 


00 01 01 05 06 06 07 

May- May- Oct- May- Oct- May- Oct- Oct- Apr- Oct- Apr- 

98 99 99 00 00 01 01 05 06 06 07 


98 99 99 00 00 01 01 05 06 06 07 

May- 

98 

May- 

99 

Oct- 

99 

May- 

00 


May- 

98 

May- Oct- 

99 99 


Oct- 

97 

Oct- 

97 

May- Oct- 

97 97 

May- Oct- 

97 97 

May- May- 

98 99 

May- May- 

98 99 

Manganese 

Cadmium 

Oct- 

00 

Copper 

May- Oct- 

00 00 

Lead 

Oct- May- 

99 00 

Oct- May- 

99 00 


01 01 05 06 06 07 


01 01 05 06 06 07 


00 01 01 05 06 06 07 

Zinc 


00 01 01 05 06 06 07 

Iron 


98 99 99 00 00 01 01 05 06 06 07 

Manganese 


98 99 99 00 00 01 01 05 06 06 07 

Saldanha Bay North 








14 

12 

10 

8 

6 

4 

2 

0 

16 

14 

12 

10 

8 

6 

4 

2 

0 

300 

250 

200 

150 

100 

50 

0 

450 

400 

350 

300 

250 

200 

150 

100 

50 

0 

250 

200 

150 

100 

50 

0 

12 

10 

8 

6 

4 

2 

0 

May- Oct- 

97 97 

May- 

97 

May- 

97 

May- 

97 

Oct- 

97 

May- 

98 

May- Oct- 

99 99 

May- May- 

98 99 

Cadmium 

May- Oct- 

00 00 


Oct- 

97 

May- May- 

98 99 

Oct- May- 

99 00 


Oct- 

97 

May- Oct- 

97 97 

May- Oct- 

97 97 

May- May- 

98 99 

Oct- May- 

99 00 

Copper 

Lead 

Oct- May- 

99 00 


01 01 05 06 06 07 


00 01 01 05 06 06 07 


00 01 01 05 06 06 07 

Zinc 

Iron 


00 01 01 05 06 06 07 


98 99 99 00 00 01 01 05 06 06 07 

Manganese 


98 99 99 00 00 01 01 05 06 06 07 







9 

8 

7 

6 

5 

4 

3 

2 

1 

0 

16 

14 

12 

10 

8 

6 

4 

2 

0 

300 

250 

200 

150 

100 

50 

0 

450 

400 

350 

300 

250 

200 

150 

100 

50 

0 

250 

200 

150 

100 

50 

0 

9 

8 

7 

6 

5 

4 

3 

2 

1 

0 

May- Oct- 

97 97 

May- 

97 

May- 

97 

Oct- 

97 


May- 

98 

May- Oct- 

99 99 


Oct- 

97 

May- Oct- 

97 97 

May- May- 

98 99 

May- May- 

98 99 

May- 

98 

Cadmium 

Oct- May- 

99 00 

May- Oct- 

00 00 

Copper 

Lead 

Oct- May- 

99 00 

May- Oct- 

99 99 

Portnet 


01 01 05 06 06 07 


00 01 01 05 06 06 07 

714.6↑ 

Recommended limit 

= 0.5 ppm 


00 01 01 05 06 06 07 

Zinc 

May- Oct- 

00 00 

Iron 


01 01 05 06 06 07 

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 

Mussel Raft 26/27 Iron Ore Jetty 







14 

12 

10 

8 

6 

4 

2 

0 

12 

10 

8 

6 

4 

2 

0 

300 

250 

200 

150 

100 

50 

0 

450 

400 

350 

300 

250 

200 

150 

100 

50 

0 

250 

200 

150 

100 

50 

0 

12 

10 

8 

6 

4 

2 

0 

May- Oct- 

97 97 

May- 

97 

Oct- 

97 

May- Oct- 

97 97 

May- 

97 

May- 

97 

Manganese 


98 99 99 00 00 01 01 05 06 06 07 

May- 

98 

May- 

98 

May- 

99 

Oct- 

99 

May- Oct- 

99 99 

Cadmium 

May- 

00 


Oct- 

97 

May- May- 

98 99 

Oct- 

00 

Copper 

May- Oct- 

00 00 

Lead 


Oct- 

97 

May- Oct- 

97 97 

May- Oct- 

97 97 

May- May- 

98 99 

Oct- May- 

99 00 

Oct- May- 

99 00 


01 01 05 06 06 07 


01 01 05 06 06 07 


00 01 01 05 06 06 07 

Zinc 

Iron 


00 01 01 05 06 06 07 


98 99 99 00 00 01 01 05 06 06 07 

Manganese 


98 99 99 00 00 01 01 05 06 06 07 

Figure 5.10. 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 or internationally are shown as a 

dotted red line (see Table 5.10 for more details on this).

Lead(mg/kg) 

Mercury (mg/kg) 

Cadmium (mg/kg) 

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 

3.5 

3 

2.5 

2 

1.5 

1 

0.5 

0 



West Coast Aquaculture (Pty) Ltd 

Blue Bay Aquafarm 

West Coast Oyster Growers 

Striker Fishing 

West Coast Aquaculture (Pty) Ltd Blue Bay Aquafarm 

West Coast Oyster Growers Striker Fishing 

West Coast Aquaculture (Pty) Ltd Blue Bay Aquafarm 

West Coast Oyster Growers Striker Fishing 

Figure 5.11. Concentrations of Cadmium, Lead and Mercury in mussels and oysters from four bivalve 

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



5.7 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 jetty 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 jetty 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 semi-sheltered 

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 most sites for 

which the relevant authorities should be commended. The situation in Small Bay remains 

concerning though, with many sites exceeding levels for safe bathing. 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, to assess the effectiveness of adopted measures, is also required. 

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, faecal coliforms, etc.). Compliance with ballast water treatment 

requirements (e.g. open ocean exchange, chlorination and ozonation) designed to minimize the risks 

of alien introductions should be rigourously 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.

6 SEDIMENTS 

6.1 Sediment particle size composition 



The types of sediments occurring in Saldanha Bay are strongly influenced by wave energy 

and current circulation patterns occurring in the system. High wave energy and strong currents 

suspend fine sediment particles (mud) which are then flushed out the Bay, leaving behind the 

coarser (heavier) sand or gravel particles. Conversely, reduced wave action and disturbed current 

patterns can result in the deposition of mud in quiescent areas. Since 1975, industrial developments 

in Saldanha Bay (iron ore jetty, multi-purpose jetty, mussel rafts 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 related to the fact that fine grained 

particles have a relatively larger surface area for the adsorption and binding of pollutants than do 

coarse sedoments. Higher proportions of mud, relative to sand or gravel, can thus lead to elevated 

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 (even if the rate 

at which pullutants discharged to the system does not change). Contaminants in the sediment can 

become buried over time and are effecteively sealed from the overlying water column. However, 

disturbance to these sediment (e.g. dredging) can lead to re-suspension 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 become buried or are scoured out of the Bay by prevailing wave and tidal action. Changes in 

sediment particle size in Saldanha Bay are thus of considerable interest here, and are summarised in 

Figure 6.1, Figure 6.3 and Figure 6.4 and in the text that follows. 

6.1.1 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 

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 

6.1). 

Due to concern in the deteriorating water quality in Saldanha Bay, 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 jetty had been established 

dividing the Bay into Small Bay and Big Bay, the multi-purpose terminal had been added to the jetty, 

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 6.1). 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 jetty 

was dredged (indicated by arrows in Figure 6.1), 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 

jetty, the Yacht Club basin and the Mussel Farm area (Figure 6.1). 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 indicated almost complete recovery of 

sediments over the 1999 situation to a majority percentage of sand in five of the six sites examined 

for this study (Figure 6.1). 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 to the maintenance dredging that took place at the Mossgas and multipurpose 

terminals at the end of 2007/beginning of 2008 (see §4.3.1 for more details on this). 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. There has been a 

progressive increase in the mud content of sediments adjacent to the Multi-purpose Quay from 

2000-2008, and this is having a noticeable effect on the health of the macrobenthic community in 

this area. The 2008 benthic macrofauna survey revealed that benthic health at both the Yacht Club 

basin and adjacent to the Multi-purpose Quay is alos severely compromised, with benthic organisms 

being virtually absent from the former (see §8 for more details on this). 

In summary, the natural, pre-development state of sediment in Saldanha Bay comprised 

predominantly sand particles, however, increasing development and human impact in the Bay has 

reduced the overall wave energy and altered the current circulation patterns. As a result, mud 

(cohesive sediment) has been accumulating progressively in surface sediments in the Bay. Dredging 

of Small Bay in 1997/98 also re-suspended large amounts of mud from the deeper lying sediments, 

which then settled out in the surface sediments. These fine sediments have, however, gradually 

been washed out of the Bay or have been reburied through the course of time. The situation in 

2008/2009 reflected that of the reduced wave action and current velocities with slightly higher than 

normal amounts of mud in the sediments. 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 §6.3.2 for more details on 

this).

6.1.2 Sediment Particle size results for 2010 



Results from the 2010 survey are presented in Figure 6.4. These results indicate that muddy 

sediments are mostly located in Small Bay at the yacht club basin and along the ore jetty, and at two 

sites in the middle of Big Bay. There has been a reduction in the mud content of sediments at the 

Mussel Farm and at all sites along the ore jetty in Small Bay between 2009 and 2010. This suggests 

either improved flushing of fine sediments out of Small Bay (with the exception of the Yacht Club 

basin) or reduced deposition. This is a sign of improved environmental health within Small Bay. The 

mud content of the sediments at the Yacht club basin has fluctuated drastically over the last decade. 

Indeed, the mud content was found to have increased between 2009 and 2010 (from 5.3% to 16.5%) 

following the reduction observed between 2008 and 2009 (from 53% to 5.3%). It is not clear why 

there have been such marked fluctuations in the mud content of the sediments at the Yacht Club 

Basin over time, except possibly due to small-scale spatial variations in mud content. 

Dredging of the shallow subtidal zone in Salamander Bay occurred between May 2009 and 

May 2010 as part of the construction of a new boat park for the Special Forces Regiment of the 

South African National Defence Force (SANDF) at Donkergat (indicated by blue arrow in Figure 6.2). 

A marine ecology report was prepared retrospectively in July 2010 as the required EIA had not been 

conducted prior to commencing development (Robinson 2010). As a result, sediment particle size 

composition in Salamander Bay was not assessed prior to and after dredging. The sites BB29, BB30 

and LL38 are the closest to Salamander Bay of all the sites monitored in this report. Data from the 

State of the Bay surveys indicate that there has been a stepwise increase in the mud content of the 

sediments at site BB29 since 2004, however the mud content is still much lower than that recorded 

in 1999 following the dredging for the ore jetty (Figure 6.2). A stepwise increase in the mud content 

of sediments between 2004 and 2009 was also observed at other Big Bay sites, however, this 

decreased for all sites other than BB29 between 2009 and 2010 (Figure 6.1). Given that the mud 

content of sediments at all sites within Big Bay, other than BB29, decreased between 2009 and 2010 

it is possible that the increase at BB29 (from 8% to 10.4%) may be associated with the dredging 

events that took place in Salamander Bay in 2009. The mud content of the sediments at the next 

closest sites to Salamander Bay (LL38 and SB30) decreased between 2009 and 2010 (Figure 6.2). 

This indicates that the dredging had no impact on the sediment size composition at these sites and, 

in fact, conditions seem to be improving. The results of this survey therefore indicate that the 

dredging conducted in 2009 may have had a minor, localized impact on the sediments particle size 

composition in the south western region of Big Bay, and that the system is recovering elsewhere. 

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 strong currents. Unfortunately no historical data was available for grain size distribution in 

Langebaan Lagoon, and only the recent results from the 2004, 2008, 2009 and 2010 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 (Figure 6.3). A 

slight reduction in the mud content of sediments at several sites in Langebaan was noted between 

2009 and 2010 in the previous (2009) State of the Bay report. The only site within Langebaan 

Lagoon that has shown considerable temporal variation in sediment composition is site LL 37, East of 

the Channel. This site was comprised principally of sand in 2004, and contained a high fraction of 

gravel in 2008. In 2009 there was a dramatic increase in mud at this site, comprising 52% of the 

sediment sample, while in 2010 the mud content was reduced to 1%. The high degree of variation in 

sediment composition at this site may indicate that it is an area of variable water flow and current 

strength. Flemming (1977) found that the major energy responsible for the deposition and transport 

of sediments in Langebaan Lagoon is tidal and current energy. The Lagoon can be divided into four 

specific units according to their physiographic characteristics, namely: tidal channels, subtidal flats



and sandbanks, inter tidal flats, and salt marshes. East of the channel, fine sands dominate whereas 

west of the channel coarser sands dominate (Flemming 1977). Grain size composition of sediment 

samples collected from Small Bay (SB), Big Bay (BB) and Langebaan Lagoon (LL) in 2010 are listed in 

Table 6.1 and Table 6.2. 

Table 6.1. Sediment Composition of samples collected from Small Bay (SB), Big Bay (BB) and Langebaan 

Lagoon (LL) in 2010; Particulate organic nitrogen (PON), particulate organic carbon (POC) and 

grain size composition (Sediment analyzed by Scientific Services) 

%POC %PON %Gravel %Sand %Mud 

SB1 4.491 0.57 0.059078 83.47775 16.46317 

SB2 0.237 0.024 0.605871 98.23235 1.161774 

SB3 0.381 0.048 1.135427 95.42023 3.444339 

SB8 0.634 0.087 0.049533 95.31918 4.631292 

SB9 1.052 0.144 0.891784 85.54804 13.56018 

SB10 0.277 0.036 0.778182 98.02182 1.2 

SB14 3.963 0.545 0.056029 83.34827 16.5957 

SB15 2.714 0.367 2.304725 96.39344 1.301832 

SB16 0.895 0.118 0.055854 92.97633 6.967814 

BB20 0.687 0.105 1.200966 94.64134 4.157692 

BB21 0.416 0.056 0.342759 93.94898 5.708259 

BB22 0.565 0.06 0.445143 92.26892 7.285939 

BB25 0.184 0.022 0.089296 98.63824 1.272463 

BB26 0.484 0.067 0.104603 88.33682 11.55858 

BB29 0.592 0.083 0.704095 88.9383 10.35761 

BB30 0.103 0.009 0.0205 99.8975 0.082001 

LL31 0.227 0.031 0.050352 99.32024 0.629406 

LL32 0.116 0.01 0.061013 99.23734 0.701647 

LL33 0.187 0.024 0 99.44188 0.558117 

LL34 0.32 0.045 0.327953 97.91653 1.755514 

LL37 0.124 0.013 0.104545 98.89921 0.996249 

LL38 0.619 0.091 3.415906 94.25684 2.327249 

LL39 0.042 0.003 0.006338 99.3979 0.595766 

LL40 0.15 0.019 0.026566 99.10341 0.870027 

LL41 0.087 0.009 0.033706 99.67642 0.289875 

Figure 6.5 represents the average concentration of mud found within the sediment of Small 

Bay, Big Bay and Langebaan Lagoon samples over time. It is clear from the graph of Small Bay that 

the concentrations on fine grained particles were highest in 1999 after the dredge event, and have 

been showing a decreasing trajectory of change since then. As mentioned earlier, the peak in the 

% mud in the 2008 samples may be a result of maintenance dredging within Small Bay. The



concentrations of mud in the sediments of Big Bay and Langebaan Lagoon are well below those of 

Small Bay. The average concentration of fine grained particles has decreased at both Big Bay and 

Langebaan Lagoon between 2009 and 2010 (Figure 6.5). The mud content in the lagoon is lower 

than the level recorded in 2004, while that in Big Bay still exceeds the levels recorded in 2004 (Figure 

6.5). The increase and subsequent reduction of fine grained particles in the Lagoon may be 

indicative of variable flows and current strengths in this environment. The decreasing trend in the 

concentration of mud in Big Bay may be due to a reduction the deposition of fine particles or the 

increased flushing of the Bay. The reduction of fine grained particles in both Small Bay and Big Bay 

since 2008 is an indication of improved environmental health. 

Table 6.2. Concentrations of metals (mg/kg) surface sediments collected from Small Bay (SB), Big Bay 

(BB) and Langebaan Lagoon in 2010 (Sediment analyzed by Scientific Services) 

Al Fe Cd Cu Ni Pb Zn 

SB1 8180 8049 1 34.3 10.2 18.4 78.3 

SB2 1405 1876 0 2.3 1.7 2.0 6.0 

SB3 1596 1749 0 3.5 1.0 11.0 6.4 

SB8 1677 1835 0 2.0 1.4 1.4 5.3 

SB9 2951 4093 0 3.7 3.1 3.3 11.6 

SB10 824 1295 0 1.5 0.6 0.8 3.9 

SB14 4976 6747 0 13.9 7.6 44.8 32.1 

SB15 4013 5577 0 8.5 5.4 23.4 24.1 

SB16 2178 2849 0 3.7 2.5 2.4 9.3 

BB20 2032 1985 0 2.8 2.4 0 6.3 

BB21 2222 2554 0 2.3 2.4 0.7 10.2 

BB22 2917 3365 0 3.0 2.9 2.4 12.1 

BB25 698 866 0 1.2 0.4 0 2.3 

BB26 2254 2387 0 2.2 2.1 0 8.6 

BB29 2637 2256 0 2.7 3.0 0 7.3 

BB30 579 691 0 1.0 0 0 2.1 

LL31 2316 3460 0 2.8 3.7 0.6 4.6 

LL32 1996 4293 0 2.7 3.1 0.9 4.3 

LL33 1381 3215 0 3.2 4.1 0 1.8 

LL34 2356 2764 0 2.6 3.8 0 6.7 

LL37 1367 2562 0 2.7 3.2 0 4.4 

LL38 3691 4717 0 3.7 5.6 2.0 9.1 

LL39 892 1620 0 1.7 1.1 0 1.5 

LL40 780 1601 0 2.1 1.4 0 2.1 

LL41 652 930 0 1.9 1.1 0 0.4

100% 

90% 

80% 

70% 

60% 

50% 

40% 

30% 

20% 

10% 

0% 

100% 

90% 

80% 

70% 

60% 

50% 

40% 

30% 

20% 

10% 

0% 

1977 

1977 

1989 

1989 

1990 

1990 

Dredge 1997 

Dredge 1997 

1999 

1999 

2000 

2000 

Yacht club basin (SB1) 

Mussel Farm (SB9) 

2001 

2001 

2004 

2004 

2008 

2008 

2009 

2009 



Gravel 

Sand 

Mud 

Gravel 

Sand 

Mud 

100% 

90% 

80% 

70% 

60% 

50% 

40% 

30% 

20% 

10% 

0% 

1977 

1989 

1990 

1999 

2000 

North channel Small Bay (SB3) 

2001 


Figure 6.1. Particle size composition of sediment at six locations in Saldanha Bay between 1977 and 2010 

2004 


2008 

2009 


Gravel 

Sand 

Mud 

100% 

90% 

80% 

70% 

60% 

50% 

40% 

30% 

20% 

10% 

0% 

100% 

90% 

80% 

70% 

60% 

50% 

40% 

30% 

20% 

10% 

0% 

1977 

1977 

1989 

1989 

1990 

1990 

Dredge 1997 

1999 

2000 

Multi-purpose Quay (SB14) 

1999 

2000 

Channel end of ore jetty (SB16) 

2001 

2001 

2004 

2004 

2008 

2008 

2009 

2009 



Gravel 

Sand 

Mud 

Gravel 

Sand 

Mud

100% 

90% 

80% 

70% 

60% 

50% 

40% 

30% 

20% 

10% 

0% 

100% 

90% 

80% 

70% 

60% 

50% 

40% 

30% 

20% 

10% 

0% 

1999 2004 2008 2009 2010 

BB29 

2004 2009 2010 

LL38 

100% 

90% 

80% 

70% 

60% 

50% 

40% 

30% 

20% 

10% 

0% 

1999 2004 2008 2009 2010 

BB22 

Gravel 

Sand 

Mud 

Gravel 

Sand 

Mud 

Gravel 

Sand 

Mud 

100% 

90% 

80% 

70% 

60% 

50% 

40% 

30% 

20% 

10% 

0% 


1999 2004 2008 2009 2010 


BB21 

100% 

90% 

80% 

70% 

60% 

50% 

40% 

30% 

20% 

10% 

0% 

100% 

90% 

80% 

70% 

60% 

50% 

40% 

30% 

20% 

10% 

0% 

1977 

Gravel 

Sand 

Mud 

1989 

1990 

1999 

2000 

BB26 

1999 2009 2010 

Figure 6.2. Particle size composition (percentage gravel, sand and mud) of sediment at five locations in Bay and one at the entrance to Langebaan Lagoon 

BB30 

2001 

2004 

2008 

2009 


Gravel 

Sand 

Mud 

Gravel 

Sand 

Mud

100% 

90% 

80% 

70% 

60% 

50% 

40% 

30% 

20% 

10% 

0% 

100% 

90% 

80% 

70% 

60% 

50% 

40% 

30% 

20% 

10% 

0% 

100% 

90% 

80% 

70% 

60% 

50% 

40% 

30% 

20% 

10% 

0% 

2004 2008 2009 2010 

Entrance to Lagoon (LL31) 

2004 2008 2009 2010 

Oudepos site (LL32) 

2004 2008 2009 2010 

Postberg (LL33) 

%Gravel 

%Sand 

%Mud 

%Gravel 

%Sand 

%Mud 

%Gravel 

%Sand 

%Mud 



100% 

90% 

80% 

70% 

60% 

50% 

40% 

30% 

20% 

10% 

0% 

100% 

90% 

80% 

70% 

60% 

50% 

40% 

30% 

20% 

10% 

0% 

2004 2008 2009 2010 

East of Channel (LL37) 

2004 2008 2009 2010 

Kraalbaai (LL34) 

Figure 6.3. Particle size composition (percentage gravel, sand and mud) of sediment at five locations in Langebaan Lagoon in 2004, 2008 and 2009 

%Gravel 

%Sand 

%Mud 

%Gravel 

%Sand 

%Mud



Figure 6.4. Variation in the percentage mud in sediments in Saldanha Bay and Langebaan Lagoon as 

indicated by the 2010 survey results. 

Small Bay Big Bay 


Figure 6.5. Average (± 95% confidence intervals) percentage mud occurring in Small Bay, Big Bay and 

Langebaan Lagoon sediments over time

6.2 Particulate Organic Carbon (POC) and Nitrogen (PON) 



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 to that of mud particles (less than 60 µm) and settles out of the water column together with 

the mud. The most likely sources of organic matter in Saldanha Bay are from phytoplankton 

production at sea and the associated detritus that forms from the decay thereof, fish factory waste 

discharged into the Bay, faecal waste concentrated beneath the mussel and oyster rafts in the Bay, 

and treated sewage effluent discharged into the Bay from the waste water treatment works at 

Saldanha and Langebaan, and leakage from sewage transfer stations, septic tanks and conservancy 

tanks. POC and PON is most likely to accumulate in sheltered areas with low current strengths, 

where there is limited wave action and hence limited dispersal of organic matter. Elevated 

concentrations of PON in the sediments may indicate the presence of relatively fresh organic matter 

originating from phytoplankton. High carbon to nitrogen ratios in the past suggests that the matter 

was nitrogen depleted which may indicate that the matter was of fish waste origin (Monteiro et al. 

1997), at least at this time anyway. Accumulation of organic matter in the sediments doesn’t 

directly impact the environment, however, bacterial breakdown of the organic matter may lead to 

anoxic conditions. Under such conditions anaerobic decomposition prevails, which results in the 

formation of sulphides such as hydrogen sulphide (H2S). Sediments high in H2S concentrations are 

characteristically black, foul smelling, and toxic for most living organisms. 

