The Diet of the White-Breasted Cormorant Phalacrocorax carbo lucidus Along the Atlantic Coast of West Africa

[摘要] TheWhite-breastedCormorantPhalacrocoraxcarbolucidusoccursinCentral,West,EastandSouthAfrica.TheWestAfricanpopulationbreedsontheCapeVerdeIslandsandalongtheAtlanticcoastfromMauritaniatoGuinea.Thespeciesforagesinmarine,brackishandfreshwatersandisthoughttobe(almost)completelypiscivorous.However,dataondietarepoorlyavailableandcompletelylackingfortheWestAfricanpopulation.Wecollectedregurgitatedpelletsatthreesites,inMauritania(IslandofZira,Bancd'Arguin)andSenegal(IlotauxOiseaux,asmallisletintheestuaryoftheSenegalRiverandIledelaMadeleinenearDakar).Onthebasisofotoliths,34fishspeciesbelongingto21familieswereidentified.Therewasgreatvariationinthedietofthecormorantsatthedifferentsites,withHaemulidaeandBatrachoididaebeingdominantonIledelaMadeleine,AriidaeandCynoglossidaeonIlotauxOiseauxandSparidae,MugilidaeandBatrachoididaeontheIslandofZira.Mostfishconsumedwerecoastalspecies,manyofwhichmayalsoenterbrackishorfreshwaters.Thecormorantsmainlyatebenthicandbentho-pelagicfishspeciesvaryinginsizebetween10and20cm.TherewasgreatvariationinthenumberofotolithsperpelletatthedifferentsiteswitharemarkablysmallnumberintheZirasample.Weinvestigatedwhetherasmallnumberofotolithsperpelletcanbeexplainedbythepreyfishbeinglargerorbytheotolithsbeingmoreeroded.Thelattermightbeanindicationthatpartoftheotolithshadbeentotallydissolvedandthusdisappearedfromthesamples.NeitherfishsizenorextentofwearcouldexplainthesmallnumberofotolithsintheZirasample.AcomparisonbetweenartisanalfisheriescatchesandthedietofthecormorantsshowedhardlyanyoverlapfortheSenegalesesites.However,substantialoverlapwasfoundattheBancd'ArguininMauritania.ThesedifferencescanbeexplainedbythehighproportionofpelagicspeciescaughtintheSenegalesesites.

[学科分类] 动物科学

[关键词] West African Coast