Chiang Mai J. Sci. 2021; 48(4) : 1009-1020http://epg.science.cmu.ac.th/ejournal/Short Communication
Species Composition and Distribution Pattern of Stingrays in the Coastal Waters of Terengganu, Malaysia, the South China SeaNur Arina Hayati Binti Mohidin [a], Sukree Hajisamae [b], Maizah M. Abdullah [c], Mazlan Hashim [d], Ahasan Habib [a], Rashedul Islam [e] and Hisam Fazrul*[a,f][a] Faculty of Fisheries and Food Sciences, Universiti Malaysia Terengganu, 21030 Kuala Terengganu, Terengganu Malaysia.[b] Faculty of Science and Technology, Prince of Songkla University,Pattani, 94000 Thailand.[c] Faculty of Science & Marine Environmental, Universiti Malaysia Terengganu, 21030 Kuala Terengganu,
Terengganu, Malaysia.[d] Faculty of Built Environment and Surveying, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor Darul
Takzim Malaysia.[e] Department of Marine Fisheries and Oceanography, Patuakhali Science and Technology University, Dumki,
Patuakhali-8602, Bangladesh.[f] Higher Institution Centre of Excellence (HICoE), Institute of Tropical Aquaculture and Fisheries (AKUATROP),
Universiti Malaysia Terengganu, 21030 Kuala Nerus, Terengganu, Malaysia.
*Author for correspondence; e-mail: [email protected]: 21 May 2020
Revised: 6 February 2021 Accepted: 15 February 2021
ABSTRACT Stingraysarepartof commercialfisheriesworldwide;Malaysiaisrankedastheeighth-largest
stingrayfisheryintheworld.SampleswerecollectedmonthlyfromJanuary2018toDecember2018usingstingraygillnetsinCoastalSouthChinaseawatersof Terengganu.Thepresentstudyaimedtodeterminetheabundanceanddistributionof stingraysbasedonspeciesandsizesatdifferenthabitatandseasonsintheTerengganu,Malaysiacoastalwaters.Atotalof 10stingrayspecieswerecollectedfrom122samples.Stingrayspeciesaredistributeddifferentlyaccordingtohabitatandseasonal.Theresultof atwo-wayANOVAshowedthathabitatandseasonsignificantlyaffecttheabundanceof stingrays(P<0.001).Mostcatcheswerein20mdepthduringthedryseason.Theresultof anon-metricmultidimensionalscalingordinationindicatesthatthegroupingoverlappedinhabitatandseasonwithsimilarspeciescollected.
Keyword:ray,stingray,habitat,seasonal,gillnet,Terengganu,coastalSouthChinasea
1. INTRODUCTIONStingrayshavebecomeamajorpartof
commercialfisheriesaroundtheworldduetothehighinterestfromthemarket[1].Mostcatchesof elasmobrancharefrombycatchcases,whichareincidentallycaughtbythefishermanduringthe
fishingactivity.Frompreviousstudies,stingrayswerecaughtasthebycatchspeciesmostlybyusingpelagiclonglineandhook,bottomlongline,surfacelongline,trawlandgillnetsasfishinggear[2-5].
Chiang Mai J. Sci. 2021; 48(4)1010
Mostmarinepopulationdynamicsareinfluencedbybehaviouralresponsestowardstheecologicalprocess, includingbothabioticandbioticfactors[6,7].Understandingthefactorsthataffecthabitatshiftsisimportantforbetterawarenessof populationdynamicsinfisheriesthataretargetorbycatchspecies[6,7].Abioticfactorscantriggermovementandchangesinbehaviourandhabitatof elasmobranchs[8,9].Salinityandwatertemperaturearemostselectivefactorsinmoststudies;however,turbidity,dissolvedoxygenconcentrationandpHalsoprovideanimportantaspectforthespatialdistributionandecologyof rays[8,9].Changesintheenvironmentcantriggerthemovementandchanges inbehaviourandhabitatforelasmobranchspecies[8].Temperatureaffectsthephysiologyof mostsharksandrays;theyaresensitivetotemperaturechanges.Mostraysarestrictlystenohaline; itgivesastronginfluencetowardssalinityonphysiology.Salinityinfluencesthedistributionandabundanceof sharksandrayssuchasCarcharhinus amboinensis (pigeyesharks)andRhinoptera bonasus(cownoserays)[8].Forstudyingtheecologyof rays,itisimportanttounderstandtheroleof thespeciesinthemarineecosystemandtheirtrophicrelations.Understandingthesetrophic interactionsandthepositionof aspecieswithinafoodwebisanimportantstepindefiningthedynamicsof marinecommunitiesandtheimpactstospecies.Failuretoidentifythoseimportantaspectswillleadtogapsinunderstandingtheimportanceof raysinthemarineecosystem.Changesinthefoodwebcanaffectthesystemintensely,resultinginchangesinabundanceandwebconnectivitywithotherspecies.Raysareconsideredakeystonespeciesinmarineecosystemswithanimportantroletomaintainthesustainabilityof theecosystem[10].