The percentage of POC and PON recorded in the sediments in Saldanha Bay and Langebaan 

Lagoon is presented in Figure 6.6 and Figure 6.7. The concentrations of both POC and PON are 

highest in the deeper parts of Saldanha Bay, particularly around the ore jetty and in the north east 

corner of the Bay near the yacht basin. POC levels in Saldanha Bay have not always been as high as 

they are now, and were in fact very low (between 0.2 and 0.5%) throughout the Bay prior to any 

major development (pre-1974). The next available POC data was collected in 1989 after the 

construction of the iron ore jetty and the establishment of the mussel farms in Small Bay. At this 

stage all sites monitored had considerably elevated levels of POC with the greatest increase 

occurring in the vicinity of the Mussel Farm. POC levels peaked at a record high (16.9%) at this site 

in 1990. The reason for this extremely high POC percentage is uncertain. Through all subsequent 

years of POC monitoring (1990, 1999, 2000, 2001, 2004, 2008, 2009 and 2010), levels have remained 

higher than those reported prior to development. 

The sediments from the Yacht Club basin, Mussel Farm and Multi-purpose Quay have 

consistently had the highest POC content of the six sites sampled over the last 20 years. High 

organic carbon concentrations at the Mussel Farm site is attributed to the deposition of faecal 

pellets and biogenic waste, while high organic carbon content of the sediments at the Yacht Club 

basin and Multi-purpose Quay is due to long term deposition at these sheltered sites. Organic 

carbon content of the sediments at the end of the ore jetty and within Big Bay show irregular 

temporal trends, with concentrations spiking and dipping from one year to the next. These 

fluctuations are most likely due the higher wave energy and tidal forcing at these sites, which would 

prevent long term accumulation of organic matter by continually scouring and flushing sediments. 

All POC levels recorded in 2004 were lower than in 2000 and 2001, except at the Mussel Farm site, 

suggesting some degree of recovery in Saldanha Bay between 2001 and 2004. However, the POC 

content increased at all sites in 2008, except the Mussel Farm, with the greatest increases observed 

in Big Bay, at the Yacht Club basin and the Multi-purpose quay. The increase in POC at the two latter 

sites corresponded to an increase in fine grained sediments in 2008. 

POC at the Mussel Farm increased from 1.3% in 2008 to 3.4% in 2009 and decreased to 1.1% 

in 2010. The increase between 2008 and 2009 may have been due to increased deposition of faecal 

matter from the mussel rafts given that mussel production in the Bay was at its highest during 2008. 

Similarly the reduced level of POC recorded at the Mussel Farm site in 2010 may be due to the



reduced production of mussels in the Bay during the course of 2009 (see section §4.2 for more 

details on this). The noticeable decline in POC at the Yacht Club basin over the decade is 

encouraging and may indicate recovery of sediment health at this site. In addition, POC levels 

recorded in 2010 at the Channel end of the ore jetty, North Channel small bay and Big Bay are lower 

than in 2009, and are close to those measured prior to development. This is indicative of improved 

environmental health. 

No historical percentage organic nitrogen (PON) data were attainable for the purposes of 

this report, however, data from 1999 to 2009 of the PON measured at selected sites within Small 

and Big Bay indicates that the highest levels of organic nitrogen in Saldanha Bay were recorded at 

the Yacht Club basin and near the Mussel rafts (Figure 6.9). This is predicted to be as a result of fish 

factory waste discharge and faecal waste accumulating beneath the mussel rafts. The 

concentrations of PON in the sediments of the Yacht Club basin and Multi-purpose Quay have 

increased steadily over the last decade, which indicates long term deposition of nitrogen-rich 

matter. Only in the 2009 survey was a reduction in PON observed at the Yacht Club basin. This site 

has also shown a reduction in mud content as well as POC content, suggesting improved health of 

the sediments possibly linked to increased flushing or water movement. The nitrogen content of the 

sediments at all other sites remained fairly constant between 2008 and 2009. 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. 

The high organic loading at these sites has had a detrimental impact on marine benthic fauna as is 

evident from the macrofauna survey results (see §8). An increase in the organic loading of the 

sediments generally results in hypoxic conditions, which are unsuitable for most life forms. 

A slightly elevated concentration of organic content in the sediments in Salamander Bay was 

noted in July 2010 following the dredging of the shallow subtidal zone for the construction of the 

boat park (Robinson 2010). The results of the 2010 State of the Bay survey indicated that there were 

no notable increases in the percentage POC or PON in the sediments at sites BB29 or LL38 (closest 

sampled sites to Salamander Bay) between 2009 and 2010 (Figure 6.10). This suggests that the 

impact of the dredging on the organic content of the sediments was limited to a small area.

Figure 6.6. Variation in the % Organic Carbon in the sediments in Saldanha 

Bay and Langebaan Lagoon as indicated by the 2010 survey 

results 


Figure 6.7. Variation in the % Organic Nitrogen in the sediments in Saldanha 

Bay and Langebaan Lagoon as indicated by the 2010 survey 

results 


% POC 

18 

16 

14 

12 

10 

8 

6 

4 

2 

0 

% POC 

18 

16 

14 

12 

10 

8 

6 

4 

2 

0 

% POC 

18 

16 

14 

12 

10 

8 

6 

4 

2 

0 

Yacht club basin 

Mussel farm 

North Channel - Small Bay 

% POC 

% POC 


18 

16 

14 

12 

10 

8 

6 

4 

2 

0 


% POC 

18 

16 

14 

12 

10 

8 

6 

4 

2 

0 

% POC 

18 

16 

14 

12 

10 

8 

6 

4 

2 

0 

Channel end of ore jetty 

Multi -purpose Quay 

Figure 6.8. Particulate Organic Carbon (POC) percentage occurring in sediments of Saldanha Bay at six locations between 1974 and 2010 

Big Bay

% PON 

1.2 

1 

0.8 

0.6 

0.4 

0.2 

0 

% PON 

% PON 

1.2 

1 

0.8 

0.6 

0.4 

0.2 

0 

1999 2000 2001 2004 2008 2009 2010 


1999 2000 2001 2004 2008 2009 2010 

1.2 

1 

0.8 

0.6 

0.4 

0.2 

0 

Yacht club basin 

1999 2000 2001 2004 2008 2009 2010 

Mussel farm 


% PON 


% PON 

1.2 

1 

0.8 

0.6 

0.4 

0.2 

0 

% PON 

1.2 

1 

0.8 

0.6 

0.4 

0.2 

0 

1999 2000 2001 2004 2008 2009 2010 

% PON 

1.2 

0.8 

0.6 

0.4 

0.2 

Multi -purpose Quay 

1999 2000 2001 2004 2008 2009 2010 

1 

0 


1999 2000 2001 2004 2008 2009 2010 

Figure 6.9. Particulate Organic Nitrogen (PON) percentage occurring in sediments of Saldanha Bay at six locations between 1999 and 2010 


Percentage 

Percentage 

1.8 

1.6 

1.4 

1.2 

1 

0.8 

0.6 

0.4 

0.2 

0 

1.8 

1.6 

1.4 

1.2 

1 

0.8 

0.6 

0.4 

0.2 

0 

POC PON 

BB29 

POC PON 

LL38 

1999 

2004 

2008 

2009 


2004 

2009 




Figure 6.10. Percentage particulate organic carbon and nitrogen found in the sediments at two sites near 

Donkergat. 

6.3 Trace Metals 

Several metals occur naturally in the marine environment, and some are important in 

fulfilling certain physiological roles. Disturbance to the natural environment by either anthropogenic 

or natural factors can lead to an increase in metal concentrations occurring in the sediment. An 

increase in metal concentrations above certain established safety thresholds can result in negative 

impacts on various marine organisms, especially filter feeders like mussels that tend to accumulate 

metals in their flesh. High concentrations of metals can also render some marine 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 6.3). The BCLME 

guidelines cover a broad concentration range and 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 6.3.



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 6.3. Summary of BCLME and NOAA metal concentrations in sediment quality guidelines 

Metal 

(mg/kg dry wt.) 

South Africa 1 

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) 

6.3.1 State of the Bay survey results for 2010 

A total of 25 sites were sampled for sediment metal concentrations in 2010, nine of which 

were in Small Bay, seven in Big Bay and nine in Langebaan Lagoon (Figure 6.11). 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 and Ni 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 (HNO3) / Perchloric 

Acid (HClO3)/ Hydrogen Peroxide (H2O2)/ 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 

2010 are shown in Table 6.4 and Figure 6.13, Figure 6.14, and Figure 6.15. The concentrations of the 

majority of metals were highest at sites SB 1 (Yacht Club basin) and SB 14 (Multi-purpose Quay). 

This is consistent with results observed in 2008 and 2009. The concentration of cadmium detected at 

the Yacht Club basin (SB1) fell below the ERL values (the concentration at which toxic effects are 

observed in sensitive species), indicating a reduction of cadmium since 2009. In addition, cadmium 

was not detected at any other site sampled in 2010. Concentrations of copper were detected at all 

sites in Saldanha Bay and Langebaan Lagoon in 2010 (Table 6.4). This is unusual given that copper 

was only detected at sites SB1 (Yacht Club Basin), SB 14 (Multi-purpose Quay) and SB 15 and at no 

other sites throughout the system in 2009. However, all sites, with the exception of sites SB1 and 

SB14, had low concentrations of copper. The concentration of copper found in the sediments at the 

yacht club increased between 2009 and 2010 such that they exceeded the ERL in 2010. The 

concentration of lead at site SB 14 (Multi-purpose Quay) fell just below the ERL value in 2010, 

thereby indicating an improvement in sediment quality since 2008. Lead was detected at just over 

half of the sites sampled; however the concentrations detected did not exceed the ERL value at any 

site. Nickel was recorded at nearly all the sites; however the concentrations were well below the 

toxic effects guidelines stipulated by the NOAA.

o 

33 3’S 

o 

33 10’S 

Yacht Club 

Basin 

0m 1500m 3000m 4500m 6000m 

o 

17 50’E 

North Channel Small Bay 

1 


2 

Mussel Farm 

8 

9 


20 

10 

16 

14 

15 

3 

22 

Multi-purpose 

quay 

21 


29 

26 



LL 38 

LL 31 

25 

30 

LL 32 

LL 34 

LL 37 

LL 39 

LL 33 


LL 40 

LL 41 


Figure 6.11. Sediment sampling sites in Saldanha Bay and Langebaan Lagoon for 2010. Sites sampled from 

pre-1980 to 2010 are marked and labelled in red

Table 6.4: Concentrations (mg/kg) of metals in sediments collected from Saldanha Bay in 2010. 



Sample Al Fe Cd Cu Ni Pb 

*ERL Guideline (mg/kg) - - 1.2 34 20.9 46.7 

Small Bay (SB) SB1 8180 8049 1 34.3 10.2 18.4 

SB2 1405 1876

Figure 6.12. Variation in the concentration of Cadmium (Cd) in the sediments 

in Saldanha Bay and Langebaan Lagoon as indicated by the 2010 

survey results. 


Figure 6.13. Variation in the concentration of Copper (Cu) in the sediments in 

Saldanha Bay and Langebaan Lagoon as indicated by the 2010 



Figure 6.14. Variation in the concentration of Lead (Pb) in the sediments in 




Figure 6.15. Variation in the concentration of Nickel (Ni) in the sediments in 




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 

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 terminal and industrial activity in Saldanha Bay. 

Enrichment factors were also calculated for Saldanha Bay samples by dividing metal concentrations 

obtained in 2009 by the average metal concentrations recorded for pre-development sediments in 

1980. 

Figure 6.16. Metal:Al ratios for Copper, Lead, Cadmium and Nickel for sediments sampled in 2010 from 

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

The concentration of cadmium and the normalized Cd:Al ratios were highest at site SB 1 

(Yacht Club Basin) which is historically an area of high metal contamination (Figure 6.16 and Figure 

6.18). This may be due to the discharge of a variety of anthropogenic contaminants related to 

boating activity (fuel leakage, anti fouling paints etc). The normalized Cu:Al ratios show a 

considerable amount of spatial variability. The sites in the southern region of the lagoon (LL33, LL37, 

LL39, LL40 and LL41) and along the ore jetty (SB3, SB14 and SB15) and in the yacht club basin (SB1) 

in Small Bay have high normalized copper concentrations. Sites SB1, SB14 and SB15 correspond to 

areas of high boating activity, and also exhibited elevated Cu:Al ratios in 2008 and 2009. The input 

of copper at these sites may thus be related to the use of antifouling paints which characteristically 

State of the Bay 2010: Saldanha Bay and Langebaan Lagoon

have a high copper content. There is no apparent reason for the elevated Cu:Al ratios found at the 

southern end of the lagoon and this may warrant further investigation. 

It is clear that lead contamination was highest in Small Bay at sites SB1, SB3, SB14 and SB15. 

The normalized Pb:Al ratios were highest at sites SB3, SB14 and SB15, suggesting anthropogenic 

input at these points. The lead concentrations and normalized Pb:Al ratios were also elevated at 

these sites in 2008 and 2009. 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 only sites where concentrations 

may have been ‘unnaturally’ elevated (according to Ni:Al ratio) would be sites LL33 and LL37. 

Metal enrichment factors were calculated for Cd, Pb and Cu relative to the 1980 sediments 

(Table 6.5). 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. 

Table 6.5. 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 0.80 

Small Bay SB1 15.92000 83.609760 23.03875 

SB2 - 5.729268 2.456250 

SB3 - 8.639024 13.713750 

SB8 - 4.970732 1.716250 

SB9 - 9.014634 4.110000 

SB10 - 3.741463 0.988750 

SB14 - 33.824390 56.036250 

SB15 - 20.614630 29.305000 

SB16 - 9.019512 2.9387500 

Big Bay BB20 - 6.775610 - 

BB21 - 5.612195 0.8825000 

BB22 - 7.285366 2.9662500 

BB25 - 2.853659 - 

BB26 - 5.429268 - 

BB29 - 6.617073 - 

BB30 - 2.375610 - 

At the Yacht Club Basin (SB1) cadmium concentrations are approximately 16 times higher 

than the 1980 average, lead concentrations are 23 times higher, and copper concentrations are 70 

times higher. Concentrations of copper are 33 and 20 times greater than the historical average at 

sites SB14 and SB15 respectively (Multi-purpose Quay and Iron Ore terminal), while Lead 


concentrations are 56 and 29 times higher respectively. These sites are depositional zones for 

organic matter and are also associated with a high degree of boating/shipping activity and the 

export of iron and lead ore. Elevated Lead concentrations in Saldanha Bay, particularly along the 

iron ore terminal 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). Small Bay has clearly 

been subject to greater accumulation of metals relative to Big Bay. It should also be noted though 

that the concentration of lead at all sites around the Multi-Purpose Terminal is still lower than the 

critical sediment concentration of 100mg/kg determined in the Water Quality Management Plan for 

Saldanha Bay (Monteiro and Kemp 2004), which implies that the contribution from this source to 

lead concentrations elsewhere in the Bay remains below 10% of background (natural levels) as 

suggested by their hydrodynamic modelling studies. 

The concentration of iron in sediments recorded during 2010 sampling was highest at sites 

along the Small Bay side of the ore jetty, in the Yacht Club Basin and at the northern end of the 

Lagoon. The elevated iron concentrations in the vicinity of the ore jetty and the yacht club basin 

generally correlate well with the distribution of mud (as expected due to the cohesion of iron to fine 

sediment particles) in the Bay (Figure 6.4 and Figure 6.17). The notable exceptions are in the region 

of the base of the ore jetty (multipurpose quay) on the Small Bay side and the northwestern end of 

the lagoon where mud concentrations are average to low, and it appears likely that anthropogenic 

sources of iron are responsible for the observed high concentrations in these areas. In the case of 

the ore jetty, spillages and losses due to windborne dispersal of iron oxide during iron ore loading, 

stockpiling and transfer are the most likely sources of iron enrichment to the sediments in this 

locality. Monitoring of the windblown dust flux, at the multipurpose jetty, stock piles and ship 

loaders revealed average monthly iron oxide concentrations frequently greater than 300 mg.m -2. day - 

1 , and exceeding 2 400 mg.m -2. day -1 during December 2009- January 2010 at the multipurpose jetty 

(Zuncknel 2010). The source of elevated iron concentrations in the northwest end of the lagoon is 

unknown. It does not appear to be associated with the dredging activities and wharf construction 

taking place Donkergat as Fe concentrations in these localities are low (Figure 6.17). 

6.3.2 Trends in sediment metal concentrations over time 

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 trends in the concentration of these metals in 

sediments were plotted for several Small Bay sites as the concentrations of these metals have shown 

the greatest fluctuations and have most often exceeded the ERL value in this area. 

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 jetty. 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 6.18, Figure 

6.19, Figure 6.20 and Figure 6.21). 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 6.18, Figure 6.19, Figure 

6.20 and Figure 6.21). 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 2000-2009, 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 events between 2001 and 2010 (most recent), have revealed that with a few exceptions, 

metal concentrations have continued to decrease in Saldanha Bay and are much reduced from the 

exceptionally high concentrations recorded in 1999 and 2000. 

Figure 6.17. Variation in the concentration of Iron (Fe) in the sediments in Saldanha Bay and Langebaan 

Lagoon as indicated by the 2010 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 Jetty exceeded the ERL toxicity 


threshold of 1.2 mg/kg established by NOAA (Figure 6.18). 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 jetty 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. 

The temporal variations in the concentration of lead in Saldanha Bay sediments can be seen 

in Figure 6.19. 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 lead 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 jetty) showed an increase in lead 

concentrations in 2008. This is concerning considering that there was an apparent decline in lead 

concentrations at these sites between 1999/2000-2004. This increase in lead in the sediments may 

be linked to the maintenance dredging that took place at the Multi-Purpose Terminal and Mossgas 

Quay at the end of 2007/beginning of 2008 (see §4.3.1). The concentration of lead decreased again 

at all sites within Small Bay except the Multi-purpose Quay and the Channel End of the Ore Jetty in 

2009. Subsequent samples taken in 2010 revealed that lead concentrations had been further 

reduced at all sites with the exception of the Yacht Club basin, which increased very slightly. All lead 

concentrations detected in 2010 fell below the ERL indicating the recovery of the system since the 

2007/2008 dredge event. The sites where lead concentrations remain high are those associated 

with the export of lead and iron ore. The concentrations of lead in Big Bay have decreased 

progressively over the last eight years, which is encouraging and either indicates a reduction in the 

input of lead or an improvement in flushing/scouring of the sediments in this area. 

Figure 6.20 shows the temporal variation in copper concentrations within Saldanha bay 

sediments. As with all the other metals in Saldanha Bay sediments, copper concentrations peaked in 

1999 after the major 1997 dredging event. There was a subsequent decline in copper 

concentrations over the period 1999-2004 at the Mussel Farm, Channel end of the ore jetty, at the 

Multi-purpose quay and within Big Bay. The concentrations of copper in Big Bay and at the Mussel 

Farm have remained low (

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. Detailed studies examining the origin of the metals present in the Bay 

revealed that other metals occurring in Saldanha Bay are mostly of natural origin, except for the area 

adjacent to the Multi-purpose Quay where elevated concentrations are associated with ore dust fallout 

occurring during loading and unloading activities. Cadmium 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). 

The temporal variations in the concentration of iron in sediments around the ore jetty in 

Saldanha Bay can be seen in (Figure 6.22). The concentration of iron increased between 1999 and 

2004 at sites 14 and 15 which are closest in proximity to and on the downwind side (of the 

predominant SE winds) of the multi-purpose terminal. 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 jetty between 2004 and 2010. 

Dredging took place at the multi-purpose terminal 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 2008 sampling. Sediment iron concentration at this site did increase to 

the highest levels yet recorded in 2009, but decreased again in 2010 samples. 

The concentrations of iron around the ore jetty and multi-purpose terminal in Saldanha Bay 

decreased progressively at all sites between 2009 and 2010, which is encouraging and either 

indicates a reduction in the input of iron or an improvement in flushing of the sediments in this area. 

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 modeling and monitoring) amongst others. The volume of 

ore handled at the bulk terminal 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 jetty have remained stable or decreased. 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. 

Much concern was expressed over the possible contamination of the Bay and Lagoon by 

trace metals following the dredge event at Salamander Bay between 2009 and 2010. The trace 

metal concentrations in sediment collected from Donkergat and Salamander Bay were determined 

during the impact assessment process (Robinson 2010). It was revealed that none of the metals 

detected exceeded the ERL value, however the ratios of Cu:Al, Pd:Al and Ni:Al in Salamander Bay 

were found to exceed those reported in Big Bay and Langebaan Lagoon in 2008. The 2010 survey 

results revealed that both copper and nickel concentrations increased at sites BB29 and LL38 

(nearest to Salamander Bay) between 2009 and 2010 (Figure 6.23). Lead concentrations were found 

to increase dramatically at LL38, while lead was not detected at BB29. Increases in copper 

concentration were noted throughout the Big Bay and it is therefore unlikely that the dredge event 

lead to this increase at these sites. Furthermore the Cu:Al ratios at these sites are not elevated in 

relation to other sites in Big Bay and Langebaan Lagoon suggesting that the driver of this increase in 

Cu concentration may not be anthropogenic. 



8 

7 

6 

5 

4 

3 

2 

1 

0 


8 

7 

6 

5 

4 

3 

2 

1 

0 


8 

7 

6 

5 

4 

3 

2 

1 

0 

1980 1999 2000 2001 2004 2008 2009 2010 

1980 1999 2000 2001 2004 2008 2009 2010 

Yacht Club Basin 

1980 1999 2000 2001 2004 2008 2009 2010 

Mussel Farm 


Cadmium 


8 

7 

6 

5 

4 

3 

2 

1 

0 




8 

7 

6 

5 

4 

3 

2 

1 

0 

1980 1999 2000 2001 2004 2008 2009 2010 


8 

7 

6 

5 

4 

3 

2 

1 

0 

Multi -Purpose Quay 

1980 1999 2000 2001 2004 2008 2009 2010 


1980 1999 2000 2001 2004 2008 2009 2010 

Figure 6.18. Concentrations of Cadmium (Cd) in mg/kg recorded at six sites in Saldanha Bay between 1980 and 2009. Red lines indicate Effects Range Low values for 

sediments 


Lead (mg/kg) 

80 

70 

60 

50 

40 

30 

20 

10 

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80 

70 

60 

50 

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Lead (mg/kg) 

80 

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1980 1999 2000 2001 2004 2008 2009 2010 

1980 1999 2000 2001 2004 2008 2009 2010 


1980 1999 2000 2001 2004 2008 2009 2010 

Mussel Farm 


Lead 



Lead (mg/kg) 

80 

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50 

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Lead (mg/kg) 

80 

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1980 1999 2000 2001 2004 2008 2009 2010 

Lead (mg/kg) 

80 

70 

60 

50 

40 

30 

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0 


1980 1999 2000 2001 2004 2008 2009 2010 


1980 1999 2000 2001 2004 2008 2009 2010 

Figure 6.19. Concentrations of Lead (Pb) in mg/kg recorded at six sites in Saldanha Bay between 1980 and 2009. Red lines indicate Effects Range Low values for 

sediments 


Copper (mg/kg) 

45 

40 

35 

30 

25 

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45 

40 

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45 

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1980 1999 2000 2001 2004 2008 2009 2010 

1980 1999 2000 2001 2004 2008 2009 2010 


1980 1999 2000 2001 2004 2008 2009 2010 

Mussel Farm 


Copper 




45 

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0 


45 

40 

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1980 1999 2000 2001 2004 2008 2009 2010 

Cu (mg/kg) 

45 

40 

35 

30 

25 

20 

15 

10 

5 

0 


1980 1999 2000 2001 2004 2008 2009 2010 


1980 1999 2000 2001 2004 2008 2009 2010 

Figure 6.20. Concentrations of Copper (Cu) in mg/kg recorded at six sites in Saldanha Bay between 1980 and 2009. Red lines indicate Effects Range Low values for 

sediments 


Nickel (mg/kg) 

35 

30 

25 

20 

15 

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5 

0 


35 

30 

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35 

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1999 2000 2001 2004 2008 2009 2010 

1999 2000 2001 2004 2008 2009 2010 


1999 2000 2001 2004 2008 2009 2010 

Mussel Farm 


Nickel 




35 

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5 

0 


35 

30 

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10 

5 

0 

1999 2000 2001 2004 2008 2009 2010 


35 

30 

25 

20 

15 

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5 

0 


1999 2000 2001 2004 2008 2009 2010 


1999 2000 2001 2004 2008 2009 2010 

Figure 6.21. Concentrations of Nickel (Ni) in mg/kg recorded at six sites in Saldanha Bay between 1980 and 2009. Red lines indicate Effects Range Low values for 

sediments. 


