BULETIN PERIKANANFISHERIES BULLETIN No. 68

DISTRIBUTION AND BIOLOGICALSTATUS OF THE PELAGIC

RESOURCESOFFSARAWAKMALAYSIA

ByHadil Bin Rajali

And Richard Rumpet

Research SectionMarine Fisheries Department Sarawak

Bintawa, Kuching

{b,.c'hutintt Pmy(" .

~ ~.hfl4i~

DISTRIBUTION AND BIOLOGICALSTATUS OF THE PELAGICRESOURCESOFFSARAWAK

MALAYSIA

ByHadil Bin Rajah

And Richard Rumpet

Research SectionMarine Fisheries Department Sarawak

Bintawa, Kuching

DEPARTMENT OF FISHERIESMINISTRY OF AGRICULTURE MALAYSIA

1991

Ust of FiguresUst of TablesUst of PlatesUst of AppendicesABSTRAKABSTRACTI. INTRODUCTION2. MATERIAL AND METHODS3. RESULTS4. DISCUSSION

4.1 Biological Status4.2 Geographic Distribution of Habitat and Fishing Grounds of

Majors Species Groups4.2.1 . Tuna4.2.2 Other Scombrids4.2.3 Carangids4.2.4 Clupeids4.25 Others

S. CONCLUSIONACKNOWLEDGEMENTREFERENCES

Fig. I: South China Sea Off Sarawak - DepthsDistribution

Fig. 2: South China Sea Off Sarawak - SpeciesDistribution

Fig. 3: Size composition of frigate tuna, Auxis lhazard caught byK.K. MANCHONG purse-seine in April, 1987 around aFAD very near to Terumbu Layang-Iayang (Swallow Reef).

Fig. 4: Size composition of yellowfin tuna, Thttnnus albacares caught by 16trolling in waters off Terumbu Layang-Iayang during the April 1987 Trip.

Table 2: Summary of Regression of log Weight on log Length for ea(h species of Jfish .

Plate 2: The caraitgids that are mostly caught by purse seine and here is 18mostly selar specifically Atule mate

Plate 3: A bumper catch of Decapterus (Selayang) off Terumbu 19Layang-Iayang

Plate 4: A good harvest of sardine by purse-seining carried out more 20towards the inshore waters

Plate 5: Yellowfin (Thunnus albacares) caught by a longliner 5 NM off 21Terumbu Layang-Iayang

Pukat tunda, pukatjerut dan mengeret merupakan cara-cara penyampelan yang digunakandalam kajian ini. Status biologi dan taburan geografi bagi kumpulan spesies utama ikan pelagikadalah didokumenkan. Ikan tuna neritik terdapat banyak di sekitar perairan terumbu-terumbukarang di laut Mukah dan Miri. Ikan tuna ini adalah bersaiz lebih kecil berbanding denganspesies-spesies tUJla 'yellowfin' dan 'bigeye' yang terdapat di perairan laut dalam bahagiantimur-laut Zon Ekonomik Eksklusif Sarawak. Ikan pelagik yang terdapat di perairan terumbu-terumbu karang laut dalam seperti Terumbu Layang-layang adalah bersaiz lebih besar ber-banding yang terdapat di perairan pantai. Sumber ikan pelagik yang terdapat di perairan lautChina Selatan adalah bertaburan. Kumpulan-kumpulan ikan pelagik kecil didapati ban yak dikawasan perairan sedalam kurang daripada 60 m.

The bottom trawl net, purse-seine and troll line were used as sampling gears. Thebiological status,and the geographical distribution of the major pelagic species groups weredocumented. Neritic tuna were caught very near to atolls especially in waters off Mukah andMiri. These tuna are smaller in size when compared to the yellowfin and bigeye caught inthe more open and deeper, oceanic waters of the north-eastern part-of Sarawak's EconomicExclusive Zone. Pelagic fish caught around deep sea reefs for example around TerumbuLayang-layang were of bigger size as compared to that caught in the shallow coastal waters.Pelagic resources of the South China Sea are scattered. Small pelagic schools occupied mostof the waters of the shelf under 60 m deep.

The 1986 Malaysian Offshore Fisheries Resources Survey showed a substantial biomassof pelagic stock off Sarawak (over the Sunda Shelf) with particularly high density (8.3tonnes/NM2). The total biomass for Sarawak was estimated at about 216,300 tonnes andof this, the potential yie1d is 108,150 tonnes (Fisheries Research Institute 1987, unpublished).

