孵育温度对锯缘青蟹幼体质量的影响

2210200210ACTAECOLOGICASINICAVol.22,No.10Oct.,2002,,(,,361005)::2001206201;:2001211201:(1966),,,,,Email:[e-mail]:1(Z1)(DW)(EC,Jömg).:,(E,Jöind);,2,,,;12,2,(DWE)01746,,(DWE)1:;;;;EffectofBroodingTemperatureonLarvalQualityofMudCrabScyllaserrataZHUXiao2Ming,LIShao2Jing,JINJian2Feng(DepartmentofOceanography&InstituteofSubtropicalOceanography,XiamenUniversity,Xiamen361005,China).ActaEcologicaSinica,2002,22(10):16291634.Abstract:MudcrabScyllaserratafarminghasbeengoingonforatleastthreedecadesinsouthChina,es2peciallyinrecentdecade,butithasnotreachedevenitsoptimumpotential.Themajorconstraintforfur2therexpansionofmudcrabcultureisthelimitedsupplyofcrabseed’.Mudcrabculturestilldependsonwild2caughtcrablets,butitsquantitiesarenotsufficienttomeetdemandevenatthecurrentsizeofmudcrabculturefarming.Thereisagreatneedtodevelopahatcherytechnologyforthemassproductionofseedtomeetthede2mandsofmudcrabfarming.Mudcrabcultureresearch,particularlylarvalrearing,hasbeenconductedatDepartmentofOceanography,XiamenUniversityovertenyears.Ithasbeenobviousthatproductionofeggsandnewlyhatchedlarvaeisnotanissueaffectingthehatcherysuccessofmudcrab.Maturefemalebroodstockanditscultivationisonekeyofsuccessfullarvalrearing.Qualityofnewlyhatchedlarvaeortheirinherentviabilityisregardedasamainissueinfluencingthesuccessofhatcheryproduction.Thenu2tritionforbroodstockwasshownaconsiderableeffectongonadgrowthandfecundity,hatchingandlarvalquality.Butlittleisknownofecologicalfactorssuchastemperature,light,salinity,bottomsubstrates,etc.thatinfluencelarvalquality.Ifreadilymeasuredcriteriacouldbeusedtopredictthesubsequentper2formanceoflarvae,itwouldimprovetheconsistencyofproductionandreducetheresourcesexpendedonlarvaeofinadequateviability.Theobjectiveofthisinvestigationis,firstly,todeterminetheeffectofbroodingtemperatureondryweightandenergyofnewly2hatchedzoea21ofScyllaserrata,andonlarvalsurvivalanddevelopment,andsecondlytoformulateacriteriathatcanbeusedasajudgementofnewlyhatchedlarvalquality.Dry©1994-2006ChinaAcademicJournalElectronicPublishingHouse.Allrightsreserved.(undernormalrearingconditions)fromthedifferentbatcheswereob2served.Maturefemalewerecollectedfromcoastalwaterorshrimppond.Thebroodstocktank(61542m3)iswithsand2coveredbottomandflowthroughseawater.Thetankismaintainedunderlowlightcondi2tionsandtemperatureis25to32,salinityrangesbetween2510-12and3210-12.Thestockingdensityis23crabsöm2.Thebroodstockarefedtwiceoneday,ineveningandinmorning.Thedietisconsistedofcrustaceans,molluscsandfish.Followingovulationthecrabswereremovedfrombroodstocktankandmaintainedindividuallyin1000dm3tankswithfreshseawaterandnodiet.Afterhatching,larvaearecollectedfordryweightandenergycontentmeasurementandestimatesofunhatchedeggs,prezoea,deadzoeaaremade.Thelivezoeaistransferredtorearingtankandthestockingdensitiesofthelarvaeareabout200ödm3.Seawaterissettled,filtered,andformedgreenwaterbyaddingunicellalgae(104cellsöcm3).Thetankismaintainedunderlowlightconditionsatzoealstageandtemperatureis25to32.Salinityrangesbetween2510-12and3210-12.Zoea21toZoea22isfedwithrotifers(Brachionusplicatilis),Zoea23andfollowingstagelarvaeisfedwithArtemianauplii.Nutritivevalue,especiallyforhighlyunsaturatedfattyacid(HUFA)ofrotifersandArtemianaupliicouldbeelevatedthroughnutritionalenrichment.Theembryonicdevelopmentofmudcrabisexpeditedwithbroodingtemperaturerising,embryonicde2velopmentaltimeisshortunderhighbroodingtemperature.Andtherearenospecificrelationsbetweendryweight(DW),orenergycontent(EC,Jömg)ofnewly2hatchedzoea21andbroodingtemperature.Buteffectsofthedailydifferenceintemperatureduringembryonicdevelopmentondryweight,energy(E,Jöind)ofnewly2hatchedzoea21areobviously,andlarvalsurvivalanddevelopmentareaffectedsubse2quently.Whenthedailydifferenceinbroodingtemperature2,threephenomenonwilldetected.First,mudcrabembryonicdevelopmentorhatchingisirregular,theproportionofprozoeaanddiedeggproduc2tionishigher.second,thenewlyhatchedzoea21couldnotexuviatetozoea22.Third,theenergycontentofnewlyhatchedzoea21islowerthan0.10Jöind.Thenewlyhatchedzoea21whichdryweightislower(6.0Lgöind)andenergycontentishigh(25Jömg)ofmudcrabcouldnotexuviatetozoea22whenbrood2ingtemperature(30)andthedailydifferenceinbroodingtemperature(2)ishighduringsomedayofbroodingtime.Theresomeexceptionsthatthenewlyhatchedzoea21whichdryweightandenergycontentislowercouldnotexuviatetozoea22whenbroodingtemperatureisnormal,thismayberelatedwithqualityofberriedfemalemudcrab.Therearethreecharactersofabnormalorpoorqualitynewlyhatchedzoea21ofmudcrab:(1)Dryweightislowandenergycontentishigh.(2)Energyandenergycontentisalsolow.(3)Dryweightandenergyisalsolow.Therearenocertainrelationsbetweendryweightorenergyofnewly2hatchedzoea21anddifferenceinbroodingtemperature.Buttheprobabilityof(DWE)0.75ofnewly2hatchedzoea21increasessignificantlywhenthedaily