16000 

14000 

12000 

10000 

8000 

6000 

4000 

2000 

0 

16000 

14000 

12000 

10000 

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1999 2000 2001 2004 2008 2009 2010 

1999 2000 2001 2004 2008 2009 2010 

16000 

14000 

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10000 

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6000 

4000 

2000 

0 

15 

16 

14 

1999 2000 2001 2004 2008 2009 2010 

±0 1 2 km 

Iron (mg/kg) 

!( 


!( 

!( 



!( 

!( 


Figure 6.22. Trends in sediment Iron concentrations over time at sediment sampling sites in the vicinity of the bulk terminal Saldanha. 

16000 

14000 

12000 

10000 

8000 

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1999 2000 2001 2004 2008 2009 2010 

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1999 2000 2001 2004 2008 2009 2010

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Cu Ni Pb 

BB29 

Cu Ni Pb 

LL38 

5 

0 

Cu Ni Pb 

1999 

2004 

2008 

2009 


2004 

2009 


BB22 

1999 

2004 

2008 

2009 


25 

20 

15 

10 

5 

0 

Cu Ni Pb 

Figure 6.23. Variation of trace metal concentrations in sediments in the Donkergat area and Big Bay as indicated by the 2010 results. 



BB21 

25 

20 

15 

10 

35 

30 

25 

20 

15 

10 

5 

0 

5 

0 

1999 

2004 

2008 

2009 


Cu Ni Pb 

BB26 

Cu Ni Pb 

BB30 

1999 

2004 

2008 

2009 


1999 

2009 

2010

In summary, 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 jetty 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 resuspends 

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. 

6.4 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 carboncontaining 

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. Low levels of contamination by aliphatic (straight chain) 

molecules, which pose the lowest ecological risk, were detected suggesting 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 terminal 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. While this is not of 

major concern at present, it is recommended that petroleum hydrocarbons in the vicinity of the ore 

terminal continue to be monitored in future. 


Table 6.6. Poly-aromatic hydrocarbons in sediment samples collected from Saldanha Bay and Langebaan 

Lagoon in April 2010. 

Hydrocarbon (mg/kg) ERL * ERM** SB14 SB15 SB16 SB21 SB22 

Acenaphthene 0.016 0.5

6.5 Summary of sediment health status of Saldanha Bay 

The overall health of sediments in Saldanha Bay have been monitored through four closely 

related aspects, namely; 1) sediment particle size composition, 2) concentrations of particulate 

organic matter (particulate organic carbon or POC, and particulate organic nitrogen or PON), 3) trace 

metal concentrations and 4) Poly-aromatic hydrocarbon concentrations. Organic matter and trace 

metals have been shown to be present in higher concentrations with an increasing cohesive fraction 

(mud) of sediment (i.e. a greater percentage of mud component results in higher concentrations of 

both organic matter and trace metals). The earliest records from Saldanha Bay (pre-development) 

indicate that the major component of the sediment comprised of sand particles, with an associated 

low concentration of POC, PON and trace metals. Construction of the Marcus Island causeway and 

ore jetty in the 1970’s led to a disruption (reduction) in water movement and circulation in the Bay, 

accompanied by an increase in the fine particulate fraction (mud) in the sediments of the Bay. This 

was also accompanied by a significant increase in concentrations of trace metals in the sediment 

(either from natural or anthropogenic sources) over the same period. Small Bay was dredged 

extensively in 1997/98 resulting in a massive disturbance to the sediment during which the mud 

fraction, together with the associated trace metals, was re-suspended and subsequently settled in 

the surface layers of the sediment. Subsequent to the dredging (1999), the percentage of mud 

present in Saldanha Bay was dramatically higher with a concomitant increase in organic matter and 

trace metal concentrations. Frequent sediment health monitoring (2000, 2001, 2004, 2008, 2009 

and 2010) has revealed an overall decrease in mud component and an increase in sand component 

since this time. This has been associated with an overall decrease in POC and trace metal 

concentrations over the same time period. Trace metals concentrations in the sediments in 

Saldanha Bay have improved dramatically since the extremely high levels recorded in 1999. 

However, concentrations are still elevated somewhat over natural levels. Two areas of concern in 

the Bay (consistently having comparatively high percentage mud component) are the Yacht Club 

basin and the Multi-purpose Quay. Concentrations of organic nitrogen in the Bay appear to be 

increasing with time, however, the increase is not directly associated with dredging events alone. 

The highest nitrogen concentrations are evident at the Yacht Club basin where high nitrogen load is 

expected due to fish factory waste effluent. 

Concentrations of Poly-aromatic hydrocarbons in sediment in the Bay has recently 

commenced again owing to concerns over crude oil imports and exports from the oil terminal in the 

Bay. Results at this stage indicate that concentration of poly-aromatic hydrocarbons in the 

immediate vicinity of the oil terminal are elevated above natural level but are not necessarily of 

concern. 


7 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, Calianassa 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 7.1. Seagrass (black) and saltmarsh (green) near Bottelarey in Langebaan Lagoon. Source: Google 

Earth. 


7.1 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 7.2). 

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 to 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 7.2). 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 


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

Langebaan Lagoon, 1972-2006. 


7.2 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 a 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 7.3,). 

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). 

Saltmarsh area (million m 2 ) 

20 

15 

10 

5 

0 

1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 

Figure 7.3. Change in saltmarsh area over time in Langebaan Lagoon. (Data from Gerricke 2008) 

No. saltmarsh patches 

30 

25 

20 

15 

10 

5 

0 

1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 

Figure 7.4. Change in the number of discrete saltmarsh patches over time in Langebaan Lagoon. (Data 

from Gerricke 2008) 


8 BENTHIC MACROFAUNA 

8.1 Background 

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 relatively rapidly 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. 

Benthic macrofauna community responses to anthropogenic impacts include changes in the 

growth rates of individual organisms, changes in reproductive output, and mortality, all of which can 

lead to changes in the relative abundance of individual species and hence community composition, 

reduction in the number of species present, and even complete disappearance of benthic organisms 

under severe circumstances (Warwick 1993). Common anthropogenic impacts of benthic 

macrofauna communities include physical disturbance (e.g. dredging), increased organic inputs 

(eutrophication) which can lead to hypoxia or even anoxia in sediment, elevated levels of trace 

metals, hydrocarbons and/or other anthopogenically produced compounds (e.g. pesticides) in 

sediments. 

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 that can be 

used to examine changes in community structure and hence ecosystem health, which are based on 

benthic invertebrate fauna information. These indices include those based on community 

composition, diversity and species abundance and/or 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 2010, are considered in 

this chapter. 

8.2 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 jetty and Marcus Island causeway. Available data 

from this time is mostly anecdotal (i.e. non-quantitative), and is 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 in 1975 (Christie and Moldan 1977), 

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. 


Figure 8.1. Benthic macrofauna sampling stations in 1975, 1999, 2004 and 2008. 

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 owing to the fact that techniques used to collect these samples were different from 

those used in earlier and subsequent studies. Samples from these earlier studies were mostly 

collected using some form of grab sampler, while the more recent studies (and some of the older 

studies - Christie and Moldan 1977, Bickerton 1999 and Anchor Environmental Consultants 2004, 


2009, 2010) all employed diver-operated suction sampling equipment to collect their samples. For 

example, 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 all of the studies since 1999 have made use of a diver-operated suction sampler 

which sampled an area of 0.08 m 2 to a depth of 30 cm. The former sampling technique (von Veen 

grab) would be expected to sample a smaller proportion and a different range of benthic 

macrofauna due to its limited ability to penetrate the sediment beyond the surface layers. The 

suction sampler employed in subsequent studies effectively samples to a much deeper depth, where 

many of the larger organisms, like prawns and worm, are expected to occur. The exact location of 

sites sampled during 1975 and 1999-2009 studies also differed slightly (Figure 8.1), which further 

confounds comparisons between these different data sets. 

Sampling for the State of the Bay reporting has been standardised to be comparable with 

the techniques employed in the later studies (Christie and Moldan 1977, Bickerton 1999 and Anchor 

Environmental Consultants 2004, 2009, 2010) both in terms of the equipment employed (diver 

operated suction sampler) and sites that are sampled. This is to ensure that direct comparisons 

between sampling events is possible and any changes in the community composition reflect real 

changes in the environment and are not an artefact of the sampling techniques used. Details of 

these methods are provided below. 

8.3 Approach and methods used in monitoring benthic macrofauna in 


8.3.1 Sample collection 

A total of 25 sites were sampled for benthic macrofauna in 2010, nine of which were in Small 

Bay, seven in Big Bay and nine in Langebaan Lagoon (Figure 8.2). 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, 2008 and 2009 and thus facilitate comparisons between 

these sets of data. The water depth ranged at the sampling stations ranged from 1.8 m to 21.0 m, 

with the shallowest sites being those in Langebaan Lagoon (Table 8.1). Samples were stored in 

plastic bottles and preserved with 5% formalin. 

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. 

8.3.2 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 (Small 

Bay, Big Bay and Langebaan Lagoon) in 2010 and 2) to assess changes in benthic community 

structure over time (i.e. in relation to the 1999, 2004, 2008 and 2009 surveys). Both the spatial and 

temporal assessments are necessary to provide a good indication of the state of the system. In 

addition, the ecological indicators were linked to environmental variables in an effort to ascertain 

what the dominant drivers of change are. 


Table 8.1. Depth at each of the sites sampled in 2010. 

Small Bay Depth (m) Big Bay Depth (m) Langebaan Lagoon Depth (m) 

SB1 9.9 BB20 21.0 LL31 4.6 

SB2 8.0 BB21 10.2 LL32 4.0 

SB3 6.3 BB22 12.5 LL33 3.1 

SB8 11.1 BB25 11.6 LL34 4.9 

SB9 15.5 BB26 16.0 LL37 1.8 

SB10 7.4 BB29 16.6 LL38 6.3 

SB14 16.0 BB30 3.9 LL39 4.7 

SB15 13.0 

SB16 17.0 

8.3.2.1 Community structure and composition 

LL40 3.8 

LL41 3.3 

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). 

The statistical package PRIMER 6 (Clarke and Warwick 1993) was used to analyze the benthic 

macrofauna data. Cluster analysis was performed in order to identify ‘natural groupings’ between 

samples (sites). Prior to cluster analysis data were root-root (fourth root) transformed and 

converted to a similarity matrix using the Bray-Curtis similarity coefficient. A dendrogram and a 

multi-dimensional scaling plot (MDS) were constructed from the similarity matrix in order to 

graphically view similarities between sample sites (Figure 8.4). Samples (sites) with similar species 

composition and abundance cluster together in such a plot, while those that are less similar are 

placed further apart in the cluster diagrams and ordination plots. Stress values associated with MDS 

plots are influenced by reduced dimensionality and increasing quantity of data (Clarke and Warwick 

1994), both of these factors resulting in higher stress values. Stress values

Figure 8.2. Benthic macrofauna stations sampled within Saldanha Bay and Langebaan Lagoon in 2010. 

8.3.2.2 Abundance Biomass Indices 

Abundance-Biomass Comparison (ABC) curves (Warwick 1993), also called k-dominance 

curves, were plotted using PRIMER v6. This procedure is a graphic method that compares the 

contribution by individual species to abundance and biomass in a particular sample (Warwick 1993). 

The theory supporting ABC curves states that under stable conditions where the frequency or 

intensity of disturbance is low, k-selected or larger, long-lived species make an important 

contribution to communities present (Warwick 1993). While they seldom dominate numerically, 


these species usually provide the largest contribution to biomass. Smaller r-selected, opportunistic 

species with a shorter life-span are also represented, and usually dominate numerically but make a 

small (often insignificant) contribution to overall biomass (Warwick 1993). However, in an area 

affected by pollution (or some other form of disturbance), the large and long-lived (k-selected) 

species are less favoured and opportunistic (r-selected) species eventually become dominant in both 

biomass and numbers. When cumulative contributions by species to overall abundance and biomass 

are plotted together on the same graph, in the case of undisturbed communities the curve for 

biomass generally lies above the curve for abundance for its entire length (Figure 8.3a). However, 

under moderate or low levels of pollution, the large competitive species are eliminated and the 

inequality between abundance and biomass dominants is reduced so that the curves coincide closely 

and may cross one another (Figure 8.3b). As pollution becomes more severe, benthic communities 

become increasingly dominated by one or a few small species and the abundance curve lies above 

the biomass curve throughout its length (Figure 8.3c). 

Cumulative % 

100 

50 

0 

UNDISTURBED 

1 5 10 

a b c 

MODERATELY 

DISTURBED 

GROSSLY 

DISTURBED 

1 5 10 1 5 10 

Species Rank (log scale) 

Figure 8.3. Hypothetical ABC curves for species biomass and abundance showing undisturbed, moderately 

disturbed and grossly disturbed conditions (after Warwick 1993). 

When examining large numbers of ABC curves, the area between the abundance curve and 

biomass curve is important, and is represented by the W statistic (Warwick 1993). Algebraically, the 

W statistic ranges between –1 and +1 with W = +1 for even abundance across species but biomass 

dominated by a single species (undisturbed) and W = –1 for patchy abundance and biomass being 

compiled of many species (severely disturbed) (Clarke and Warwick 1994). 

For 2010 data, the W statistic was calculated for each individual sampling station within 

Small Bay, Big Bay and Langebaan Lagoon to indicate the level of disturbance at different locations. 

The average W-statistic was also then calculated for Small Bay, Big Bay and Langebaan Lagoon for 

1999, 2004, 2008, 2009 and 2010. In order to test if the observed changes in W-statistic were 

statistically significant (p

8.3.2.3 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’ = - Σipi(log pi) (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 

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. 

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. 

8.3.2.4 Integration of Indices with Environmental Variables 

The aim of these analyses was to determine how the environmental variables (metal 

concentrations, organic content of sediment, grain size) relate to the observed biological patterns in 

macrobenthic community structure. This was done in two ways. Firstly, the concentrations of 

individual environmental variables were superimposed onto biotic MDS plots as circles of varying 

diameter (the larger the circle, the higher the concentration). These are known as ‘bubble plots’ and 

they allow one to easily identify the sites at which certain contaminants are elevated, as well as to 

determine if contamination patterns have any correlation to biotic structure. The second approach 

was to run principal component analysis (PCA) on environmental data, and determine if there was 

any contamination gradient among the sediment samples. 

Principal component analysis has been widely used for the analysis of environmental data as 

it can ‘unmask’ significant relationships between variables and relationships between samples 


(2)

(clustering of similar groups) (Meglen 1992). PCA is thus very similar to the MDS analysis that was 

used to discern similarities in biological data. PCA has also been used as a tool to characterize the 

anthropogenic loads of metals by the extraction of ‘latent’ variables (principal components) that 

explain the underlying variability in the data set (Simeonov et al. 2000, Wenchuan et al. 2001, 

Boruvka et al. 2005). PCA was applied using the PRIMER V 6 software package to sediment data 

(metals concentrations: Al, Fe, As Cd, Cr, Cu, Ni, Pb, Zn and organic carbon and nitrogen) to reduce 

the dimensionality of data set and understand the underlying variability in the data (Meglen 1992). 

Data were log transformed and normalized prior to analysis. The principal component that 

represented increasing/decreasing contamination load was thus extracted. 

8.4 Benthic macrofauna survey results 

8.4.1 Community Structure and Composition 

Five species that can be described as ‘typical’ of Small Bay, Big Bay and Langebaan Lagoon 

(based on Bray-Curtis Similarities) are shown in Table 8.2. Small Bay samples were mostly 

dominated in terms of abundance, by the mud prawn Upogebia capensis, the bivalve Tellina 

gilchristi, the gastropod Nassarius speciosus and the polychaete Nephtys hombergii. 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 jetty and the 

Marcus Island causeway (Jackson and McGibbon 1991). The deposit feeding bivalve T. gilchristi and 

the carnivorous purple-lipped dog whelk N. speciosus are also opportunistic species that can tolerate 

anoxic conditions, and have been known to occur in high abundance under the mussel rafts in Small 

Bay (Stenton-Dozey 2001). The large bristle worm, 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. The species is also known to tolerate a low oxygen concentration (Fauchald and Bellan 

2009), which is characteristic of Small Bay. The predatory crown crab (Hymenosoma obiculare), also 

found at most of the Small Bay sites, lives in soft sediments, spending the day buried and coming out 

at night to feed on small crustaceans (Hill and Forbes 1979). 

The Big Bay sites were dominated by the polychaetes Scolaricia dubia, Glycera convoluta and 

Mediomastus capensis. The deposit feeding bivalve T. gilchristi and the carnivorous purple-lipped 

dog whelk N. speciosus, were also common at sites in Big Bay. The polychaete M. capensis is an 

opportunistic species that can tolerate anoxic conditions, and have been known to occur in high 

abundance under the mussel rafts in Small Bay (Stenton-Dozey 2001). The highly active carnivorous 

predator, G. convoluta, burrows in soft sediment and feeds on crustaceans and other polychaetes 

(Meunier et al. 2002). 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). Many of the same species are found within Small Bay and Big Bay indicating that these two 

locations are characterised by similar environmental variables which govern species distribution. 

The macrofauna in Langebaan Lagoon was dominated by three species of polychaetes, 

Marphysa depressa, G. convoluta and a species of Maldanidae. M. depressa and Maldanidae are 

deposit feeding polychaetes which burrow in soft sediment. In addition, the opportunistic isopod 

Cirolana hirtipes was found in high numbers at eight of the sites sampled in Langebaan Lagoon, 

while Ostracoda were found at six of the sites. 


Table 8.2. Five most dominant species within Small Bay, Big Bay and Langebaan Lagoon recorded in 

sampling conducted during 2010. 

Small Bay Big Bay Langebaan Lagoon 

Species Common Species Common Species Common 

Name 

Name 

Name 

Upogebia capensis Mud prawn Scolaricia dubia Polychaete Marphysa 

depressa 

Polychaete 

Tellina gilchristi Gilchrist's Glycera convoluta Polychaete Cirolana hirtipes Hairy- 

tellin 

legged 

cirolanid 

Nassarius speciosus Dog whelk Nassarius speciosus Dog whelk Glycera convoluta Polychaete 

Nephtys hombergi Sand worm Tellina gilchristi Gilchrist's 

tellin 

Maldanidae sp. Polychaete 

Hymenosoma Crown crab Mediomastus Polychaete Ostracoda Sp. Ostracod 

orbiculare 

capensis 

8.4.1.1 Spatial analyses 

Dendrogram and 2-dimensional MDS ordination plots (Figure 8.4, representing the similarity 

of benthic macrofauna communities between the sites sampled in 2010), indicates that at the 20% 

level of similarity there is a clear distinction between samples collected from Langebaan Lagoon (LL) 

and those collected in Saldanha Bay (SB and BB). In addition there was a grouping of Big Bay 

samples BB25 and BB29 at the 35% level of similarity, and Small Bay samples SB3, SB2, SB8 and SB10 

at the 45% level of similarity. The site BB30, which previously clustered with BB25 and BB29, is now 

grouped at the 20% level with the Langebaan Lagoon sites. The results from the ANOSIM analysis 

confirm that the species composition in Langebaan Lagoon is significantly different from that in Big 

Bay (p = 0.02) and Small Bay (p = 0.01), but that there is no significant difference in species 

composition between Big Bay and Small Bay (p = 0.66). Langebaan Lagoon thus appears to support a 

different benthic community to Saldanha Bay, and this is consistent with results obtained in 2004, 

2008 and 2009. 

The cluster analysis and MDS also allows 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 2008 and 

2009, the site SB1 is an obvious outlier, most likely due to the fact that it had very low species 

abundance and diversity (only 2 species in 2008 and 4 species in 2009 and 2010). As found in 2008 

and 2009, this site is characterized by very high levels of organic pollution and high trace metal 

concentrations. One Langebaan Lagoon sample is separated from all the other Lagoon samples, 

namely LL38. The sediment at this site contains a very high percentage of coarse grained particles 

(% Gravel), is deeper than all the other Langebaan Lagoon sites and hence has a very different 

species composition to the other sites within the lagoon. 

The water depth at site BB30 in Big Bay is similar to that of the Lagoon. The macrofauna 

sample taken at BB30 was, like the samples from Langebaan Lagoon, characterised by the presence 

of the polychaete M. depressa and Ostracoda sp., and the absence of the mud prawn U. capensis 

and the dog whelk N. speciosus, which was found at all other Saldanha Bay sites. This clearly 

indicates that depth plays a major role in influencing the community composition in this system, 

whether it be a direct or indirect influence. Given the depth and the similar community 

composition, it is likely that the conditions experienced at BB30 are more similar to those 

experienced in the Lagoon than those at the other Saldanha Bay sites. 


The Big Bay samples BB 25 and BB29 grouped at the 35% level of similarity. These samples 

were characterized by the virtual absence of the coastal mud prawn U. capensis which was common 

throughout Small Bay and the rest of Big Bay. The opportunistic whelk N. speciosus, which was in 

2009 absent at BB25 and BB29, was recorded at these sites in 2010. The suspension feeding Sea-Pen 

Virgularia schultzei was found in high abundance at BB25, BB29 and BB30 in 2004 and 2009. It was 

not recorded at these sites in 1999 and 2008 and was found at a much lower abundance in 2010. 

These three sites are the only sites within Saldanha Bay where the sea pen has been recorded since 

1999 and it is possible that these sites are more exposed and have better water circulation than the 

other Big Bay sites. The fluctuations in the numbers of sea pens at these sites may be indicative of a 

very patchy distribution. 

(a) 

(b) 

Figure 8.4. Dendrogram (a) and MDS ordination plot (b) showing similarities between sites based on the 

species composition for benthic macrofauna in Saldanha Bay, 2010. SB = Small Bay, BB = Big 

Bay, LL = Langebaan Lagoon. Brackets on the dendrogram show groups of samples at the 25% 

level of similarity. 


SIMPER analysis revealed that the species that contributed most to the dissimilarity in 

species composition between Langebaan Lagoon and Saldanha Bay, were Upogebia capensis, 

Marphysa depressa, Notomastus latericeus and Ampelisca spinimama. The numbers of the mud 

prawn U. capensis and the amphipod A. spinimama were relatively low in Langebaan Lagoon when 

compared to Small and Big Bay, whereas the polychaetes M. depressa and N. latericeus were found 

almost exclusively within Langebaan Lagoon. Species composition within Langebaan Lagoon was 

also characterized by large numbers of Ostracods, which were not common in either Small Bay or Big 

Bay. Ostracods are small crustaceans (1-4 mm), commonly known as seed shrimps, that mostly 

crawl through surface layers of sand or mud. They may be carnivores, filter feeders or scavengers 

(Branch and Griffiths 1994). In addition the scavenging isopod Cirolana hirtipes was found 

exclusively in Langebaan Lagoon in while the dog whelk Nassarius speciosus was found exclusively 

Saldanha Bay. 

8.4.1.2 Temporal Analysis 


The suspension feeding sea-pen communities, which were reported to occur in abundance 

in Small Bay in 1975, have never been recovered at any sites in Small Bay since this time. To some 

extent this species seems to have been replaced by a range of detritivores which have become the 

dominant functional group in terms of biomass and abundance in Small Bay. The dominance of 

detritivores and loss of a suspension feeding community from Small Bay is most likely a function of 

reduced flow, altered wave energy, deposition of fine sediments and increased organic matter, 

which resulted from harbour construction and fish factory, mussel farm and sewerage effluents that 

have been discharged into the Bay over the years. 

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 Terminal 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 2010. Interestingly the abundance of crustaceans reduced 

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 and then reduced 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 possibly an indication of the succession of the benthic macrofauna communities following the 

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. 


