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 lactatin...

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Bibliographic Details
Published in:Polar biology 2024-11, Vol.47 (11), p.1187-1202
Main Authors: Foster-Dyer, Rose T. N., 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
Language:English
Subjects:
Anesthesia
Aquatic crustaceans
Aquatic mammals
Behavior
Biology
Biomedical and Life Sciences
Body mass
Crustaceans
Demographics
Depth recorders
Ecology
Ecosystem biology
Females
Fisheries
Foraging
Foraging behavior
Juveniles
Ketamine
Leptonychotes weddellii
Life Sciences
Marine mammals
Microbiology
Oceanography
Physiology
Plant Sciences
Population
Predation
Prey
Seals
Seals (animals)
Video recorders
Weaning
Zoology
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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 ~ 5 days 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 > 50 m, maximum depth was 449.3 m and maximum duration was 31.1 min. 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.
ISSN:0722-4060
1432-2056
DOI:10.1007/s00300-024-03294-1