SWIOP/WP/63 - Gillnetting Trials for Deepwater Red Snappers on the Seychelles Plateau

Table of Contents

by

D.C. Bean
Consultant Masterfisherman

January 1991
RAF/87/008/DR/63/E

REGIONAL PROJECT FOR THE DEVELOPMENT & MANAGEMENT OF FISHERIES IN THE SOUTHWEST INDIAN OCEAN

PROJET REGIONAL POUR LE DEVELOPPEMENT ET L'AMENAGEMENT DES PECHES DANS L'OCEAN INDIEN SUD-OCCIDENTAL

c/o UNITY HOUSE, P.O. BOX 487, VICTORIA, MAHE, SEYCHELLES

TELEPHONE: 23773
TELEX: 2254 SWIOP SZ

FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS UNITED NATIONS DEVELOPMENT PROGRAMME

The designations and the presentation of material in this publication do not imply the expression of any opinion whatsoever by the Food and Agriculture Organization of the United Nations concerning the legal status of any country, territory, city or area or of its authorities or concerning the delimitation of its frontiers or boundaries. The views expressed are those of the authors.

Bibliographic reference:

Bean, D.C., (1991), Gillnetting Trials for Deepwater Red Snappers on the Seychelles Plateau, FAO/UNDP
RAF/87/008/DR/63/E, 15 pp.

This electronic document has been scanned using optical character recognition (OCR) software and careful manual recorrection. Even if the quality of digitalisation is high, the FAO declines all responsibility for any discrepancies that may exist between the present document and its original printed version.

Table of Contents

SUMMARY

CONTEXT

1. BACKGROUND

3. SEA TRIPS - METHODOLOGY

4. RESULTS

5. DISCUSSION

6. RECOMMENDATIONS

7. CONCLUSION

8. COSTING

9. ACKNOWLEDGEMENTS

SUMMARY

The consultancy involved fishing trials with gillnets targeting deepwater snappers in order to establish the feasibility of this method. This resource is perceived to have the potential to permit economic operation of larger vessels in the artisanal fishery. The stocks targeted are lightly exploited at present, and are all varieties in demand for export by the Seychelles Marketing Board (SMB).

A total of 16 days at sea spread over three trips was achieved during the consultancy, using the vessel Etelis, belonging to the Seychelles Fishing Authority (SFA). Forty three sets of the nets were made, all in different locations scattered around the edge of the shelf of the Seychelles Plateau.

The most difficult conditions were encountered during first trip to the Southeast in the area of the Constant Bank because of the strong currents. Less current was encountered during the second trip to the Northeast edge of the plateau and the third trip to locations Southwest and a better understanding of the problems involved improved performance. Throughout the period, the weather was excellent with only light sea breezes and very little swell.

A total of 3 964 kg of fish and 5 626 kg of shark were caught, giving catches per unit effort for the three trips of 18.7, 23.2 and 30.3 kg/net/set for fish, and 15.1, 38.9 and 50.5 kg/net/set for sharks.

These figures indicate an improving catch rate for each successive trip probably due to the better understanding of local conditions. The final trip was made during the spring tides and to an area alleged to be overfished by the local fishermen. Contrary to predictions, it seems that deepwater gillnetting can be operated during spring tides and that the handline catch in a specific area may not actually be indicative of the stock present but rather more the catchability of that stock.

The target species were the high value deepwater red snappers, mainly Pristipomoides and Etelis spp.. In practice, the deeper horizons which form the habitat of Etelis spp. were found to be difficult to fish as the nets frequently arrived at the bottom off target because of strong currents.

Later sets were generally more successful at targeting the horizon at the top of the drop-off (60-100 m) where the two dominant species of red snapper were Pristipomoides filamentosus and Aphareus rutilans. These two snappers together made up the bulk of the fish catch (60-70%).

The tremendous variation in the results achieved from different sets makes them very susceptible to misinterpretation. At one end of the scale, the catch was spectacular, with catch rates as high as anything the consultant had previously encountered. At the other end of the scale, there were a number of very poor results, mainly due to technical difficulties in being able to secure the gear to the target area because of the strong local currents and activities of very large sharks.

Economic projections show the highly positive potential for this fishery for 12 m boats and a slightly less encouraging result for 21 m boats.

However, before recommendations can be made to the SFA that they commit large sums of money into equipping their new and larger vessels for gillnetting, it is considered necessary to continue the research, attacking the problems from three different standpoints:

- to continue to identify the best fishing locations,
- to modify the gear to obtain better holding abilities in current and
- to lighten the work load on board by having better gear and fish handling procedures.