2007/08 dredging. Other signs of the recovery of the system evident from the 2010 survey include 

the increase in the average biomass and abundance of gastropods and bivalves between 2008 and 

2010. 

Temporal differences in the community composition could also be seen at a finer scale 

within Small Bay. These differences were not however significant. Sites SB14 and SB15, at the Multi 

Purpose Terminal, grouped separately to all other Small Bay sites at a 30% level of similarity, while 

SB1, in the yacht club basin, was a clear outlier. Both 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 macrobenthic community at the yacht club basin is in a 

depauperate state. The overall abundance and biomass has been significantly lower than all other 

sites in Small Bay since 1999 and there has been no consistency in the community composition. This 

either suggests that the community is extremely patchy or that it is in a constant state of change 

given the high levels of environmental stress. The biomass of the macrobenthic communities at the 

Multi Purpose Terminal has been consistently lower than other Small Bay sites, while the abundance 

of organisms has been comparable to other sites in Small Bay. This indicates that the macrobenthic 

communities at the Multi Purpose Terminal comprise mostly r-selected opportunistic species with 

low biomass. The benthic community around the Multi Purpose Terminal is characterised, in terms 

of biomass, by the carnivorous whelk N. speciosus and the deposit feeding bivalve T. gilchristi while 

other sites in Small Bay are characterised by the detritivores Upogebia capensis and Ochaestoma 

capense. These differences may be attributed to differences in particle size composition and organic 

loading at the sites. 

The biomass of the benthic community in Small Bay decreased between 2004 and 2008. The 

most noticeable decreases of biomass were seen at the multipurpose terminal. The maintenance 

dredging that took place at the Multi Purpose Terminal in 2007/8, is most likely the main contributor 

to this change, however the effects cannot be isolated from other anthropogenic activities in this 

area of the Bay given the lack of data between 2005 and 2007. Since 2008 most of the sites have 

shown clear signs of recovery, however this recovery process is not consistent at all sites in Small 

Bay. The differences in the recovery process include differences in the species assemblages 

colonising sites as well as differences in the rates of increase of large, k-selected species. These 

differences are most likely due to the varied current conditions in the Bay as well as other localised 

anthropogenic impacts such as sewerage, mussel farm and fish factory effluent. 


Proportion of total number of individuals 

Average number of individuals per m² 

2500 

2000 

1500 

1000 

500 

0 

100% 

90% 

80% 

70% 

60% 

50% 

40% 

30% 

20% 

10% 

0% 

1999 2004 2008 2009 2010 


1999 2004 2008 2009 2010 



Average wet mass per m² 

Proportion of total Biomass 

1400 

1200 

1000 

800 

600 

400 

200 

0 

100% 

90% 

80% 

70% 

60% 

50% 

40% 

30% 

20% 

10% 

0% 

1999 2004 2008 2009 2010 


1999 2004 2008 2009 2010 


Figure 8.5. Overall trends in the biomass and abundance of benthic macrofauna in Small Bay as shown by taxonomic and functional groups. 

Polychaeta 

Crustacea 

Gastropoda 

Bivalvia 

Echinodermata 


Pennatulacea (sea pen) 

Echiuroidea (Tongue worm) 


SCAVENGER 

PREDATOR 

GRAZER 

FILTER FEEDER 

DETRITIVORE

Wet mass per m² 


45 

40 

35 

30 

25 

20 

15 

10 

5 

0 

3500 

3000 

2500 

2000 

1500 

1000 

500 

0 

DREDGE 

DREDGE 

BIOMASS/m² 


DREDGE 

1999 2004 2008 2009 2010 

SB1 

Mussel Farm 

DREDGE 

1999 2004 2008 2009 2010 

SB9 


3500 

3000 

2500 

2000 

1500 

1000 

500 

0 

1999 2004 2008 2009 2010 

Upogebia capensis Thaumastoplax spiralis Tellina sp. Squilla armata Polydora sp. 

Philine aperta Other Ochaetostoma capense Nephtys hombergi Nassarius sp. 

Mediomastus capensis Marphysa sp. Hymenosoma orbiculare Ampelisca sp. 


DREDGE 

Bok River Mouth 

DREDGE 

SB3 


450 

400 

350 

300 

250 

200 

150 

100 

50 

0 

DREDGE 


1999 2004 2008 2009 2010 


450 

400 

350 

300 

250 

200 

150 

100 

50 

0 

3500 

3000 

2500 

2000 

1500 

1000 

500 

0 

DREDGE 

DREDGE 

Multi Purpose Terminal 

DREDGE 

SB14 


DREDGE 

1999 2004 2008 2009 2010 

SB15 

Ore Jetty 

DREDGE 

1999 2004 2008 2009 2010 

Figure 8.6. Trends in the biomass of dominant benthic macrofauna species at six sites in Small Bay. (important to note different scales used on graphs). 

SB16 

Anchor Environmental

Number of individuals per m² 


700 

600 

500 

400 

300 

200 

100 

0 

4500 

4000 

3500 

3000 

2500 

2000 

1500 

1000 

500 

0 

700 

600 

500 

400 

300 

200 

100 

0 

DREDGE 

DREDGE 

ABUNDANCE/m² 

1999 2004 2008 2009 2010 

SB1 

1999 2004 2008 2009 2010 

1999 2004 2008 2009 2010 


DREDGE 

Mussel Farm 

DREDGE 

SB9 


4500 

4000 

3500 

3000 

2500 

2000 

1500 

1000 

500 

0 

1999 2004 2008 2009 2010 

Upogebia capensis Thaumastoplax spiralis Tellina sp. Squilla armata Polydora sp. 

Philine aperta Other Ochaetostoma capense Nephtys hombergi Nassarius sp. 

Mediomastus capensis Marphysa sp. Hymenosoma orbiculare Ampelisca sp. 

DREDGE 

Bok River Mouth 


DREDGE 

SB3 


4500 

4000 

3500 

3000 

2500 

2000 

1500 

1000 

500 

0 

DREDGE 



1999 2004 2008 2009 2010 

4500 

4000 

3500 

3000 

2500 

2000 

1500 

1000 

500 

0 

4500 

4000 

3500 

3000 

2500 

2000 

1500 

1000 

500 

0 

DREDGE 

DREDGE 


DREDGE 

SB14 

DREDGE 

1999 2004 2008 2009 2010 

Ore Jetty 


DREDGE 

SB15 

1999 2004 2008 2009 2010 

SB16 


Figure 8.7. Trends in the abundance of dominant benthic macrofauna species at six sites in Small Bay. (important to note different scales used on graphs)


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 may have 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 a large increase 

in the numbers of polychaetes (low biomass species) within Big Bay. This increase in polychaetes in 

2009 was principally owing to the presence of Spionidae sp. and Prionospio saldanha, although their 

distribution was mostly limited to site BB30 and BB25 (also sites where the sea-pen was most 

abundant). Other detritus feeding polychaetes found throughout Big Bay in both 2008 and 2009 

include Nephtys hombergi and Glycera convoluta. It is not clear why there was this increase in the 

numbers of polychaetes in Big Bay between 2008 and 2009. The increase in the overall biomass of 

the benthic community between 2008 and 2009 was principally attributed to an increase in large 

crustacean species such as the mud prawn Upogebia capensis, several species of crab as well as the 

mantis shrimp Pterygosquilla armata capensis. 

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. Indeed, much of the reduced abundance could 

be attributed to the decrease in the numbers of small bodied polychaetes. This is a typical sign of 

succession in a system following a disturbance, and indicates that the benthic macrofauna 

community is probably recovering following disturbances that occurred in Saldanha Bay between 

2004 and 2008. 

The biomass of the benthic community in Big Bay has been dominated by detritivores in all 

years except 2008 where 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 themselves in this part of the Bay. 

Filter feeding organisms are more abundant and make a greater contribution to the biomass of 

benthic macrofauna in Big Bay than in Small Bay. 

Spatial and temporal differences in the community composition could also be seen at a finer 

scale within Big Bay. These differences were not significant, however. The sites along the ore jetty 

and at the mouth of the Bay were, like most sites in Small Bay, dominated by the detritivores 

Upogebia capensis and Ochaestoma capense. These sites have consistently supported higher 

biomass and lower abundance of benthic macrofauna than sites further south. This is related to the 

fact that the community at these sites is dominated by the relatively large coastal mud prawn 

Upogebia capensis. The benthic community composition varied between sites further south and in 

the middle of the Bay with no clear pattern. The sensitive sea-pen communities have made up a 

notable proportion of the overall biomass and abundance of two sites along the eastern edges of Big 

Bay since 2004. These sites had a lower percentage mud than other sites in Big Bay suggesting that 


the spatial differences in community composition in Big Bay could be attributed to particle size 

composition. 

Both the abundance and biomass of benthic macrofauna decreased at site BB29 between 

2009 and 2010. The results of the sediment analysis revealed that there had been an increase in the 

percentage mud at BB29 between 2009 and 2010, which may have been related to the dredging 

conducted in Salamander Bay in 2009. The results of this survey suggest therefore that the dredging 

conducted in 2009 may have had minor localized impacts on the benthic macrofauna community in 

the south western region of Big Bay. However, it is not possible to isolate the disturbance that may 

have lead to this reduction in biomass and abundance as the abundance and biomass of benthic 

macrofauna was reduced at two other sites (BB20 and BB30) which were further from the dredged 

site and experienced no increase in the percentage mud content of the sediment. 

The biomass and abundance of the benthic community at the northern end of Big Bay 

decreased between 2004 and 2008. The maintenance dredging that took place at the Multi-Purpose 

Terminal in 2007/8, is most likely the main contributor to this change, however, the effects cannot 

be isolated from other anthropogenic activities in the Bay given the lack of data between 2005 and 

2007. Since 2008, most of the sites at the northern end of Big Bay have shown clear signs of 

recovery, however, this recovery process has differed in terms of species composition and in the 

extent of increases in biomass and abundance. These differences are most likely due to the varied 

current conditions in the bay as well as other localised anthropogenic impacts such as minor 

dredging events. 


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 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 loss or reduction in the abundance of many of the taxa present 

in 1975 (bivalves, polychaete worms, gastropods, echinoderms, and sea-pens). 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 (Figure 8.11). 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 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 overall 

biomass measured in 2010 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 system is in a disturbed state and may have undergone an ecosystem shift. The 2010 survey 

reveals that the benthic community in the Lagoon is in a state of recovery and that conditions are 

potentially improving given the increase in the proportion of filter feeder present. 




3000 

2500 

2000 

1500 

1000 

500 

0 

100% 

90% 

80% 

70% 

60% 

50% 

40% 

30% 

20% 

10% 

0% 

1999 2004 2008 2009 2010 


1999 2004 2008 2009 2010 




Proportion of total biomass 

800 

700 

600 

500 

400 

300 

200 

100 

0 

100% 

90% 

80% 

70% 

60% 

50% 

40% 

30% 

20% 

10% 

0% 

1999 2004 2008 2009 2010 


1999 2004 2008 2009 2010 

Figure 8.8. Overall trends in the biomass and abundance of benthic macrofauna in Big Bay as shown by taxonomic and functional groups. 


Polychaeta 

Crustacea 

Gastropoda 

Bivalvia 

Echinodermata 





SCAVENGER 

PREDATOR 

GRAZER 

FILTER FEEDER 

DETRITIVORE




3000 

2500 

2000 

1500 

1000 

500 

0 

3000 

2500 

2000 

1500 

1000 

500 

700 

600 

500 

400 

300 

200 

100 

0 

0 

DREDGE 

DREDGE 

1999 2004 2008 2009 2010 

N/S 

DREDGE 

DREDGE 

BB21 

1999 2004 2008 2009 2010 

BB20 

1999 2004 2008 2009 2010 

BB29 

DREDGE 

SALAMANDER 


3000 

2500 

2000 

1500 

1000 

500 

0 

DREDGE 

1999 2004 2008 2009 2010 


DREDGE 

BB22 




700 

600 

500 

400 

300 

200 

100 

700 

600 

500 

400 

300 

200 

100 

700 

600 

500 

400 

300 

200 

100 

0 

0 

0 

DREDGE 

DREDGE 

1999 2004 2008 2009 2010 

DREDGE 

DREDGE 

BB26 

1999 2004 2008 2009 2010 

DREDGE 

BEACH 

BB25 

N/S 

1999 2004 2008 2009 2010 

BB30 


1400 

1200 

1000 

800 

600 

400 

200 

0 

1999 

2008 

BB20 



Virgularia schultzei 

Upogebia sp. 

Tellina sp. 

Pterygosquilla armata capensis 

Philine aperta 


Ochaetostoma capense 

Nautilocorystes ocellata 

Nassarius sp. 

Macoma sp. 

Hydroids 

Holothurian sp. 

Goneplax rhomboides 

Dosinia spp. 

Diopatra sp. 

Choromytilus meridionalis 

Callianassa sp. 

Bullia annulata 

Figure 8.9. Trends in the biomass of dominant benthic macrofauna species at six sites in Small Bay. (important to note different scales used on graphs) 

Anemone

Number Individuals per m² 



4500 

4000 

3500 

3000 

2500 

2000 

1500 

1000 

500 

4500 

4000 

3500 

3000 

2500 

2000 

1500 

1000 

500 

0 

0 

7000 

6000 

5000 

4000 

3000 

2000 

1000 

0 

DREDGE 

DREDGE 

N/S 

DREDGE 

1999 2004 2008 2009 2010 

DREDGE 

BB21 

1999 2004 2008 2009 2010 

BB20 

DREDGE 

SALAMANDER 

1999 2004 2008 2009 2010 

BB29 


4500 

4000 

3500 

3000 

2500 

2000 

1500 

1000 


500 

0 

DREDGE 

DREDGE 

1999 2004 2008 2009 2010 

BB22 

Abundance/m² 




7000 

6000 

5000 

4000 

3000 

2000 

1000 

4500 

4000 

3500 

3000 

2500 

2000 

1500 

1000 

7000 

6000 

5000 

4000 

3000 

2000 

1000 

500 

0 

0 

0 

DREDGE 

DREDGE 

DREDGE 

DREDGE 

1999 2004 2008 2009 2010 

1999 2004 2008 2009 2010 

DREDGE 

BEACH 

BB26 

BB25 

N/S 

1999 2004 2008 2009 2010 

Figure 8.10. Trends in the abundance of dominant benthic macrofauna species at six sites in Small Bay. (important to note different scales used on graphs) 

BB30 


1200 

1000 

800 

600 

400 

200 

0 

BB20 


Virgularia schultzei 

Urothoe sp. 

Upogebia capensis 

Spionidae sp. 

Sabellides sp. 

Prionospio sp. 

Polydora sp. 

Pinnixa occidentalis 


Orbinia sp. 

Ochaetostoma capense 

Nemertea 

Nassarius sp. 

Maldanidae sp. 

Hydroids 

Holothuroidea 

Dosinia sp. 

Diopatra sp. 

Cirratulus sp. 

Callianassa kraussi 

Brachyura sp. 

Anemone 

Ampelisca sp.



1800 

1500 

1200 

900 

600 

300 

0 

100% 

90% 

80% 

70% 

60% 

50% 

40% 

30% 

20% 

10% 

0% 

1999 2004 2008 2009 2010 


1999 2004 2008 2009 2010 




Proportion of total biomass 

350 

300 

250 

200 

150 

100 

50 

0 

100% 

90% 

80% 

70% 

60% 

50% 

40% 

30% 

20% 

10% 

0% 

1975 1999 2004 2008 2009 2010 


1975 1999 2004 2008 2009 2010 



Polychaeta 

Crustacea 

Gastropoda 

Bivalvia 

Echinodermata 




SCAVENGER 

PREDATOR 

GRAZER 

FILTER FEEDER 

DETRITIVORE 

Figure 8.11. Overall trends in the abundance and biomass of benthic macrofauna in Langebaan Lagoon as shown by taxonomic and functional groups.

8.4.2 Abundance Biomass Indices 

8.4.2.1 Spatial analyses 

The W statistics calculated for Small Bay, Big Bay and Langebaan Lagoon in 2010 are 

represented in Figure 8.12. The majority of sites within Small Bay appear to be moderately 

disturbed, with the exception of site SB15 (lowest W-statistics), which is slightly more than 

moderately disturbed (< 0). The area below the ore jetty in Small Bay has been recognized as a ‘key 

problem area’ that suffers from reduced water movement. Fine grained particles and organic 

matter, to which toxic substances such as metals and hydrocarbons adsorb, tend to accumulate in 

this area (CSIR 2002). Indeed hydrocarbons were detected at sites SB14 and SB15 and the highest 

concentration of lead was reported at these sites in 2010. 

The sites in Big Bay range from moderately disturbed in the region near the ore jetty (BB21, 

BB22 and BB26) and at the southern extent of the Bay, near the opening to Langebaan Lagoon, to 

undisturbed in the middle section of the Bay (BB25 and BB29). It is likely that the middle section of 

Big Bay is comparatively well flushed, which would ensure that pollution loading at these sites 

remains low. The slightly higher levels of disturbance at the southern end of Big Bay (BB30) is most 

likely natural disturbance given that this site is relatively shallow and is most likely subject to high 

water movements (Table 8.1). The W statistic for the Langebaan Lagoon sites varied and appeared 

patchy. Sites LL39 and LL41 were moderately disturbed. The disturbance at these sites may be due 

to natural variability given that these are shallow sites which are subjected to high water movement 

and tidal variation. The remainder of the lagoon was slightly less disturbed in comparison. 

Overall the W statistic indicates that Saldanha Bay and Langebaan Lagoon are both 

moderately disturbed systems (W statistic ranging between -0.05 and 0.33) with some areas 

subjected to slightly higher levels of disturbance which is most likely a result of both anthropogenic 

(Small Bay area) and natural (southern reaches of Langebaan Lagoon) disturbance. 


Figure 8.13 shows the average W-statistic for Small Bay, Big Bay and Langebaan Lagoon for 

each of the sampling years (1999, 2004, 2008, 2009 and 2010). It is clear that there was a significant 

decrease in benthic health within Small Bay (decreased W-statistic) between 1999 and 2008, and 

that high-abundance low-biomass species were becoming more dominant over this time period. The 

average W-statistic however increased significantly within Small Bay between 2008 and 2009, 

indicating improved benthic health and a reduction in the numbers of opportunistic r-selective 

species. This was reflected in the composition of species recorded in 2009 which revealed an 

increase in the percentage contribution of bivalves and gastropods between 2008 and 2009. The W 

statistic however reduced between 2009 and 2010. 


Figure 8.12. Variation in the W statistic calculated for the benthic macrofauna in Saldanha Bay and 

Langebaan Lagoon as indicated by the 2010 survey results. (1 = Undisturbed, 0 = moderately 

disturbed, -1 = disturbed) 

Changes in the average W-statistic for Big Bay over the last decade show a positive 

trajectory of change until 2008. Between 2008 and 2009 the average W-statistic for Big Bay 

decreased, and this may be due to the proliferation of the polychaetes as discussed above. A 

sudden increase in the abundance of small opportunistic species such as polychaetes (and hence a 

reduction in the W-statistic) typically indicates that there has been some form of environmental 

disturbance. This disturbance may however be natural, which is most likely the case since Big Bay is 

an area subjected to high wave activity and good water circulation. Examination of the sediment 

results reveals that there had not been a significant increase in the percentage organic carbon (POC) 


and percentage organic nitrogen (PON) between 2008 and 2009 in Big Bay, and the concentrations 

of mud and heavy metals were very low within Big Bay. These results together with the lack of 

obvious anthropogenic discharges into Big Bay suggest that the changes in species composition 

within the Bay are most likely a result of natural perturbations. The sites at which the numbers of 

polychaetes increased the most were also the sites where the sensitive sea-pen were found. It is 

thus unlikely that the sudden appearance of polychaetes is due to an increase in pollution. The 

average W statistic calculated for Big Bay in 2010 was higher than that of 2009. This may be due to 

the reduction in the densities of polychaetes which suggests that pollution levels had reduced 

between 2009 and 2010. However, this does not correlate with physical data recorded in Big Bay, 

which suggests that these fluctuations may be a consequence of natural perturbations and 

community interactions. 

The W statistics calculated for each of the sites in Big Bay in 1999, 2004, 2008, 2009 and 

2010 were compared in Table 8.4. The W statistic at three of the seven sites in Big Bay has reduced 

since these sites were first surveyed (in 1999 or 2008). All three sites were positioned near the ore 

jetty at the northern end of Big Bay. The disturbance level, as indicated by the W statistic, at these 

sites is moderate and it is most likely that the source of the disturbance is primarily anthropogenic. 

The W statistic increased at six of the seven sites in Big Bay between 2009 and 2010 indicating that 

the proportion of large, long-lived species in the community had increased. This suggests that 

disturbance has been reduced and that the benthic community is recovering at these sites. 

Average W statistic 


0.35 

0.30 

0.25 

0.20 

0.15 

0.10 

0.05 

0.00 

-0.05 

-0.10 

0.35 

0.30 

0.25 

0.20 

0.15 

0.10 

0.05 

Year; LS Means 

Current effect: F(4, 53)=3.8349, p=.00825 

Effective hypothesis decomposition 

Vertical bars denote 0.95 confidence intervals 

Include condition: V3="SB"$ 

1999 


Current effect: F(3, 24)=.33708, p=.79866 

Effective 2004hypothesis 2008 decomposition 2009 2010 


Include condition: Year V3="LL"$ 

2004 2008 2009 2010 

Year 







Include condition: V3="BB"$ 

1999 2004 2008 2009 2010 



0.5 

0.4 

0.3 

0.2 

0.1 

0.0 

-0.1 

Year 


Figure 8.13. Mean W statistic (± 0.95 confidence intervals) for all years sampled in Small Bay, Big Bay and 

Langebaan Lagoon (W = 1 indicates undisturbed, W = 0 indicates moderately disturbed, W = -1 

indicates grossly disturbed)

Table 8.3. W statistics at all stations sampled between 1999 and 2010 in Small Bay (1 = Undisturbed, 0 = 

moderately disturbed, -1 = Grossly disturbed) (Red indicates a decrease an green indicates an 

increase since the previous year) 

1999 2004 2008 2009 2010 

SB1 0.203 0.135 0.033 0.834556 0.194043 

SB2 0.201 0.128 0.059 0.127981 0.21042 

SB3 0.237 0.158 0.131 0.078899 0.17621 

SB8 0.145 0.094 0.02 0.091269 0.072487 

SB9 0.321 0.121 0.097 0.15265 0.03729 

SB10 0.251 0.144 0.018 0.222488 0.213037 

SB14 0.37 0.212 0.07 0.048497 0.123344 

SB15 0.073 0.01 -0.067 0.043537 -0.0529 

SB16 0.326 0.199 0.082 0.155185 0.148646 

Table 8.4. W statistics at all stations sampled between 1999 and 2010 in Big Bay (1 = Undisturbed, 0 = 

moderately disturbed, -1 = Grossly disturbed)(Red indicates a decrease and green indicates an 

increase since the previous year). 

1999 2004 2008 2009 2010 

BB 20 - - 0.523014 0.121988 0.167017 

BB21 0.277 0.223 0.078068 0.063047 0.162386 

BB22 0.098 0.147 -0.07879 0.035334 0.109971 

BB25 -0.07 0.182 0.028515 0.108905 0.290485 

BB26 0.306 0.094 0.549562 0.180872 0.112742 

BB29 0.083 0.266 0.419399 0.226174 0.248659 

BB30 0.07 0.153 - -0.03724 0.095815 

The W statistics calculated for each of the sites in Langebaan Lagoon in 2004, 2008, 2009 

and 2010 were compared in Table 8.5. The long term fluctuations in the mean W statistic for 

Langebaan Lagoon did not correlate with physical parameters or any obvious anthropogenic 

discharges suggesting that the variations in the benthic community is caused predominantly by 

natural disturbance. The W statistic at six of the nine sites in Langebaan Lagoon reduced between 

2009 and 2010. Most of the disturbance in the lagoon, particularly in the sanctuary (southern 

reaches), is most likely a result of the shallow nature of the lagoon and the fact that it is subject to 

strong currents and tidal activity. Indeed, the mud content recorded in the sediments in 2010 had 

reduced at most sites since 2009, suggesting increased flushing. 