InMalaysia,thedemandforstingrayshasincreased[11,12].Stingrays(Dasyatidae)areoneof themost importantbatoidfishes incommercialfisheries,consistingof smalltoverylargesizes;adult’sspecimenscanreachbetween22cmand260cmDWwithdiversedistribution
inAsia[13].InAsia,thereislessknownaboutrayecologycomparedtotheAmericas[9];withinAsia,MalaysiahaslessresearchcomparedtoothercountriessuchasIndonesia[14].InMalaysia,previousstudieshavefocusedonfishinggearsuchasbarriernets,gillnetsandbeamtrawlstocatchstingraysincoastalmudflatsinKualaSelangortostudythelength-weightrelationship[15].FewerstudieshavefocusedonstingraydistributioninMalaysia.FromthepreviousresearchinMalaysia,atotalof sixspeciesof stingraysweresampled:Himantura walga,Dasyatis bennetti,Dasyatis zugei,Neotrygon kuhlii,Taeniura lymmaandHimantura pastinacoides[15].
Theresearchconductedonstingrays inMalaysiaisstillinitsearlystageswithmostof theresearchfocusedonothermarineorganismssuchassharksandturtle.Thisstudyisthefirstinvestigationof thehabitatandseasonalpatternsof abundanceanddistributionof stingrayspeciesinTerengganucoastalwaters.Theobjectivesof thisstudyaretodeterminetheabundanceanddistributionof stingraysbasedonspeciesandsizesatdifferenthabitatsandseasonsintheTerengganu,Malaysiacoastalwaters.Thereislessknowledgeof habitat,characteristicsanddistributionof stingrayspecies inMalaysiacomparedtootherAsiancountries.Thisstudyexaminedtheinfluenceof habitatandseasonaldivisionsontheabundanceanddistributionof stingrayspeciesinMalaysia.Moreover,itcontributesdataonthepopulationsizeof stingrayscaughtinTerengganuwaters.ThisstudymayhelptoachieveasustainablestingraystockinMalaysiaandprovideinformationonstingraysforartisanalfisheries.
2. MATERIAL AND METHODS2.1 Study Area
Threedifferentdepthcontoursalongthecoastalareaof Terengganuwereselected:10m,15mand20mdepths.Threesub-stationswereonthelinetransectbasedonlocality:BidongIsland,KapakIslandandGelokIslandwerechosenforeachdepthcontour(Figure1).Allthedepthsat
Chiang Mai J. Sci. 2021; 48(4) 1011
eachsamplingstationweremeasuredbysonarSIMRADEK15.Thestingrayisthemaintargetorganismcaughtbylocalfishermenusinggillnets.
2.2 Collection of SamplesSampleswerecollectedmonthlyfromJanuary
2018toDecember2018byuwsingstingraygillnetsinTerengganuwaters.Thesamplingforthisstudy(Prk.ML.S.04/32/2Jld.9(22)hasbeengivenpermissionbyDepartmentof FisheriesMalaysia.Ateachsub-stationof eachdepthcontour,anetwassetupwith2.00mdeep,2,100mlongand26cmstretchmeshsize.Thegearsweresetat0600hoursinmorning,leftovernightfor24hoursandhauledonboardthenextmorning(Figure2).Altogether,6,300mof nettingweresampledateachdepthcontourtotalling18,900mfromallthreedepthcontourseachsamplingmonths.For
seasonaldivisionbasedonHisametal.(2015),threedifferentseasonswerebasedonthequantityof rainfall:(1)therainyseasonwasfromSeptembertoDecember,(2)themoderatelyrainyseasonwasfromMaytoAugustand(3)thedryseasonwasfromJanuarytoApril.Thestingraysampleswereremovedfromthenetsandtransportedtothelaboratoryforfurtheranalysis.
