The Behavioral Response of Harbor Seals to Seasonal Prey Pulses of Spawning Pacific Herring
The Pacific harbor seal (Phoca vitulina) is a noteworthy omission from the list of predators that aggregate at herring spawning sites, despite strong suggestive evidence that they are likely to respond to herring pulses. Working with the hypothesis that spawning herring aggregations are seasonally i...
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ftwestwashington:oai:cedar.wwu.edu:wwuet-1062 2023-06-11T04:12:25+02:00 The Behavioral Response of Harbor Seals to Seasonal Prey Pulses of Spawning Pacific Herring Thomas, Austen C. 2010-01-01T08:00:00Z application/pdf https://cedar.wwu.edu/wwuet/63 https://doi.org/10.25710/w79g-1x82 https://cedar.wwu.edu/context/wwuet/article/1062/viewcontent/364.pdf English eng Western CEDAR https://cedar.wwu.edu/wwuet/63 doi:10.25710/w79g-1x82 https://cedar.wwu.edu/context/wwuet/article/1062/viewcontent/364.pdf Copying of this document in whole or in part is allowable only for scholarly purposes. It is understood, however, that any copying or publication of this thesis for commercial purposes, or for financial gain, shall not be allowed without the author's written permission. WWU Graduate School Collection Marine Biology text 2010 ftwestwashington https://doi.org/10.25710/w79g-1x82 2023-05-07T16:42:25Z The Pacific harbor seal (Phoca vitulina) is a noteworthy omission from the list of predators that aggregate at herring spawning sites, despite strong suggestive evidence that they are likely to respond to herring pulses. Working with the hypothesis that spawning herring aggregations are seasonally important prey for harbor seals, we tested several predictions using an analysis of harbor seal prey remains, GPS telemetry, and satellite-linked time/depth recorder data. Contrary to predictions, herring in harbor seal diet was comprised of 77% juveniles and 23% adults in the spawn season, versus 33% juveniles and 67% adults in the post-spawn season. Seal diving focus peaked at night during the post-spawn season, and seals exhibited less diving effort during the spawn season. Harbor seals did not however appear to alter their foraging behaviors to take advantage of spawning herring aggregations. The lack of response by harbor seals to spawning herring pulses is likely explained by seasonal differences in adult herring profitability, the availability of alternative prey, or a decline in local herring biomass. Text harbor seal Phoca vitulina Western Washington University: CEDAR (Contributing to Education through Digital Access to Research) Pacific |
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Open Polar |
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Western Washington University: CEDAR (Contributing to Education through Digital Access to Research) |
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ftwestwashington |
language |
English |
topic |
Marine Biology |
spellingShingle |
Marine Biology Thomas, Austen C. The Behavioral Response of Harbor Seals to Seasonal Prey Pulses of Spawning Pacific Herring |
topic_facet |
Marine Biology |
description |
The Pacific harbor seal (Phoca vitulina) is a noteworthy omission from the list of predators that aggregate at herring spawning sites, despite strong suggestive evidence that they are likely to respond to herring pulses. Working with the hypothesis that spawning herring aggregations are seasonally important prey for harbor seals, we tested several predictions using an analysis of harbor seal prey remains, GPS telemetry, and satellite-linked time/depth recorder data. Contrary to predictions, herring in harbor seal diet was comprised of 77% juveniles and 23% adults in the spawn season, versus 33% juveniles and 67% adults in the post-spawn season. Seal diving focus peaked at night during the post-spawn season, and seals exhibited less diving effort during the spawn season. Harbor seals did not however appear to alter their foraging behaviors to take advantage of spawning herring aggregations. The lack of response by harbor seals to spawning herring pulses is likely explained by seasonal differences in adult herring profitability, the availability of alternative prey, or a decline in local herring biomass. |
format |
Text |
author |
Thomas, Austen C. |
author_facet |
Thomas, Austen C. |
author_sort |
Thomas, Austen C. |
title |
The Behavioral Response of Harbor Seals to Seasonal Prey Pulses of Spawning Pacific Herring |
title_short |
The Behavioral Response of Harbor Seals to Seasonal Prey Pulses of Spawning Pacific Herring |
title_full |
The Behavioral Response of Harbor Seals to Seasonal Prey Pulses of Spawning Pacific Herring |
title_fullStr |
The Behavioral Response of Harbor Seals to Seasonal Prey Pulses of Spawning Pacific Herring |
title_full_unstemmed |
The Behavioral Response of Harbor Seals to Seasonal Prey Pulses of Spawning Pacific Herring |
title_sort |
behavioral response of harbor seals to seasonal prey pulses of spawning pacific herring |
publisher |
Western CEDAR |
publishDate |
2010 |
url |
https://cedar.wwu.edu/wwuet/63 https://doi.org/10.25710/w79g-1x82 https://cedar.wwu.edu/context/wwuet/article/1062/viewcontent/364.pdf |
geographic |
Pacific |
geographic_facet |
Pacific |
genre |
harbor seal Phoca vitulina |
genre_facet |
harbor seal Phoca vitulina |
op_source |
WWU Graduate School Collection |
op_relation |
https://cedar.wwu.edu/wwuet/63 doi:10.25710/w79g-1x82 https://cedar.wwu.edu/context/wwuet/article/1062/viewcontent/364.pdf |
op_rights |
Copying of this document in whole or in part is allowable only for scholarly purposes. It is understood, however, that any copying or publication of this thesis for commercial purposes, or for financial gain, shall not be allowed without the author's written permission. |
op_doi |
https://doi.org/10.25710/w79g-1x82 |
_version_ |
1768388280647155712 |