It will be necessary to purchase and rig further gear of different specifications to those on site to a design more suitable to the local conditions. Shallower nets with heavier footropes are thought to be one way of achieving more accurate positioning of the nets on the sea bed and getting them to stay there for the duration of the set, thus reducing the number of unproductive sets.

CONTEXT

The Masterfisherman was contracted by the FAO to act as consultant to the Seychelles Fishing Authority (SFA) in the field of deepwater gillnetting. The expert had previously extensively and successfully applied the technique in the areas of continental slope in several countries surrounding the Red Sea.

For the duration of the consultancy, he worked with the Research Department of the SFA using their well equipped 18 m FRV Etelis. Funding for the consultancy came from UNDP. Fishing gear used during the sea trials was provided by the SFA, funded from Japanese aid sources.

1. BACKGROUND

In an effort to increase the catch from the artisanal sector of the Seychelles from the present 4 392 metric tonnes to the estimated 7 000 metric tonnes of total sustainable yield, it was agreed that additional effort should be devoted to exploiting the deeper water species from the rim of the Seychelles Plateau. These species, primarily Pristipomoides and Etelis spp, were considered to be under least pressure from the traditional fishery and could offer opportunities for expansion of the local fleet, in particular the larger vessels capable of fishing at long range.

Presently, the SFA is in the process of building two 22 m and a number of 12 m vessels. The development of a fishing method capable of giving these and other large vessels within the artisanal sector, a viable operation is required. Furthermore, this would be an opportunity to much increase the supply of fish to the Seychelles Marketing Board's (SMB) extensive and under-utilised shore facility.

The SMB is the sole exporter of the artisanal catch and has an important role in the island economy. The target species of deepwater gillnetting are all suitable for export.

3. SEA TRIPS - METHODOLOGY

3.1 Equipment

Net hauler

The FRV Etelis was equipped with a hydraulically powered surface gillnet hauler. The drum surface of theis hauler was smooth and lacked sufficient friction to allow nets to be hauled from deep water. The consultant supervised the conversion of the drum so as to make it grip monofilament nets. This was done in the SFA workshop by local staff. By the second trip, following a few modifications, a very satisfactory net hauler was produced, lacking only a line hauler attachment which could be purchased later.

The conversion consisted of welding 12 mm steel bars radiating from the middle of the drum, fixed on their outer ends to the extended wings of the hauler (see photographs). These bars were staggered alternately on each side, overlapped the centerline by two centimeters, producing a herringbone pattern on the drum. This caused the net to travel a zigzag path as it passed over the drum, producing enough friction for the net to be gripped tightly. Even when being hauled from 200 m depth, a single man could operate the hauler. For safety and to strengthen the drum, 6 mm steel plate webs were cut to fit under the bars and welded in place.

Preparation of gear

Five deepwater gillnets were rigged in the first three days by the consultant and members of the FRV Etelis crew. The design is given in the diagrams in Annex I. The gear components were on site at the time of the consultant's arrival.

3.2 Methodology

The FRV Etelis with its normal crew of 6 persons was additionally staffed by a biologist and assistant and, on the second trip by a Mauritian gear technologist. On the third trip, David Ardill, Project Manager and Michael Sanders, Senior Fishery Development Specialist of the SWIOP accompanied the vessel.

The trips were of 3 to 7 days duration and each was in a different location on the rim of the Seychelles Plateau.

Ground Survey

On arriving at the rim of the Plateau, the position was checked with the satellite navigator and the steepness of the slope determined using the three echo sounders on board. A track on a particular chosen contour was then surveyed in the depth range between 60 and 200 m.

Where the slope was gentle enough, gear was targeted to lie diagonally down the slope from one limit to the other of the selected range. In practice, it was found that targeting 200 m was particularly hazardous as the currents and steepness of the drop-off at that depth frequently caused the gear to carry off into much deeper and unfishable waters.

Shooting the nets

Having determined a suitable track on which to target the nets, the gear was shot off the stern of the boat from the up-current end of the location. The speed of shooting was kept to a minimum to allow the crew to tie matchbox sized pieces of bait (bonito) to the net at roughly five meter intervals.

Anchoring the nets

As it became more and more apparent during the course of the trials that anchoring the nets securely was a major factor in procuring a catch, more effort was made to achieve this objective. In later sets, not only were 50 kg irons and grapnels used at the ends of the gear, but intermediate 20 kg irons were used between individual nets and the bridles/veering lines shortened to only 50 m.

