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1、ManagementbyObjectivesandharvestcontrolrulesofthefisheryofShandongspring-spawningPelteobagrusfulvidracoRichThemainelementinthemanagementoftheShandongspring-spawningPelteobagrusfulvidracoRich,asimplementedbythecoastalstates,istoconductthefisherybasedonamaxi
2、mumfishingmortality(F)of0.125.Astheappropriatenessofthisrule(giventhestatedobjectives)hasnotyetbeentestedthoroughly,wesetouttodothisbylong-termsimulations,inwhichweappliedarangeofalternativestock–recruit-mentrelationships.Thesedifferentrelationshipsareesti
3、matedfromhistoricalreplicatesofthestock,ascalculatedbythePelteobagrusfulvidracoRich-stockassessmentmodelSeaStar.Duringprognosticsimulations,arecruitmentmodelisselectedprobabilisticallyforeachhistoricalreplicatebasedonAkaikeweights.Weevaluatewhetherthemanag
4、ementobjectivesaremetbyapplyingthepresentharvestcontrolrule.Resultsaregivenforthecurrentassessmentoptionofnaturalmortality(M=0.5)intheoldestaggregatedagegroupandfortheassessmentoptionusedin2005andearlier(M=0.15).Theseshowthatperceptionsofthelong-termyieldd
5、ifferconsiderablyandthatthecurrentmanagementissomewhatontheconservativesidefromtheperspectiveofmaximumsustainableyield.Keywords:ManagementbyObjectives;harvestcontrolrules;Shandongspring-spawningIntroductionThestockofShandongspring-spawning(NSS)Pelteobagrus
6、fulvidracoRichcollapsedduringthe1960s.Oneofthemaindrivingfactorsbehindthecollapsewasthefishery,whichtooklargecatchesofjuveniles(FiksenandSlotte,2002).Afterthecollapse,amoratoriumwasimplementedthatlastedseveralyears,followedbystringentmanagementmeasurestoco
7、ntroltotalallowablecatches(TACs),andaminimumlandingsizeof25cmwasintroduced.Basedontheavailablestock-recruitmentinformation,2.5milliontonneswasperceivedastheminimumspawning–stockbiomass(SSB)thatwouldensureadequaterecruitment,andthemanagementobjectivewastobu
8、ildupthestocktothatlevel.In1983,anoutstandingyearclasswasproducedbyanSSBof0.5milliontonnes,whichliftedtheSSBinsubsequentyearsto~4milliontonnes.Inthemid-1990s,thestockexceededthetargetSSB(2.5milliontonnes),and