OnthebasisofthedataofoceanographicsurveyintheEastChinaSeainfourseasonsduring1997～2000(23°30′～33°00′N,118°30′～128°E),thevariationoftotalbiomassanddietbiomassofzooplanktonandtheirspatial-temporaldistributionandrelationshipwiththefishinggroundofEngraulisjaponicusareapproachedandanalyzed.Theresultsshowthattheaveragebiomassis65.32mg/m3infourseasons,autumn(86.18mg/m3)beinggreaterthansummer(69.18mg/m3)greaterthanspring(55.67mg/m3)greaterthanwinter(50.33mg/m3).Theaveragevalueofdietzooplanktonbiomassis40.9mg/m3.Thetrendsofhorizontaldistributionbothinthetotalbiomassandthedietbiomassofzooplanktonaresimilar.Thehighbiomassregion(250～500mg/m3)isverylimited,onlyaccountingfor1%oftheinvestigationarea.SeasonalvariationofthebiomassisveryremarkableinthewestandnorthpartsofEastChinaSeacoastalwaters(29°30′N,125°E).Thehorizontaldistributionofdietzooplanktondependsontheabundancedistributionofcrustacean.ThedistributionofdietzooplanktonisrelatedtothefishinggroundofEngraulisjaponicusandthehigh-densityareaofyoungfishandlarval.Inspring,thecentralfishinggroundofEngraulisjaponicus(＞100kg/h)andthehigh-densityareaofyoungfishandlarval(＞100inpidualspernet)arelocatedatthesameplaceofhigh-density(100～250mg/m3)areaofdietzooplanktoninthemiddle-southernpartofEastChinaSeaortheedgeofitswaters.
