Prey targeted by lactating Weddell seals (Leptonychotes weddellii) in Erebus Bay, Antarctica

Female Weddell seals (Leptonychotes weddellii) display a mixed capital-income breeding strategy, losing up to 40% of their body mass between birthing and weaning their pups. How and when they regain energy stores, however, remains to be fully explored. To better understand the foraging by lactating...

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Bibliographic Details
Published in:Polar Biology
Main Authors: Foster-Dyer, Rose TN, Goetz, Kimberly T, Iwata, Takashi, Holser, Rachel R, Michael, Sarah A, Pritchard, Craig, Childerhouse, Simon, Costa, Daniel P, Ainley, David G, Pinkerton, Matthew H, LaRue, Michelle A
Format: Article in Journal/Newspaper
Language:unknown
Published: eScholarship, University of California 2024
Subjects:
Zoology
Biological Sciences
Antarctica
Animal-borne video
Bio-logging
Foraging behaviour
Leptonychotes weddellii
Ross sea
Weddell seal
Marine Biology & Hydrobiology
Antarc*
Antarctic
Antarctic silverfish
Antarctic Toothfish
Ross Sea
Weddell Seal
Weddell Seals
Online Access:https://escholarship.org/uc/item/5xj92486
https://doi.org/10.1007/s00300-024-03294-1
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Summary:Female Weddell seals (Leptonychotes weddellii) display a mixed capital-income breeding strategy, losing up to 40% of their body mass between birthing and weaning their pups. How and when they regain energy stores, however, remains to be fully explored. To better understand the foraging by lactating Weddell seals, we fitted time-depth recorders and head-mounted cameras on 26 seals in Erebus Bay, Ross Sea, for ~ 5days in November and December 2018 and 2019. We aimed to (1) identify prey species and foraging depth and (2) investigate relationships between seal physiology and demographics and probability of foraging. We recorded 2782 dives, 903 of which were > 50m, maximum depth was 449.3m and maximum duration was 31.1min. Pup age likely contributes to the probability of a lactating Weddell seal foraging (Est. = 1.21 (SD = 0.61), z = 1.97, p = 0.0484). Among 846 prey encounters, the most frequent prey items were crustaceans (46.2%) and Antarctic silverfish (Pleuragramma antarcticum, 19.0%); two encounters were observed with juvenile Antarctic toothfish (Dissostichus mawsoni, 0.2%). We identified substantial variability in foraging behaviour, individually and between locations, and found that lactating seals target many species and some may specialise on certain prey groups.

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