Seasonal habitat preference and foraging behaviour of post-moult Weddell seals in the western Ross Sea

Weddell seals (Leptonychotes weddellii) are important predators in the Southern Ocean and are among the best-studied pinnipeds on Earth, yet much still needs to be learned about their year-round movements and foraging behaviour. Using biologgers, we tagged 62 post-moult Weddell seals in McMurdo Soun...

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Bibliographic Details
Published in:Royal Society Open Science
Main Authors: Kimberly T. Goetz, Michael S. Dinniman, Luis A. Hückstädt, Patrick W. Robinson, Michelle R. Shero, Jennifer M. Burns, Eileen E. Hofmann, Sharon E. Stammerjohn, Elliott L. Hazen, David G. Ainley, Daniel P. Costa
Format: Article in Journal/Newspaper
Language:English
Published: The Royal Society 2023
Subjects:
Weddell seal
distribution
seasonal movement
habitat
foraging behaviour
Ross Sea
Science
Q
Southern Ocean
McMurdo Sound
Weddell
Weddell Seal
Weddell Seals
Online Access:https://doi.org/10.1098/rsos.220500
https://doaj.org/article/7ec7626a3c1d4dd2b0a594a320e72959
Description
Summary:Weddell seals (Leptonychotes weddellii) are important predators in the Southern Ocean and are among the best-studied pinnipeds on Earth, yet much still needs to be learned about their year-round movements and foraging behaviour. Using biologgers, we tagged 62 post-moult Weddell seals in McMurdo Sound and vicinity between 2010 and 2012. Generalized additive mixed models were used to (i) explain and predict the probability of seal presence and foraging behaviour from eight environmental variables, and (ii) examine foraging behaviour in relation to dive metrics. Foraging probability was highest in winter and lowest in summer, and foraging occurred mostly in the water column or just above the bottom; across all seasons, seals preferentially exploited the shallow banks and deeper troughs of the Ross Sea, the latter providing a pathway for Circumpolar Deep Water to flow onto the shelf. In addition, the probability of Weddell seal occurrence and foraging increased with increasing bathymetric slope and where water depth was typically less than 600 m. Although the probability of occurrence was higher closer to the shelf break, foraging was higher in areas closer to shore and over banks. This study highlights the importance of overwinter foraging for recouping body mass lost during the previous summer.

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