Long-term species, sexual and individual variations in foraging strategies of fur seals revealed by stable isotopes in whiskers.

<h4>Background</h4>Individual variations in the use of the species niche are an important component of diversity in trophic interactions. A challenge in testing consistency of individual foraging strategy is the repeated collection of information on the same individuals.<h4>Methodo...

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Autores principales:	Laëtitia Kernaléguen, Bernard Cazelles, John P Y Arnould, Pierre Richard, Christophe Guinet, Yves Cherel
Formato:	article
Lenguaje:	EN
Publicado:	Public Library of Science (PLoS) 2012
Materias:	Medicine R Science Q
Acceso en línea:	https://doaj.org/article/e31498cfa6944e21b1e357b31777e864
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spelling	oai:doaj.org-article:e31498cfa6944e21b1e357b31777e8642021-11-18T07:25:13ZLong-term species, sexual and individual variations in foraging strategies of fur seals revealed by stable isotopes in whiskers.1932-620310.1371/journal.pone.0032916https://doaj.org/article/e31498cfa6944e21b1e357b31777e8642012-01-01T00:00:00Zhttps://www.ncbi.nlm.nih.gov/pmc/articles/pmid/22431988/pdf/?tool=EBIhttps://doaj.org/toc/1932-6203<h4>Background</h4>Individual variations in the use of the species niche are an important component of diversity in trophic interactions. A challenge in testing consistency of individual foraging strategy is the repeated collection of information on the same individuals.<h4>Methodology/principal findings</h4>The foraging strategies of sympatric fur seals (Arctocephalus gazella and A. tropicalis) were examined using the stable isotope signature of serially sampled whiskers. Most whiskers exhibited synchronous δ(13)C and δ(15)N oscillations that correspond to the seal annual movements over the long term (up to 8 years). δ(13)C and δ(15)N values were spread over large ranges, with differences between species, sexes and individuals. The main segregating mechanism operates at the spatial scale. Most seals favored foraging in subantarctic waters (where the Crozet Islands are located) where they fed on myctophids. However, A. gazella dispersed in the Antarctic Zone and A. tropicalis more in the subtropics. Gender differences in annual time budget shape the seal movements. Males that do not perform any parental care exhibited large isotopic oscillations reflecting broad annual migrations, while isotopic values of females confined to a limited foraging range during lactation exhibited smaller changes. Limited inter-individual isotopic variations occurred in female seals and in male A. tropicalis. In contrast, male A. gazella showed large inter-individual variations, with some males migrating repeatedly to high-Antarctic waters where they fed on krill, thus meaning that individual specialization occurred over years.<h4>Conclusions/significance</h4>Whisker isotopic signature yields unique long-term information on individual behaviour that integrates the spatial, trophic and temporal dimensions of the ecological niche. The method allows depicting the entire realized niche of the species, including some of its less well-known components such as age-, sex-, individual- and migration-related changes. It highlights intrapopulation heterogeneity in foraging strategies that could have important implications for likely demographic responses to environmental variability.Laëtitia KernaléguenBernard CazellesJohn P Y ArnouldPierre RichardChristophe GuinetYves CherelPublic Library of Science (PLoS)articleMedicineRScienceQENPLoS ONE, Vol 7, Iss 3, p e32916 (2012)
institution	DOAJ
collection	DOAJ
language	EN
topic	Medicine R Science Q
spellingShingle	Medicine R Science Q Laëtitia Kernaléguen Bernard Cazelles John P Y Arnould Pierre Richard Christophe Guinet Yves Cherel Long-term species, sexual and individual variations in foraging strategies of fur seals revealed by stable isotopes in whiskers.
description	<h4>Background</h4>Individual variations in the use of the species niche are an important component of diversity in trophic interactions. A challenge in testing consistency of individual foraging strategy is the repeated collection of information on the same individuals.<h4>Methodology/principal findings</h4>The foraging strategies of sympatric fur seals (Arctocephalus gazella and A. tropicalis) were examined using the stable isotope signature of serially sampled whiskers. Most whiskers exhibited synchronous δ(13)C and δ(15)N oscillations that correspond to the seal annual movements over the long term (up to 8 years). δ(13)C and δ(15)N values were spread over large ranges, with differences between species, sexes and individuals. The main segregating mechanism operates at the spatial scale. Most seals favored foraging in subantarctic waters (where the Crozet Islands are located) where they fed on myctophids. However, A. gazella dispersed in the Antarctic Zone and A. tropicalis more in the subtropics. Gender differences in annual time budget shape the seal movements. Males that do not perform any parental care exhibited large isotopic oscillations reflecting broad annual migrations, while isotopic values of females confined to a limited foraging range during lactation exhibited smaller changes. Limited inter-individual isotopic variations occurred in female seals and in male A. tropicalis. In contrast, male A. gazella showed large inter-individual variations, with some males migrating repeatedly to high-Antarctic waters where they fed on krill, thus meaning that individual specialization occurred over years.<h4>Conclusions/significance</h4>Whisker isotopic signature yields unique long-term information on individual behaviour that integrates the spatial, trophic and temporal dimensions of the ecological niche. The method allows depicting the entire realized niche of the species, including some of its less well-known components such as age-, sex-, individual- and migration-related changes. It highlights intrapopulation heterogeneity in foraging strategies that could have important implications for likely demographic responses to environmental variability.
format	article
author	Laëtitia Kernaléguen Bernard Cazelles John P Y Arnould Pierre Richard Christophe Guinet Yves Cherel
author_facet	Laëtitia Kernaléguen Bernard Cazelles John P Y Arnould Pierre Richard Christophe Guinet Yves Cherel
author_sort	Laëtitia Kernaléguen
title	Long-term species, sexual and individual variations in foraging strategies of fur seals revealed by stable isotopes in whiskers.
title_short	Long-term species, sexual and individual variations in foraging strategies of fur seals revealed by stable isotopes in whiskers.
title_full	Long-term species, sexual and individual variations in foraging strategies of fur seals revealed by stable isotopes in whiskers.
title_fullStr	Long-term species, sexual and individual variations in foraging strategies of fur seals revealed by stable isotopes in whiskers.
title_full_unstemmed	Long-term species, sexual and individual variations in foraging strategies of fur seals revealed by stable isotopes in whiskers.
title_sort	long-term species, sexual and individual variations in foraging strategies of fur seals revealed by stable isotopes in whiskers.
publisher	Public Library of Science (PLoS)
publishDate	2012
url	https://doaj.org/article/e31498cfa6944e21b1e357b31777e864
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Long-term species, sexual and individual variations in foraging strategies of fur seals revealed by stable isotopes in whiskers.

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