The Fisheries Department Research Vessel, K.K. MAN CHONG was deployed in 1987to do experimental surveys in the offshore waters (> 60 NM from the coastline) (Fig.1). On several occasions, substantially large schools of pelagics were observed. Smallpelagics such as the sardines, selar, Decapterus and other carangids were frequentlyencountered and caught mostly by purse-seine (Plate 1). Other pelagic fish such as tunawere either caught by the purse-seine or by the troll line.

~_Pelagic fish resources of the South China Sea are scattered. The installation of FADs(Fish Aggregating Devices) for example in waters off Terumbu Layang-layang archipela-gos help to ~regate these scattered and low density pelagic fish resource of which tunais the main component. The highly migratory nature of tuna makes this resource difficultto assess and the fish only stayed for a short while at the FADs possibly' in search offood. Other pelagics beside the tuna sampled at FADs in the Terumbu Layang-layangwaters were mostly of mature size as compared to that sampled in the inshore waters(less than 60 NM from the coastline).

This paper is based on K.K. MAN CHONG trips in 1987 carried out in Exclusive EconomicZone (EEZ) waters off the Sarawak coast. It is aimed to document the biological statusand area distribution of the fish caught in the area surveyed.

The bottom trawl net (Appendix 1), purse-seine net (Appendix 2) and troll lines wereused to sample the fish. Although the fishing operation could not give us the actual catchrates or densities, the survey revealed the nature and distribution pattern of pelagicresources in Sarawak waters. The position and the weight of individual haul were recorded.The catches were sorted and the fish species were identified based on SEAFDEC (1982)and Gloerfelt-Tarp and K~ilola (1982) manuals. The fish total length was measured tothe nearest millimeter using a standard measuring board. The individual fish weight wasmeasured to the nearest one gram using the top-pan weighing balance. The length-weightrelationship was calculated using a PC-based Microstat statistical software.

Table 1 shows the catch landed comprising a large number of species. This species listgives an indication of the major commercial pelagic species found in Sarawak waters.A large percentage of the catch especially from trawling was trash fish.

The size range of the commercial fish caught during the survey is shown in Table 2.Fish size varies considerably, and this could be due to the different area of catch, thepartial un selective nature of the sampling gear (example purse-seine) and in some casesthe number of sample (n) is too low.

Table I: Species of Pelagics Caught During K.K. MAN CHONG trips, 1987

Common names Local names Scientific names

A. Tunai) Bonito/Skipjack tuna Tongkol Katsuwonus pelamis

ii) Longtaillbluefin tuna Aya hitam Thunnus tong go Iiii) Mackerel tuna/kawakawa Aya kurik Euthynnus affinisiv) Frigate mackerel Tongkol Auxis thazardv) Yellowfin tuna Thunnus alhacares

vi) Bigeye tuna Thunnus ohesus

B. Small PelagicCarangidae

i) Yellowtail scad Selar gelek Atule mateii) Round Scad Selayang Decapterus macrosoma

iii) Round scad Selayang Decapterus maruadsiiv) Rainbow runner Pisang-pisang Elagatis bipinnulatusv) Hardtail scad Cincaru Megalaspis cordyla

vi) Queenfish/Leatherskin Talang Scomberoides tolvii) Ox-eye scad Selar Selar boops

viii) Big-eye scad Selar pucat Selar crumenophthalmusix) Yellowstripe trevally Selar kuning Selaroides leptolepisx) Horse mackerel Caranx sexfasciatus

Clupeidaexi) Rainbow sardine Tamban bulat Dussumieria acuta

xii) Goldenstripe sardinella Tamban Sardinella gibbosaxiii) Spotted sardinella Tamban beluru Sardinella sirm

Formionidaexiv) Black pomfret Bawal hitam Formio niger

Scombridaexv) Short-bodied mackerel Pelaling Rastrelliger brachysoma

xvi) Indian mackerel Kembong Rastrelliger kanagurtaxvii) Narrow-barred spanish

mackerel Tenggiri batang Scomberomorus commerson

Table 2: Summary of Regression of Log Weight on Log Length for each species of fish

Range in Regression Goodness Regression Number ofSpecies Length slope Intercept offit Coeffici~nt Sample

