ThespatialandtemporalcharacteristicsoftrophicstructureoffishcommunitiesinthesouthernHuanghaiSeawereexaminedbasedonthedatasampledfrombottomtrawlsurveysconductedduringtheautumnof2000andthespringof2001.HierarchicalagglomerativeclustermethodandbootstraprandomizationwereusedtoidentifysignificanttrophicgroupsforeachfishassemblageinthesouthernHuanghaiSea.Atotalofsixmajortrophicgroupswereidentifiedwithinthissystem,whichclassifiedpredatorsbaseduponlocationinthewatercolumnorpreysize(i.e.,benthictopelagicpredatorsorfishtosmallinvertebratepreypredators).Thesimilaritylevelusedtoidentifysignificanttrophicgroupsineachassemblagerangedfrom24%to34%.Althoughplanktivoreswerethedominanttrophicgroupineachassemblage(60%~79%),therewerespatialandtemporalvariationsinthetrophicstructure,whichreflectedthedifferencesintheabundanceandavailabilityofdominantpreys.Simplifiedfoodwebswereconstructedtoevaluatethemostimportanttrophicrelationshipsbetweenthedominantpreytaxaandthefishesineachassemblagewithinthissystem.Althoughthereweresomedifferencesinthekeypreyspeciesamongdifferentfoodwebs,pelagicpreyitems(mainlyeuphausiidsandcopepods)representthemostimportantenergeticlinkbetweenprimaryproducersandhighertrophiclevelpredators.Thetrophiclevelformostfisheswasbetween3and4,andtheweightedmeantrophiclevelforeachassemblagerangedfrom3.3to3.4.Comparedwithpreviousstudyinthemid-1980s,therewasanobviousdownwardtrendinthetrophiclevelformostfishspecies,whichresultedmainlyfromthefluctuationinkeypreyspeciesintheHuanghaiSea.ThedecreaseintheimportanceofJapaneseanchovyseemstobeoffsetbyotherabundantpreyspeciessuchasEuphausiapacificaandcopepods(mainlyCalanussinicus).