FieldsamplingsweredonemonthlyfromJanuary2018toDecember2018,withsupplementarysamplingsonFebruary2019andOctober2019tocomplementexistingdatabasedonseasonal,sizes,sex,habitatchangeandseasonsforthesame months in 2018.
2.3 Laboratory WorkInthelaboratory,stingraysizesweremeasured
bydiscwidth(DW),disclength(DL)andtotal
Figure 1.Threesub-stationsaslinetransectbasedonlocality;BidongIsland(A),KapakIsland(B)andGelokIsland(C)withdifferentdepthcontour(A1,B1,C1:10m;A2,B2,C2:15m;A3,B3,C3:20m).
Chiang Mai J. Sci. 2021; 48(4)1012
length(TL)usingameasuringtape.Thetotallength(TL)wastakenfromthetipof snouttotheendof thetail,discwidth(DW)wastakenfromthemaximumdistancebetweenwingtipsanddisclength(DL)wastakenfromthetipof thesnouttotheposterioredgeof thedisc[16].Stingrayweightsweremeasurewithanelectronicweightbalance;thecalibrationwasdonebeforeweighing.Stingraysweresexedbasedontheoccurrenceof clasper.Thepresenceof aclasperindicatesthatastingrayismale[17].
2.4 Statistical AnalysisAtwo-wayanalysisof variancewasusedto
testwhethertheabundanceof stingrayscollecteddifferedsignificantlyamongstseasonandhabitat.Abundancedatawerelog(x+1)transformedtoreducenon-normalitybeforeanalysis.Oncethedifferencewasdetected,aposthocanalysiswasconductedusingtheTukeyTest.Atwo-wayanalysisof variancewasusedtotestwhethernumbersof stingraysdiffersignificantlyamongsthabitatandseason.Therawdatawaslog(x+1)transformedtoreducenon-normalitybeforeanalysis.ATukeytestwasusedoncethedifferencedetected.Therelationshipbetweenmeandiscwidth(cm),weight(g)of thestingrayandwaterdepth(m)weremeasuredtoquantifyahabitatshift.
Anon-metricmultidimensionalscaling(nMDS)ordinationwasconductedtoassesstheextenttowhichindividualgroupingswerebasedonhabitatsandseasonsforparticularareas.ThenMDSwasperformedusingPRIMERstatisticalpackageversion7.0.ABray-Curtissimilaritybasedonlog(x+1)transformationswasusedtoexaminethedifferencesbetweenstingraycommunityassemblagesinallhabitatsandseasons.Analysisof similarity(ANOSIM)wasusedtodeterminedifferencesinstingrayassemblagesseparatedbynMDSordination.Oncethesignificantdifferenceswerefound,asimilaritypercentage(SIMPER)wasusedtoexaminewhichstingrayspeciescontributedmosttothedifference
3. RESULTSAtotalof 122stingrayswerecollectedwithgill
nets;16(10m),29(15m)and77(20m)stingrayswerecaughtinthisstudy(Table1).Tenstingrayspecieswerepresent inthisstudy(Figure4).Theresultsfrom20mdepthcaughtlarger-sizedstingrayscomparedto10mand15mdepth.Forexample,thesizeof stingrayscaughtwere59.70±28.94cm,81.80±31.42cm,76.20±36.85cmin20mduringthedry,moderateandrainyseasons,respectively.Thereweremorecatchesof femalestingraysthanmalestingrays(Table1).Thedetails
Figure 2.Characteristicof stingraygillnetsusedduringsampling.
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Table 1.Totalabundance,sex,size,andweightof stingrayspeciescaughtfromgillnetseachhabitatfromJanuary2018toDecember2018.
