Decadal changes in blood δ 13 C values, at-sea distribution, and weaning mass of southern elephant seals from Kerguelen Islands

• Published in: Proceedings of the Royal Society B: Biological Sciences
• Main Authors: Mestre, Julie, Authier, Matthieu, Cherel, Yves, Harcourt, Robert, McMahon, Clive, R, Hindell, Mark, Charrassin, Jean-Benoît, Guinet, Christophe
• Other Authors: Centre d'Études Biologiques de Chizé - UMR 7372 (CEBC), La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Observatoire pour la Conservation de la Mégafaune Marine (PELAGIS), LIttoral ENvironnement et Sociétés (LIENSs), La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS)-La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), LEB Aquitaine Transfert-ADERA, Macquarie University Sydney, Institute for Marine and Antarctic Studies Hobart (IMAS), University of Tasmania Hobart (UTAS), Processus et interactions de fine échelle océanique (PROTEO), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X), Institut Polytechnique de Paris (IP Paris)-Institut Polytechnique de Paris (IP Paris)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-École normale supérieure - Paris (ENS-PSL), Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X), Institut Polytechnique de Paris (IP Paris)-Institut Polytechnique de Paris (IP Paris)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Institut Polytechnique de Paris (IP Paris)-Institut Polytechnique de Paris (IP Paris)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), This study contributes to SENtinels of the SEa Ice program funded by the BNP Paribas Foundation. It benefited from a discussion held in the framework of the KER-TREND project supported by the French National program LEFE (Les Enveloppes Fluides et l'Environnement). The marine mammal data were sourced from the International MEOP Consortium and the national programs that contribute to it (http://meop.net), including the French National Observatory Mammals as samplers of the Ocean Environment (SNO-MEMO) data and the Integrated Marine Observing System (IMOS) for the Australian data. The French satellite tagging program was financially supported by the program Terre, Océan, Surfaces Continentales, Atmosphère (TOSCA) of the Centre National d'Etudes Spatiales - over the whole study period -, the Agence Nationale de la Recherche and the Total Foundation. IMOS is a national collaborative research infrastructure, supported by the Australian Government. It is operated by a consortium of institutions as an unincorporated joint venture, with the University of Tasmania as lead agent. We finally thank the Institut Polaire Français Paul Emile Victor (IPEV programs 109, H. Weimerskirch, and 1201, C. Gilbert) for providing logistical and financial support.
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2020
• Subjects: foraging habitat; stable isotopes; bio-logging; population strategies; decadal change; Indian sector of the Southern Ocean; [SDE]Environmental Sciences; Antarctic; Indian; Kerguelen; Kerguelen Islands; Southern Ocean; Antarc*; Elephant Seals; Southern Elephant Seals
• Online Access: https://hal.science/hal-02928065; https://hal.science/hal-02928065v1/document; https://hal.science/hal-02928065v1/file/mestre-et-al-2020-decadal-changes-in-blood-%CE%B413c-values-at-sea-distribution-and-weaning-mass-of-southern-elephant-seals.pdf; https://doi.org/10.1098/rspb.2020.1544

International audience Changes in the foraging environment and at-sea distribution of southern elephant seals from Kerguelen Islands were investigated over a decade (2004–2018) using tracking, weaning mass, and blood δ13C values. Females showed either a sub-Antarctic or an Antarctic foraging strategy, and no significant shift in their at-sea distribution was detected between 2004 and 2017. The proportion of females foraging in sub-Antarctic versus Antarctic habitats did not change over the 2006–2018 period. Pup weaning mass varied according to the foraging habitat of their mothers. The weaning mass of sub-Antarctic foraging mothers’ pups decreased by 11.7 kg over the study period, but they were on average 5.8 kg heavier than pups from Antarctic foraging mothers. Pup blood δ13C values decreased by 1.1‰ over the study period regardless of their sex and the presumed foraging habitat of their mothers. Together, these results suggest an ecological change is occurring within the Indian sector of the Southern Ocean with possible consequences on the foraging performance of southern elephant seals. We hypothesize that this shift in δ13C is related to a change in primary production and/or in the composition of phytoplankton communities, but this requires further multidisciplinary investigations.