Table 8.5. W statistics at all stations sampled between 2004 and 2010 in Langebaan Lagoon (1 = 

Undisturbed, 0 = moderately disturbed, -1 = Grossly disturbed)(Red indicates a decrease an 

green indicates an increase since the previous year) 

2004 2008 2009 2010 

LL 31 0.276 0.178 0.26497 0.220529 

LL 32 0.108 0.303 0.077271 0.232452 

LL 33 0.216 0.099 0.415304 0.281207 

LL 34 0.233 0.057 0.265976 0.247906 

LL 37 0.295 0.362 0.256901 0.333258 

LL 38 - - 0.166232 0.183672 

LL 39 - - 0.244047 -0.06678 

LL 40 - - 0.188317 0.184814 

LL 41 - - 0.195189 0.032135 

8.4.3 Species Diversity Indices 

8.4.3.1 Spatial Analysis 

Mean values (± SE) for various diversity indices associated with macrobenthic communities 

in Small Bay, Big Bay and Langebaan Lagoon have been represented graphically in Figure 8.14. 

Species diversity (H’), species evenness (J), species richness (d) and the total number of species (S) is 

notably higher in Big Bay and Langebaan Lagoon when compared to Small Bay, but the difference is 

not significant (p > 0.05). These results, coupled with the W statistics and the results of the 

sediment analysis (see §6), indicate that macrobenthic communities in Small Bay are subject to the 

greatest degree of anthropogenic stress when compared to Big Bay and Langebaan Lagoon. 

The species diversity (represented by the Shannon Weiner Index, H’) for Saldanha Bay and 

Langebaan Lagoon in 2010 is represented in Figure 8.15. The diversity of species in Small Bay is 

lowest at the Yacht Club Basin (SB1), Mussel farm (SB9), along the Multi-Purpose Terminal (SB15) 

and in the middle of the bay (SB8). The low species diversity in the Yacht Club Basin is most likely 

due to the polluted state of this site (see §6), while the low diversity at the Multi-Purpose Terminal is 

most likely due to dredging that occurred in the area in 2007/08. Furthermore both the yacht club 

basin and the area below the ore jetty in Small Bay have been recognized as ‘key problem areas’ that 

suffer from reduced water movement which leads to the accumulation of fine grained particles and 

organic matter, to which toxic substances such as metals and hydrocarbons adsorb (CSIR 2002). The 

remaining five sites in Small Bay have low levels of diversity (H’ values ranging from 0.91 to 1.90). 

Overall the diversity in Big Bay is low to moderate (H’ values ranging between 1.4 and 2.3). 

The diversity of benthic macrofauna in Big Bay was lowest at sites near the ore jetty and Small Bay. 

The lower levels of diversity are most likely a consequence of anthropogenic disturbances that have 

occurred along the ore jetty (dredging) and within Small Bay (fish factory effluent, mussel farms, 

sewerage). Sites BB25 and BB29 both had a relatively high diversity compared to other Big Bay sites. 

Examination of the sediment characteristics and the concentration of contaminants provide no 

apparent reason for the variation in diversity between sites. 


Total no species (S) 

Species richness (d) 

28 

26 

24 

22 

20 

18 

16 

14 

12 

4.4 

4.2 

4.0 

3.8 

3.6 

3.4 

3.2 

3.0 

2.8 

2.6 

2.4 

2.2 

Site; LS Means 





SB Current effect: F(2, 22)=1.0900, BB p=.35369 LL 


Vertical bars denote 0.95 Site confidence intervals 

SB BB LL 

Site 


SB Current effect: F(2, 22)=3.5247, BB p=.04700 LL 


Site 


SB BB LL 


Eveness (J') 

0.9 

0.8 

0.7 

0.6 

0.5 

0.4 

0.3 





Figure 8.14. Mean (± 0.95 confidence intervals) Species diversity (H'), Species richness (d'), Evenness (J') 

and Total number of species (S) for benthic macrofauna samples collected from Small Bay (SB), 

Big Bay (BB) and Langebaan Lagoon (LL), Saldanha, 2010. 

The diversity of benthic macrofauna recorded in 2010 in the lagoon appeared patchy, with 

moderate levels of diversity at most sites and low levels of diversity at sites LL39 and LL41. The W 

statistic was also lowest at sites LL39 and LL41 compared to other sites in the lagoon. The low 

diversity value is most likely a consequence of natural disturbance due to the fact that Langebaan 

Lagoon is very shallow and is subjected to strong currents and tidal activity. 


Species Diversity (H’) within Small Bay, decreased significantly between 1999 and 2008 

(p

Figure 8.15: 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) 

The average species diversity (H’) in Big Bay decreased between 2004 and 2009. The 2010 

survey revealed that there had been a slight increase in the diversity of benthic macrofauna in Big 

Bay since 2009. The W statistic revealed that there had been an increase in the proportion of slow 


growing, large bodied species in Big Bay between 2009 and 2010 suggesting that disturbance had 

been reduced. It is possible that the slightly reduced level of disturbance occurring in Big Bay 

between 2009 and 2010 allowed for a greater diversity of species (both r and K strategists) to coexist. 

This is a sign of the recovery of the system following disturbance. 

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. The W statistic revealed that there had been a slightly increased level of 

disturbance in the lagoon between 2009 and 2010. This was most likely a natural fluctuation in 

response to community interactions and natural changes to the physical environment. Indeed the 

results of the 2010 sediment survey suggest that there had been improved flushing of fine sediments 

in the southern reaches YEAR; of LS Means the Lagoon, suggesting stronger water movements YEAR; LS Means in the area. 

Diversity (H') 


2.2 

2.0 

1.8 

1.6 

1.4 

1.2 

1.0 

0.8 

0.6 

0.4 

2.5 

2.4 

2.3 

2.2 

2.1 

2.0 

1.9 

1.8 

1.7 

1.6 

1.5 




Include condition: V3="SB"$ 

1999 

YEAR; LS Means 


Effective 2004 hypothesis 2008 decomposition 2009 


Include condition: YEAR V3="LL"$ 




2004 2008 2009 2010 

YEAR 




Include condition: V3="BB"$ 

1999 2004 2008 2009 2010 



2.4 

2.2 

2.0 

1.8 

1.6 

1.4 

1.2 

1.0 


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 and 2010. 

8.4.4 Linking Ecological Indices to Environmental Variables 

MDS plots were generated from macrobenthic abundance data to detect 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). 

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 

YEAR

percentage of mud compared to Langebaan Lagoon. This higher proportion of fine grained particles 

enhances the level of trace metals accumulated in the sediments. This is clearly seen at site SB1, 

which had the highest mud content and the highest concentrations of trace metals. The benthic 

community composition at this site was a clear outlier. 

Site SB1 represents an impoverished community with a very low abundance and diversity of 

benthic macrofauna (only 4 species and 14 individuals found). This site was also identified as 

impoverished in 2008 and 2009, most likely owing to the high concentrations of organic matter and 

anoxic conditions within the sediments. This site also has an extremely elevated concentration of 

cadmium relative to all the other sites sampled. In addition it has relatively high concentrations of 

lead, copper, nickel, organic nitrogen (PON), organic carbon (POC) and mud. Any further distinction 

between the other sites sampled in Saldanha 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 Big Bay and Small Bay. 

Figure 8.17. MDS of Saldanha Bay and Langebaan Lagoon benthic macrofauna abundance (2010) with 

superimposed circles representing depth (Increasing circle size = deeper) 

Figure 8.18, Figure 8.17 and Figure 8.19 clearly shows that Langebaan Lagoon is 

characterised by shallow water depths, and sediments with low mud, particulate organic carbon, 

particulate organic nitrogen compositions and no or very low to negligible concentrations of trace 

metals. 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 and 

vegetation cover as well as community interactions influence the species composition within the 

lagoon. 


Figure 8.18. MDS of Saldanha Bay and Langebaan Lagoon benthic macrofauna abundance (2010) with 

superimposed circles representing abiotic factors: Particulate Organic Carbon (POC), 

Particulate Organic Nitrogen (PON), % Gravel and % Mud (Increasing circle size = larger 

measurement). 

Environmental variables (Al, Fe, As Cd, Cr, Cu, Ni, Pb, Zn and organic carbon and nitrogen) 

were analyzed using principal component analysis, and the results are shown in Figure 8.20. The 

sediment sample SB1 is clearly different from all others (characterized by a high pollution load), and 

this is also the case with the benthic macrofauna sample. Sediment samples SB14 and SB15 have 

been grouped together and have a very similar chemical make-up, and this too has resulted in 

similar groups of pollution tolerant species being found at these sites. 


Cu (mg/kg) Cd (mg/kg) 

Ni (mg/kg) Pb (mg/kg) 

Figure 8.19. MDS of Saldanha Bay benthic macrofauna abundance (2009) 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) 

Figure 8.20. Two-dimensional PCA ordination of the environmental variables (metals, POC and PON; 

transformed and normalized) for Saldanha Bay 2010. 


8.5 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. A 

number of species had declined severely and there was a shift in 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 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 jetty were found to be anoxic and high in hydrogen 

sulphide (characteristically foul smelling black sludge). 


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 

since 2004. 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, the diversity index (H’) decreased, and the W statistic 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. Analysis of sediment data in 2008 revealed that species diversity (H’) was 

inversely correlated to an increasing contamination gradient. The correlation was significant (R 2 = 

0.312) and suggests that contaminants are one of the main drivers of change within Saldanha Bay 

benthic communities. All these results indicate that there had been substantial anthropogenic 

impacts on the benthic community in Small Bay between 2004 and 2008. 

There are a variety of activities within Small Bay which are likely sources of contamination. 

These include 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. Furthermore dredging activities can lead to the suspension of fine particles and the 

release of contaminants adsorbed to sediments. Maintenance dredging took place at Mossgas quay 

and the Multi-Purpose Terminal 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 baywide 

increases in the percentage mud, particulate organic carbon and various trace metals suggests 

that the principle driver of change was the dredging event which suspended fine sediments and 

released contaminants that had accumulated from a variety of sources due to the poor circulation 

and reduced wave energy within Small Bay. 

The 2009 survey indicated that percentage mud, particulate organic carbon and trace metal 

concentrations had reduced since 2008. Thus physical parameters were improving in the Bay. The 

benthic macrofauna community also showed signs of recovery. The average biomass of benthic 

macrofauna increased, the diversity index (H’) increased, and the W statistic increased. The 

community composition had shifted such that the abundance and biomass of Ampelisca sp. had 

reduced drastically while polychaetes had become dominant. Interestingly the abundance of 

individuals did not increase, while the biomass did (this is reflected by the increased W statistic) 

indicating that the proportion of slow growing, larger species in the community had increased, 

suggesting that disturbance had decreased. 

The assessment of sediment samples collected in 2010 revealed that there had been further 

improvements of the physical parameters in Small Bay. The percentage mud, particulate organic 

carbon and concentrations of trace metals (with the exception of copper) had reduced at most sites 

in the Bay (the most notable exception being the Yacht Club Basin). The benthic macrofauna survey 

conducted in 2010 revealed that there had been further recovery of the benthic community in Small 

Bay with overall increases in biomass, abundance and diversity. The community composition, 

broken down by taxonomic groups, indicated that there had been an increase in the proportion of 

gastropods, bivalves and crustaceans and a decrease in the proportion of polychaetes in the 

community since 2009. Indeed, the bivalve Tellina gilchristi and the gastropod Nassarius speciosus 

were dominant species in 2010 while the abundance and biomass of the mud prawn, Upogebia 

capensis, also increased between 2009 and 2010. When assessed at a finer scale, the 2010 survey 

revealed that there was considerable spatial variation in the recovery process which is likely to be a 

result of different anthropogenic and environmental drivers experienced at different locations 

throughout the Bay. 


The survey conducted in 2008 revealed that there had been an increase in the percentage 

mud throughout Big Bay since 2004, while the overall abundance, biomass and diversity of benthic 

macrofauna had decreased at sites throughout the Bay. The average W statistic decreased between 

2004 and 2008 indicating that the proportion of fast growing opportunistic species in the community 

had increased. It is likely that these changes in the benthic community are related to the dredging 

activities that were conducted during 2007 and 2008 at the Multi-Purpose Terminal in Small Bay and 

along Langebaan North Beach. 

There was no clear trend regarding the percentage mud in the sediments at sites in Big Bay 

between 2008 and 2009. Some sites experienced an increase while at others there was a reduction 

in the percentage mud. The biomass and abundance of benthic macrofauna increased considerably 

between 2008 and 2009. Much of the increase in abundance was attributed to substantial increases 

in the number of small-bodied opportunistic polychaetes, while the increased biomass was 

dominated by large crustacean species such as the mud prawn Upogebia capensis, several species of 

crab as well as the mantis shrimp Pterygosquilla armata capensis. The increased biomass and 

abundance results suggested that Big Bay benthic communities were in a state of recovery between 

2008 and 2009. Indeed, the total biomass and abundance of benthic macrofauna found within Big 


Bay for 2009 was very similar to those values for 2004. In addition, recent surveys (2004, 2008, 2009 

and 2010) revealed that the filter-feeding sea-pen returned to selected sites in Big Bay, possibly 

indicating improved water circulation and localized recovery within Big Bay. However, the diversity 

and the W statistic decreased suggesting that there had been an increase in the level of disturbance. 

It is important to note, when interpreting diversity values, that predation, competition and natural 

and anthropogenic disturbance all play a role in shaping a community. It is likely that benthic 

macrofauna community interactions and natural environmental fluctuations in the Bay may have 

lead to a reduced diversity between 2008 and 2009. 

The 2010 survey of benthic macrofauna provided evidence of the recovery of the Big Bay 

benthic community. There was an increase in the overall biomass of macrofauna between 2009 and 

2010 and the average biomass of gastropods and bivalves increased. In addition, the W statistic 

increased between 2009 and 2010 indicating and increase in the proportion of large organisms in 

the community which suggests a reduction in disturbance. 


Cluster analysis of 2004, 2008, 2009 and 2010 benthic abundance data revealed that 

Langebaan Lagoon supports communities that are distinct from those in Small and Big Bay. 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). In general, 

benthic communities in Langebaan Lagoon appear healthier than those in the Bay. However, it is 

concerning that there was a drastic reduction in species diversity in the Lagoon after the 1975 

dredge programme. Langebaan Lagoon is shallow and benthic organisms would be subjected to 

extreme tidal activity and strong currents, which may alter community structure over time. Changes 

in macrobenthos in Langebaan Lagoon may also be related to the recent invasion by the European 

mussel Mytilus galloprovincialis. 

During the mid-1990s 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 noninvaded 

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 and hopefully we will see evidence of recovery in the benthic macrofaunal communities in the 

lagoon in the future. Given the high conservation status of Langebaan Lagoon it is important to 

continually monitor the health of the benthic environment, so that human induced impacts can be 

identified and mitigated before it’s too late. 

The overall abundance of macrofauna in Langebaan Lagoon declined sharply 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 abundance then increased between 2008 and 

2010, principally owing to a marked increase in crustaceans. The overall biomass measured in 2010 

exceeded that measured in 1975, however, the diversity of taxa has been reduced and crustaceans 

overwhelmingly dominate the benthic macrofauna biomass. The 2010 survey revealed that the 

increase in the overall biomass in Langebaan Lagoon was mainly due to increases in the biomass of 

polychaetes and echinoderms. This is potentially a sign of the recovery of the system. 

8.6 Summary of benthic macrofauna findings 

A range of benthic community health indicators examined in this study over the period 1999 

to 2010 has revealed that benthic health most likely deteriorated in Small Bay from 1999 to 2008, 

but has recently (2009 and 2010 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. 


Isopod spp Amphipod spp 

Polychaete spp Polychaete spp 

Whelks ( Nucella spp) White mussels ( Donaxspp ) 

Figure 8.21. Benthic macrofauna species frequently found to occur in Saldanha Bay and Langebaan Lagoon, 

photographs by: Charles Griffiths. 


Brittle star ( Ophiuroidea spp) 

Sea Cucumber ( Holothuroidea spp.) 

Sand Prawn ( Callianassa craussi) Mud prawn ( Upogebia capensis) 

Figure 8.22. Benthic macrofauna species frequently found to occur in Saldanha Bay and Langebaan Lagoon, 

photographs by: Charles Griffiths. 


9 INTERTIDAL INVERTEBRATES (ROCKY SHORES) 

9.1 Background 

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 thus initiated as part of the State 

of the Bay monitoring programme. 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 and 2009 (Anchor Environmental Consultants 2009, 2010). 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 filterfeeders. 

It was suggested that the construction of the Marcus Island causeway and the Iron Ore Jetty 

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. 

This chapter present results from the third annual monitoring survey conducted in May 2010. 


9.2 Approach and Methodology 

9.2.1 Study Sites 

The locations of the eight study sites are illustrated in Figure 9.1. The sites Dive School and 

Jetty are situated along the northern shore in Small Bay. Marcus Island, Iron Ore Jetty 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. The sites have first been sampled during the baseline survey in 2005, followed by 

annual monitored since 2008. The 2010 survey was conducted from 26-29 May. 

Table 9.1. GPS positions (in WGS84), wave exposure, and topographical description of the eight rocky 

intertidal study sites in Saldanha Bay. 

Sampling Site 

Dive School 

Jetty 

Schaapen Island 

East 


West 

Iron Ore Jetty 

Lynch Point 

North Bay 

Marcus Island 

GPS Position 

(WGS84) 

S 33°00.598’ 

E 017°56.927’ 

S 33°00.490’ 

E 017°56.838’ 

S 30°05.528’ 

E 018°01.465’ 

S 33°05.408’ 

E 018°01.121’ 

S 33°00.500’ 

E 018°00.010’ 

S 33°02.680’ 

E 018°02.260’ 

S 33°02.020’ 

E 017°56.099’ 

S 33°02.580’ 

E 017°58.285’ 

Wave Exposure Topography 

Very Sheltered Boulders and rubble 

Very Sheltered Boulders and rubble 

Sheltered – Semiexposed 

Sheltered – Semiexposed 

Flattish with some ragged sections 

Semi-steep with some ragged sections 

Semi-exposed Very steep with large boulders 

Semi-exposed Flat with crevices 

Semi-exposed - 

exposed 

Exposed Flat shore 

Flat mid and high shore, large 

boulders in the low shore 

Sampling sites had 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 9.2). Schaapen Island East is situated in a little baylet and is 

relatively sheltered and mostly flattish with some rougher rock sections (Figure 9.2). Schaapen Island 

West is slightly more exposed, flat with some parts of ragged topography (Figure 9.2). The site at the 

Iron Ore Jetty (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 

jetty (Figure 9.1), 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 9.1). North Bay (NB) is semi-exposed to exposed with a relatively flat high and 

mid shore (Figure 9.1). 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 9.1). Detailed geographic positions and shore descriptions are provided in Table 9.1. 

Figure 9.1. Positions of the eight rocky intertidal study sites in Saldanha Bay. 

9.2.2 Survey Method 

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 (0.5 m 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. 

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 and g) 

articulated coralline algae, h) corticated and i) ephemeral foliose seaweeds and j) kelps. 

Dive School 

Schaapen Island East 


Jetty 

Schaapen Island West 

Figure 9.2. The rocky shore study sites in 2009 from top right to left bottom: Dive School, Jetty, Schaapen 

Island East, and Schaapen Island West.



Lynch Point 

Marcus Island 

Figure 9.3. The rocky shore study sites in 2009 from top right to bottom left: Iron Ore Jetty, Lynch Point, 

North Bay, and Marcus Island. 


9.2.3 Data Analysis 

The similarities or dissimilarities among the quadrats from the eight different study sites 

were 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 multidimensional 

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 the PERMANOVA routine, contained in the PERMANOVA+ for 

PRIMER 6 software package. 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

9.3 Results and Discussion 

9.3.1 2010 Survey 

A total of 82 species/taxa were recorded from the eight sampling stations, of which the 

majority were invertebrates (48 species/taxa or 58.5%) were 34 are (41.5%) algae. In terms of 

functional groups, 21 algal species/taxa were corticated 2 (or foliose) seaweeds, 6 ephemerals 3 , 2 

kelps, 4 crustose (or encrusting) 4 corallines and 1 articulated 5 coralline (this is an underestimation of 

coralline species as most species cannot be identified in the field and were thus lumped into groups). 

The faunal component was represented by 18 species of filter-feeders, 17 grazers, 3 trappers, 6 

predators, and 4 predatory anemones. The species are generally common to the South African West 

Coast (Day 1974, Branch et al. 2010), and most species were also recorded in the previous 

monitoring years (Anchor Environmental Consultants 2006, 2008, 2009), and are listed by other 

studies conducted in the Saldanha Bay area (e.g. Simons 1977, Schils et al. 2001, Robinson et al. 

2007a). 

The dominant barnacle species, the acorn barnacle Balanus glandula, is an alien invasive 

species, which is native to the west coast of North America. The presence of B. glandula in South 

Africa has only been noticed recently as it has up to then always been misidentified as the native 

barnacle Chthamalus dentatus (Simon-Blecher et al. 2008). At the monitoring study sites it was first 

confidently identified in 2008. It is, however, assumed that it had been present 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. 

Rocky intertidal community structure at the sites was strongly influenced by the degree of 

wave exposure as well as shore topography, and within a site by height on the shore. The effects of 

wave action are attenuated upshore and superseded by the uniformly severe desiccation 

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 accumulated amongst the boulders across the whole 

shore. High shore species included the winkle Oxystele variegata and the barnacle Amphibalanus 

amphitrite (Figure 9.4). The small snail Afrolittorina knysnaensis frequented high shores of sheltered 

to exposed sites, congregating in moist crevices (Figure 9.4). The alien barnacle Balanus glandula 

was present at most sites but scarcely. Algal presence in the high shore is usually sparse consisting of 

Porphyra capensis and the occasional tuft of the ephemeral green alga Ulva spp. At Schaapen East 

and West, however, the high shore was for the most part covered by an encrusting layer of dried-out 

blue green algae mixed with low growing Ulva spp. (Figure 9.4). 

O. variegata and A. amphitrite continued into the mid shore at the very sheltered sites, 

joined by another winkle, O. tigrina and the limpet Cymbula granatina (Figure 9.5). Algal cover was 

low with the encrusting coralline Ralfsia verrucosa and some Ulva spp. Algal presence at the mid 

shore increased at the two sheltered to semi-exposed Schaapen Island sites where Ulva spp. reached 

2 

Corticated algae - Algae that have secondarily formed outer cellular covering over part or all of an algal 

thallus. Usually relatively large and long-lived. 

3 

Ephemeral algae – Opportunistic algae with a short life cycle that are usually the first settlers on a rocky 

shore. 

4 

Crustose (or encrusting) corallines – Crustose corallines are typically slow growing crusts of varying thickness 

that can occur on rock, shells, or other algae. 

5 

Articulated corallines – Articulated corallines are branching, small tree-like plants, which are attached to the 

substratum by crustose or calcified, root-like holdfasts. 


40%, co-occurring with sponges especially around rock-depressions (Figure 9.5). The pulmonate 

false-limpet Siphonaria serrata could also be found in these depressions. Other algae were primarily 

crustose corallines. Animals included the cushion star Parvulastra (=Patiriella) exigua, the scavenging 

whelk Burnupena spp. and B. glandula. 

Oxystele variegata 

Blue-green algae 

Afrolittorina knysnaensis 

Porphyra capensis 

Figure 9.4. Top left to bottom right: High shores at Dive School, Iron Ore Jetty, Schaapen West with blue 

green algal cover, and at Marcus Island. 

With increasing wave activity, mid shores were characterized by sessile filter-feeders such as 

the alien barnacle B. glandula and the alien Mediterranean mussel Mytilus galloprovincialis. At Iron 

Ore Jetty in particular, mid-shore barnacle spread could exceed 80% (Figure 9.5). Mobile animals 

included the limpets Scutellastra granularis, Siphonaria serrata, S. capensis, few O. variegata and A. 

knysnaensis seeking shelter amongst the barnacles (Figure 9.5). Algal cover was generally low with 

the exception of the exposed site Marcus Island where ephemeral algae (e.g. Ulva spp.) flourished 

(Figure 9.5). Other seaweeds included P. capensis, Caulacanthus ustulatus, and various coralline 

algae. 