(cm) 'b' 'a' r2 r n

Euthynnus affinis 24.5-53.5 3.1120 . 0.01096 0.9706 0.9852 70

Katsuwonus pelamis 29.0-57.5 3.0486 0.01496 0.9710 0.9854 19

Thunnustonggol 36.0-49.0 1.8873 0.97611 0.8080 0.9550 10

Auxis thazard 22.5-28.5 2.6574 0.04277 0.6623 0.8138 76

Thunnus alhacares 23.5-63.5 2.1808 0.4429 0.8781 0.9371 66

Elagatis hipinnulatus 42.6-94.0 2.6808 0.02468 0.9743 0.9871 21

Selar crumenophthalmus 15.4-28.6 2.9803 0.01378 0.9454 0.9723 94

Atule mate 20.5-25.8 2.3678 0.08525 0.6406 0.8004 55

Decapterus russelli 15.1-19. I 2.2239 0.09013 0.7489 0.8654 16

Decapterus macrosoma 13.5-36.5 2.9532 0.01 I 18 0.9684 0.9841 186

Raslrelliger kanagurla 23.4-26.4 4.4801 0.00008 0.7854 0.8862 13

Scomheromorus commerson 53.5-81.0 2.1555 0.21213 0.9532 0.9763 9

Table 3: Size and area distribution of pelagic species

MeanSpecies Length Range (cm) Type General Area

(cm)

Thunnus alba cares 40.8 23.5-83.0 Oceanic 100 miles offshore and more(Yellowfin) than 1000 m depth

Thunnus obesus 58.4 58.0-59.0 Oceanic - same -(Bigeye)

Auxis thazard 27.6 22.5-28.5 Neritic Around atolls(Frigate)

Thunnus tonggol 42.8 36.0-49.0 Neritic 10 nautical miles offshore(Longtail tuna) and around atolls

Euthynnus affinis 30.5 24.5-53.5 Neritic - same -(kawakawa)

Katsuwonus pelamis 37.6 29.0-57.5 Neritic 30 miles offshore(Skipjack)

Rastrelliger kanagurta 25.7 23.4-26.4 Shallower, less than 60 m d

Rastrelligerbrachysoma - same -

Decapterus russelli 16.9 15.1-19.1 Distribution over the Shelfbetween 50 miles offshore

Selarcrumenophthalmus 24.9 21.3-26.3 - same -

Scomberomoruscommerson 65.6 58.5-86.0 Shallow areas

A generalised area distribution of major pelagic fish is shown by Figure 2 and Table3. Most of the tuna species were caught in waters more than 60 m deep. Small pelagicfish like the carangids and the mackerels were caught in shallower waters.

The fish sampled vary in size and the different area of catch, partial selectivityof the gears used and insufficient number of samples were suspected to be thecontributing factors. This survey showed that different area of sampling causedvariation in fish size distribution. For Euthynnus affinis, there were three mainareas of catch: around Terumbu Layang-Iayang, Luconia Shoals and west of MuaraTebas. Fish caught in area around Terumbu Layang-Iayang were smaller in size(mean size of 26.73 cm) when compared to fish caught in areas West of MuaraTebas with mean size of 39.8 cm and Luconia Shoals with mean size 51.5 cm.

Katsuwonus pelamis were caught in areas around Terumbu Layang-Iayang andFAD station I (tat. 03° 56.2'N, Long. 110° 08.7'E). The mean size of skipjackfound in Terumbu Layang-Iayang waters is 38.1 cm. In FAD station 1 the meansize is 47.7 cm. A tail of Katsuwonus pelamis was caught in Luconia Shoals andit measures 57.5 cm in length.

The mean size of Thunnus tonggol caught is 42.8 cm and the areas of catch wereLydie Shoals (Beting Mukah) and FAD station 1. The fish caught in these areasis similar in size to that caught in West Malaysia (lPTP, 1986b). According toKlinmuang (1978 and 1981) and Cheunpan (1984) the smallest sexually maturefemale skipjack determined from the Gulf of Thailand was 34.2 cm long so thelongtail tuna caught around Lydie Shoal and FAD stations could be matured too.However, Chiampreecha (1978) mentioned that females in the 31 - 47 cm intervalwere mostly immature. Klinmuang (1978) suggested that females in the 45 - 50cm interval could be matured as the case in the Gulf of Thailand.

Both Auxis thazard and Thunnus albacares were caught in areas of TerumbuLayang-layang and the mean size are 27.6 cm and 40.8 cm respectively. Figures3 and 4 show the length frequency distribution of the fishes respectively.

The saiz of rainbow runner, Elagatis bipinnulatus, caught in areas around JamesShoal (Beting Serupai) is smaller (mean size of 51.5 cm) compared to that caughtin Terumbu Layang-Iayang waters (mean size of 84.6 cm). Rainbow runners caughtwere mostly of mature size since the first maturity is 13.0 cm long according toIngles and Pauly (1984) for that of the Philippines waters.

