Foraging behavior of adult female and young-of-the-year Steller sea lions in Alaskan waters
One explanation for recent declines in the Alaskan Steller sea lion (Eumetopias jubatus) population is that the availability of preferred prey has changed. Part of our evaluation of this hypothesis involved the use of conventional radio and satellite-linked time–depth recorder transmitters to compar...
Published in: | Canadian Journal of Zoology |
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Language: | English |
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Canadian Science Publishing
1997
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Online Access: | http://dx.doi.org/10.1139/z97-099 http://www.nrcresearchpress.com/doi/pdf/10.1139/z97-099 |
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crcansciencepubl:10.1139/z97-099 2024-09-15T17:59:36+00:00 Foraging behavior of adult female and young-of-the-year Steller sea lions in Alaskan waters Merrick, Richard L. Loughlin, Thomas R. 1997 http://dx.doi.org/10.1139/z97-099 http://www.nrcresearchpress.com/doi/pdf/10.1139/z97-099 en eng Canadian Science Publishing http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining Canadian Journal of Zoology volume 75, issue 5, page 776-786 ISSN 0008-4301 1480-3283 journal-article 1997 crcansciencepubl https://doi.org/10.1139/z97-099 2024-06-27T04:11:02Z One explanation for recent declines in the Alaskan Steller sea lion (Eumetopias jubatus) population is that the availability of preferred prey has changed. Part of our evaluation of this hypothesis involved the use of conventional radio and satellite-linked time–depth recorder transmitters to compare summer and winter foraging of adult female and young-of-the-year Steller sea lions in Alaska waters. Foraging effort was not significantly different seasonally for postpartum adult females, though females with dependent young in winter may increase their foraging effort. In winter, all adult females made longer trips over larger home ranges and dove deeper. Young sea lions exerted less foraging effort, had the shallowest and briefest dives, and had home ranges intermediate in size to the two groups of adult females. Their foraging ability appears to develop throughout the first year. We conclude that adult female sea lions can exploit prey throughout the Gulf of Alaska and Bering Sea, and are constrained only by their reproductive status and seasonal changes in prey availability. Young sea lions' diving is more limited because their physiological and behavioral development constrains them from diving like an adult. Perhaps most important, dives remain shallow through the first year. Consequently, young sea lions could be more easily food-limited by changes in prey distribution. Article in Journal/Newspaper Bering Sea Alaska Canadian Science Publishing Canadian Journal of Zoology 75 5 776 786 |
institution |
Open Polar |
collection |
Canadian Science Publishing |
op_collection_id |
crcansciencepubl |
language |
English |
description |
One explanation for recent declines in the Alaskan Steller sea lion (Eumetopias jubatus) population is that the availability of preferred prey has changed. Part of our evaluation of this hypothesis involved the use of conventional radio and satellite-linked time–depth recorder transmitters to compare summer and winter foraging of adult female and young-of-the-year Steller sea lions in Alaska waters. Foraging effort was not significantly different seasonally for postpartum adult females, though females with dependent young in winter may increase their foraging effort. In winter, all adult females made longer trips over larger home ranges and dove deeper. Young sea lions exerted less foraging effort, had the shallowest and briefest dives, and had home ranges intermediate in size to the two groups of adult females. Their foraging ability appears to develop throughout the first year. We conclude that adult female sea lions can exploit prey throughout the Gulf of Alaska and Bering Sea, and are constrained only by their reproductive status and seasonal changes in prey availability. Young sea lions' diving is more limited because their physiological and behavioral development constrains them from diving like an adult. Perhaps most important, dives remain shallow through the first year. Consequently, young sea lions could be more easily food-limited by changes in prey distribution. |
format |
Article in Journal/Newspaper |
author |
Merrick, Richard L. Loughlin, Thomas R. |
spellingShingle |
Merrick, Richard L. Loughlin, Thomas R. Foraging behavior of adult female and young-of-the-year Steller sea lions in Alaskan waters |
author_facet |
Merrick, Richard L. Loughlin, Thomas R. |
author_sort |
Merrick, Richard L. |
title |
Foraging behavior of adult female and young-of-the-year Steller sea lions in Alaskan waters |
title_short |
Foraging behavior of adult female and young-of-the-year Steller sea lions in Alaskan waters |
title_full |
Foraging behavior of adult female and young-of-the-year Steller sea lions in Alaskan waters |
title_fullStr |
Foraging behavior of adult female and young-of-the-year Steller sea lions in Alaskan waters |
title_full_unstemmed |
Foraging behavior of adult female and young-of-the-year Steller sea lions in Alaskan waters |
title_sort |
foraging behavior of adult female and young-of-the-year steller sea lions in alaskan waters |
publisher |
Canadian Science Publishing |
publishDate |
1997 |
url |
http://dx.doi.org/10.1139/z97-099 http://www.nrcresearchpress.com/doi/pdf/10.1139/z97-099 |
genre |
Bering Sea Alaska |
genre_facet |
Bering Sea Alaska |
op_source |
Canadian Journal of Zoology volume 75, issue 5, page 776-786 ISSN 0008-4301 1480-3283 |
op_rights |
http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining |
op_doi |
https://doi.org/10.1139/z97-099 |
container_title |
Canadian Journal of Zoology |
container_volume |
75 |
container_issue |
5 |
container_start_page |
776 |
op_container_end_page |
786 |
_version_ |
1810436717025427456 |