Handling the nets

Starting with the up-current end, the gear was hauled with the converted hauler. The skipper kept the boat up on the gear from his key observation position on the flying bridge.

Fish were taken from the nets by two or three men immediately behind the hauler before the cleaned net was pulled astern, and spread, ready for baiting and shooting by three other crew members.

Biologists monitored the catch at all times during the hauling procedure, identifying the species and sex of each fish and taking its length and weight.

Fasteners and sharks

On the occasions when the net fouled the bottom, the hauler was stopped once it had reached the vertical position and a short piece of 20 mm rope was secured to the net just above the water line, the other end of which was tied to a cleat or towing position on the boat. Usually a little forward motion on the engine would release the fastener and hauling by the net drum would proceed. This method was necessary to prevent unnecessary strain on the bearings of the hauler.

Sharks of 100 kg and over were treated in a similar way, the thick rope being secured either to the head or the tail at the water line. The weight of the fish was then taken on the thick rope, thus minimising net damage. Very large sharks involved the use of a second thick rope and the capstan. Sharks smaller than 100 kg were systematically eased over the top of the hauler, with one crewman on the rail helping the fins around the net guides.

Handling of fish

After extraction from the net, the fish were placed in a slurry of ice and seawater contained in a 1-ton insulated container on deck. Once or twice a day, this container was emptied and the chilled fish were gutted, gilled and scrubbed clean of blood particles by the crew members, after which they were layered systematically by species in the fish hold. Each layer was well separated by crushed ice. The top layer of ice was covered with empty ice bags. Any additional space was also covered by unused bags before the hatches were securely put back in place (see Discussion).

Handling of sharks

Only the fins of the sharks were retained after the species and biological data had been collected by the biologists. Some large jaws were kept and some smaller specimens were kept by the crew for salting and taking home.

Duration of sets

A soak time¹ of two and a half to three hours was generally allowed for each set. This time got extended to six or more hours during the midnight to dawn period when the crew were catching up on their rest. At no time whatsoever was any fish found to be deteriorated in any form due to being in the nets too long. All the grouper and most of the Pristopomoides were still alive on hauling.

¹ "Soak time" refers to the time interval between the end of setting of the net and the beginning of hauling.

Aphareus rutilans were rarely alive on hauling due to their large size and the "gilling" position of the net bars. The 150 mm mesh was not wide enough to allow the gills to pass through the mesh and the fish would have died immediately on entangling in the net due to the fact that its gills would have been unable to open. Even so, no deterioration in quality was noticeable.

Repairs and modifications

Running repairs to the nets were done aboard the FRV Etelis as the nets were pulled back and spread ready for the next shot. The crew overhauled the nets thoroughly between trips and repaired all the damage using the 'lacing' method. Most damage to the nets was caused by sharks.

Modifications to the gear were also carried out on board when thought necessary. These mainly entailed adding additional anchors and weight to the footrope, but also involved shortening the veering lines to achieve more directional positioning of the nets in the shallower sets.

4. RESULTS

4.1 Fishing results

A total of 16 days at sea spread over three trips was achieved during the consultancy, using the SFA vessel Etelis. The detailed fishing results are presented in Table 1. Forty three different sets of the nets were made in different locations on the edge of the shelf.

The most difficult conditions were encountered because of the strong currents during first trip to the Southeast in the area of the Constant Bank. Less current was encountered during the second trip to the Northeast edge of the plateau and the third trip to locations Southwest and a better understanding of the problems resulted in improved catches. The weather was excellent throughout the period, with only light sea breezes and very little swell.

A total of 3 964 kg of fish and 5 626 kg of shark were caught, giving catches per unit effort (CPUE) for the three trips of 18.7, 23.2 and 30.3 kg/net/set for fish, and 15.1, 38.9 and 50.5 kg/net/set for sharks². The catch per day on each trip was 157, 293 and 335 kg for fish and 137, 504 and 714 kg for shark. The catch per day, however, is not strictly comparable in that varying quantities of gear were used with less nets in the second cruise and a second fleet of nets in the third.

² This gave CPUE* of 7.69, 6.78 and 5.46 kg/net/hour for fun, and 5.8, 8.93 and 7.52 kg/net/hour for sharks. The apparent drop in the catch rates presented in this manner was due to long soak times in the last cruise when nets were left overnight.