In the area north of Sematan (Lat. 02° 19.48'N, Long. 109° 53.01 'E) and areasaround position (Lat. 03° 59.29'N, Long. 112° 15.71 'E), the mean size of Selarcrumenophthalmus is 24.9 cm. Most of the selar caught have already attained theirfirst maturity stage which is around 19.4 (Department of Fisheries, Thailand 1984,for Gulf of Thailand).

Atule mate which were caught in areas north of Sematan (Lat. 02° 11.40'N, Long.110° 05.87'E) have mean size of 22.9 cm. According to Aglen et al., (1981), thesize of Atule mate caught has approximately attained full growth size (Plate 2),

where the maximum body size ever captured is only 28.0 cm in the Straits ofMalacca.

Decapterus russelli was found to have mean size of 16.9 cm. Magnusson (1970),Tiews et al., (1970), Ronquillo (1974) and Ingles and Pauly (1984) mentioned thatthis scad attained its first maturity length at 16.6 cm for Palawan waters.

The two areas ot catch for Decapterus macrosoma were in areas around TerumbuLayang-Iayang and north of Sematan (Lat. 02° 12.40'N, Long 110° 05.87'E). Thesize of the scad caught in these areas are 31.7 cm and 17.1 cm respectively. Theround scad caught around Terumbu Layang-Iayang were of big size (Plate 3) ascompared to maximum size captured, 25.0 cm for Manila Bay and Palawan waters(Magnusson 1970; Tiews et al., 1970; Ronquillo 1974) and 25.4 cm for Java Sea(Dwiponggo and Pauly 1986 c.i. Chullasorn and Martosubroto 1986). Length atfirst maturity is at about 16.5cm as reported by Chullasorn and Martosubroto(1986).

Rastrelliger kanagurta and Scomheromorus commerson caught have a mean sizeof 25.7 cm and 65.6 cm respectively. Size at first maturity for R. kanagurta fromthe Straits of Malacca is 18.75cm (Pathansali 1961, 1967 and Chee 1980).According to Chullasorn et al., (1973); and Suponggon and Chayokwi (1979) forGulf of Thailand, size at first maturity for S. commerson is 58.6 cm.

4.2 Geographic Distribution of Habitat and Fishing Grounds ofMajor Species Groups

The prevalence of oceanic conditions for waters around Terumbu Layang-layang suited the presence of highly migratory oceanic tunas like yellowfin(Thunnus albacares) and bigeye (Thunnus ohesus). Furthermore, accordingto Marquez (1977) and Boonragsa (1987), larva of yellowfin were foundto be present in Terumbu Layang-Iayang waters and that of bigeye weresampled in waters at about 100 NM off Bintulu around Luconia Shoals.As observed by K.K. MANCHONG, most of the tunas in Sarawak watersmigrated close to the reef areas where the water current is irregular andswift.

The deep sea FAD pilot project conducted by the Department of Fisheriesin Terumbu Layang-Iayang waters enabled K.K. MAN CHONG to carryout two monitoring surveys in 1987. At the FADs (set in April, 1987) sitednearer to the oceanic trench with depth of about 1000 metres or more,yellowfin and bigeye tunas were observed to aggregate for sometime. Inthe earlier part of the survey (June, 1987) most of the yellowfin and bigeyetunas caught by trolling and purse seining comprised immature tuna of thesize range of 3-5 kg. per tail. But in the second monitoring trip (September1987), large schools were observed through the sonar and echo sounderat a depth of more than 60 meters.

Probably large tunas are aggregating at the deeper zone. The catch of largetuna by a longliner (Plate 5) proved that large tuna do exist in the TerumbuLayang-Iayang waters. Oceanic tuna resource is difficult to access due to

its highly migratory nature. Tuna stayed at FADs for only a short whileand probably when food are scarce they move away.

The neritic tuna with species like frigate tuna (Auxis thazard), longtail tuna(Thunnus tonggol) and kawakawa (Euthynnus affinis) were also caught inTerumbu Layang-layang waters in areas nearer to the atoll or at FAD setnear the Luconia Shoals. Skipjack (Katsuwonus pelamis) were also foundin Terumbu Layang-layang waters. Most of the oceanic or neritic tuna inTerumbu Layang-Iayang waters form their own school separately. Yellow-fin tuna (mostly juvenile) were found to form a school together withskipjack. This is probably because skipjack and juvenile yellowfin tunawere of the same physical size and tend to have similar behaviour(Masterfisherman Yoshibumi Kihara 1987 - personal communication). Ithas been known that mature yellowfin form their own school, but this couldnot be confirmed during K.K. MANCHONG FAD monitoring trip toTerumbu Layang-layang (Kihara, 1988).

