SPC/Fisheries 20/WP.33 27 July 1988 ORIGINAL: ENGLISH SOUTH PACIFIC COMMISSION TWENTIETH REGIONAL TECHNICAL MEETING ON FISHERIES (Noumea, New Caledonia, 1 - 5 August 1988) PROGRESS REPORT ON SPC GEAR DEVELOPMENT PROJECT Paper presented by the Secretariat INTRODUCTION Background 1. Since September 1986, the SPC Gear Development Project (GDP), an activity of the Deep Sea Fisheries Development Project, has been based in Vava'u, Kingdom of Tonga. Project personnel consisted of one SPC Master Fisherman and a single local trainee/ crewman employed by the Commission. Tonga Fisheries Division was to have attached extension officers to the Project as trainee/ counterparts but due to staff shortages this only happened occasionally. SPC Project personnel were assisted in FAD construction and deployment by Tonga Fisheries Division staff and local fishermen. Tonga's main contribution to the Project consisted of FAD materials, boats, a secure storeroom, and strong logistical and moral support. The FAO/UNDP Regional Fishery Support Programme made major contributions of fishing gear and FAD materials. In addition to staff, SPC provided some FAD hardware, running costs for the Project boats, and fishing gear. Objectives 2. The main objectives of the Project were: - to adapt and improve techniques for catching bait, i.e. the small fish suitable for use, usually whole and sometimes alive, on handlines and vertical longlines set for tuna (e.g. scads such as Decapterus spp and Selar spp) and on surface and sub­ surface trolling lines (e.g. flying fish, Exocoetus and Cypselurus spp); - to experiment with existing techniques of deep trolling, particularly those used by salmon fishermen in the north-east Pacific, and by sports fishermen in the USA, and adapt them to the capture of deep-swimming tunas, especially those found in association with FADs. 3. Secondary objectives were: - to carry out deep bottom fishing trials in depths greater than 400m, and (in all depth ranges) on the windward sides of established fishing areas, where conventional fishing using wooden handreels or handlines is difficult or impossible; - to provide advice to the Government of Tonga as required on aspects of local fisheries development. 892/38 SPC/Fisheries 20/WP.33 Page 2 Activities 4. In order to meet these objectives, the following activities were carried out: Construction, deployment, maintenance and monitoring of fish aggregation devices (FADs); Experimentation with a variety of bait catching methods including jigging, trolling, the use of two different types of lift net, and scoop-netting; Surface, sub-surface and deep-trolling in inshore and open waters and around FADs; Experimental deep-bottom fishing using bottom longlines and droplines 5. In addition, vessel maintenance, record keeping and other routine activities occupied substantial parts of the Projects time. 6. The purpose of this progress report is to provide an update of the Projects more important activities since it commenced operations. The report is necessarily incomplete as Project activities will not conclude until later in the year. A more detailed terminal report will be prepared at that time. Project vessel and facilities 7. The Tonga Government made available for the Projects full-time use the 8m fibreglass Yamaha fishing vessel Vete. The vessel was equipped with a 24hp Yanmar ME series dry-exhaust inboard diesel engine, and had a small cabin where electronic and fishing gear could be stored and kept dry while at sea, but which was inadequate for crew accommodation. The vessel had two integral holds in the after deck and three forward, all of which were watertight and one of which was insulated for ice storage. Deck equipment included a Japanese pressure-roller type line hauler, and Koden dry paper echo-sounder with 50 kHz transducer. The Master Fisherman added Koden 8812P chromascope with a dual 28/200 kHz transducer. All the transducers were mounted on lengths of galvanised pipe which could be attached to brackets fixed on the side of the boat. This allowed easy removal of the transducers and avoided major structural work on the hull to mount them. However, the sounders did not function as effectively as they would have if they had been mounted through the hull. In addition, the pipe mounts caused obstructions to some of the fishing operations, as well as being hazardous for the crew. 8. The Project also made occasional use of another fishing boat belonging to Tonga Fisheries Division. This was an open 9.6m Yamaha skiff with self-draining deck and powered by a 55hp Evinrude outboard motor, which was used for hoop-net trials. 