Source Total Male Female BW±SD DW±SD
10 m
Dry 10 5 5 1239.00±6500.13 36.65±12.53
Moderate 1 1 0 4900.00 58.60
Rainy 5 2 3 4200.00±1823.46 54.00±15.46
Total 16 8 8
15m
Dry 14 7 7 7720.00±14835.17 36.65±39.84
Moderate 13 4 9 16000.00±13474.58 85.20±32.22
Rainy 2 1 1 8050.00±2474.87 61.35±4.88
Total 29 12 17
20 m
Dry 43 16 27 7130.00±16702.97 76.20±36.85
Moderate 31 22 9 14000.00±14708.54 81.80±31.42
Rainy 3 1 2 7750.00±12325.37 59.70±28.94
Total 77 39 38
Figure 3. Measurementof discwidth(DW),disclength(DL)andtotallength(TL).
Chiang Mai J. Sci. 2021; 48(4)1014
forthetotalcatch,sex,bodyweightanddiscwidthof stingrayscaughtatdifferenthabitatsandseasonarepresentedinTable1.
TheresultsfromtheANOVAfoundthatthecatchesof stingrayspeciesweresignificantlyinfluencedbothbyhabitatandseason(P<0.001,respectively;Table2).Detailof resultsforTukeyHSDtestforhabitatcanbefoundinTables3
and4.Bothmeanabundanceof stingrayswasnosignificantdifferentatdepthof 10mand15m,andalsoatdryandmoderateseason.Monthlycatchesof stingrayspeciesfromdifferenthabitatsandseasonsaredetailedinTable5.
ResultfromnMDSplotsrevealedthatthegroupingof stingrayspeciesoverlappedbasedondifferenthabitatdepths(Figure5).However,
Figure 4. Stingray’sspeciescollected,A,Himantura uarnak;B,Pastinachus ater;C,Maculabatis gerrardi; D,Aetobatus acellatus;E,Hemitrygon parvonigra;F,Urogymnus asperrimus;G,Gymnura poecilura;H,Pateobatis jenkinsii;I,Rhinoptera javanica;J,Brevitrygon walgai.
Table 2.Two-wayanalysisof varianceof theeffectsof habitatandseasononabundanceof stingrayscollectedbygillnets.
SourceAbundance
df MS P-value
Habitat(h) 2 114.70 1.12 × 10-4
Season (s) 2 91.81 3.81×10-4
h × s 4 35.09 8.14×10-3
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Table 3.TukeyHSDtestonmeanabundanceof stingrayscollectedbygillnetsindifferenthabitat.
Habitat (mean abundance)
10 m 15 m 20 m
10m - - -
15m >0.05 - -
20 m <0.05 <0.05 -
Table 4.TukeyHSDtestonmeanabundanceof stingrayscollectedbygillnetsduringdifferentseason.
Season (mean abundance)
Dry Moderate Rainy
Dry - - -
Moderate >0.05 - -
Rainy <0.05 <0.05 -
Table 5.Numberof stingray’sspeciescaughtateachhabitatandseasonineachmonthatthesamplingsiteof TerengganuwatersfromJanuary2018toDecember2018.
MonthsHabitat
TotalDry Moderate Rainy 10 m 15 m 20 m
January 11 0 0 1 3 7 22
February 26 0 0 8 8 10 52
March 19 0 0 0 2 17 38
April 11 0 0 1 1 9 22
May 0 5 0 0 1 4 10
June 0 11 0 1 3 7 22
July 0 13 0 0 3 10 26
August 0 16 0 0 6 10 32
September 0 0 4 1 0 3 8
October 0 0 1 0 1 0 2
November 0 0 4 4 0 0 8
December 0 0 1 0 1 0 2
Total 67 45 10 16 29 77 244
Chiang Mai J. Sci. 2021; 48(4)1016
Non-metric MDSTransform: Square rootResemblance: S17 Bray-Curtis similarity
Depth10M15M20M
2D Stress: 0.01
Figure 5.ThenMDSplotforassemblagesatvarioushabitatof stingrayspeciescollectedbygillnetinBidong,GelokandKapakislands.
allhabitatassemblagesweresimilar toeachother.ThenMDSplotsrevealedthatthestingrayspeciesdistributionoverlappedbasedondifferentseasons(Figure6).Speciesof stingraysineachof habitatandseasonwereidentifiedbysimilarityof percentage(Table6).