Small tuna were observed along the coastal water belt (more than 10nautical miles offshore) in areas like off Tanjung Sirik and Tanjung Datukand in waters of Lydie Shoal and Luconia Shoals. Lydie Shoal was observedto be the most popular habitat for neritic tuna. Chen and Wei (1981)reported that larvae of longtail tuna have been collected in South ChinaSea. This observation was also mentioned by Chullasorn and Martosubroto(1986), where areas off Lydie Shoal were found to be the spawning groundfor this coastal tuna. Market landings (Marine Fisheries DepartmentSarawak 1987) showed that Mukah contributed more than 50% with Miriabout 30%. The Miri tuna landings comprised of 50% kawakawa. 25%frigate tuna, 20% longtail tuna and about 5% skipjack. In the area off Miriwhere the outer edge of Sunda Shelf is only about 30 nautical miles outand nearer to the Pacific Ocean (Fig. 1) the influence of high saline-deepwaters attracts the presence of skipjack to this north-eastern part of Sarawakwaters.

The Indian mackerel and Spanish mackerel were mostly caught in shal-lower (less than 60 m deep) coastal waters off Sarawak. This was alsomentioned by Menasveta et al., (1973). The Indian mackerel (Rastrelligerspp.) were usually caught by purse seine with the aid of light. Once thefish was attracted to the light, the school stayed for @out two hours, afterwhich the school reduced in size and move to some other areas possiblyin search of food. Two species of Rastrelliger found in Sarawak namelyRastrelliger kanagurta and R. brachysoma. R. kanagurta were found tobe more abundant off-shore. This was also confirmed by Druzhinin (1970).

There were two species of Spanish mackerel namely Scomberomoruscommerson and S. guttatus with the former bigger in size (58.5-86.0 cm).These two species of Spanish mackerel were usually found in the sameschool. This barred Spanish mackerel can also be found in shallowundulating coral areas like Lydie Shoal, Parons Shoal, James Shoal andcaught usually by handline.

Most of the carangids were caught by purse seine (using light as attractant)and occasionally by trawl or trolling. Small carangids like selar (S. cru-menophthalmus and Atule mate), hard-tail scad (Megalaspis cordyla),round scad (Decapterus maruadsi) were distributed all over the shelf inthe coastal waters stretching to 50 NM offshore. Bigger carangids likerainbow runner (Elagatis hipinnulatus) and hard tail scad were distributedaround reef waters like James Shoal, Lydie Shoal and Luconia Shoals.Other bigger carangids like trevally (Selaroides leptolepis and Caranxsexfasciatus) and queenfish (Scomheroides tol) were mostly caught inshallow coastal waters near coral areas like off Sematan and off Mukah.Bigger and mature size carangids (23.5-36.3 cm) for example Decapterusmacrosoma were caught in deep waters of Terumbu Layang-Iayang,whereas the smaller size Decapterus (\ 3.5 - 18.6cm) were found to inhabitthe shallower coastal waters for example off Sematan.

Most of the c1upeids were small pelagics of the sardines (tamban) speciesnamely: rainbow sardine (Dussumiera acuta), goldenstripe sardinella (S.gihhosa) (Plate 4) and spotted sardinella (S. sirm). The sardines werecaught mostly in inshore waters (less than 60 m deep) along the coastalbelt of Sarawak from Tg. Datuk to Brunei Bay. The sardines were attractedby florescent light especially during the dark-phase of the moon. But asthe light was shown for more than 3 hours, the fish school were reducedto a smaller mass, probably due to the absence of food.

The triggerfish of the species Canthidermis maculatus were observed tobe abundant around the 20 FADs set in the offshore waters (\ 00 - 150NM off Kuching). When the aggregating materials (palm leaves) of theFADs were rotten after about five months, Ahalistes were observed toaggregate around the area. Ahalistes were also mentioned to be confinedlargely in the area where the depth range is 50 to 90 m (Fisheries ResearchInstitute 1987) .. This fish is of low commercial value in the local market.Other fishes found aggregating around the FADs were carangids, rainbowrunner, Seriola rivoliana and Coryphaenidae (dolfinfish) of speciesCoryphaena hippurus. Through diving, it was estimated that about 10 to100 kg of these fishes were observed to aggregate around the FAD (Kihara1988).