Although sufficient data were not available to establish this statistically, a tendency was noted for the catch of fish to drop and that of sharks to increase with soak times in excess of three hours, particularly in the night sets. The presence of sharks in the net was almost invariably associated with tears in the netting and with partially eaten fish. It thus seems likely that the above finding was due to sharks eating the fish meshed in the nets. Further confirmation comes from the fact that, even in long sets, many fish were still alive: it is presumed that the fish netted early in the set had been eaten by sharks.

Again, although detailed records were not kept of catch for each individual net, a tendency was noted for the catch to be concentrated in the initial and terminal nets in a set. Furthermore, the nets in the centre of a set frequently contained more rubble than those in the ends. These findings were interpreted to mean that the centre of the net tended to be swept along the bottom by the current (and large sharks). The addition of more intermediate weights and anchors in later sets improved these features. A reduction of the depth of the net may also help, hopefully with no drop in catch as fish were consistently meshed in proximity to the bait attached to the nets.

The target species were the high value deepwater red snappers, mainly Pristipomoides and Etelis spp.. In practice, the deeper horizons which form the habitat of Etelis spp. were found to be difficult to fish as the nets frequently arrived at the bottom off target because of strong currents. Many sets were wasted at the beginning of the trials whilst trying to position nets at depths of 150-200 m. These negative results abnormally affected the catch per unit effort in the earlier days.

Later sets were generally more successful at targeting the horizon at the top of the drop-off (60-100 m) where the two dominant species of snapper were Pristipomoides filamentosus and Aphareus rutilans. These two snappers together made up the bulk of the fish catch (60-70%).

Aphareus rutilans, usually at an insignificant level in the handline catch, represented a much bigger proportion of the red snappers caught in the gillnetting operations (up to 30% by weight).

Sets made in the shallower end of the range in proximity to coral areas provided good catches. The species diversity was very high, however, many of the fish not being readily exportable species. This, as well as the perceived competition with traditional gears, would provide arguments against specifically targeting these areas.

The tremendous variation in the results achieved from different sets makes them very susceptible to misinterpretation. At one end of the scale, the catch was spectacular, with catch rates as high as anything the consultant had previously encountered, showing beyond doubt that the method worked in the Seychelles. At the other end of the scale, there were a number of very poor results, mainly due to technical difficulties in being able to secure the gear to the target area because of the strong local currents and activities of very large sharks.

With shallower nets, more intermediate anchors and better knowledge of the fishing grounds, it is likely that the average catch rates achieved can be improved upon.

4.2 Economic evaluations

Inputs

Economic projections were made using a spreadsheet model (Ardill, pers. comm.). The initial catch hypotheses represented a catch rate of 630 kg per day, with 20 nets being set daily³ (Table 2). These catch rates were used for both the 21 m and 12 m boats studied, as were costs of gear replacement and crew.

³ These catch rates were achieved in the third cruise (Table 1).

Eight different scenarios were examined. These are shown below:

Scenario	I	II	III	IV	V	VI	VII	VIII
Boat	21 m	21 m	21 m	21 m	21 m	12 m	12 m	12 m (subsidised)
Catch/day	(Base)	+25%	+50%	+25%	+25%	(Base)	+25%	(Base)
Fish price	(Base)	(Base)	(Base)	+10%	+25%	(Base)	(Base)	(Base)

The value of the sharks is not taken into account, as there is no market at this time in Seychelles for fresh or salted shark (the fins can be sold, but could be considered a "crew bonus"). If a market is found, the economic performance of the fishery will certainly improve. Extra costs involved would include a crew member specifically for dressing down the sharks on board as well as, presumably, the cost of salt.

The prices taken are those offered by SMB for large snappers. Smaller snappers and groupers in particular fetch a higher price, and this will also improve economic performance if substantial numbers of smaller fish are caught⁴.

⁴ Increased catches of smaller fish can be determined partially by the choice of tone* and depths fished and may also be one of the effects of a sustained fishing effort on these stocks.

Based on the experience of the consultancy, it was assumed that the netting would have to be replaced after 20 days fishing, with the ropes, floats, leadlines, etc. being replaced at longer intervals. Crew salaries were also kept the same in all simulations: the work is unrelenting, and a high salary level would be necessary to motivate the crews.

In the simulations on the 21 m boats, the assumed cost for the hull and machinery were lower than the real costs for these vessels. This is justified by the fact that these vessels were constructed for other uses, and this occasioned cost overruns in the construction and equipment fitted which should not be reflected in a simulation.