Differences among sites were most pronounced in the low-shore zone were differences in 

wave action is most effective. Generally, species cover was for all sites greatest in the low shore, but 

a clear trend of increasing cover with increasing wave force is also noticeable (e.g. from 25% at Jetty 

to 97% cover at Marcus Island). Sheltered low-shores were seaweed dominated, particularly by the 

red alga Gigartina polycarpa, the crustose coralline R. verrucosa and the green alga Ulva spp. Filterfeeders, 

on the other hand, were rare with the occasional barnacle and/or mussel. Despite this low 


mussel abundance, the sheltered boulder sites Dive School and Jetty are the only sites were all three 

mytilids, the indigenous mussels Aulacomya ater and Choromytilus meridionalis as well as the alien 

M. galloprovincialis, co-occur (Figure 9.6). Other invertebrates included the predatory anemone 

Pseudoactinia flagellifera and the sea urchin Parechinus angulosus, both typically found in pools 

(Figure 9.6), as well as Oxystele tigrina, C. granatina, P. exigua and the scavenging whelk Burnupena 

spp. At Schaapen East and West, dense clusters of the red-chested sea cucumber Pseudocnella 

insolens of up to 150 individuals/0.5m 2 were recorded. This sea cucumber was not found at any of 

the other sites. 

Balanus amphitrite 

Balanus glandula 

Ulva spp. 

Mytilus 



Siphonaria 

serrata 

Sponge 

Ulva spp. 

Figure 9.5. From top right to bottom left: Mid shores at Jetty, Schaapen East showing rock depression with 

orange sponge and Ulva spp., Iron Ore Jetty with dense Balanus glandula cover (insert showing 

Afrolittorina knysnaensis nestling among barnacles), and Mytilus galloprovincialis, B. glandula 

and Ulva spp. partially growing on mussels recruits at Marcus Island. 

With an increase in wave exposure, the low shores became increasingly dominated by filterfeeders, 

primarily M. galloprovincialis, which achieved on average >50% cover at Marcus Island. 

Barnacles were less common. In 2009, the indigenous ribbed mussel Aulacomya ater was the 

dominant species in the low zone at Marcus Island but in this survey, A. ater contributed on average 

stands of the kelp Ecklonia maxima emerged (Figure 9.7). Limpet species included Scutellastra 

granularis, S. barbara and S. cochlear. The latter limpet typically maintains a narrow ‘garden’ around 

its shell of fast-growing, fine red algae on which the limpet feeds and which are territorially defended 

and fertilized by the limpet (Branch et al. 2010). The predatory whelk Burnupena spp. could be 

found in and around the mussel matrix, feeding on the mussels. 

Gigartina polycarpa 

Pseudoactinia 

flagellifera 

Parechinus 

angulosus 

Ralfsia verrucosa 

Ulva spp. 

Choromy 

tilus meridionalis 

Aula 

comya ater 

Figure 9.6. Low shore at the sheltered site Dive School dominated by the algae Gigartina polycarpa (top 

left), Ralfsia verrucosa and Ulva spp.(top right), the anemone Pseudoactinia flagellifera 

(bottom left), and the sea urchin Parechinus angulosus in rock pools with sparse cover of the 

indigenous mussels Aulacomya ater and Choromytilus meridionalis (bottom right). 

Table 9.2 lists the diversity measures of the rocky shore communities at the eight study sites. 

The boulder beaches Jetty and Iron Ore Jetty had the lowest total species numbers (number of all 

species recorded from all quadrats combined). The other sites had total species counts of 37-38, 

with the exception of North Bay where 45 species were recorded. On average, species number was 

also lowest at Jetty, followed by the other two boulder beaches, and Lynch Point and Schaapen East. 

Highest average species number was found at Marcus Island. The amount of rock surface covered by 

invertebrates and seaweeds tended to increase with increasing wave exposure. Exceptions are 

Schaapen West and North Bay. The first had relatively high cover, which was due to the blue-green 

algae high at the shore. North Bay, on the other hand, had despite its higher wave exposure 

relatively low cover, especially in the mid shore where much of the smooth rock surface was devoid 

of intertidal life. It is likely that the smooth surface is firstly a less suitable ground for larval 

settlement (Eckman 1990, Herbert & Hawkins 2006), and secondly offers little protection from 

hydrodynamic forces (O’Donnell & Denny 2008). Many mobile species avoid topographically simple 


surfaces and prefer those with more structural complexity (e.g. crevices, rugged surface) 

(McGuinness & Underwood 1986, Menconi et al. 1999, Kostylev et al. 2005, O’Donnell & Denny 

2008). Species evenness was lowest at Marcus Island and Lynch Point and highest at the two very 

sheltered boulder-shores Dive School and Jetty. The other sites had intermediate values. This 

indicates that Marcus Island and Lynch Point were primarily dominated by one or few species. Both 

sites had extensive cover of the mussel Mytilus galloprovincialis and/or the barnacle Balanus 

glandula. In contrast, Dive School and Jetty have no single or few species that characterize the shore 

as most species were similarly abundant. The Shannon-Wiener diversity varied only from 1.92 to 

2.51, and was greatest at Dive School and lowest at Lynch Point. 

Table 9.2. Total and average (±standard deviation) number of species, and average (±standard deviation) 

percentage cover, evenness (J’) and Shannon-Wiener diversity index (H’) for the intertidal 

communities at the eight study sites in Saldanha Bay in 2010. 

Site 

Total Species 

Number 

(per site) 

Species Number 

(mean) 

Percentage 

cover 

Evenness 

Shannon 

diversity 

Dive School 37 22.3 ±2.7 25.7 ±4.0 0.81 ±0.05 2.51 ±0.22 

Jetty 29 15.3 ±2.8 14.4 ±4.0 0.79 ±0.08 2.15 ±0.20 

Schaapen East 38 23.2 ±5.5 39.7 ±15.0 0.67 ±0.15 2.09 ±0.47 

Schaapen West 37 27.3 ±3.6 67.7 ±12.9 0.66 ±0.07 2.19 ±0.29 

Iron Ore Jetty 31 24.3 ±4.4 46.9 ±7.8 0.68 ±0.06 2.16 ±0.28 

Lynch Point 38 23.0 ±2.4 62.1 ±6.0 0.61 ±0.05 1.92 ±0.16 

North Bay 45 27.8 ±2.3 33.3 ±11.9 0.71 ±0.10 2.37 ±0.33 

Marcus Island 38 29.2 ±4.7 70.3 ±6.8 0.60 ±0.03 2.01 ±0.12 

The abundances (as opposed to the space they occupy on the rock surface specified as 

percentage cover) of the most important mobile species per site are illustrated in Figure 9.8. At the 

very sheltered sites Dive School and Jetty, Oxystele variegata was common at the high shore and O. 

tigrina at the low shore. O. variegata occasionally also occurred at more exposed sites high at the 

shore. With increasing wave exposure, A. knysnaensis was particularly abundant at the high shore, 

while the mid and low shores were occupied by Scutellastra granularis. The pear-shaped S. cochlear 

is also restricted to semi-exposed to exposed sites. The dwarf cushion star Parvulastra exigua could 

be locally abundant, concentrated in small rock pools and depressions. The keyhole limpet Fissurella 

mutabilis, occurring generally in low numbers, was very abundant at Schaapen West due to a recent 

successful settlement event. Most of the specimens counted were recruits of

Plocamium spp. 

Ecklonia maxima 

Scutellastra cochlear 

Mytilus 


‘pink’ encrusting 

coralline algae 


Abundance (no/0.5m 2 ) 

Figure 9.7. Top: Low shore at the semi-exposed/exposed site North Bay showing mussel band and 

emerging kelp Ecklonia maxima. Bottom: Low shore at the exposed site Marcus Island with the 

mussel bed overgrown by red algae and patches of ‘pink’ encrusting corallines in between. The 

limpet Scutellastra cochlear, which is associated with the encrusting corallines, is fringed by a 

narrow garden of fine red algae. 

100 

90 

80 

70 

60 

50 

40 

30 

20 

10 

0 

Dive 

School 

Jetty Schaapen 

East 

Schaapen 

West 

Figure 9.8. The mean abundance (number/0.5 m 2 ) of the most important mobile species at the eight rocky 

shores in 2010. 

The within-site similarity at each site was relatively high (between 60-80%), as evidenced by 

the close grouping of the six replicates per site both in the dendrogram and the MDS plot (Figure 

9.9). At a 40% similarity level, the sites separate into two major groups according to wave exposure: 

Group 1 consists of the very sheltered boulder sites Dive School and Jetty, as well as the two 

sheltered Schaapen Island sites, whereas all other more exposed shores are contained in Group 2. 

Wave exposure as the critical shaping force of rocky shore communities at a local scale is a well 

described phenomenon (e.g. McQuaid & Branch 1984, Petraitis 1991, Bustamante et al. 1997, Menge 

& Branch 2001, Schils et al. 2001, Steffani & Branch 2003a, Hammond & Griffith 2004, Blamey & 

Branch 2009). Specifically, wave action enhances filter-feeders (McQuaid & Branch 1985) by 

increasing the concentration and turnover of particulate food (Bustamante & Branch 1996), leading 

to an elevation of overall biomass (Bustamante et al. 1995). In contrast, sheltered shores are 

typically dominated by algae as filter-feeder cover is typically lower. 


37 

Iron Ore 

Jetty 

5 

Lynch 

Point 

Scutellastra granularis Scutellastra cochlear 

Cymbula granatina Fissurella mutabilis 

Siphonaria serrata Afrolittorina knysnaensis 

Oxystele tigrina Oxystele variegata 

Patiriella exigua Burnupena spp. 

North Bay Marcus 

Island

20 

40 

A 

Group 1 

B 

60 

Similarity 

C 

Group 2 

Stress: 0.12 

Dive School 

Jetty 

Schaapen East 

Schaapen West 


Lynch Point 


Marcus Island 

Figure 9.9. Dendrogram (top) and multi-dimensional scaling (MDS) plot (bottom) of the rocky shore 

communities at the eight study sites in 2010. The circles in the MDS plot indicate a 40% (black) 

and 50% (red) similarity level. See text for further explanation. 


80 

D 

100

With an increase in similarity (50%), the sites separate further into smaller clusters: Group 1 

splits into subgroups A, containing the boulder beaches, and B, consisting of the flattish Schaapen 

Island sites. In Group 2, the steep boulder shore Iron Ore Jetty splits from the other sites. This 

secondary clustering is most likely linked to the difference in shore topography. Boulder shores 

typically contain greater micro-habitat diversity (e.g. upper and lower side of the boulders) than 

rocky platforms (McGuiness & Underwood 1986, Hir & Hily 2005). 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 decrease the water current and accumulate detritus, 

potentially leading 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 large rocks (McGuinness 1987, Londoño-Cruz & Tokeshi 2007, McClintock et al. 2007). Boulder 

fields 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). 

The difference in community structure between Dive School and Jetty, and the rocky shores 

on Schaapen Island is probably also 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. 2007a). For example, there is a distinct separation 

in algal composition between communities from the Bay and the Lagoon, as the latter harbors 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 (see Figure 9.1), 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, 

Atkinson et al. 2006, Clark et al. 2009, 2010). 

The various functional groups were nearly equally represented at Jetty and Dive School, with 

a slightly greater proportion of grazers at the latter (Figure 9.10). Schaapen East and West were 

clearly dominated by algae particularly encrusting corallines, as well as ephemerals at Schaapen 

West. Schaapen Island is an important bird sanctuary providing refuge for breeding colonies of Kelp 

and Hartlaub’s gulls, and Cape and Crowned cormorants. The presence of ample amounts of 

terrestrial and upper intertidal guano deposits that are washed through the intertidal zone is likely to 

supply a substantial nutrient input into the intertidal system, probably sustaining this abundant floral 

cover. The hypothesis that guano run-off enhances intertidal algal growth was demonstrated 

experimentally at a site on the west coast of South Africa (Bosman et al. 1986), and is described for 

other seabird islands along the coast (Bosman & Hockey 1986, 1988). 

As expected, filter-feeders dominated the shores of the more exposed sites. Grazers and 

encrusting corallines were the second largest groups, but Marcus Island had also substantial cover of 

ephemerals. As the most exposed site, physical disturbances by wave action are a constant feature 

at this site leading to a mosaic of patches in various stages of recovery, and ephemerals are typical 

early stage colonizers after disturbances (Sousa 1985). 


Percentage Cover 

80 

70 

60 

50 

40 

30 

20 

10 

0 

Dive 

School 

Jetty Schaapen 

East 

Figure 9.10. Contribution of the various functional groups to the biotic cover (%) at the eight rocky shore 

sites. The sites are sorted from left to right according to increase in wave exposure. 

9.4 Temporal Comparison 

Schaapen 

West 

Iron Ore 

Jetty 

Lynch 

Point 

North Bay Marcus 

Island 

Corticated Algae Ephemeral Algae Kelp 

Crustose Coralline Articulated Coralline Filter Feeders 

Grazers Trappers Predators&Scavengers 

Anemone 

Temporal changes in population measures (e.g. biotic cover, species number, evenness, and 

species diversity) are illustrated in Figure 9.11 and Figure 9.12, and univariate statistical tests results 

(ANOVA) are contained in Table 9.3. Changes at the sheltered boulder shore Dive School site were 

small with a significant increase in biotic cover from 2008 to 2010. At the other sheltered boulder 

beach Jetty, there is a general trend of increase in all indices, which was significant for all but 

evenness. Schaapen East had also experienced increases in species number, evenness and diversity 

from 2005 to 2009, but these decreased again in 2010. At Schaapen West, on the other hand, 

percentage cover had constantly increased since 2005 due to the overabundance of ephemeral and 

blue-green algae. This temporal dominance of ephemerals has probably led to the considerable 

decline observed for evenness and diversity from 2005 to 2008, which are, however, on the increase 

again over the last two years. The same trend can be seen for species number, although this is 

statistically non-significant. Rocky shore communities at Iron Ore Jetty changed little in terms of 

species number and cover, but both evenness and diversity have, after being constant for some 

years, drastically increased in 2010. Variations in population measures are small or non-significant at 

Lynch Point and North Bay. The most obvious changes had occurred at Marcus Island were species 

number and especially biotic cover had increased in 2009, continuing into 2010. After a similar 

increase in evenness and diversity from 2008 to 2009, these two indices are reduced again in 2010. 


Percentage cover 

Species Number 

36 

34 

32 

30 

28 

26 

24 

22 

20 

18 

16 

14 

12 

10 

8 

90 

80 

70 

60 

50 

40 

30 

20 

10 

0 

M10 

M09 

M08 

M05 

NB10 

NB09 

NB08 

NB05 

L10 

L09 

L08 

L05 

IO10 

IO09 

IO08 

IO05 

SW10 

SW09 

SW08 

SW05 

SE10 

SE09 

SE08 

SE05 

J10 

J09 

J08 

J05 

DS10 

DS09 

DS08 

DS05 

M10 

M09 

M08 

M05 

NB10 

NB09 

NB08 

NB05 

L10 

L09 

L08 

L05 

IO10 

IO09 

IO08 

IO05 

SW10 

SW09 

SW08 

SW05 

SE10 

SE09 

SE08 

SE05 

J10 

J09 

J08 

J05 

DS10 

DS09 

DS08 

DS05 

a 

b 

a a 

ab 

ab 

ab 

a 

a 

ab 

b 

b 

a 

b 

abc 

c 

Mean 

Mean±SE 

Mean±SD 

Figure 9.11. Box & whisker plots comparing species number (top) and percentage cover (bottom) among 

the years 2005, 2008, 2009 and 2010 at the eight study sites. The ovals encircle the sites with 

significant differences and different letters indicate which of the years differ (see text). 


a 

b 

ab a 

a 

b 

a a 

b 

b 

b 

b

Evenness 

Shannon Wiener 

0.9 

0.8 

0.7 

0.6 

0.5 

0.4 

0.3 

3.0 

2.8 

2.6 

2.4 

2.2 

2.0 

1.8 

1.6 

1.4 

1.2 

1.0 

M10 

M09 

M08 

M05 

NB10 

NB09 

NB08 

NB05 

L10 

L09 

L08 

L05 

IO10 

IO09 

IO08 

IO05 

SW10 

SW09 

SW08 

SW05 

SE10 

SE09 

SE08 

SE05 

J10 

J09 

J08 

J05 

DS10 

DS09 

DS08 

DS05 

M10 

M09 

M08 

M05 

NB10 

NB09 

NB08 

NB05 

L10 

L09 

L08 

L05 

IO10 

IO09 

IO08 

IO05 

SW10 

SW09 

SW08 

SW05 

SE10 

SE09 

SE08 

SE05 

J10 

J09 

J08 

J05 

DS10 

DS09 

DS08 

DS05 

a 

ab 

ab 

b 

a 

a 

ab 

ab 

b 

b 

ab 

ab 

a 

a 

b 

b 

ab ab 

ab 

ab 

a a a 

a 

a 

Mean 

Mean±SE 

Mean±SD 

Figure 9.12. Box & whisker plots comparing evenness (top) and Shannon-Wiener diversity indices (bottom) 

among the years 2005, 2008, 2009 and 2010 at the eight study sites. The ovals encircle the 

sites with significant differences and different letters indicate which of the years differ (see 

text). 


a 

b 

b 

a 

a 

a a 

b 

b 

a 

a

Table 9.3. Results of one-way ANOVA’s analyzing differences in species number, percentage cover, 

evenness and Shannon-Wiener diversity index among the years 2005, 2008, 2009 and 2010 at 

the eight study sites. Site name abbreviations used in the figure are provided in brackets 

behind the site name. df = 3,20 for all analyses; significant tests are highlighted in bold italic. 

Site Species Number 

Dive School (DS) 

Jetty (J) 

Schaapen East (SE) 

Schaapen West (SW) 

Iron Ore Jetty (IO) 

Lynch Point (L) 

North Bay (NB) 

Marcus Island (M) 

F = 1.86 

p >0.05 

F = 4.26 

p = 0.018 

F = 2.31 

p >0.05 

F = 2.69 

p >0.05 

F = 2.13 

p >0.05 

F = 3.70 

p = 0.03 

F = 2.24 

p >0.05 

F = 7.86 

p = 0.001 

Percentage 

cover 

F= 10.02 

p 0.05 

F = 34.45 

p 0.05 

F = 2.06 

p >0.05 

F = 1.13 

p >0.05 

F = 19.63 

p 0.05 

F = 3.04 

p >0.05 

F =4.90 

p = 0.01 

F = 5.37 

p = 0.007 

F = 10.17 

p 0.05 

F = 0.28 

p >0.05 

F = 13.84 

p 0.05 

F = 3.83 

p = 0.025 

F = 6.77 

p = 0.002 

F = 5.31 

p = 0.007 

F = 9.04 

p 0.05 

F = 2.24 

p >0.05 

F = 17.47 

p 5% to the dissimilarity at any 

specific site are listed in Table 9.5. For the sake of brevity, only comparisons between 2009 and the 

current dataset are presented here. 


2005 2008 2009 2010 

Dive School 

Jetty 

Schaapen East 

Schaapen West 


Lynch Point 


Marcus Island 

Stress: 0.18 

Figure 9.13. Multi-dimensional scaling (MDS) plot of the rocky shore communities at the eight study sites in 

2005 (red symbols), 2008 (green symbols), 2009 (blue symbols) and 2010 (grey symbols). The 

line separates samples at a 40% similarity level, and the blue circles delineate the 50% 

similarity level. 

At most sites, only one or two species contributed to the differences between the years 2009 

and 2010, but even these often contributed

Table 9.4. PERMANOVA pairwise-testing results following significant main-tests. Only the relevant 

pairwise comparisons for the years 2005 versus 2008, 2008 versus 2009, and 2009 versus 2010 

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. 

Groups Pseudo-F Significance Level % Similarity 

Dive School 2005 vs. 2008 2.504 0.0024 62.1 

Dive School 2008 vs. 2009 2.920 0.0019 59.3 

Dive School 2009 vs. 2010 1.595 0.0045 70.2 

Jetty 2005 vs. 2008 2.813 0.002 54.1 

Jetty 2008 vs. 2009 3.442 0.0025 47.7 

Jetty 2009 vs. 2010 2.253 0.0051 59.5 

Schaapen East 2005 vs. 2008 3.495 0.0021 52.9 

Schaapen East 2008 vs. 2009 2.364 0.0015 64.5 

Schaapen East 2009 vs. 2010 2.476 0.0022 58.4 

Schaapen West 2005 vs. 2008 3.465 0.0027 48.0 

Schaapen West 2008 vs. 2009 2.893 0.0027 55.8 

Schaapen West 2009 vs. 2010 2.487 0.0018 66.9 

Iron Ore Jetty 2005 vs. 2008 3.262 0.003 50.2 

Iron Ore Jetty 2008 vs. 2009 2.798 0.0034 60.6 

Iron Ore Jetty 2009 vs. 2010 3.141 0.0018 61.8 

Lynch Point 2005 vs. 2008 2.402 0.0023 56.3 

Lynch Point 2008 vs. 2009 2.683 0.0029 58.2 

Lynch Point 2009 vs. 2010 2.609 0.0021 60.0 

North Bay 2005 vs. 2008 1.935 0.0019 59.5 

North Bay 2008 vs. 2009 1.801 0.0023 63.4 

North Bay 2009 vs. 2010 1.722 0.0047 67.1 

Marcus Island 2005 vs. 2008 3.559 0.0026 56.8 

Marcus Island 2008 vs. 2009 2.568 0.0018 63.7 

Marcus Island 2009 vs. 2010 2.867 0.0017 67.2 


Table 9.5. Results from the SIMPER analysis listing the species that contribute >5% to the dissimilarity 

among the years at each site. The % cover data are averages across the six replicates per site, 

and are on the fourth-root transformed scale. 

Site Species 


2008 

% cover 

2009 

% cover 

Contribution 

Dive School Nothogenia erinacea 0.32 0.66 5.11 

Jetty 

Gigartina polycarpa 0.24 1.02 8.62 

Porphyra capensis 0.82 0.11 8.21 

Ulva spp. 0.41 1.03 7.41 

Cymbula granatina 0.49 1.01 5.75 

Schaapen East Blue-green algae 0 1.76 9.47 

Schaapen West Blue-green algae 0 1.85 11.54 


Amphibalanus amphitrite 0 1.24 7.59 

Hildenbrandia lecanellierii 0 1.22 7.41 

Centroceras clavulatum 1.10 0 6.77 

Austromegabalanus 

cylindricus 

0.96 0.11 5.25 

Lynch Point Porphyra capensis 1.43 0.5 4.90* 

North Bay Mytilus galloprovincialis 1.15 1.78 4.06* 

Marcus Island 

Cladophora spp. 1.93 0.27 9.15 

Blue-green algae 0 1.05 5.78 

*Note that at these sites none of the species contributed >5% to the dissimilarity. The species with the highest 

contribution is thus listed. 

Figure 9.14 depicts the contributions of the various functional groups to the biotic 

community at the study sites over the four survey years. At the two sheltered boulder shores, filterfeeders 

had decreased over the years, whereas corticated algae and grazers had increased. At 

Schaapen East, filter-feeders have slightly increased with time. Ephemeral algae were highest in 

2008, replacing encrusting algae, but this had reversed in 2010. At Schaapen West, there was a 

continuous increase in biotic cover, especially in the amount of encrusting algae but also in filterfeeders. 

Functional groups showed minor variations at Iron Ore Jetty and Lynch Point, whereas 

North Bay experienced an increase in filter-feeders with a concomitant decline in encrusting algae. 

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, however, ephemerals have reduced and corticated algae as 

well as filter-feeders are starting to return. 