The density of pelagic fish over certain areas vary with season. During the calm off-monsoon season (April-September), it was suggested that there is an inshore movementof pelagics whereas during the monsoon (October-March) offshore migration anddispersion prevailed (Fisheries Research Institute, 1987). This phenomenon was alsoobserved by K.K. MANCHONG.

mostly in the inshore waters (15-30 m depth) during the onset of the monsoon in themonths of September and October. Larger pelagics like neritic tuna and few carangidswere observed to occur in the 50-60 m depth zone. This distribution pattern of pelagicfish seemed to stretch all the way along the inshore waters off Sarawak. This observationwas in accordance to that shown by Malaysian EEZ survey, 1986 (Fisheries ResearchInstitute, 1987).

Tuna resources were confined to the high saline water around the reefs like South andNorth Luconia Shoals, Terumbu Layang-layang and other atolls which are more than60 NM from the coastline of Sarawak.

Basically, shoals of pelagic fish were scattered and small in size. The western part ofBatang Lupar Basin (inshore water) is a potential area for pelagic fishery. This was alsomentioned as one of the three high density areas from the Malaysian EEZ Survey, 1986(Fisheries Research Institute, 1987).

The authors wish to convey their sincere gratitude to the Director-General of FisheriesMalaysia, Y. Bhg. Dato' Shahrom b. Hj. Abd. Majid, Director of Marine FisheriesDepartment Sarawak (MFDS), Mr. Teo Chee Kwang and the Director of FisheriesResearch Institute Malaysia Mr. Ong Kah Sin for their encouragement and invaluablesupport in carrying out this work. A debt of gratitude is also due to Mr. George ChongChiaw Min (Head of Research Section MFDS) and Mr. Albert Chuan Gambang for theircritical comments on this presentation.

Appreciation also goes to Mdm. Annie Lim PK, Puan Dayang Mariayani and En. PeterTingkau for processing the data and finally typing the report. Last but not least tounspecified assistants, those who have rendered their help directly or indirectly towardsthe preparation of this paper.

Aglen, A., Foyn, L., Godo, O.R., Myklevoll and Ostvedt, OJ. (1981) Surveys of the MarineFish Resources of Peninsular Malaysia, June-July 1980. Report on surveys with the R/V Dr Fridtjof Nansen. Bergen, Institute of Marine Research, 70p.

Boonragsa, V. (1987) Tuna resources in the Thai waters, Andaman Sea. In: Collective Volumeof Working Documents presents at the "Expert Consultation on Stock Assessment ofTunas in the Indian Ocean", Colombo, Sri Lanka, 4-8 December 1986. Indo-Pacific TunaDevelopment and Management Programme, 267-280.

Chee, P.E. (1980) The reproductive pattern of Rastrelliger kanagurta. In Proceedings of thesecond Annual Seminar. Kuala Lumpur, Malaysian Society of Marine Science, pp. 33-44.

Chen, Z., and S. Wei (1981) An investigation on the distribution of tuna fish larvae in thecentral region of Nan Hili. J. Fish. China, 5(1}: 41-47.

Cheunpan, A. (1984) Sexual maturity, size at first maturity and spawning season of longtailtuna (T. tonggol), eastern little tuna (E. affinis) and frigate mackerel (A. thazard) in theGulf of Thailand. Tech. Rep. Pelagic Fish Sub-Diy. Mar. FishDiv., Bangkok (4): 25p.

Chiampreecha, B. (1978) Biological studies on tuna and tuna-like fishes in the west coastof the Gulf of Thailand and off east coast of Peninsular Malaysia. Tech. Rep. PelagicFish. Unit. Mar. Fish. Div., Bangkok (4): 25p.

Chullasorn A. and P. Martosubroto (1986) Distribution and important biological features ofcoastal fish resources in Southeast Asia._FAO Fisheries Technical Paper 278 FAO

Chullasorn, S., K. Chotiyaputta and Chayakul (1973) Preliminary studies on the narrow-barredSpanish mackerel Scomberomorus commerson (Lacepede, 1802) in the Gulf of Thailand.Tech. Rep. Pelagic Fish. Unit Fish. Div. Bangkok, (1973): 47p (in Thai).

Department of Fisheries Thailand (1984) Purse seine fisheries and the present status of pelagicfish resources in the Gulf of Thailand. Paper presented to the Marine Fisheries Seminar,Bangkok, 4-7 September 1984, 68p. (Mimeo in Thai)

Department of Marine Fisheries Sarawak (1987) Annual Report 1987, Ministry of Agriculture,Malaysia.