Bodyweightanddiscwidthof stingrayspeciesincreasedtowardsthedeeperwaterdepth(Figure7).Bodyweightof stingrayspeciesfromeachhabitatwassignificantlydifferentasthesmallersizestingraytendedtoinhabitshallowwatersandmigratetodeeperwaterwhengrowinglarger.
4. DISCUSSION Totalof 10stingrayspecieswerecollected
basedonhabitatandseason.Thisstudyshowsthathabitatandseasonhaveanimpactontheabundanceof stingrayspecies inTerengganuwaters.Therearesignificantdifferencesbetweentheinteractionof habitatandseasonwiththeabundanceof stingrayscaught(Table2).Thisis
duetodifferentphysicalandbiologicalconditionsbetweenthedifferenthabitatsandseasons.However,forthehabitatsat10mand15mdepth,therewasnosignificanteffectonspeciesabundancecomparedto10mwith20mand15mwith20mdepth(Table3).Stingraystendedtolocateatadeeperdepthcomparedtoshallowwater.Theseasonalfactorshowedasignificantdifferenceof thespeciesabundancebetweendryandrainyandbetweenmoderateandrainyseasons;therewasnodifferencebetweenthedryandmoderateseasons(Table4).
Thisstudyshowsthatmostof thestingraycatchesoccurredindeeperwater(20m)andduringthedryseason(Table5).Previousresearchstatedthatsomeof thestingrayspeciesreactdifferentlyduringdayandnight;theysearchforpreyinshallowwaterduringthenightandrestindeeperplacesduringtheday.Thedistributionof youngstingrayswascloselyrelatedtotheshallowwaterandsandybeaches[18,19].Somelarge
Chiang Mai J. Sci. 2021; 48(4) 1017
Non-metric MDSTransform: Square rootResemblance: S17 Bray-Curtis similarity
SeasonDryModerateRainy
2D Stress: 0.01
Figure 6.ThenMDSplotforassemblagesatdifferentseasonof stingrayspeciescollectedbygillnetinBidong,GelokandKapakislands.
Table 6.StingrayspeciesassemblagesinhabitatandseasonbasedonnMDSplots.
Habitat Season Species %Contribution
10 m Dry Hemitrygon parvonigra 50
Brevitrygon walga 50
Moderate Nosimilarities 0
Rainy Nosimilarities 0
15m Dry Maculabatis gerrardi 53.68
Hemitrygon parvonigra 25.48
Moderate Maculabatis gerrardi 60.85
Pastinachus ater 21.64
Rainy Nosimilarities 0
20 m Dry Pateobatis jenkinsii 27.72
Pastinachus ater 25.81
Aetobatus acellatus 16.48
Moderate Maculabatis gerrardi 26.26
Rhinoptera javanica 24.57
Himantura uarnak 24.14
Rainy Nosimilarities 0
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Rainy No similarities 0
20 m Dry Pateobatis jenkinsii 27.72
Pastinachus ater 25.81
Aetobatus acellatus 16.48
Moderate Maculabatis gerrardi 26.26
Rhinoptera javanica 24.57
Himantura uarnak 24.14
Rainy No similarities 0
224
225
Body weight and disc width of stingray species increased towards the deeper water depth 226
(Figure 7). Body weight of stingray species from each habitat was significantly different as the 227
smaller size stingray tended to inhabit shallow waters and migrate to deeper water when 228
growing larger. 229
a) 230
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Figure 7. Relationship between water depth (m) and a) body weight; and b) disc width of 250
stingray species caught by gill net. 251
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4. DISCUSSION 253
Total of 10 stingray species were collected based on habitat and season. This study shows that 254
habitat and season have an impact on the abundance of stingray species in Terengganu waters. 255
There are significant differences between the interaction of habitat and season with the 256
abundance of stingrays caught (Table 2). This is due to different physical and biological 257
conditions between the different habitats and seasons. However, for the habitats at 10 m and 258
15 m depth, there was no significant effect on species abundance compared to 10 m with 20 m 259
and 15 m with 20 m depth (Table 3). Stingrays tended to locate at a deeper depth compared to 260
shallow water. The seasonal factor showed a significant difference of the species abundance 261
between dry and rainy and between moderate and rainy seasons; there was no difference 262
between the dry and moderate seasons (Table 4). 263
This study shows that most of the stingray catches occurred in deeper water (20 m) and 264
during the dry season (Table 5). Previous research stated that some of the stingray species react 265
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Figure 7.Relationshipbetweenwaterdepth(m)andbodyweight(a);anddiscwidthof stingrayspeciescaughtbygillnet(b).