%





80 

70 

60 

50 

40 

30 

20 

10 

0 

80 

70 

60 

50 

40 

Corticated 

Encrusting 

30 

Grazers 20 

Ephemeral 

80 Articulated 

Trappers 

Kelp 

Filter-Feeders 

Predators&Scavengers 

Anemones 10 

70 

0 

80 

70 

60 

50 

40 

Corticated 30 Ephemeral Kelp 

Filter-Feeders 

Encrusting 30 

Articulated Filter-Feeders Articulated 

Grazers 20 

20 Trappers Predators&Scavengers Encrusting 

Anemones 

10 

10 

Kelp 

0 

Ephemeral 

80 

0 

Corticated 

70 

60 

50 

40 

Corticated Ephemeral Kelp 

Encrusting 30 

Articulated Filter-Feeders 

Grazers 20 

Anemones 

10 

Trappers Predators&Scavengers 

0 


60 

50 

40 

Anemones 

Predators&Scavengers 

Trappers 

Grazers 

Corticated Ephemeral Kelp 

Figure 9.14. The mean percentage cover of the various functional groups at the study sites in 2005, 2008, 

Encrusting Articulated Filter-Feeders 

2009 and 2010. 

Grazers Trappers Predators&Scavengers 

Anemones 


In general, the inter-annual differences at the sites were relatively small and not related to 

sudden drastic increases/decreases or appearances/disappearances of important species. For many 

shores, differences were primarily due to varying cover of ephemeral algae. 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. 

In the Western Cape, recruitment of the common ephemeral Porphyra peaks in spring and autumn, 

leading often too dense summer and winter populations. Recruitment and survival success is also 

strongly related to environmental conditions that will vary from year to year. Furthermore, within a 

specific site, the ephemeral algae can occupy different zones dependent on season. For example, 

during the summer the common ephemeral alga Porphyra can grow in the low shore (mostly 

attached to other algae or animal shells) but is restricted to the upper shore in winter (Griffin et al. 

1999). 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 inter-annual 

phenomenon, and there is no reason to assume anthropogenic influences. 

Next to changes in seaweed cover, temporal differences in filter-feeder abundances were 

also observed. A closer look at the relative changes in cover of the three most important filterfeeders, 

the two alien species Balanus glandula and Mytilus galloprovincialis and the indigenous 

ribbed mussel Aulacomya ater, revealed some clear spatial and temporal trends (Figure 9.15). At 

sheltered shores, B. glandula is mostly restricted to the high shore with very low cover, but it has 

now also invaded the mid shore at Schaapen Island achieving >10% cover. At semi-exposed sites, the 

barnacle is increasingly common and occasionally the most dominant species at the mid-shores. At 

the Iron Ore Jetty, for example, barnacle cover could exceed on average 70%. Its presence at the 

high or low shore of semi-exposed sites, however, is sparse. 

At sites with greater wave exposure (e.g. Marcus Island), barnacle cover in the mid shore is 

reduced again. A similar shore-distribution pattern was observed during a survey along the West 

Coast (Laird & Griffiths 2008). There was a consistent increase in barnacle cover from 2005 to 2009 

for most sites and shore heights, which was particularly apparent for the mid-shore zones at Iron Ore 

Jetty and Lynch Point. In 2010, however, barnacle cover at Iron Ore Jetty had reduced by nearly 20%, 

and even halved at the mid shore at Lynch Point. 

The second alien invasive in the Saldanha Bay system is the Mediterranean mussel M. 

galloprovincialis. A worldwide well known coastal invader, M. galloprovincialis is ecologically the 

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, 2010). In general, it’s competitive strength and its impact on other 

elements of the fauna increases with wave exposure (Branch et al. 2008, 2010). 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). 



Percentage cover Percentage cover 


12 

12 

10 

10 

8 

6 

4 

2 

0 

8 

6 

4 

80 

70 

60 

50 

40 

30 

20 

10 

0 

80 

70 

60 

50 

40 

30 

20 

10 

0 

2 

0 

High 05 

High 08 

High 09 

High 05 

High 08 

High 09 

High 10 

Mid 05 

Mid 08 

Aulacomya ater 

Mytilus 


High 05 

High 08 

High 09 

High 05 

High 08 

High 09 

High 10 

Mid 05 

Mid 08 

Mid 09 

Mid 10 

Mid 09 

Mid 10 

Low 05 

Low 08 

Low 05 

Low 08 


Mytilus galloprovincialis 


High 10 

Mid 05 

Mid 08 

Mid 09 

Mid 10 

Dive School 10 

Jetty 

Low 05 

Low 08 




High 10 

Mid 05 

Mid 08 


Mid 09 

Mid 10 

Low 05 

Low 08 

Low 09 

Low 10 

Schaapen 

Low 09 

Low 10 

Low 09 

Low 10 

Low 09 

Low 10 

East 

Iron 

Ore Jetty 


12 

8 

12 

6 

10 

8 

4 

6 

2 

4 

0 

2 

0 

80 

70 

60 

50 

40 

30 

20 

10 

0 

High 05 

High 08 

High 09 

High 05 

High 08 

High 09 

High 05 

High 08 

High 09 

High 10 

Mid 05 

Mid 08 

Mid 09 

Mid 10 

Low 05 

Low 08 




High 10 

Mid 05 

Mid 08 

Mid 09 

Mid 10 

Low 05 

Low 08 




High 10 

Mid 05 

Mid 08 

Mid 09 

Mid 10 

Low 05 

Low 08 




Low 09 

Low 10 

Low 09 

Low 10 

Low 09 

Low 10 

Figure 9.15. 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 and the bottom four graphs. 





80 

70 

60 

50 

40 

30 

20 

10 

0 

High 05 

High 08 

High 09 

High 10 

Mid 05 

Mid 08 

Schaapen West 

Mid 09 

Mid 10 

Lynch Point 

Marcus Island 

Low 05 

Low 08 

Low 09 

Low 10

The temporal distribution of M. galloprovincialis at the study sites demonstrated the 

opposite pattern to that of the alien barnacle. The mussels’ presence had clearly declined from 2005 

to 2009, which was noticeable at all semi-exposed to exposed sites, but most striking at Marcus 

Island in the low shore and Lynch Point in the mid shore (Figure 9.15). This decrease in alien mussel 

cover was accompanied by an increase in abundance of the local mussel Aulacomya ater. In 2010, 

however, M. galloprovincialis populations have recovered to similar or even higher values than 

before, whereas A. ater reduced to

is determined by the mussel. The future annual surveys will at least help in determining whether the 

contrasting abundance patterns observed for the two species continuous, which would strongly 

point towards competitive interaction between them. 

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 harbor 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. 

9.5 Summary of Results 

A total of 82 species/taxa were recorded from the eight sampling stations in Saldanha Bay, of 

which 58.5% were invertebrates and the rest seaweeds. The species are generally common to the 

South African West Coast, and most species were also recorded in the previous surveys. 

The most important factor responsible for community differences among the sites is the 

exposure to wave action. There was a general trend of increasing biotic cover with increasing wave 

force. Multivariate analysis identifies two distinct groups according to wave exposure: one group 

consists of the very sheltered boulder sites Dive School and Jetty, as well as the two sheltered 

Schaapen Island sites, whereas all other more exposed shores are contained in a second group. 

Sheltered sites were typically dominated by seaweeds and grazers, whereas more exposed sites are 

characterized by filter-feeders. 

A secondary factor structuring the communities is shore topography. At a higher similarity 

level, the boulder shores separate from the flattish rocky platforms. Four groups thus emerge, i) the 

two very sheltered Small Bay boulder beaches Dive School and Jetty, ii) the two Schaapen Island 

sites, iii) the semi-exposed boulder shore Iron Ore Jetty, and iv) the semi-exposed to exposed shores 

at Lynch Point, North Bay and Marcus Island. 

Differences between the sheltered sites in Small Bay (e.g. Dive School and Jetty) and the two 

sites on Schaapen Island may also be linked the geographic locations of the sites in the overall 

Saldanha Bay system with the Schaapen Island sites belonging to a transitional zone between the Bay 

and the Lagoon, and the nutrient input through seabird guano that favors algal growth on Schaapen 

Island. 

Temporal comparison of rocky shore communities shows that the grouping of the sites 

according to wave exposure and, at a higher similarity level to topography, is consistent throughout 

the years. There is, however, also a certain grouping according to years, which is more evident at 

some sites than at others. Generally, these inter-annual differences were minor and mostly related 

to temporal changes in ephemeral algae cover. Particularly the two Schaapen Island sites as well as 

Marcus Island had greatly increased cover of blue-green algae in the high shore, which might be 

linked to nutrient input from terrestrial seabird guano. Ephemeral algae typically show strong 

temporal variation in their abundances and dense populations are therefore only temporarily. 

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. 


Consistent with the previous years, the alien invasive barnacle Balanus glandula was most 

common at semi-exposed shores reaching highest densities in the mid shore. There was an increase 

in barnacle cover from 2005 to 2009 at most sites, particularly in the mid shores. Barnacle cover in 

2010, however, had at some sites declined by 20-50%. The alien mussel M. galloprovincialis, on the 

contrary, had reduced in abundance from 2005 to 2009, both in the mid and the low shores. This 

was most evident at the low shore at Marcus Island, where the decline in M. galloprovincialis was 

accompanied by an increase in the indigenous mussel Aulacomya ater, which historically was the 

dominant mussel in this zone prior to the invasion by Mytilus. In 2010, Mytilus returned and 

outcompeted A. ater again from the low shore. The reason for the temporary decline in Mytilus 

abundance at the low shore is unknown. The reduction in mussel cover in the mid shore might, on 

the other hand, be related to competitive interaction with the alien barnacle, but experimental work 

is needed to substantiate this. 

It is likely that one of the greatest threats to rocky shore communities in Saldanha Bay is the 

introduction of alien species, and their potential to become invasive. 


10 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 net fishing 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. 

Despite the importance and long history of fisheries in the Bay and Lagoon, scientific data on 

the fish community in the area was until recently, limited to a few studies, mostly by students and 

staff of the University of Cape Town. 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 (Anchor 

Environmental Consultants, 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 MSc student Clement Arendse who was investigating white stumpnose 

recruitment. These data were reported on in the “State of the Bay 2008” report (Anchor 

Environmental Consultants 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 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 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 (Anchor Environmental Consultants 

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 and 2010 as part of the monitoring of 

ecosystem health 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 chapter presents and summarizes the data for the 2010 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) in the Saldanha- Langebaan system. 

10.2 Methods 

10.2.1 Field sampling 

Experimental seine netting for all surveys covered in this report were 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 50m apart at each site during daylight hours. The net was usually 

deployed from a small rowing dinghy 30-50m 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 Bay and 

Lagoon. During 2007, 21 hauls were made at seven sites in the both Bays and Lagoon and for the last 

three years, 2-3 hauls have been made at each of 15 standard sites every April (2008-2010) (Figure 

10.1). Large hauls were sub-sampled at the site, the size of the sub-sample estimated visually and 

the remainder of the catch released alive. 

10.2.2 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 five most recent seine-net surveys (2005, 

2007, 2008, 2009 & 2010) 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 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. 

Figure 10.1. Sampling sites within Saldanha Bay and Langebaan lagoon where seine net hauls were 

conducted during 2005, 2007, 2008, 2009 and 2010 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: Bottelary, 14: Churchhaven, 15: Kraal aai 


The average abundance of the four 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 sites and 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 sites and years 

were represented using multidimensional scaling and these were statistically tested using a one way 

or nested (sites nested within years) ANOSIM tests. The principal species contributing to 

dissimilarities between years or sites were identified using the SIMPER routine. 

10.3 Results 

10.3.1 Description of inter annual trends in fish species diversity 

At least thirty-six fish species have been recorded in the six seine-net surveys conducted 

during 1986-87, 1994, 2005, 2007-2010. This is one less than recorded previously as both sand shark 

species, R annulatus and R. blockii were thought to occur in the area and new research indicates that 

only the latter species inhabits the Bay and lagoon (Dunn & Schultz in prep.). During recent surveys 

three different species of goby of the genus Caffrogobius, namely: C. nudiceps, C. gilchristi and C. 

caffer have been identified. Due to the uncertainty surrounding identification of these species in 

earlier surveys, they have been grouped at the generic level for data presented in this report. 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 Figure 10.3, Table 10.1 & Table 10.2 respectively. Considering 

data from all surveys combined, a similar number of species have been captured in Big Bay (26) and 

Small Bay (26) with slightly fewer found in the Lagoon (19) (Figure 10.3, Table 10.1 & Table 10.2). 

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 (Figure 10.2). Little 

variation in the number of species caught over the period of sampling is apparent for Langebaan 

lagoon and the decrease in the number of species caught in Big Bay between 2008 & 2009 noted in 

last year’s report appears more a result of increased diversity in 2008 catches as all the other annual 

surveys in Big Bay recorded similar number of species in catches (Figure 10.2). 

The actual species composition in the different areas between the five surveys did, however 

change substantially (Figure 10.3, Table 10.1 & Table 10.2). Despite the small decrease in species 

caught in Small Bay during the 2009 and 2010 sampling surveys, the same nine occurred in all 

surveys. For the first time in 2010, the Knysna sand goby was found in hauls made in Small Bay at 

both the campsite and Blue Water Bay sites. Five of the 25 species recorded in Big Bay occurred in all 

surveys with two more, silversides and elf only absent in one survey each (2007 and 2009 

respectively). Similarly, only 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. This is probably related to the greater temporal variation in 

oceanographic conditions in Big Bay and Langebaan Lagoon than in Small Bay and to differences in 

habitat type. Short term fluctuations in diversity and abundance of nearshore sandy beach fish 

communities with changes in 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 usually highest in Small Bay and lowest in Big Bay (Figure 10.2, Figure 10.4). 

Although this pattern still holds in the 2009 and 2010 surveys, with the average fish density in Small 

Bay still double that recorded for Big Bay, similar or greater average abundance was recorded in the 

Lagoon samples (Figure 10.4). This was mostly a result of some very large harder catches at two of 

the lagoon sites (Schaapen Island and Bottelary) and 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 


ather than an indication in fundamental changes in the fish communities. The general trend of 

increasing fish diversity and abundance with decreasing wave exposure between Big and Small Bay, 

identified by Clark (1997) still holds for all of the more recent surveys. 

In the 2006 report, concern was expressed over the apparent disappearance of pipefish 

during the 2005 survey. This species was once again present, albeit in low numbers, in hauls made in 

Small Bay during 2009. It is noteworthy that elf were absent in Big Bay samples for the first time and 

also from Small Bay samples, where it occurred during most years. Steentjies that had also 

previously been recorded in Small Bay samples were absent in 2009, whilst two species, dark 

shyshark and False Bay klipvis were caught for the first time. With the exception of pipe fish, no 

species that was consistently present in the earlier Langebaan Lagoon surveys (1986/87, 1994, 2005) 

are absent from the latter surveys (2007-2009). The continued absence of pipefish is probably the 

result of excluding the remote Geelbek sampling site, where its eelgrass habitat exists, from the 

latter surveys. The blenny, Parablennius cornutus was caught in the lagoon for the first time during 

the 2009 survey. 

Number of species 

18 

16 

14 

12 

10 

8 

6 

4 

2 

0 

2250m 2 

7200m2 3750m2 1986 1994 2005 2007 2008 2009 2010 

5600m 2 

4950m 2 

4275m 2 

5525m 2 


5400m 2 

6250m 2 

Small Bay Big Bay Lagoon 

Area 

Figure 10.2. 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. 

10500m 2 

5850 m 2 

7500m 2 

1800m 2 

7125m 2 

7200m 2 

6000m 2 

9000m 2 

6150m 2 

11325m 2



Figure 10.3. 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 

Species Common name 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 

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 

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 

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 

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 

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 

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 

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 

Pomatomus saltatrix elf 0.0009 0.0009 0.0013 0.0013 0.0003 0.0003 

Poroderma africana striped catshark 0.0009 0.0005 

Psammogobius knysnaensis Knysna sand goby 

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 

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 

Spondyliosoma emarginatum steentjie 0.0013 0.0009 0.0092 0.0072 0.0003 0.0003 

Syngnathus temminckii pipe fish 0.0022 0.0012 0.0037 0.0019 0.0257 0.0125 0.0004 0.0002 0.0035 0.0021 

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 

Number of species 26 16 14 14 15 12 12 

Number of hauls 59 5 12 6 12 12 12 

Total area sampled(m 2 ) 28025 2250 7200 3750 5600 4950 4275



Table 10.1. Average abundance of fish species (number.m -2 ) recorded during annual beach seine-net surveys in Big 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-2010 

Species Common name 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 

Blennophis blenny sp. 0.0001 0.0001 0.0001 0.0001 

Caffrogobius sp. goby 

0.0002 0.0002 0.0031 0.0020 

Callorhinchus capensis St Joseph 0.0017 0.001 

Cancelloxus longior Snake eel 0.0001 0.0001 

0.0003 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 

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 

Clinus sp. larvae Klipvis larvae 

0.0027 0.0019 

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 

Mustelus mustelus smoothhound shark 0.0013 0.0006 0.0001 0.0001 

Myliobatis aquila eagle ray 0.0049 0.0027 

0.0003 0.0003 

Pomatomus saltatrix elf 0.0005 0.0003 0.0001 0.0001 0.0159 0.0157 0.0430 0.0265 

0.0068 0.0031 

Psammogobius knysnaensis Knysna sand gobi 

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 

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 

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 

Trachurus trachurus horse mackerel 

0.0001 0.0001 

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 

Number of species 26 14 12 10 17 12 13 

Number of hauls 86 14 12 6 18 18 18 

Total area sampled(m 2 ) 41025 5525 5400 6250 10500 5850 7500



Table 10.2. Average abundance of fish species (number.m -2 ) recorded during annual beach seine-net surveys in Langebaan Lagoon. Ave. = average, SE = standard 

error. 

Species Apr&Jun Apr-94 Oct-05 Apr-07 Apr-08 Apr-09 Apr-10 

Common name 1986-87 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 

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 

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 

Parablennius cornutus blenny 

0.0002 0.0002 

Pomatomus saltatrix elf 0.0001 0.0001 

0.0002 0.0002 

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 

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 

Rhinobatos blockii bluntnose guitar fish 0.0176 0.0100 0.0011 0.0006 0.0008 0.0004 0.0065 0.0032 

Solea bleekeri blackhand sole 0.0006 0.0003 0.0004 0.0003 0.0003 0.0002 

0.0001 0.0001 

Spondyliosoma emarginatum steentjie 0.0001 0.0001 

0.0009 0.0009 

0.0001 0.0001 

Syngnathus temminckii pipe fish 0.0063 0.0025 0.0007 0.0004 

Trachurus trachurus horse mackerel 0.0001 0.0001 

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 

Number of species 19 9 14 

11 

8 11 11 

9 

Number of hauls 114 30 20 

12 

9 15 13 

15 

Total area sampled(m 2 ) 64800 18000 7125 7200 6000 9000 6150 11325


10.3.2 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. White stumpnose and blacktail were also abundant during 

the 2007 and 2008 surveys but the density of these two species had returned to, or below historical 

levels in 2009. Overall fish abundance (all species combined) in Small Bay, Big Bay and Langebaan 

Lagoon during the 2007 survey was substantially greater than during earlier two (1994 & 2005) and 

the following two surveys (2008 & 2009)(Figure 10.4). Higher than average fish density was again 

observed in Small Bay during the 2008 sampling, but fish densities in Big Bay and Langebaan Lagoon 

were similar to the levels recorded during earlier surveys. 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 2010 survey saw a recovery in the 

density of harders and white stumpnose in Small Bay and Big Bay, and elf in Big Bay, to the levels 

recorded during earlier surveys. Indeed the elf densities recorded in Big Bay during the 2010 

sampling were the highest yet and harder densities in Small bay were second only to those recorded 

during the 2007 survey (Figure 10.5) 

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 slightly better recruitment are seen in 

the 2010 data. Naturally high variability in recruitment strength is however, 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. In Langebaan lagoon, the number of silverside 

remained low in the 2010 sample (for the fifth consecutive year) and it does appear that the 

relatively high densities recorded during the first two surveys are the exceptions. The abundance of 

Knysna sand gobies and gobies of the genus Caffrogobius were similar to densities recorded during 

earlier surveys (Figure 10.5). The observed density of white stumpnose and harders in Langebaan 

lagoon recorded during the 2010 sampling were higher than that recorded during all six 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 10.5). 

Fish abundance (No.m -2 ) 

18 

16 

14 

12 

10 

8 

6 

4 

2 

0 

1986 1994 2005 2007 2008 2009 2010 

Small Bay Big Bay Lagoon 

Area 

Figure 10.4. Average fish abundance (all species) during five seine-net surveys conducted in Saldanha Bay 

and Langebaan lagoon. (Error bars show one Standard Error of the mean). 



Figure 10.5. Abundance of the most common fish species recorded in annual seine-net surveys within 

Saldanha Bay and Langebaan Lagoon (1986/87, 1994, 2005, 2007-2010) (Error bars show one 

standard error of the mean). 

10.3.3 Status of fish populations at individual sites sampled during 2010 

The average abundance of the four most abundant species in catches made during all earlier 

surveys and the most recent 2010 survey at each of the sites sampled is shown in Figure 10.6 & 

Figure 10.7. The fish species include two commercially important species, (white stumpnose, 

harders), benthic gobies of the genus Caffrogobius and the ubiquitous shoaling silverside (an 

important forage fish species). The generally higher abundance of these species within Small Bay 

compared to Big Bay is clear, with the exception of the Sea Farm Dam site where catches are similar 

to the Small Bay sites (Figure 10.6). 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 sites along the western shore of Small 



Bay or sites within Big Bay (Figure 10.6). Although the average densities of these more common 

species are variable, the differences between Small Bay and most Big Bay sites are up to an order of 

magnitude and are significant (more than two standard errors) (Figure 10.6). 

The densities of silverside, harders and white stump within Big Bay were highest at the Sea 

Farm Dam site and generally higher than at the two North Bay sites (Figure 10.6). With the 

exception of the North Bay, Strandloper and Small craft sites, 2010 sampling revealed a significant 

reduction from the long term average in estimated abundance of white stumpnose at all other sites. 

The density of the other species in Small Bay and Bog Bay was comparable to historical levels at 

most sites. 

In the earlier surveys, most sites within the Lagoon had lower estimate fish abundance than 

that recorded in Small Bay and had similar fish densities to those found at the Big Bay sites (Figure 

10.6 & Figure 10.7). However, the 2010 densities of harders and white stump were at four of the 

five lagoon sites the highest yet recorded, and comparable to and/or greater than those recorded at 

sites in Small Bay and Big Bay. 

Figure 10.6. Average abundance of the four most common fish species at each of the sites sampled within 

Small Bay and Big Bay during the earlier surveys (1994, 2005, 2007-2009) and during the 2010 

survey. Errors bars show plus 1 Standard error. Note the scale change on vertical axis shows a 

maximum of either 1 or 3 fish.m -2 . 



Figure 10.7. Average abundance of the four most common fish species at each of the sites sampled within 

Langebaan lagoon during the earlier surveys (1994, 2005, 2007-2009) and during the 2010 

survey. Errors bars show plus 1 Standard error. Note the scale change on vertical axis shows a 

maximum of between 1 and 80 fish.m -2 . 

10.3.4 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) were significantly different from one another. This was related to environmental 

differences between the three areas (primarily water temperature and productivity). It was 

concluded that although the whole Saldanha Bay- Langebaan Lagoon system is connected, the nearshore 

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 possible 

changes in the health of the environment) on an area specific basis. An multidimensional scaling 

(MDS) plot that displays similar sites close together and dissimilar sites further apart, shows some 

separation of the different sites within Small Bay (Figure 10.8). Similar to the overall trend between 

in fish communities throughout the bay and lagoon, a pattern relating to the degree of exposure of 

each site is evident, from the most exposed Small craft harbour samples (left hand side of plot) 

through to the most sheltered Hoedtjies Bay samples (Figure 10.8). With the exception of the Small 

craft harbour samples taken during 2005, there is however, very little separation of samples by 

years. A two way nested design ANOSIM (sites nested within sample years) indicated significant 



differences in the fish community between sites averaged across all sample years (Global R = 0.45, 

P< 0.01) and between sample years (Global R = 0.268, P< 0.05). Pairwise tests indicate that the only 

significant differences between year groups were between 2005 and 2010 samples. However, it is 

clear from the MDS plot that 2010 samples were similar to most sites sampled in all other years 

(including some of the 2005 samples) and it is the 2005 samples that are “outliers” rather than the 

2010 samples. SIMPER analyses identified higher abundance of harders, silversides, white 

stumpnose and Cape sole and lower abundance of blacktail, gobies, gurnards and klipvis in the 2010 

samples compared to the 2005 samples, as the dominant causes (80%) of dissimilarity between 

these two sampling events. 

