Beneath the Antarctic sea‐ice: Fine‐scale analysis of Weddell seal (Leptonychotes weddellii) behavior and predator–prey interactions, using micro‐sonar data in Terre Adélie

• Published in: Ecology and Evolution
• Main Authors: Antoine, Adélie, Labrousse, Sara, Goulet, Pauline, Chevallay, Mathilde, Laborie, Joris, Picard, Baptiste, Guinet, Christophe, Nerini, David, Charrassin, Jean-Benoit, Heerah, Karine
• Other Authors: 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)-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)-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)), 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)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), 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), Aarhus University Aarhus, Bretagne Vivante, Institut méditerranéen d'océanologie (MIO), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), France Energies Marines Brest, - Institut Polaire Français Paul Emile Victor, programme 1182 ASSET- Fondation BNP-Paribas, projet “Sentinel of the Sea-Ice Environment”- Centre national d'Etudes Spatiales CNES-TOSCA, programme “Weddell seals bio-oceanographers of the Antarctic sea-ice” - Groupe de recherche Océans et mer OMER (CNRS), bourse de thèse- Marie Sklodowska Curie fellowship, project 792042 – FEAST – H2020-MSCA-IF-2017
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2023
• Subjects: Weddell seal; bio-logging; foraging behaviour; sonar tags; diving; predator-prey interaction; [SDE]Environmental Sciences; [SDV]Life Sciences [q-bio]; Antarc*; Antarctic; Antarctica; East Antarctica; Sea ice; Weddell Seal; Weddell Seals
• Online Access: https://hal.sorbonne-universite.fr/hal-04350779; https://hal.sorbonne-universite.fr/hal-04350779/document; https://hal.sorbonne-universite.fr/hal-04350779/file/ecolevol_2023_10.1002ece3.10796.pdf; https://doi.org/10.1002/ece3.10796

International audience Lactation is the most energy-demanding event in mammals’ reproduction. In pinnipeds, females are the only food providers to the young and have developed numerous behavioural and physiological lactation strategies, from capital-breeding to income-breeding. Lactating females’ fine-scale foraging strategy, and precise understanding of how females supplement their pup’s needs as well as their own are important to understand the species’ ecology and energetic balance. Polar pinnipeds, inhabiting extreme environments, are sensitive to climate change and variability, understanding their constraints and foraging strategy during lactation is therefore important. In 2019, three sonar tags were deployed on lactating Weddell seals in Terre Adélie (East Antarctica) for seven days, to study fine-scale predator-prey interactions. Feeding activity was mostly benthic, reduced, central-placed and spatially limited. Females spent most of their time hauled-out. A total of 331 prey capture attempts (PrCAs) were recorded using tri-axial acceleration data, with 125 prey identified on echograms (5 cm, acoustic size). All PrCAs occurred on the seafloor, shallower than usual records (mean depth of 88 m, versus 280 m after their molt). We also found that they only fed in three of the five identified dive shapes, during the ascent or throughout the dive. Half of the prey were reactive to the seal’s approach, either leaving the seafloor, or escaping just above the seafloor, suggesting that the seals hunt by chasing them from the seabed. Seals continuously scanned the area during the approach phase, evoking opportunistic foraging. Our results provide additional evidence that Weddell seal forage during lactation, displaying a mix of capital-breeding and income-breeding strategies during this period of physiological stress. This work sheds light on previously unexplored aspects of their foraging behaviour, such as shallow water environments, targeting benthic prey, generally focusing on single prey rather than schools, ...