Chiang Mai J. Sci. 2021; 48(4) 1019
stingraysoccupiedlocationswithdifferentdepthsduringdayandnight,alsoknownasbathymetricmigrations[18,19].Inpresentstudy,itislikelythatmoreindividualswerecaughtinthe40mhabitatbecausewehauledduringthedaytimewhenstingrayswerelocatedindeeperhabitats.Theseasonalfactorshowedasignificantimpactonthespeciesabundancebetweendryandrainyandbetweenmoderateandrainyseasons,butnotbetweenthedryandmoderateseasons.Themovementof stingrayspeciesduringtheseasonaldivisionmaybeduetobiologicalfactorssuchasreproduction,feedingorpredatoravoidance,orbecauseof seasonalphysicalchangessuchastemperature,currentsandphotoperiod[20].
Thespeciesabundanceof stingrays inTerengganuwaterswas influencedbothbyhabitatandseason.BasedonnMDSordination,theresponseof stingrayassemblageswassimilarineachhabitatandseason.Thismayleadtoaconclusionthatthespeciesassemblagescollectedbystingraygillnetfisheriesaregenerallysimilarfromdifferenthabitatandseason.Thestingrayspeciesweresimilarfromdifferenthabitatsandseasons.Thisreflectsthatmarineorganismsinthat community structure are geographically connected.
Thedeepertheseabed,thebiggerthesizeof stingraycaughtinstingraygillnets(Figure6).Thepresentfindingisconsideredthefirststudyreportingandtestingdirectlybetweenthedepthandsizeof stingrays,apartfromindirectobser-vationbysomepreviousstudies[9,14,15,21].Normallythesizesof femalestingraysaremuchbiggerthatmalestingrays.Previousresearchfocusedonthemaximumandminimumdiscwidthsizesof malesandfemalesforcertainstingrayspecies. Dasyatis violacea caughtasbycatchonlonglinesforswordfishandtunawasarelativelysmallraywithanof 800mm[21].
InIndonesia,Rhinobatos jimbaranensis females rangedfrom491to994mm,whereasmalesrangedfrom506to953mm.Thesizeof Dasyatis cf. kuhlii (Javaform)forfemalesisfrom118to379
mmandformalesisfrom128to324mmWD,whilethesizeof Dasyatis cf. kuhlii (Baliform)forfemale’srangesfrom240to471mmandmalesisfrom172to450mmWD,respectively.Moreover,Dasyatis cf. ushiei hasbeenreportedforthefemalestorangefrom729to2,020mmWDandmalesrangefrom629to1,624mmWD.Mostof thefemalestingrayscaughtwerelargerthanmalestingraysinthisstudy(Table1).
5. CONCLUSIONS Stingrayspeciesaredistributedwidely in
differenthabitatsandseasons.Theabundanceof stingrayspeciescaughtwassignificantlyaffectedbybothhabitatandseason.Thespeciesabundancewassimilaramonghabitatandseason.Thisstudyalsoconfirmsthatyoungstingraysprefershallowwatercomparedtodeeperwater,demonstratingthathabitatshifted.
ACKNOWLEDGEMENTSSpecialthankstotheMinistryof Education
forprovidinggrant researchfor thisstudyFRGS/1/2017/WAB09/UMT/03/5(No.Vot:59490).ThankstoDepartmentof FisheriesMalaysiaforgivingpermissiontoconductthesamplingforthisstudy(Prk.ML.S.04/32/2Jld.9(22).Besides, thankstoUniversityMalaysiaTerengganuespecially,theFacultyof FisheriesandFoodScienceswhoprovidedthelabfortheconvenienceof thestudy.Thanksalsotoallthefishermeninvolvedduringthesamplingactivities.Next,thankstotheDepartmentof Fisherieswhohavepermittedtousethestingraygillnetsforthisstudy.
