Seasonal Shifts in Diet Composition of Great Cormorants Phalacrocorax carbo sinensis foraging at a Shallow Eutrophic Inland Lake

Ardea

Heinz Düttmann¹  Matthias Emmrich² 

[1] 2 Am Bleissmer 25, 31683 Obernkirchen, Germany;1 Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Department of Biology and Ecology of Fishes, Müggelseedamm 310, D-12587 Berlin, Germany

关键词: Biomass Removal;   

DOI  :  

学科分类：动物科学

来源: Nederlandse Ornithologische Unie/Netherlands Ornithological Union

【 摘 要 】

ThedietofGreatCormorantsPhalacrocoraxcarbosinensisatLakeDümmer,ashalloweutrophiclakeof1240hainLowerSaxony(Germany)wasanalysedbycollecting562regurgitatedpelletsoveraperiodofoneyear.Pelletscontainedstructuresof10,645fishesbelongingto15species.Substantialdifferenceswerefoundinfrequency,compositionandsizeofpreyfishspecies.Pikeperch,Ruffe,RoachandPerchaccountedforthelargestseasonaldifferencesinthediet.Duringlateautumnandwinterthedietwasdominatedbysmall-sizedcyprinidsandRuffe.InspringGreatCormorantsprimarilyforagedonlarger-sizedcyprinids.Young-of-the-yearpercids,dominatedbyPikeperch,weretheprimarypreyduringsummer.Weestimatedthatatleast32.6tons(26.3kg/ha)oftotalfishbiomasswasremovedbyCormorants,ofwhichonethird(10.8tons)consistedofPikeperch.81%ofthePikeperchbiomasswasremovedinAugust—September,indicatingthattheGreatCormorantisanimportantpredatorofjuvenilePikeperchatLakeDümmer.OurfindingshighlighttheneedofextensivedietanalysesinallseasonstoobtainacomprehensivepictureoftheimpactofCormorantpredationonfishstocks.Snapshotsofthedietsampledovershort-timeperiodsmaybemisleadingandinadequateforlocalmanagement.

【 授权许可】

Unknown