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Migratory strategies of juvenile northern fur seals (Callorhinus ursinus): bridging the gap between pups and adults

Citation

Zeppelin, T and Pelland, N and Sterling, J and Brost, B and Melin, S and Johnson, D and Lea, M-A and Ream, R, Migratory strategies of juvenile northern fur seals (Callorhinus ursinus): bridging the gap between pups and adults, Scientific Reports, 9 Article 13921. ISSN 2045-2322 (2019) [Refereed Article]


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© The Author(s) 2019. This article is licensed under a Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/), which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

DOI: doi:10.1038/s41598-019-50230-z

Abstract

In species exhibiting differential migration by sex and age, understanding what differences exist, and the adaptive reasons for these differences is critical for determining how demographic groups will respond to environmental variability and anthropogenic perturbations. We used satellite-telemetered movement and diving data to investigate differential migration and its ontogeny in a highly migratory North Pacific Ocean predator, the northern fur seal (Callorhinus ursinus; NFS), with a focus on understudied juvenile (1- to 2-year-old) animals. We instrumented 71 juvenile NFS in two years (2006–07 and 2007–08) at three major North American breeding sites and compared their migratory strategies with pups and adults. Although sexual dimorphism is strong in adult NFS, only weak differences in body mass between sexes were found in juveniles, which had similar body mass to pups (~3–4 months). However, unlike widely-dispersed pups, juvenile male and female NFS dispersed in different directions, and used different habitats characterized by distinct hydrography and prey assemblages during migration, similar to breeding adults. Juvenile diving behavior differed only modestly among habitats and between sexes, consistent with weak differences in body mass. Evidence of habitat sexual segregation by juvenile NFS contradicts previous hypotheses that physiological differences predominantly drive the ontogeny of differential migration.

Item Details

Item Type:Refereed Article
Keywords:pinniped, migration, strategies, juvenile
Research Division:Biological Sciences
Research Group:Ecology
Research Field:Behavioural Ecology
Objective Division:Environment
Objective Group:Flora, Fauna and Biodiversity
Objective Field:Marine Flora, Fauna and Biodiversity
UTAS Author:Lea, M-A (Associate Professor Mary-Anne Lea)
ID Code:135119
Year Published:2019
Deposited By:Ecology and Biodiversity
Deposited On:2019-10-01
Last Modified:2020-01-07
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