9. Most on-shore gear preparation, construction and maintenance was carried out either on the fisheries compound by the main wharf in Vava'u, or in a small gear workshop and office under the Master Fisherman's home. FAD CONSTRUCTION AND DEPLOYMENT 10. In order to accomplish its objectives the Projects first priority was the construction and deployment of FADs. Seven FADs were deployed between September 1986 and April 1988, six for project use and one on behalf of Vava'u Fisheries Division. One of the six deployed for the Project, which was lightly constructed and deployed in a depth of 80m, was lost in heavy weather in December 1986. The FAD deployed in 60m for Fisheries Division as part of a seaweed culture experiment sunk as a result of heavy weed and shell growth. The other five FADs are still in place, two in deep water (780 - 820m) and three in shallow water (30 - 80m). SPC/Fisheries 20/WP.33 Page 3 Table 1: Summary information on FAD deployments Number Depth Conditions Deployment date Total time 11. in place months FAD1 36 Inshore sheltered waters Sept 86 23 FAD 2 82 Inshore sheltered waters Jan 88 6 FAD 3 800 Lee side of main island Nov 1986 20 FAD 4 80 Lee side of main island Nov 1986-Jan 1987 2 Redeployed April 1987 16 FAD 5 820 Open sea, strong current April 1988 4 12. All FADs were regularly inspected and maintenance work carried out when signs of wear or imminent breakage became apparent in the raft components or accessible parts of the upper mooring line. As a result, considerable experience in the design and construction of FADs has been accumulated. It is not possible to present this in detail here but this information will be documented in the Project's terminal report. TROLL BAIT FISHING 13. At the present time in Tonga, most large-sized fully-rigged trolling lures commonly used for larger rapacious pelagic fish species such as wahoo, dogtooth tuna, yellowfin tuna, barracuda and trevally, sell for T$ 15.00 to T$ 25.00. This type of lure can be destroyed by a single fish strike and their use can be a very expensive method of fishing. There are several fish species that are very effective when rigged as trolling baits, in particular shark mackerel and flying fish. Methods of catching, rigging and trolling these species have been stressed during the Projects stay in Vava'u. Capture methods experimented with were light lure trolling (for shark mackerel and barracuda) and scoop netting (for flying fish). This latter was probably the most cost effective means of acquiring good trolling bait. Scoop-netting 14. Although the technique of scoop-netting for flying-fish by light at night is well known in some areas of the Pacific, it is not practised in Tonga at the present time. Flying fish are excellent trolling baits, freeze well and stay firm on thawing, and in times of shortage can be used on several consecutive days. One 48 kg yellowfin tuna was caught in Vava'u using a flying fish that had been trolled for several hours on each of the three preceding days. 15. A box-type reflector housing two 200W bayonet-mount household light bulbs was built and mounted on a 2.5m removable pole on the front of the Vete. The bulbs were powered by the Project's portable Yamaha ET900 12/240v generator, which has a fuel consumption of about 51/ 8 hours. 1 6. The frame of the scoop net was made from a 2m length of 10mm diameter aluminium pipe, bent into a triangle. The tubing was shaped by first filling the pipe with damp sand, and then using a plumbers pipe bender to obtain the desired shape. After shaping the frame was lashed onto a 3m handle made by planing down a length of 50mm x 50mm length of pine timber. The handle was made as smooth and light as possible. The netting, which was of 19mm mesh multifilament nylon, was then tied on to form a bag. 17. On the Vete, scoop-netting required two people, one to run the boat and the other to scoop fish from the bow. All netting was carried out during moonless nights in fairly sheltered waters on the western side of Vava'u. Flying fish were generally easier to scoop on dark nights 3-4 days on either side of the new moon. SPC/Fisheries 20/WP.33 Page 4 18. Scoop-netting was carried out on 7 different occasions, producing a total catch of 594 flying fish, at an average rate of about 15 fish per fishing hour. Flying fish currently sell in Vava'u for T$ 1.00/fish. Light lure trolling 1 9. The main gear for this fishing method was essentially the same as that used for sub­ surface trolling (see paras 31 - 33), i.e. two Alvey reels fitted with 50m of 1.2mm 7x7 strand stainless steel cable. For light trolling, the cable terminated in a 8-10mm pearl head with squid skirt tied on, and rigged on a 2-4m length of 20-30kg test monofilament fishing line.