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Estimating diet composition from scat analysis in otariid seals (Otariidae): is it reliable?

1988Journal article Open access
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dc.contributor.authorDellinger, T.
dc.contributor.authorTrillmich, F.
dc.date.accessioned2021-05-24T11:04:50Z
dc.date.available2021-05-24T11:04:50Z
dc.date.issued1988
dc.description.abstractAnalysis of teleost sagittal otoliths contained in scats has been widely used to determine the diet of seals. This method is based on the assumption that relative frequencies of otoliths in scats faithfully reflect those of fish in the diet. This assumption has rarely been tested experimentally. We compared the ratios of herring (Clupea harengus) to sprat (Sprattus sprattus) oto liths in faeces (output) of captive California sea lions (Zalophus calijornianus) and South American fur seals (Arctocephalus australis) with the ratios at feeding (input). Sea lions and fur seals showed no consistent differences in recovery rates and partial digestion of otoliths. Output ratios deviated only slightly from input ratios, the smaller sprat otoliths being underrepre sented in the output by 8%. Only about 40% of the otoliths fed to the seals were found in the scats. For both species partial digestion of otoliths led to a 16% underestimation of fish length and a 35% underestimation of fish mass.pt_PT
dc.description.abstractL'analyse des otolithes de tClCostCens contenus dans les fkces est une mCthode trks rCpandue de dktermination du rCgime alimentaire des phoques. Cette mCthode suppose que les frCquences relatives d'otolithes dans les fkces reflktent fidklement les frkquences relatives des poissons dans le rCgime. Cette prCmisse n'a pratiquement jamais fait l'objet de ~Crifications expkrimentales. Nous avons mesurC la proportion d'otolithes de harengs (Clupea harengus) et celle d'otolithes de sprats (Sprattus sprattus) dans les fkces (sortie) de Lions de mer californiens, Zalophus calijiornianus, et d'otaries a fourrure sud amkricaines, Arctocephalus australis, gardCs en captivitC, et comparC ces mesures aux proportions d'otolithes ingCrCs (entrCe). I1 n'y avait pas de diffkrence constante entre lions de mer et otaries et les taux de rCcupCration et de digestion partielle d'otolithes Ctaient les memes chez les deux espkces. Les proportions a la sortie diffkraient seulement un peu des proportions a I'entrCe et les otolithes des sprats, plus petits, Ctaient sous-reprCsentCs de 8% a la sortie. Seulement 40% environ des oto lithes ingCrCs ont CtC retrouvks a la sortie. La digestion partielle des otolithes chez les deux espkces entraine une sous-estima tion de la longueur des poissons consommCs, de I'ordre de 16%, et de la masse des poissons consommCs, de l'ordre de 35%.pt_PT
dc.description.versioninfo:eu-repo/semantics/publishedVersionpt_PT
dc.identifier.citationDellinger, T., & Trillmich, F. (1988). Estimating diet composition from scat analysis in otariid seals (Otariidae): is it reliable?. Canadian Journal of Zoology, 66(8), 1865-1870.pt_PT
dc.identifier.doi10.1139/z88-269pt_PT
dc.identifier.urihttp://hdl.handle.net/10400.13/3425
dc.language.isoengpt_PT
dc.peerreviewedyespt_PT
dc.publisherNRC Research Press (Canadian Science Publishing)pt_PT
dc.rights.urihttp://creativecommons.org/licenses/by/4.0/pt_PT
dc.subjectOtariid seals (Otariidae)pt_PT
dc.subjectDiet compositionpt_PT
dc.subjectScat analysispt_PT
dc.subject.pt_PT
dc.subjectFaculdade de Ciências da Vidapt_PT
dc.titleEstimating diet composition from scat analysis in otariid seals (Otariidae): is it reliable?pt_PT
dc.typejournal article
dspace.entity.typePublication
oaire.citation.endPage1870pt_PT
oaire.citation.issue8pt_PT
oaire.citation.startPage1865pt_PT
oaire.citation.titleCanadian Journal of Zoologypt_PT
oaire.citation.volume66pt_PT
person.familyNameDellinger
person.givenNameThomas
person.identifier.ciencia-idD21E-BADC-7807
person.identifier.orcid0000-0002-2424-8620
person.identifier.scopus-author-id7003679889
rcaap.rightsopenAccesspt_PT
rcaap.typearticlept_PT
relation.isAuthorOfPublication3bf4a068-5b47-46f6-becb-79eabbb56f11
relation.isAuthorOfPublication.latestForDiscovery3bf4a068-5b47-46f6-becb-79eabbb56f11

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