In the case of the 12 m boats, two simulations (VI and VII) are based on the actual costs of the hulls (SR 700,000), while simulation VIII is based on the subsidised price at which SFA sells these hulls to fishermen (SR 300,000).

Results

In the baseline simulation, the 21 m boat does not cover operating costs from the catch value (Simulation I). If the catch (rates) are increased by 25% (which is not unreasonable as gear is improved and fishing zones better known), operating costs are covered, but the debt service keeps the cash flow negative (Simulation II). With a catch increased by 50%, the cash flow becomes positive and a project internal rate of return (IRR) of 11% is achieved (Simulation III). The project cash flow is negative as a result of the replacement of the machinery after the 10th. year: this could be compensated by a salvage value or by a longer service life.

Simulation IV assumes a catch increase of 25% and a price increase of 10% (as from a higher catch of smaller fish). Although the IRR is weakly positive, cash flows are negative. Positive economic results are again achieved with catch and price increases of 25% each (Simulation V). The IRR of 14% is satisfactory, although lower than the rate which could be obtained from bonds, and an annual profit of SR 100,000 is obtained.

Comparatively, the economic performance of the 12 m boats is far superior, with positive results being obtained even in the base case (Simulation VI, IRR = 15%). The IRR of 40% in the case of a catch increase of 25% is a high return (Simulation VII). Not surprisingly, a comparable return is achieved in the base case for the subsidised hull (Simulation VIII).

5. DISCUSSION

5.1 Current

Good catches were obtained in each of the shelf areas sampled when the nets remained in the area selected (in relation to the depth and - sometimes - fish echoes located on the echo-sounder). The overriding factor in correct positioning of the nets was always found to be the current. Too often, the nets when hauled were at depths quite different from those where they were shot three hours previously.

The conclusions drawn from these sets were that the gear had "walked" along the bottom due to substantial bottom currents; 60 kg end irons polished on their underside confirmed this. The use of home-made grapnels did little to help and it is thought that the only realistic solution is to use proper fisherman type or "Danforth" anchors in conjunction with an end iron.

Furthermore, the use of 80 meshes deep nets has exacerbated the problem and the benefits of a high net with good entangling properties for big fish was in the main lost due to it being swept down by the current.

To compensate for the adverse effects of current, much heavier footropes were constructed during the trials. These helped in securing the nets to the bottom and in raising the catch level. However, they had an adverse effect on the deck handling and shooting procedures, with additional lead weights and stones, double footropes and intermediate anchors all slowing down the overhauling. At the risk of losing the odd expensive fisherman's anchor, future trials should be conducted with these and also with shallower nets, e.g., 45 meshes deep, plus heavier leaded footrope. No lead weights should be used anywhere in the gear as they catch in the hauler ribs.

5.2 Fishing location - Target areas

At the present stage of investigation, it appears that the most easily fished sites are where the current flows onto the Plateau rather than off it. At the time of the trials, these areas were to the South or Southwest, but this may vary for different times of the year. Moon phase seemed to have little effect.

The most productive sets were hauled from depths of 60-100 m and were conspicuously better where there were some abrupt changes in contours. Typically, there were "wave platforms" on the West side of the Plateau, one at 42 m and another at 62 m, the latter marking the beginning of the continental slope (drop-off).

At both the first drop-off and the second main drop-off, fish were found to be abundant, the larger red snappers being more concentrated on the deeper rim. Both these areas and the interim plateau at 60-70 m offer good sites for future trials. As the operators become more confident with the improved gear, trials could be made down the main slope into deeper water targeting Etelis spp.

5.3 Fish handling

The present procedure for handling fish on board FRV Etelis needs to be reviewed in view of the different nature of the fishing operation and the demanding work load on the crew. Ideally, the fish after extraction from the nets should be plunged into a slurry of ice and seawater and remain there for up to six hours, by which time their temperature has been brought right down. The whole fish should then be iced down in the hold with a layer of ice between each fish layer. The smaller snappers and groupers which are valuable should be boxed and iced, top and bottom, before stowage in the fish hold.

These innovations would have to be in agreement with SMB, but records and experience show that quality fish are better preserved in this manner.

5.4 Net damage

As in any gillnetting operation, net damage is unavoidable and a necessary component of operational expenses. During the trials, one fleet of nets was fished heavily, with hauls every 3 or 4 hours and a total of 38 sets. In this period, the nets were mended twice onshore and running repairs were done from time to time on the boat. Even so, the sheet netting was nearing the end of its life and will soon need replacing. In the economic evaluations, a net life of twenty fishing days has been used.