REFERENCES[1] FAO.TheStateof WorldFisheriesand
Aquaculture.ContributingtoFood Security andNutrition for All,Rome,2016;200pp.
[2] GallagherA.J.,OrbesenE.S.,HammerschlagN.andSerafyJ.E.,Glob. Ecol. Conserv.,2014;1:50-59.DOI:10.1016/j.gecco.2014.06.003.
Chiang Mai J. Sci. 2021; 48(4)1020
[3] FerrariL.D.andKotasJ.E.,J. Appl. Ichthyol.,2013;29:769-774.DOI:10.1111/jai.12182.
[4] CoelhoR.,Fernandez-CarvalhoJ.,LinoP.G.andSantosM.N.,Aquat. Living Resour.,2012;25:311-319.DOI:10.1051/alr/2012030.
[5] AfonsoA.S.,HazinF.H.V.,CarvalhoF.,PachecoJ.C.,HazinH.,KerstetterD.W.,MurieD.andBurgessG.H.,Fish. Res.,2011;108(2-3):336-343.DOI:10.1016/j.fishres.2011.01.007.
[6] AlofsK.M.andJacksonD.A.,Global Change Biol.,2015;21:2227-2237.DOI:10.1111/gcb.12853.
[7] SnoverM.L.,Bull. Mar. Sci.,2008;83:53-67.
[8] Schlaff A.M.,HeupelM.R.andSimpfendorferC.A.,Rev. Fish Biol. Fisher.,2014;24(4): 1089-1103.DOI10.1007/s11160-014-9364-8.
[9] Carrillo-BriceñoJ.D.,CarrilloJ.D.,AguileraO.A.andSanchez-VillagraM.R.,PeerJ,2018;6:e5313.DOI10.7717/peerj.5313.
[10]BornatowskiH.,NaviaA.F.,BragaR.R.,AbilhoaV.andCorrêaM.F.M.,ICES J. Mar. Sci.,2014;71:1586-1592.DOI:10.1093/icesjms/fsu025.
[11]Departmentof Fisheries(DOF).Perang-kaanPerikananTahunan,2015.Availableat:https://www.dof.gov.my/epms/index.php/pages/view/2614.
[12]Departmentof Fisheries(DOF).Perang-kaanPerikananTahunan,2017.Availableat:https://www.dof.gov.my/epms/index.php/pages/view/2614.
[13]LastP.R.,NaylorG.andManjaji-MatsumotoB.M.,Zootaxa.,2016;4139(3):345-368.DOI:10.11646/zootaxa.4139.3.2.
[14]WindusariY.andIqbalM.,Oceanogr. Fish. Open Access J.,2018;6(3):1-4.DOI:10.19080/ofoaj.2018.06.555690.
[15]LimK.C.,ChongV.C.,LimP.E.andYurimotoT.,J. Appl. Ichthyol.,2014;30:1096-1098.DOI:10.1111/jai.12455.
[16]Serra-PereiraB.,FariasI.,MouraT.,GordoL.S.,SantosM.andFigueiredoI.,ICES J. Mar. Sci.,2010;67(8):1596-1603.DOI:10.1093/icesjms/fsq056.
[17]CarpenterK.andNiemV.,FAOspeciesidentificationguideforfisheriespurposes.Thelivingmarineresourcesof theWesternCentralPacific.1998;Vol.2.Cephalopods,crustaceans,holothuriansandsharks.Rome,FAO:687-1396.
[18]dosSantosJ.M.,dosSantosJ.C.,MarquesE.E.,deAraujoG.C.,SeibertC.S.,Lopes-FerreiraM.andLimaC.,Toxicon,2019;163:74-83.DOI:10.1016/j.toxicon.2019.03.013.
[19]GarroneNetoD.andUiedaV.S.,Neotrop. Ichthyol.,2012;10(1):81-88.DOI:10.1590/S1679-62252012000100008.
[20]LePortA.,LaveryS.andMontgomeryJ.C.,ICES J. Mar. Sci.,2012;69(8):1427-1435.DOI:10.1093/icesjms/fss120.
[21]MolletH.F.,Mar. Freshwater Res.,2002;53(2): 525-530.DOI:10.1071/MF02010.