Gambang, Albert Chuan

Southeast Asian Fisheries Development Center, Marine Fishery Resources Development and Management Department Institutional Repository

Annex 7THE THIRD REGIONAL WORKSHOP ON SHARED STOCKS IN THE SOUTH CHINA SEA AREAKuala Terengganu, Malaysia 6 - 8 October, 1997SEAFDEC/MFRDMD/WS/97/CR. 4COUNTRY STATUS REPORTMALAYSIA(2) SARAWAKSTATUS REPORT: PELAGIC FISH STOCK IN SARAWAK, MALAYSIABy: ALBERT CHUAN GAMBANGFisheries Research Institute Sarawak BranchP.O. Box 2243, 93744 Kuching, Sarawak, Malaysia1. INTRODUCTIONSouthern part of the South China SeaCurrent pattern affected by Northeast Monsoon (October to May) and Southwest Mon­soon (June - September)EEZ area of 160,000km2; continental shelf area of 125,000km2Water depth: Continental shelf up to 200 metres depth, and reach up to 2500 metres in the northern trend1995, total number of fishermen; 11,659* Total number of boats: 4,950* No. of boats by Gear Groups;Pelagic gear: 1979(Purse seine - 25; Drift nets 1,757)Bottom trawlers: 778 (Fish and prawn)Others: 648 (Handline, bottom longline, traps, traditional gear)Landing (1980 to 1995) - 85,000 - 100,000 mt* Pelagic fish 23%* Demersal 60%* Others 17%2. SMALL PELAGIC SPECIESCharacterised by maximum length of 20-30 cmEstimated biomass 216,300 mt, potential yield of 108,150 mtLandings (Fig. 2) since 1990, 15,000 - 24,000 mt, increasing yearlyPelagic species categorised into the following groups (Table 5)Main groups categorised as shared stocks* Bigeye Scad, Selar crumenophthalmus* Round Scad, Decapterus macrosoma* Hardtail Scad, Megalaspis cordyla* Sardine, Sardinella spp* Round Herring, Dussumiera acuta* Indian Mackerel, Rastrelliger spp* Arriommatids, Arriomma sp* Spanish Mackerel, Scomberomorus guttatus, s. commersoniiLandings of main shared stock species as shown in Fig. 2These main species occupied 42% of the pelagic catch.70Pelagic fish as a group are scattered and distributed over a wide area and difficult to harvest unless using FADs.No comprehensive study has been carried out on the small pelagic species relating to seasonal patterns, migrations, behaviour, unit stock identification and other biological information useful in the development and management of the stock.Some biological studies and information:Decapterus russelli - size range 15.1 - 19.1cm, mean 16.9 cmsize at first maturity 16.6 cmDecapterus macrosoma - offshore mean size 31.7 cmcoastal mean size 17.1 cmLength-Weight relationshipW = 0.01118L2.9532Scomberomorus commersonii - size range 19 - 103 cmfound at coastal areaScomberomorus guttatus - size range 12 - 17 cm atcoastal areasize range 58.5 - 86.0 cmoffshore area3. SMALL TUNAUsually below 20 kg in weight, mostly at juvenile stageEstimated biomass at 90,000 mt and potential yield of 45,000 mtRecent years landing has been around 2,000 mt only (Fig. 1)Very small compared to potential yieldUnder exploitedDistribution as shown in Fig. 3. Generally neretic tunas along western part of coastline, oceanic tunas along the eastern coastline where continental shelf are close to shore and towards deeper watersCan only be harvested using FADs which attract and segregate tunasLarger species, yellowfins, found between northern coastline and Layang-Layang IslandAverage catch rate per FADs per operation range from 10 - 18 mtAverage size (length 37 - 83 cm, average weight of 0.9 - 10 kg.Six main species:Neretic species: Kawa-Kawa, Euthynnus affinisLongtail, Thunnus tonggolFrigate, Auxis thazardOceanic species: Skipjack, Katsuwonis pelamisYellowfin, Thunnus albacaresBigeye, Thunnus obesusSeasonal occurrence71Present around FAD’s from March - June, much reduced present from August to Feb­ruary Biology:Kawa-Kawa - Length at first maturity 39.0 cmGrowth at 0.16 cm/dayStudies:Tagging experiment was not successful due to poor return of tagsPresent studies carried out on tuna are to assess the effectiveness of FADs in attractingand segregating tuna and their general biology under the IRPA programme4. LARGE TUNAThose tunas more than 20 kg in weightDistribution between Luconia shoals to Pulau Layang-Layang and western coast of SabahAssessment by tuna longline shows that average catch rate is 0.41 tails per 100 hooks per operationAverage site range 10.7 cm-15.5 cmEstimated population for the area at 1,500 - 4,000 tails per season2 main species:Yellowfin, Thunnus albacaresBigeye, Thunnus obesusSeasonal and shared nutrition behaviorNo biological study yet on large tuna in area5. SHARKSLanding has been around 2,000 mt annually (see fig. 1)Caught mostly by driftnets, bottom trawl, barrier net and hook and linesDistribution (Fig. 3)Species:Biology:6. CEPHALOPODSLanding more than 1,500 mt annually since 1989 (Fig. 1)Mostly caught as by-catch of bottom trawlDistribution mainly along coastal area of SarawakSeasonal fluctuation, high catch in April/MaySpecies:Squid, Loligo edulisCuttlefish, Sepia esculenta, s. pharoanisOctopus72F igure 2: T rend o f  Landings for Pelagic Fish Species73Figure 3: Landing of Species by Months, 199574Figure 3: Continued....75Figure 3: Continued...76Figure 3: Continued...77Figure 1: Trends of fish landings for Sarawak78Figure d: L andings (m t) o f  M arine Fish by R egion and G ear G roups ( 1992).

Status report: pelagic fish stock in Sarawak, Malaysia

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Status report: pelagic fish stock in Sarawak, Malaysia

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