Résumé
Using a combinationofdiverselargepredatoryfishesandoneseabird,wecollectedinformationonthe cephalopodfaunaofthewesternIndianOcean.Weanalyzedthestomachcontentsof35fishes representingtenfamilies(Xiphiidae,Istiophoridae,Scombridae,Carangidae,Coryphaenidae,Alepisaur- idae,Dasyatidae,Carcharhinidae,AlopiidaeandSphyrnidae)andofthesootytern Onychoprionfuscata of theMozambiqueChannelfrom2000to2010.Bothfreshandaccumulatedbeakswereusedfor identifyingcephalopodprey.Cephalopodswereimportantpreyfortwelvepredators;swordfish Xiphias gladius had thehighestcephalopodproportion;sootytern(O. fuscata) andbigeyetuna(Thunnusobesus) had highproportionstoo.Werecovered23cephalopodfamiliesandidentified38species.Tenspecies fromfourTeuthidafamilies(Ommastrephidae,Onychoteuthidae,HistioteuthidaeandAncistrocheiridae) andtwoOctopodafamilies(ArgonautidaeandBolitaenidae)occurredveryfrequentlyinthestomach contents,whileSepiidawererare.Ommastrephidaewerethemostcephalopodfoodsources:the purplebackflyingsquid Sthenoteuthisoualaniensis was themostprevalentpreybyfar, Ornithoteuthis volatilis was importantforelevenpredatorsandfewbutlargespecimensoftheneonflyingsquid Ommastrephesbartramii wererecoveredinthestomachsofswordfishintheIndianSouthSubtropical Gyreprovinceonly.Predators'groupswereidentifiedbasedoncephalopodpreycomposition,ondepthin whichtheyforage,andonpreysize.Surfacepredators'dietswerecharacterizedbylowercephalopod diversitybutgreateraveragenumbersofcephalopodprey,whereasthedeep-dwellingpredators (swordfishandbigeyetuna)preyedonlargerspecimensthansurfacepredators(O. fuscata or yellowfin tunas Thunnusalbacares). Ourfindingsemphasizedtheusefulnessofacommunityofmarinepredatorsto gainvaluableinformationonthebiologyandthedistributionofthecephalopodforagefaunathatare discussedwithregardtobiogeographicprovince,marinepredator,fishinggeartocatchthelargepelagic fishes,andsizeofthebeaksrecoveredinthestomachs.