A decrease in damage would probably be experienced with a shallower net and a large decrease in damage could be expected if night shots were avoided, due to the hyper-activity of sharks during this period.

5.5 Training

The crew of FRV Etelis and members of the Research Department were fully trained in the method as it was demonstrated. The skipper of the research vessel was fully aware of the adverse effects of current and gained considerable knowledge during the trips on correctly positioning the nets. Once the problems of positioning the nets are sorted out during the next research period, the transfer of the technology to other skippers would be relatively simple.

5.6 Sharks

Five tonnes of sharks were discarded during the demonstrations and under any normal gillnetting operation would be utilised at least as a salted product. Thought should be given to this aspect if gillnetting is to be adopted by the large vessels at a later date.

5.7 Pricing

Pricing is not the concern of this consultancy but it should be pointed out that if projections are to be made to determine the economics of operating a large Seychelles vessel as a gillnetter, it is rather unfair, on one hand, to base the expenses such as fuel, replacement nets, etc., on world prices plus import tax and, on the other hand, compute the gross revenue on the prices paid for fish by the monopolistic fish buyer (SMB), which are substantially below world levels.

5.8 Economic evaluations

These show clearly that even with the catch rates achieved in experimental fishing, a 12 m boat provides a good economic return. While this is not the case for the 21 m boats, the hypotheses needed to provide a profitable operation are not unrealistic and the results are likely to be far superior to any other fishery tested to date in the Seychelles.

6. RECOMMENDATIONS

6.1 Research

It is recommended that a further period of research be conducted under supervision of a masterfisherman, as soon as the components for the modified gear are on site in Seychelles. To facilitate the extended research, it is urgent that the necessary finance and backers are contacted immediately in order to get the time framework correct. The shallow nets and leaded rope required will take at least three months to reach Victoria, as they should be shipped.

6.2 Improved gear

As a direct outcome of the research to date, it is recommended that the following gear be available for extended research and commercial trials. Enough gear could be imported by sea freight to cover the very basic needs of a trial period of three months' commercial fishing. In order to have nets available at the earliest for the FRV Etelis, it might be advantageous to have twenty percent air freighted.

Total input needed

a) 50 nets

1.5 x 12 ply x 45 meshes deep x 150 mm stretched mesh x 200 m long. Double, Selv. Top and Bottom. Colour: grey or blue;

b) 25 coils of 12 mm leaded rope approx. 20 kg/100 m;

c) 75 coils of 8 mm polypropylene rope;

d) 1 500 Deep water floats buoyancy approx. 120 g egg-shaped and with 10 mm hole. Operating depth 400 m;

e) 50 kg braided nylon setting twine equiv. to 210 d/45;

f) 50 kg 1.5 x 12 ply mending twine;

g) 15 coils 14 mm polypropylene rope, each 220 m;

h) 15 coils 12 mm polypropylene rope, each 220 m;

i) 60 8-inch diameter plastic trawl floats;

j) 10 40-inch circumference inflatable buoys;

k) 20 fishermen's or danforth anchors, 20 kg.

Approximately US $ 20 000 CIF Mahé Island.

6.3 Anchors

It is recommended that all future gillnetting trials be carried out using commercial anchors of minimum weight of 20 kg. This is now considered necessary to overcome the "walking" of the gear. The anchors could possibly be locally made and would be operated in conjunction with a "tripping" device plus an end-iron of scrap metal.

6.4 Speeding up the overhauling and turn around time of the sets

It is recommended that the following procedures be adopted on board FRV Etelis to ensure rapid turn around of gear and therefore allow both more gear to be worked and a lighter workload for the crew:

a) work shallower nets;

b) use anchors;

c) use only lead line or leaded rope - no lead weights;

d) pull the nets over a 'net bar' (steel pipe arranged horizontally 2 m above the deck) to allow small objects to fall out of the net and also spread the net better;

e) overhaul nets to a position forward of cabin and opposite to hauler, thus allowing crew to move from overhauling to clearing as the job requires. The nets would then be shot over the portside;

f) haul dahn lines with line hauler. A line hauler can be fitted onto the same shaft as the existing net hauler and mounted at the inner end. This should be procured;

g) speed up fish handling by first putting all fish into an ice slurry tank on deck and later, after shooting and a delay of some hours, put the whole fish in layers in ice in the fish hold, the smaller and more valuable fish being boxed and iced. This would avoid the lengthy gutting and washing period and also lead to a better quality product ashore.