Druzhinin, A.L. (1970) Indian mackerel, Rastrelliger spp, in Burma Waters. Proc. Indo-Pac.Fish. Counc., 13(2): 59-81

Fisheries Research Institute (1987) Offshore Fisheries Resources Survey within the MalaysianExclusive Economic Zone. Ibupejabat Perikanan, Kementerian Pertanian Malaysia, Vol.1 Mimeo: 19p

Fisheries Research Institute (1987) Offshore Fisheries Resour~es Survey within the MalaysianExclusive Economic Zone. Ibupejabat Perikanan, Kementerian Pertanian Malaysia, Vol.2 Bk. I Mimeo: 101p

Gloerfelt-Tarp, T. and Kailola, PJ. (1982) Trawl Fishes of Southern Indonesian and North-western Australia. Australian development Assistant Bureau. Directorate General ofFisheries, Indonesia. German Agency for Technical Cooperation.

Ingles, J. and D. Pauly (1984) An atlas of the growth, mortality and recruitment of Philippinesfishes. ICLARM Tech. Pap., (13): 127p

IPTP (Indo-Pacific Tuna Development and Management Programme) (1986b) Report of themeeting of Tuna Research Groups in the south-east Asian Region. Indo-Pacific TunaDevelopment and Management Programme IPTP/86/GEN/1O' 75p.

Kihara, Y. (1988) Final Consultant Report - Masterfisherman 1988. Research Section, MarineFisheries Department Sarawak. Mimeo: 27p

Klinmuang, H. (1978) Preliminary studies on the biology of tunas in the west of the Gulfof Thailand and off the east coast of Peninsular Malaysia. Tech. Rep. Pelagic Fish Unit.Mar. Fish. Div., Bangkok (1978): 27p

Klinmuang, H. (1981) Length frequency distribution and length-weight relationship of tunasin the Gulf of Thailand. Tech. Rep. Pelagic Fish Unit. Mar. Fish. Div., Bangkok (24):33p

Magnusson, J. (1970) Report on assignment as marine biologist with the UNDP(SF)/FAODeep-Sea Fishing Development Project in the Philippines (January 1966-June 1969).Rome, FAD UNFP/SF Project PH/llI: 90p

Menasveta, D., S. Shindo and S. Chullasorn (1973) Pelagic fishery resources of the SouthChina Sea and prospects for their development, Rome, FAO, South China Sea FisheriesDevelopment and Coordinating Programme, SCS/DEV /73/6: 68p

Murdoch, J, and Barnes J.A. (1982) Statistical tables for Science, Engineering, Managementand Business studies. Second Edition. The Macmillan Press Ltd. 20

Pathansali, D. (1961l A preliminary report on the Rastrelliger fishery in Malaysia. Proc. IPFC,2(2): 37-45

Pathansali, D. (1967) Observation on the gonad maturity stages of female Rastrelligerkanagurta Cuvier. Proc. IPFC, 12(2): 112-5

Ronquillo, LA. (1974) A review of the round scad fishery in the Philippines. Proc.lPFC,15(3): 351-75

Sakurai, T. and M. Miyake (1987) Manual for collecting statistics and sampling on tuna andtuna-like species in the Indian Ocean and Southeast Asian Region. Indo-Pacific TunaDevelopment and Management Programme (lPTP).

SEAFDEC (South-East Asian Fisheries Development Centre) (1982) A colour guide to theFishes of the South China Sea and the Andaman Sea. Primary Production Department/Marine Fisheries Research Department, SEAFDEC, Singapore.

Supongpan, S. and R. Chaayakul (1979) Population bionomics of the Spanish mackerel,Scomberomorus commerson (Lacepede, 1802) in the Gulf of Thailand. Tech. Rep. PelagicFish. Unit Mar. Fish. Div. Bangkok, (9): 31p

Tiews, K., LA. Ronquillo and P. Caces-Borja (1970) On the biology of round scads,Decapterus Bleeker in the Philippines waters. Proc,.IPFC, 13(2): 82-106

Yesaki, M. (1987) Synopsis of Biological Data on longtail tuna, Thunnus tonggol. Indo-PacificTuna Development and Management Programme (IPTP).

.II

1- __ ~':'<:~::'~[.~>".......". en'. "'1': ..~ "\I,.V~Terumbu Layang-Layang .-d·..· _..//~ I

./,1 _/ ./''/ ,1 1/,.' f" ..... ,/

•. ' •.- f /.,.•- r'- / ,....-.1 / 1" .I

...././(,.... (" \..........?'~.>: /

...~·:u)O...f.tm ... N. Luconi a shoals './;......."\ /' ••j" /" ,••••

....... " •.•.. ...."/ :"if..•.• ...••.. ..••.. ..I.J;:: ,...............,., ,...'..,-j ...;'. )

