nests were placed in normal density and ten nests were placed in high density in the Ma'Daerah hatchery, Terengganu,. Malaysia. A sample of at least 10 ...
KURENAI : Kyoto University Research Information Repository Title
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EFFECTS OF HATCHERY NEST DENSITY ON THE EMERGENCE SUCCESS AND QUALITY OF CHELONIA MYDAS HATCHLING Van de Merwe, Jason; Ibrahim, Kamarruddin; Irvebrant, Michaela; Whittier, Joan
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Issue Date
URL
2002
http://hdl.handle.net/2433/44170
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Type
Textversion
Conference Paper
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Kyoto University
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EFFECTS OF HATCHERY NEST DENSITY ON THE EMERGENCE SUCCESS AND QUAL］TY OF CHELONlA MYDAS blATCHLlNG
Kamarruddin and AbduトRahman，1994：Sundin，2001； With2．5cm mesh ofplasticmaterial（locally known as BlamiresandGuinea，2001；Fr）Ck，2003）．lnaddition，handling netlon）and shadedvvith nursery−tyPed blackcEoth of CanaIsoleadtomortalityofturtIeeggs（Limpuseta［．， 75％lightTetention．Thisproductionhatcheryaccommodated 251clutchesofgreenturtleeggsin2002． 1979）andithasbeenoneofthefactorsthatcommonry reduce hatch oremergence success ofeggsin the DensityexperimentrTh「eemiddlerowsofnests hatcheries． inthehatcherywereusedinthisexperiment（Fig，2）・A SetOfnormaldensitynests（a）andhighdensitynest（b） Over40years，the performance ofhatcheryln WaSSeParatedbyadistanceofabout2mtoavoidshar］ng thePeninsuIarMaIaysiahasbeenmerelybasedonemeト gencesuccess，thatis，thepercentageofhatchlingsthat e恥ctonparamete「sstLrdied．1もnclutcheswerererocated SuCCeSSfully emergefrom a numberofeggsincubated． at a higherdensityin the firstweek ofteamlofthe Althoughincubationsuccessisanimportantindicatorof EARTHWATCH v01unteerprogramme（1−8July，2002）． hatcheryperFormance，reSultanthatchlingsexratiosand NormaldensitynestshaveapproximatelyO，6mbetween hearth orin otherwords，thequalityofhatchlings have theircentreswithin rows and O．7m between rows（Fig． neverbeen attempted．This studywas promptedtofiII 2a，），Thehighdensitynests haveO．46m betweentheir CentreS（Fig．2b．）．Whenhatchlingsemerged，aSanlPleof thesegapsandtoimprovemanagementprogrammeaimlng atEeastlOhatchlingsfromthesenestsweresubJeCtedto atincreasIngtheproductionofhealthyhatchIingsincor陀Ct a runnlng trialoverl．6m trough and were weighed． SeXratios．SpecifECaIly．theobjectiveofthisstudywasto quantifytheeffectofnestdensityinthehatcheryonthe measured and scale counted．AbnormaIity was deter− emergencesuccessandqualityofgreenturt［e．CheJonia mined as any hatchlingwith a scalecountdiffe「sf「om aduItls scale count．The peTCentage Of abnormal my（ね5h8tC州∩9S． hatchlingsfrom each nest（from the sampFe，N＝10−20） WaSthencaFculated andthemean percentofabnormal hatchlings was comparedfor high and normaldensity MATER］ALSANDMETHODS nests．The nests were excavated andits contents were examinedtoquantifytheemergence success，AcomL Studysite−Weconductedthestudyataturtle hatcheryontheeast−facednestingbeachofMa■DaeTah， ParisonofaEIparameterswasnladebetweenhatchlings from highdensitynestsandthosefrom nomlaldensjty l盲rengganu．MaIaysia（Figurel）．TherectanguFarhatchery， measured20m［ongx8mwidexl．6m highwasfenced nests．TheANOVAwasusedforastatisticalanalys［SOf thefactoraffecting nestdensity．Normalitywastested byvisualinterpretationofQ−Q pIots，Homogeneitywas tested by Levene■stest．
Comparison of running speeds between hatcMings with abnormalscale counts and hatch］ings with normalscale countsin normal density nests and high density nests
Comparison of mass・SCL ratios between hatchlings with abnormal scale counts and hatch［ings with normalscale countsin nornlal density nests and high density nests
normaldensity nests had a higher massrSCL than all exchangebetweentheclutchandsur「Oundingsubstrate． Thiscouldresultfromadjacentnestscompetingforoxy− genfromthesameareaandwarrantsfurtherinvestigaq tion．The findings revealed an advantage of having CEutchesincubatedinnormaldensityoverhighdensityln DISCUSS［ON termsofrunnlngPerfo「mance．FrDmthecurrentresurts， The emergence success and the proportion of it iS recOmmended that nests continue to be relocated hatchlings with abnorma］scale counts did not differintohatcheriesatnorma［densitytomaintainthequalityof betweenhighandnormaldensitynests，Hatchlingsfrom emerging hatchIings． the higher density nests ran significantly slower than hatchlingsfromnormaldensitynestsandhad［owernlaSSL ACKNOWLEDGEMENTS length ratios．Itis argued that slower runnlng SPeeds represent a［onger exposure to shore predation and TheauthorsaregratefultotheDirectorGenera［of decreased vigourforthe offshore dispersal．Smaller Fisheries Malaysia for his persistent support．We are hatchlingsfaceincreased riskofp「edationandfurther−indebted to a11EARTHWATCH2002vDlunteers fortheir assistanceinrunnlngthestudy．ThanksarealsDdueto more，10WermaSS−length ratio represents reduced re− Sidualyolkstoresand［owe「ene「gyreservesavailable therangersatMa’DaerahSanctuaryandtechnicaLstaff OftheTurtleand Marine Ecosystem Center（TUMEC）， fortheswimfrenzyperiod．Thedevelopmentofeggsin RantaL（Abang，lbrengganu． highdensityclutchescouldbea什ectedbyreducedgas Othe「groups（P＜0，1），
EckeTt，S．A．，1992．Boundfordeepwaters．NaturalHistory，46（11）；15−19・ Fowler，LE．，1979，Hatch柚gsuccessandnestpredationinthegreenseaturtlelCheloniamydas】atlbrtuguero・ Costa Rica，Ecology．60（5）：946−955．