6.5 Fishing location

It is recommended that extended research takes place initially on the Western side of the Plateau, at least during the period of Northeasterly onshore drift of the Equatorial Counter Current, in order that, to some extent, the operators are protected from having their gear swept into deep water and possibly lost. Once anchoring and securing the nets effectively had been systematically achieved, the research area could be extended to the rest of the Plateau rim.

6.6 Utilisation of shark

In view of the shark bycatch provided by a gillnetting operation, it is recommended that a review of shark utilisation be made by SMB and/or other interested bodies. Ideally, a gillnetting operation should aim at covering its gear and maintenance costs from its shark bycatch.

7. CONCLUSION

The main conclusion drawn from the work by the consultant is that there is both an under exploited stock of deepwater snappers (ref. biological data collected during trials and numbers of very large fish) and the possibility to commercially harvest that stock using deepwater gillnets.

The second conclusion is that to exactly determine the correct gear and mode of operation, before large and possibly inappropriate investment be made, a further period of research be conducted with FRV Etelis using the recommended improved gear and procedures.

8. COSTING

8.1 Cost of one standard net fishing length 100 m

	US$
200 m sheet netting (1.5 x 12 ply x 150 mm x 80 mesh deep)	146.08
2 coils 8 mm PP rope (double headrope, false foot rope legs)	26.20
½ coil 12 mm leaded rope (12 kg/100 m)	26.40
25 deepwater floats buoyancy 190 g	24.00
1 kg nylon setting twine 210 d/45	5.00
TOTAL	227.68
Plus CIF costs to Mahé (26.6%)	60.56
TOTAL COST PER NET	US $ 288.24

Note: As per quotation Namnet-Korea, Dec. 6/90
Import tax not included

8.2 Costs of buoy ropes and bridles

Ropes required for fishing areas close to or down the drop off allowing for current and drift are as follows for each end of a fleet of nets.

	US$
Bridle/veering line 30 m 12 mm leaded	9.00
Dahn line 220 m 12 mm PP	38.00
Float top line 50 m 10 mm PP	6.00
3 pieces 40-inch dia. hard plastic trawl floats	30.00
TOTAL	US $ 123.00

NB: Import tax not included

Normally nets would be fished in fleets of 6 nets and have a dahn line at each end. Therefore, it follow that the cost of buoy ropes, etc., for a fleet of nets is 123 x 2 = US $ 246. Thus, the cost per net including the dahn line is one fifth of US $ 246, i.e., US $ 49.20, making the overall costs per net in the water 288.24 + 49.20 = US $ 337.44.

8.3 Estimated investment costs to start gillnet operation in 12 m vessel

	US$
10 complete nets with dahns 10 x US$337.44	3 374.00
10 spare nets (sheets only) 10 x US$184.93	1 849.00
Net/line hauler + complete hydraulic system	5 000.00
Echo sounder good to 300 m	1 000.00
	US $ 11 223.00

These are CIF prices Mahé but without import tax.

9. ACKNOWLEDGEMENTS

Much thanks to the following persons for their help and cooperation.

Mr. Philippe MICHAUD	Managing Director Seychelles Fishing Authority
Mrs. Ghislaine LABLACHE-CARRARA	Director of Research Seychelles Fishing Authority
Mr. David BOULLE	Research Biologist Seychelles Fishing Authority
Mr. David ARDILL	Project Manager SWIOP, RAF/87/008
Mr. Michael SANDERS	Senior Fishery Development Specialist SWIOP, RAF/87/008
Mr. Guido CARRARA	Biologist/Statistician SWIOP, RAF/87/008

The Crew of FRV "Etelis"
And all the administrative support staff

Table 1: Catch Data

Results of the 1st gillnet trials (26/11/1990 - 2/12/1990)

Results of the 2nd gillnet trials (7/12/1990 - 12/12/1990)

Results of the 3rd gillnet trials (15/12/1990 - 18/1990)

* new nets		APPROX. DEPTH	No. NETS	SOAK TIME	FISH				SHARK
					Total	Total	CPUE	CPUE	Total	Total Wt	CPUE	CPUE
SET	No.	(m)		(mins)	No.	Wt. (kg)h	(kg/net)	(kg/net/hr)	No.	(kg).	(kg/net)	(kg/net/hr)
	1T	82-110	5	200	66	219.8	44.0	13.19	5	8.7	1.7	0.52
	2T	95-155	5	185	24	38.3	7.7	2.48	0	0.0	0.0	0.00
	3T	46-82	5	220	23	38.6	7.7	2.11	7	110.0	22.0	6.00
	4T	64-68	5	185	40	165.8	33.2	10.75	9	293.0	58.6	19.01
	5T	52-87	5	260	124	209.0	41.8	9.65	6	428.0	85.6	19.75
Total No	5		25	17h30m	277				27
Total Wt.						671.5				839.7
Average							26.9	7.6			33.6	9.1