Transform: Fourth root 

Resemblance: S17 Bray Curtis similarity 

2D Stress: 0.19 

site 

Bluewater Bay 

Campsite 

Smallcraft harbour 

Hoedtjies Bay 




year 

94 

2005 

2007 

2008 

2009 


Figure 10.8. Multidimensional scaling plots showing similarities between the fish communities sampled at 

four sites within Small Bay during 1994, 2005, 2007, 2008, 2009 and 2010 sampling events. 

Note that three replicate samples were collected at each site in each year. 



Within Big Bay too, some site grouping is evident, with particularly the outer bay 

(Plankiesbaai and North Bay) sites, differing somewhat from the other Big Bay sites, but little 

grouping of sampling years in the MDS plots (Figure 10.9). It is clear that all of the 2010 samples fall 

within the range of samples collected in earlier years, indicating no substantial changes in the Big 

Bay fish communities overall at sampled sites. A nested ANOSIM test indicated significant 

differences between sites (Global R = 0.618, P < 0.01) but not between sampling events (Global R = 

0.05, P > 0.05). 







site 

Plankies Baai 

Strandloper 

Lynch Point 

Seafarm Dam 

North Bay east 

North Bay west 

Spreeuwalle 

year 

1994 

2005 

2007 

2008 

2009 



seven Big Bay sites during 1994, 2005, 2007, 2008, 2009 & 2010 sampling events. Note that 

three replicate samples were collected at each site in each year. 








site 


Geelbek 

Churchaven 

Kraal Baai 

KleinOostewal 

Botlery 


year 

1994 

2005 

2007 

2008 

2009 



six Lagoon sites during 1994, 2005, 2007, 2008, 2009 & 2010 sampling events. 

The Schaapen Island site at the mouth of Langebaan lagoon that is exposed to strong tidal 

currents, as well as the sheltered Geelbek sites at the southern end of the Lagoon grouped 

discernibly from the other lagoon sites in the MDS plots (Figure 10.10). There was however, little 

evidence of separation between sampling years (Figure 10.10). The differences between sites are 

significantly different (Global R = 0.67, p


2008 and 2009 samples. It is unlikely that the season of sampling has much to do with this as the 

1994 sampling event took place in early April – the same timing as the 2007-2009 sampling events 

(Intuitively it was expected that the October 2005 sampling that took place during Spring would be 

the outlier). SIMPER identified the high densities of silversides in the lagoon during 1994 as been the 

primary contributor (>20% in every case) to the dissimilarity in samples between this year and all 

other years. As discussed in the 2009 State of the Bay report, the decrease in silverside densities in 

the latter surveys is mostly a result of natural population size fluctuations, the tidal state during 

actual surveys and the specific sites sampled. There were no significant changes in the fish 

community between the 2005-2010 sampling events, indeed, despite the increases in abundance of 

harders and white stumpnose at most lagoon sites, the 2010 samples as a group are not significantly 

different from any other year. 

10.4 Conclusions 





in Langebaan lagoon since the 1970’s (see §7 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. 

The 2010 sampling event recorded comparable data to earlier surveys in Big Bay and Small 

Bay with clear reductions in the abundance of some species. In Langebaan lagoon, the 2010 

sampling revealed the highest densities of white stumpnose and harder juveniles yet recorded in all 

the annual seine net sampling conducted to date. This reflects natural and human induced 

variations in 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 the stock. Although correlation should 

not be interpreted as cause and effect, it is notable that white stumpnose density recorded during 

2010 was higher than the long-term average at sites further away from anthropogenic disturbance 

(Lagoon and North Bay sites), whilst densities decreased at most Small Bay and Big bay sites. The 

presence and proposed expansion of heavy industrial activity, increased urbanization and associated 

pollutants entering the Bay system as well as future large scale dredging and port expansion plans 

undoubtedly places strain on the supporting environment and ecosystem, whilst increased human 

exploitation places direct pressure on fish stocks. Ongoing, regular monitoring of the ichthyofauna 

and fisheries in Saldanha Bay and Langebaan Lagoon is therefore strongly recommended. 


11 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). 

11.2 Birds of Saldanha Bay and the Islands 

11.2.1 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 



the islands, but are thought to form a source population for mainland coastal populations through 

dispersal of young birds. 

11.2.2 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 recruit (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 Sardinops 

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 11.1). Furthermore, both prey species are exploited by purse-seine fisheries which together 

with the recent 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 506 breeding pairs in 2010, representing a 75% 

decrease in 24 years (Figure 11.1). This trend currently shows no sign of reversing, and immediate 

conservation action is required to prevent further declines. 


Number of breeding pairs 

2400 

2200 

2000 

1800 

1600 

1400 

1200 

1000 

800 

600 

400 

200 

0 

1987 

1988 

1989 

1990 

1991 

1992 

1993 

1994 

1995 

1996 

1997 



1998 

1999 

Year 

2000 

2001 

2002 

2003 

2004 

2005 

2006 

Total 

Malgas 

Marcus 

Jutten 

Vondeling 

2007 

2008 

Figure 11.1. Trends in African Penguin populations at Malgas, Marcus, Jutten and Vondeling islands in 

Saldanha Bay (Data source: Rob Crawford, Oceans & Coasts, Department of Environmental 

Affairs). 

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 penguin’s foraging efforts by 30% within 3 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 has severe negative 

consequences for penguins. When they bred in large colonies, packed close to one another, they 

were better able to defend themselves against egg and chick predation by Kelp gulls. Also, these 

losses were 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 

the penguins’ ability to locate these schools. There are also concerns that toxin loads influence 

individual birds’ fitness, 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 

2009 



at Saldanha are believed to be an increasingly important factor in the continued demise of African 

penguin colonies at the islands. 

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 a small 

but consistent sized population 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 11.2), probably due to the increase in availability of food as a result of the introduction and 

spread of the invasive alien mussel species Mytilus galloprovincialus. This does not necessarily 

represent a good impact on the ecosystem, however, as Kelp Gulls are known to eat the eggs of 

several other bird species (e.g. Cape Cormorants and Hartlaub's Gulls). 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 in 2010 (Figure 11.2). 

Number of Breeding Pairs 

14000 

12000 

10000 

8000 

6000 

4000 

2000 

0 

1978 

Total 

Malgas 

Jutten 

Schaapen 

Vondeling 

Meeuw 

1979-1984:No data 

1985 

1986 

1987:No data 

1988 

1989 

1990 

1991 

1992 

1993 

1994 

1995 

1996 

1997 

1998 

1999 

2000 

2001 

2002 

2003 

2004 

2005 

2006 

2007 

2008 

2009 


Figure 11.2. Trends in breeding population of Kelp gulls at Malgas, Jutten, Schaapen, Vondeling and 

Meeuw Islands in Saldanha Bay (Data source: Rob Crawford, Oceans & Coasts, Department of 

Environmental Affairs). ND = No data 


Year



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 coast between Cape 

Agulhas and Swakopmund. 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 Gulls, African Sacred Ibis, and Cattle Egrets, which eat eggs, chicks 

and occasionally adults (Williams et al. 1990). In Saldanha there is no discernable upward or 

downward trend over time, but there is some concern in that numbers have been at lower-thanaverage 

levels for the past three years (Figure 11.3). 

3500 

3000 

2500 

2000 

1500 

1000 

500 

0 

1987 

1988 

1989 

1990 

1991 

1992 

1993 

1994 

1995 

1996 

1997 


1998 

1999 

Year 

2000 

2001 

2002 

2003 

2004 

2005 

Total 

Malgas 

Marcus 

Jutten 

Vondeling 

Schaapen 

Figure 11.3. Trends in breeding population of Hartlaub’s Gulls at Malgas, Marcus, Jutten, Schaapen and 

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

of Environmental Affairs). 

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 

2006 

2007 

2008 

2009 


their main prey species, sardines and anchovies, since 

2005 however, population numbers decreased in the 

North and central portions of the Western Cape and 

increased further South, coinciding with the eastward 

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 is the most 

important island for breeding Swift Terns, but breeding numbers are erratic at all the islands. No long 

term trends are discernible, but there is some concern in that there has been no breeding for three 

years on any of the island (Figure 11.4). 


4000 

3500 

3000 

2500 

2000 

1500 

1000 

500 

0 

1987 

1988 

1989 

1990 

1991 

1992 

1993 

1994 

1995 

1996 

1997 


1998 

Year 

1999 

2000 

Total 

Malgas 

Marcus 

Jutten 

Schaapen 

Figure 11.4. Trends in breeding population of Swift Terns at Malgas, Marcus, Jutten and Schaapen islands 

in Saldanha Bay (Data source: Rob Crawford, Oceans & Coasts, Department of Environmental 

Affairs). 

2001 

2002 

2003 

Cape Gannets Morus capensis are 

restricted to the coast of Africa, from the Western 

Sahara, around Cape Agulhas to the Kenyan coast. 

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 IUCN’s ‘red data list’ due to its 

restricted range and population declines (Birdlife 

International 2011). 

2004 

Cape Gannets feed out at sea and will often 

2005 

2006 

2007 

2008 

2009 



forage more than 100 kilometres away from their nesting sites (Adams and Navarro 2005). This 

means that very few will actually feed in Saldanha Bay. Therefore, choice of nesting area is more 

influenced by protection from predators. 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 11.5). 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 1990’s. 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 the 

seals, between 2001 and 2006 was responsible for a 25% reduction in the size of the colony at 

Malgas Island (Makhado et al. 2006). These added threats weigh heavily on an already vulnerable 

species. 


60000 

50000 

40000 

30000 

20000 

10000 

0 

1956 

1957/66:No 

1967 

1968 

1969 

1970/77:No 

1978 

1979: No data 

1980 

1981 

1982 

1983 

1984 

1985 

1986 

1987 

1988 

1989 

1990 

1991 

1992 

1993 

1994 

1995 

1996 

1997 

1998 

1999: No data 

2000 

2001 

2002: No data 

2003 

2004: No data 

2005 

2006 

2007 

2008 

2009 


Year 

Malgas 

Figure 11.5. Trends in breeding population of Cape Gannets at Malgas Island, Saldanha Bay ((Data source: 

Rob Crawford, Oceans & Coasts, Department of Environmental Affairs). ND = No data 

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 seal, 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. 

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 

1970’s (Cooper et al. 1982). Numbers decreased again during the 

early 1990’s 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 also prey on Cape Cormorant eggs and chicks; which 

is exacerbated by human disturbance, especially during the early stages of breeding, and the 

increase in gull numbers (du Toit, 2004). 

The population on Malgas Island has been relatively stable since 1988 showing small yearon-year 

fluctuations. Since 2005, however, the population has been steadily decreasing and 

breeding birds dropped by an order of magnitude between 2005 and 2008 with a slight increase in 

2009 but dropping again in 2010 as the population on Vondeling dropped dramatically from 5 000 

birds so fewer than 300 (Figure 11.6). The population on Jutten Island has the largest breeding 

population although numbers there also fluctuate greatly from year to year (Figure 11.6). Although 

no long term trends are discernable the population has not recovered to its 1993 levels of over 

23,000 breeding pairs and ongoing monitoring is still necessary. 



26000 

24000 

22000 

20000 

18000 

16000 

14000 

12000 

10000 

8000 

6000 

4000 

2000 

0 

1988 

1989 

1990 

1991 

1992 

1993 

1994 

1995 

1996 

1997 



1998 

1999 

2000 

Year 

2001 

2002 

2003 

2004 

2005 

2006 

2007 

2008 

Total 

Malgas 

Jutten 

Schaapen 

Vondeling 

Meeuw 

Figure 11.6. 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). 

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 beds 

where they catch West Coast rock lobster, Jasus 

lalandii, with Pelagic Goby, Sufflogobius 

bibarbatus, taken in mid-water (du Toit 2004). 

Total population decreased from ca. 9,000 

breeding pairs in 1975 to less than 5 000 pairs in 1991-1997 to 2 800 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). The Bank Cormorant has as a result of ongoing population decrease been re-classified from 

Vulnerable to Endangered (Birdlife International 2011). It is very susceptible to human disturbance 

and eggs and chicks are taken by Kelp Gulls and Great White Pelicans. Increased predation has been 

2009 



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. 

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. Data suggest that 

some of these birds moved to other islands, with number of breeding birds increasing on Marcus 

and Jutten islands but there has been no recovery to peak numbers breeding in 1991 (Figure 11.7). 

In Saldanha Bay the declines are mainly attributed to scarcity of their main prey, the rock lobster 

(Jasus lalandii), which in turn has reduced recruitment to the colonies (Crawford 2007; Crawford et 

al. 2008c). 

350 

300 

250 

200 

150 

100 

50 

0 

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 



Total 

Malgas 

Marcus 

Jutten 

Vondeling 

Figure 11.7. 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). 

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 South Africa. Along the coast, White-breasted 

Cormorants occur mainly within 10 km offshore, often near 

reefs. White-breasted Cormorants that forage in the marine 

environment feed on bottom-living, mid-water and surfacedwelling 

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 local water quality (Hockey et al. 2005).


No breeding pairs have been counted on Malgas Island since the 1920’s. A low number 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). In 1995, 130 breeding pairs were present on Schaapen Island but this 

population declined to 45 pairs by 2003 with only two pairs were seen in 2004, after which breeding 

stopped (Figure 11.8). Vondeling Island had just a few breeding pairs of birds (between two and 

nine) that used the island intermittently between 1987 and 1997 with no recorded breeding since. 

Meeuw Island is currently the only island with breeding birds on. There are yearly counts available 

from all 6 islands since 1989 and in that time the total population has halved, from 202 pairs to 92 

pairs, indicating that conditions in Saldanha Bay have deteriorated for these birds. 


250 

200 

150 

100 

50 

0 

1973 

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 



Year 

Total 

Marcus 

Jutten 

Schaapen 

Vondeling 

Meeuw 

Figure 11.8. Trends in breeding population of White-breasted Cormorants at Marcus, Jutten, Schaapen, 

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

Department of Environmental Affairs). 

Human disturbance poses a serious 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 with high boating, kite-boarding and 

other recreational use of the area, it is possible that the decline in White-breasted cormorants is due 

at least in part to increased levels of human disturbance. 

Crowned Cormorants, Phalacrocorax coronatus, are 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


800 

700 

600 

500 

400 

300 

200 

100 

0 

Total 

Malgas 

Marcus 

Jutten 

Schaapen 

Vondeling 

Meeuw 

1977 

1978 

1979 

1980 

1981 

1982 

1983 

1984:ND 

1985 

1986 

1987 

1988 

1989 

1990 

1991 

1992 


benthic fish and invertebrates, which they forage for in 

shallow coastal waters and among kelp beds (du Toit 

2004). 

The overall population in Saldanha Bay has 

increased since 1989. Populations on Malgas and Jutten 

Islands show general stability in the number of breeding 

birds, and while the populations on Schaapen and Meeuw 

Islands are larger, they do show greater fluctuation in 

numbers making them less predictable (Figure 11.9). In 

general the Crowned Cormorant population does not 

seem threatened by lack of food or predation in the 

Saldanha Bay area. 


1993 

1994 

1995 

1996 

1997 

1998 

1999 

2000 

2001 

2002 

2003 

2004 

2005 

2006 

2007 

2008 

2009 


Figure 11.9. Trends in breeding population of White-breasted Cormorants at Malgas, Marcus, Jutten, 

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

& Coasts, Department of Environmental Affairs). ND = No data 

African Black Oystercatchers, Haematopus 

moquini, are endemic to southern Africa is listed as 

Neat Threatened in the IUCN’s a Red Data List owing 

to its small population and limited range (Birdlife 

International 2011). They breed 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 11.10). This steady 

Year


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 (Loewenthal in prep.). 

African Black Oystercatchers are resident on the islands, feeding in the rocky intertidal. 

While the mussels arrived 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 and the carrying capacity of the islands has probably 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. 


600 

500 

400 

300 

200 

100 

0 

1976 

1978 

1980 

1982 

1984 

Total 

Marcus 

Malgas 

Jutten 

1986 

1988 

1990 


1992 

Figure 11.10. Trend in breeding population of African Black Oystercatchers older than 1 year, on Marcus, 

Malgas and Jutten Islands in Saldanha Bay. (Data source: Douglas Loewenthal, Oystercatcher 

Conservation Programme). 

Year 

1994 

1996 

1998 

2000 

2002 

2004 

2006 

2008 


11.3 Birds of Langebaan Lagoon 

11.3.1 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 Palearctic 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 

important wetland for waders on the west coast of southern Africa (Siegfried, 1977). Langebaan 

Lagoon is 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 strictly controlled within the Lagoon through 

zonation. 

11.3.2 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 11.1), the most species-rich being the Charadriiformes, which include the waders, gulls and 

terns. Table 11.1 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 11.11). 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 11.1. Taxonomic composition of waterbirds in Langebaan Lagoon (excluding rare or vagrant species). 

Common groupings Order SA 

Resident 

Waterfowl Podicipediformes (Grebes) 1 

Cormorants, darters, 

pelicans 

Anseriformes (Ducks, geese) 9 

Gruiformes (Rails, crakes, gallinules, coots) 7 

Pelecaniformes (Cormorants, darters, pelicans) 7 

Wading birds Ciconiiformes (Herons, egrets, ibises, spoonbill, etc.) 14 

Phoenicopteriformes (Flamingos) 2 

Birds of prey Falconiformes (Birds of prey) 4 

Migrant 

Waders Charadriiformes: Waders 8 18 

Gulls Gulls 2 

Terns Terns 3 4 

Kingfishers Alcediniformes (Kingfishers) 2 

Total 59 22 

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 

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% 

Waterfowl 

0% 

Herons, 

egrets, ibises 

1% 

Summer 

Gulls, terns 

8% 

Resident 

waders 

1% 

Migratory 

waders 

87% 

Gulls, terns 

15% 

Herons, 

egrets, ibises 

7% 

Flamingos 

37% 

Winter 

Resident 

waders 

7% Migratory 

waders 

30% 

Waterfowl 

1% 

Pelicans 

1% 

Cormorants 

2% 



Figure 11.11. 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. 

11.3.3 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 

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 (Figure 11.12). 

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 11.13). 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 §7) and human disturbance, which has been shown to 

have a dramatic impact on bird numbers in other estuaries (Turpie and Love 2000). 


Number of birds 

45000 

40000 

35000 

30000 

25000 

20000 

15000 

10000 

5000 

0 


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 

Figure 11.12. Long term trends in the numbers of summer migratory waders on Langebaan Lagoon 

Number of birds 

1200 

1000 

800 

600 

400 

200 

0 

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 

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

11.4 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. 



12 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 12.1). 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) and the recently detected barnacle 

Balanus glandula (Laird and Griffiths, in press). 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 a newly discovered marine alien species known only from Saldanha Bay and identified 

through the State of the Bay monitoring programme is presented below 

Table 12.1. 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. in prep. a & b) 

Taxon 

PROTOCTISTA 

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 

Pinauay ralphi Likely North Atlantic SF/BW 


Taxon 


Occurrence 

in Saldanha 


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 

Cerapus tubularis Confirmed North American Atlantic BS 

Decapoda 

Carcinus maenas Confirmed Europe SF/BW/OR 

INSECTA 

Coleoptera 

Cafius xantholoma Likely Europe BS 

MOLLUSCA 


Taxon 

Gastropoda 


Occurrence 

in Saldanha 


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 

CHLOROPHYTA 

Codium fragile fragile (tomentosoides strain) Confirmed Japan SF/BW 

VASCULAR PLANTS 

Ammophila arenaria Confirmed Europe I 


Taxon 


Occurrence 

in Saldanha 


Spartina maritima Confirmed Europe BS 

12.1 The occurrence and spread of the 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 

reported from South Africa waters. Sampling for the State of the Bay surveys entails the collection of 

three replicate sediment samples from 20-25 sites in Salnaha Bay and Langebaan using a diveroperated 

suction sampler, which sampled an area of 0.08 m 2 to a depth of 30. It appears to be an 

alien species that 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 it becoming established in the 

Bay, 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 12.1). 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, 

and then extended through into the upper reaches of Langebaan lagoon in 2009 (Figure 12.1). The 

distribution in 2010 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). 

No. sites 

Abundance (no. ind. m -2 ) 

10 

8 

6 

4 

2 

0 

40 

30 

20 

10 

0 

1999 2004 2008 2009 2010 

1999 2004 2008 2009 2010 

Figure 12.1 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 and top number of individuals 

collected from these sites (bottom). 



Figure 12.2. Map showing changes in the distribution of the Western Pea crab Pinnixa occidentalis in 

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



13 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. 

13.1 Activities and discharges affecting the health of the Bay 

13.1.1 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, or from the Langebaan golf course which is irrigated with 

treated sewage effluent), nor is it adequately controlled at present (e.g. the Saldanha sewage works 

still operates 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 

Langebaan Lagoon. 

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 



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. 

13.1.2 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. 

13.1.3 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 Oosterwal, 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. 

13.1.4 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 Small Bay. 

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 has in fact shut down 



their operations in Saldanha (although operations are 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. 

13.1.5 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. 

13.1.6 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. 

13.1.7 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 plant) 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. 


13.2 Water Quality 

13.2.1 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. 

13.2.2 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. 

13.2.3 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. 

13.2.4 Trace metal concentrations in biota (MCM 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. 

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). 

13.2.5 Microbiological monitoring (Faecal coliform) 

Water samples are currently analysed fortnightly for faecal coliform and E. coli 

concentrations from 18 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. 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 does not appear to be any bacterial contamination within Langebaan 

Lagoon (with occasional exceptions), but 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. 

13.3 Sediments 

13.3.1 Particle size, Particulate Organic Carbon and Trace metals 

Sediment monitoring in the Bay has revealed that key heavy metal contaminants (Cd, Pb, Cu, 

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 

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. 

13.3.2 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. 


13.4 Benthic macrofauna 


A range of benthic community health indicators examined in this study over the period 1999 

to 2010 has revealed that benthic health most likely deteriorated in Small Bay from 1999 to 2008, 

but has recently (2009 and 2010 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. 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. 

13.5 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. 

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. 

13.6 Fish 





in Langebaan lagoon since the 1970’s (see §7 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. 

13.7 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. 

13.8 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 

(temperature, salinity, 

dissolved oxygen, nutrients 

and chlorophyll) 

Current circulation patterns 

and current strengths 

Microbiological (faecal 

coliform) 

Heavy metal contaminants 

in water 

SEDIMENTS 

Particle size 

(mud/sand/gravel) 

Particulate Organic Carbon 

(POC) 

Particulate Organic Nitrogen 

(PON) 

Trace metal contaminants 

in sediments 

BENTHIC MACROFAUNA 

1974-2000 No clear change attributable to development 

1977 vs. 1991 Reduced wave energy, and impaired circulation 

and rate of exchange in Small Bay 

Increased current strength alongside obstructions 

(e.g. ore jetty) 

1999-2010 Faecal coliform counts in Small Bay frequently 

exceed safety levels. 

Big Bay and Langebaan Lagoon mostly remain 

within safety levels for faecal coliform pollution 

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. 

1977-2010 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). 

1974-2010 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. 

1980-2010 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. 

Species biomass 1975-2010 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 2004 - 

2008 

Species diversity 1975-2010 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 

1980-2010 Displacement of local mussel and other native 

species from the lower shore leading to decreased 

species diversity (negative). 

1986-2010 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. 

1977-2010 Decreasing populations of Cape, Bank and Whitebreasted 

Cormorants are attributed to 

construction of causeway and increasing human 

disturbance. 

1976-2010 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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