Weddell seal behaviour during an exceptional oceanographic event in the Filchner-Ronne Ice Shelf in 2017

Sara Labrousse (1) , Svenja Ryan (2) , Fabien Roquet (3) , Baptiste Picard (4) , Clive R. Mcmahon (5, 6) , Robert Harcourt (7, 8, 9) , Mark A. Hindell (10) , Hervé Le Goff (11) , Antonio Lourenço (11) , Yves David (12) , Jean-Baptiste Sallée (1) , Jean-Benoit Charrassin (1)

1 PROTEO - Processus et interactions de fine échelle océanique
2 WHOI - Woods Hole Oceanographic Institution
3 Department of Marine Sciences [Gothenburg]
4 CEBC - Centre d'Études Biologiques de Chizé - UMR 7372
5 IMOS Animal Tagging [New South Wales, Australia]
6 Macquarie University - Department of Biological Sciences [New South Wales, Australia]
7 IMAS - Institute for Marine and Antarctic Studies [Hobart]
8 AIMS - Australian Institute of Marine Science
9 Macquarie University [Sydney]
10 Institute for Marine and Antarctic Studies and Centre for Marine Socioecology
11 DITM - Développement Instrumental et Techniques Marines
12 TBM environnement

Rapid and regionally contrasting climate changes have been observed around Antarctica. However, our understanding of the impact of these changes on ecosystems remains limited, and there is an urgent need to better identify habitats of Antarctic species. The Weddell seal ( Leptonychotes weddellii ) is a circumpolar mesopredator and an indicative species of Antarctic marine communities. It has been extensively studied in the western Ross Sea and East Antarctica, and an understanding of its ecology in the Weddell Sea in the wintertime is emerging. We documented the behavioural response(s) of four Weddell seals from February to June in 2017 in the Filchner-Ronne Ice Shelf region and related these to unusual oceanographic conditions in 2017. Unexpectedly, we found that Weddell seals had the longest foraging effort within the outflow of Ice Shelf Water or at its turbulent boundary. They also foraged on the eastern side of the trough from April to June within the Modified Warm Deep Water and seem to take advantage of the unusual conditions of persistent inflow of warm waters through the winter. Linking animal behavioural responses to oceanographic conditions is informative for quantifying rarely recorded events and provides great insight into how predators may respond to changing conditions.

Mots clés: Antarctic predators; bio-telemetry; foraging behaviour; physical oceanography; spatial ecology; Weddell Sea

Domaines: Sciences de l'environnement; Planète et Univers [physics]

Sara Labrousse, Svenja Ryan, Fabien Roquet, Baptiste Picard, Clive R. Mcmahon, et al.. Weddell seal behaviour during an exceptional oceanographic event in the Filchner-Ronne Ice Shelf in 2017. Antarctic Science, 2021, 33 (3), pp.252-264. ⟨10.1017/S0954102021000092⟩. ⟨hal-03197794⟩