* old nets		APPROX. DEPTH	No. NETS	SOAK TIME	FISH				SHARK
					Total	Total	CPUE	CPUE	Total	Total	CPUE	CPUE
SET	No.	(m)		(mins)	No.	Wt. (kg)	(kg/net)	(kg/net/hr)	No.	Wt. (kg)	(kg/net)	(kg/net/hr)
	1F	75-105	4	370	86	379.5	94.9	15.39	8	198.0	49.5	8.03
	2F	72-78	4	480	14	44.9	11.2	1.40	8	358.4	89.6	11.20
	3F	80-124	4	240	33	110.7	27.7	6.92	0	0.0	0.0	0.00
	4F	75-98	3	155	13	36.3	12.1	4.68	4	78.0	26.0	10.06
	5F	53-72	3	675	64	114.4	38.1	3.39	7	134.0	44.7	3.97
	5F	72-98	3	900	23	43.2	14.4	0.96	7	534.0	178.0	11.87
Total No.	6		21	47h00m	233				34
Total Wt.						729.0				1302.4
Average							33.1	5.5			64.6	7.5
Global average							23.2	7.0			32.7	7.7

Table 2: Simulations for a gillnetter working in Seychelles Service life 15 years

INPUTS	21 m boat	12 m boat	COSTS	21 m boat	12 m boat
Insurance rate %	3.5 %	3.5 %	Maintenance	150,000 SR	84,558 SR
Engine power	225 Hp	70 Hp	Fuel	186,524 SR	45,078 SR
Auxiliary Power	40 Hp	NONE	Lubricants	9,326 SR	9,326 SR
Standby power %	10 %	10 %	Crew	320,000 SR	320,000 SR
Fuel price/l	2.10 SR	2.10 SR	Insurance	70,000 SR	29,595 SR
Cost of Hull	1,000,000 SR	700,000 SR	Cost of Ice	0 SR	0 SR
Cost Machinery	1,000,000 SR	145,580 SR	Cost of Bait	18,438 SR	18,438 SR
Replacement Mach.	10 yr	10 yr	Licence cost	0 SR	0 SR
Cost of Gear	16,650 SR	16,650 SR	Miscellaneous	43,339 SR	33,321 SR
Replacement gear	112,500 SR	112,500 SR	TOTAL OPERATING COSTS	910,127 SR	699,744 SR
Working capital	100,000 SR	100,000 SR
Maintenance hull	5 %	10 %	Debt service	294,352 SR	92,328 SR
Maintenance Mach	10 %	10 %	Crew costs/month
Cost of Ice/tonne	0 SR	0 SR	Skipper	5,000 SR	5,000 SR
Days inactive/year	70 d	70 d	Mate	3,750 SR	3,750 SR
Days/trip	6 d	6 d	Engineer	3,750 SR	3,750 SR
Days at sea/yr	221 d	221 d	Crew	2,500 SR	2,500 SR
Days fishing/yr	184 d	184 d	Total including food for 7 crew	320,000 SR	320,000 SR

Results of Simulations

Simulation	I	II	III	IV	V	VI	VII	VIII
21 m boat	(Base)	(Catch + 25%)	(Catch + 50%)	(Catch + 25%) (Price + 10%)	(Catch + 25%) (Price + 25%)	(Base)	(Catch + 25%)	(Hull subsidised)
Catch/day (kg)	630	788	945	788	788	630	788	630
Catch/year (t)	116	145	174	145	145	116	145	116
Price fish/tonne	7,500	7,500	7,500	8,250	9,375	7,500	7,500	7,500
Catch value	871,174	1,088,967	1,306,760	1,197,864	1,361,209	871,174	1,088,967	871,174
Annual cash flow	-390,005	-172,212	45,581	-63,315	100,030	37,617	255,410	165,693
Project cash flow	-6,750,080	-3,483,183	-216,286	-1,849,732	600,443	518,680	3,785,577	2,439,821
Project IRR (%)	-	-	11.1	2.4	14.7	15,2	40	43

Figure 1: Design of Deepwater Gillnet

Figure 2: Design of Dahn Lines for Deepwater Gillnetting