Foraging habitats of southern elephant seals, Mirounga leonina , from the Northern Antarctic Peninsula

• Published in: Deep Sea Research Part II: Topical Studies in Oceanography
• Main Authors: Muelbert, MMC, de Souza, RB, Lewis, MN, Hindell, MA
• Format: Article in Journal/Newspaper
• Language: English
• Published: Pergamon-Elsevier Science Ltd 2013
• Subjects: Biological Sciences; Ecology; Marine and Estuarine Ecology (incl. Marine Ichthyology); Antarctic; Antarctic Peninsula; Antarc*; Elephant Seals; Mirounga leonina; Southern Elephant Seals
• Online Access: https://doi.org/10.1016/j.dsr2.2012.07.009; http://ecite.utas.edu.au/89056

ElephantIsland(EI)isuniquelyplacedtoprovidesouthernelephantseals(SES)breedingtherewithpotentialaccesstoforaginggroundsintheWeddellSea,thefrontalzonesoftheSouthAtlanticOcean,the PatagonianshelfandtheWesternAntarcticPeninsula(WAP).QuantifyingwheresealsfromEI foragethereforeprovidesinsightsintothetypesofimportanthabitatsavailable,andwhichareofparticularimportancetoelephantseals.TwentynineSES(5sub-adultmalesSAM and24adultfemalesAF) wereequippedwithSMRUCTD-SLDRsduringthepost-breeding(PB2008,2009)andpost-moulting(PM2007,2008,2009,2010)tripstosea.Therewerestrikingintra-annualandinter-sexdifferencesinforagingareas,withmostofthePBfemalesremainingwithin150kmofEI.OnePBAFtravelleddowntheWAPasdid16outofthe20PMfemalesandforagednearthewinterice-edge.MostPM sub-adultmalesremainedclosetoEI,inareassimilartothoseusedbyadultfemalesseveralmonthsearlier, althoughoneSAMspenttheearlypartofthewinterforagingonthePatagonianShelf.ThewatersoftheNorthernAntarcticPeninsula(NAP)containabundantresourcestosupportthemajorityof theIslandsSESforthesummerandearlywinter,suchthattheanimalsfromthispopulationhaveshortermigrationsthanthosefrommostotherpopulations.Sub-adultmalesandPBfemalesarecertainlytakingadvantageoftheseresources.However,PMfemalesdidnotremainthereoverthewintermonths,insteadtheyusedthesamewatersattheice-edgeinthesouthernWAPthatfemalesfrom bothKingGeorgeIslandandSouthGeorgiaused.Femalesmademorebenthicdivesthansub-adultmalesagain thiscontrastswithothersiteswhereSAMsdomorebenthicdiving.Unlikemostother populationsstudiedtodateEIisarelativelysoutherlybreedingcolonylocatedontheAntarcticcontinentalshelf.EIsealsareusingshelfhabitatsmorethanotherSESpopulationsbutsomeindividualsstill employopenwaterforagingstrategies.Sea-icewasalsoveryinfluentialforPMfemaleswithmoreforagingoccurringinheavierpack-ice.Largerfemalesusedareaswithheavierice-concentrationthansmallerfemales.Thestudydemonstratestheimportanceofshelfandslopehabitattoelephantseals,but alsohighlightedtheinfluenceofsea-iceandfine-scalebathymetryandlocaloceanconditionindeterminingforaginghabitat.