From warm to cold waters: new insights into the habitat and trophic ecology of Southern Oceansquids throughout their life cycle

• Published in: Marine Ecology Progress Series
• Main Authors: Queirós, José Pedro, Hilário, José Ana, Thompson, David, Ceia, Filipe R., Elliott, Graeme, Walker, Kath, Cherel, Yves, Xavier, Jose C
• Other Authors: Centre d'Études Biologiques de Chizé - UMR 7372 (CEBC), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2020
• Subjects: Ontogenetic changes; Antarctica; Cephalopods; Stable isotopes; Climate change; South Pacific; [SDE]Environmental Sciences; Southern Ocean; Pacific; Adams Island; Antarc*
• Online Access: https://hal.archives-ouvertes.fr/hal-03003260; https://doi.org/10.3354/meps13551

International audience Cephalopods play a major role in marine ecosystems, yet very little is known aboutthe dynamics of their habitat use and trophic ecology across the stages of their life cycle, particu-larly in the Southern Ocean. Here, we used stable isotope analyses of δ13C (a proxy for foraginghabitat) and δ15N (a proxy for trophic position) to investigate the habitat use and trophic eco logyof 10 squid species, collected from the diet of Antipodean (Diomedea antipodensis antipodensis)and Gibson’s (D. a. gibsoni)albatrosses breeding at Antipodes and Adams Island (South Pacific),respectively. We analyzed isotopes in 2 sections of squid lower beaks, representing 2 stages of thelife cycle: the tip of the rostrum (juvenile stage) and the wing (adult stage). Higher δ13C values inearly life stages (−20.8 ± 1.7 ‰) than in adult life stages (−21.6 ± 1.9 ‰) suggest that SouthernOcean squids tend to move southwards as they grow, with oceanic fronts being an important habi-tat for these species. Our results might indicate that adults may move southwards with climatechange, possibly impacting top predators living on northern islands. Overall, δ15N values revealedan increase in trophic position from early (6.7 ± 2.7 ‰) to adult life stages (9.0 ± 2.5 ‰) in all spe-cies. Nevertheless, significant differences between δ15N values of the 10 species, in both beak sec-tions, suggest different feeding strategies between species and life stages.