S.Luconl-.;l stlOa:}'S'.....:./ ..,/ j'".,•..........' ...- - __7 .' ..' I: 50·-f-till .....•..-."" ,I) \>- r..........•....../ .../' '.... ..,/ , ~l:.:~·-.- "..

f. ...;} 1._~ •••~(1J..r~ CHI N A 5 E A :~/,/

\. <In' ft;>o.. /..... .I .•• ;"JU "p., .....• Ir....· ,.-._,,,,-:Beting Serupai./i / Beti ng Tugarr'{ ....F·....~.J Beti ng MUk.~~!., /....lO...f-tm·.....i ( --'

J !f~··/··~..··..,,,..ji,I

I

I' .Datu Bt .L'~...... 9 ...~'ata~··..·..···.B.aI.;·i n

Kuc ng. Si

.","'''

••• J" •••, •••

/,,",

II

I',,I,",,'.•'.•.•".•.•',.•,",","

".~I'·I'.

""-,'..II\ ""\

\III,III,,II,II

IIII..III. ,II,III.,,,..

III,,

I

," ,,' ),. ~•..

i::/-···,·/'t!(;J.: .' ..../".) '0

Thunnus albacar..q·' .. (" ';!Thunnus obeso's) ... ' .I {....---~ ... , ;Auxis t~a~llr:Jl.' /. ...../Katsuwanu~' pel~.is !Mh~:;;t"'i'(finis .D~~ter(us nc,..os· .

../' .--I .•.•J'~ .. \.......... _ .... -

j ..•... -,

.' ··....f")

ClupeidsTrev\,ll.ifiS I

lIega-iaspi:.!i...tordy la

r~nnus ton~ ...i uthynnus affinis .Selar cru.e 'ptn~ii~elliget gurta

.......... ./ R. brachys~.o;;capteru(

s.• ate /

LENGTH FREQUENCYAuxis thazard

40

35

30

25

;>,us:::II) 20;j0"II)•....~

15

10

5

024 25 26 27 28

Fork Length (cm)

Figure 3: Size composition of frigate tuna, Auxis thazard caught by K.K. Manchongpurse-seine in April 1987 around a FAD very near to Terumbu Layang-layang.

LENGTH FREQUENCYTlIlIllIIIlS alhacares

20

18

16

14

12

>-, 10uc::<1.l::lc:r<1.l•...u. 8

6

4

2

022 26 30 34 38 42 46 50 54 58 62

Fork Length (cm)

Figure 4: Size composition of yellowfin tuna, Thunnus albacares caught by trolling in waters offTerumbu Layang-layang during the April 1987 trip.

The carangids that are mostly caught by purse-seine and here is mostly selar specificallyAtule mate.

210d/48150mm

21Od/48150mm

210d/48150mm

210d/48114mm

21Od/3376mm

21Od/3350mm

210d/3338mm

2lOdn2150mm

2lOdn2150mm

21Od/60114mm

21Od/4876mm

210d/3350mm

210d/3338mm

Headrope length 471 mGroundrope length 55.5 mNet height (Theoritical) 4.0 mTwine size 210/33-210/48Materials (Nylon polyamide)Estimates Resistance 4.0 tons

Purse Seine Net for K.K. Manchon in 1987Appendix 2

TOTAL FLOAT LINE LENGTH 449.1 M

39.8m 73.2m 287.1 m 49.1 m

I I0.7 54.5m 96.0m 384.1 m 64.0m 0.7

2 3 4 5 6 7 8 9 lO II 12 13 14 15 16 17 18 19

PE380D 3 1 5Om/m 12MD rilN N2lOD N2lOD N2lOD N2lOD N2lOD N2lOD ~

12 12 9 9 7 7"25m/m 25m/m 25m/m 25m/m 25m/m 25m/m i5600md 600md 600md 600md N2lOD17 600md 600md -32.0m 32.0 In 32.0m 37·0m N2lOD17 25m/m 32.0 m 32.0 m '"

t::l 3 pes 25m/m fv; 25m/m'~ 900md N

fj 3 900m1 4 pes 600mdlt64.Om 6OOmdlt64.Om ~N

5 pes ...•~ 5 pes ~,. 6 pes~f 6 pes 7 pes 7 pes

PE380D 3/21 5Om/m 12MD

23.7 46.2 61.2 76.2 91.2 11J6.2m 11J6.2m 91.2 76.2I ' NET DEPTH STR. m

20.3% 43.9m 18.1% 78.7m 17.6% 316.4m 19.2% 52.2mI

3 48 76 82 96 96 82 74 62 62 62 62 62 76 90 102 114 102 90 76 3I , , ,