Seasonal differences in foraging and isotopic niche width related to body size in Gulf of Alaska harbor seals
Harbor seals (Phoca vitulina Linnaeus, 1758) use different foraging strategies based on body size and sex, but this difference can be difficult to evaluate across seasons. We used stable isotope analysis of harbor seal whiskers from 32 individuals to assess seasonal foraging of seals inhabiting tide...
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crcansciencepubl:10.1139/cjz-2019-0108 2023-12-17T10:31:14+01:00 Seasonal differences in foraging and isotopic niche width related to body size in Gulf of Alaska harbor seals Smith, Justin Karpovich, Shawna Horstmann, Lara McIntyre, Julie O’Brien, Diane M. 2019 http://dx.doi.org/10.1139/cjz-2019-0108 http://www.nrcresearchpress.com/doi/full-xml/10.1139/cjz-2019-0108 http://www.nrcresearchpress.com/doi/pdf/10.1139/cjz-2019-0108 en eng Canadian Science Publishing http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining Canadian Journal of Zoology volume 97, issue 12, page 1156-1163 ISSN 0008-4301 1480-3283 Animal Science and Zoology Ecology, Evolution, Behavior and Systematics journal-article 2019 crcansciencepubl https://doi.org/10.1139/cjz-2019-0108 2023-11-19T13:39:20Z Harbor seals (Phoca vitulina Linnaeus, 1758) use different foraging strategies based on body size and sex, but this difference can be difficult to evaluate across seasons. We used stable isotope analysis of harbor seal whiskers from 32 individuals to assess seasonal foraging of seals inhabiting tidewater glacial habitat in Southeast Alaska. We analyzed stable isotope ratios from serial sections of whiskers, estimated deposition date for each section, and used mixed models to determine if sex and body size influence stable isotope ratios. Seals were grouped by size (>1.4 m or ≤1.4 m curvilinear length) as a proxy for sexual maturity to describe isotopic differences between groups using standard ellipse corrected area. Mean carbon and nitrogen isotope ratios differed significantly between size classes (p < 0.005), with no effect of sex. Larger seals exhibited a broader isotopic niche in the fall, winter, and spring relative to smaller seals, but not in the summer. Our results suggest that seals using tidewater glacial habitat share common foraging behavior in the summer, while larger seals exhibit more diverse foraging throughout the rest of the year. These results highlight the importance of tidewater glacial habitat for this population of harbor seals during the summer. Article in Journal/Newspaper harbor seal Phoca vitulina Alaska Canadian Science Publishing (via Crossref) Gulf of Alaska Canadian Journal of Zoology 97 12 1156 1163 |
institution |
Open Polar |
collection |
Canadian Science Publishing (via Crossref) |
op_collection_id |
crcansciencepubl |
language |
English |
topic |
Animal Science and Zoology Ecology, Evolution, Behavior and Systematics |
spellingShingle |
Animal Science and Zoology Ecology, Evolution, Behavior and Systematics Smith, Justin Karpovich, Shawna Horstmann, Lara McIntyre, Julie O’Brien, Diane M. Seasonal differences in foraging and isotopic niche width related to body size in Gulf of Alaska harbor seals |
topic_facet |
Animal Science and Zoology Ecology, Evolution, Behavior and Systematics |
description |
Harbor seals (Phoca vitulina Linnaeus, 1758) use different foraging strategies based on body size and sex, but this difference can be difficult to evaluate across seasons. We used stable isotope analysis of harbor seal whiskers from 32 individuals to assess seasonal foraging of seals inhabiting tidewater glacial habitat in Southeast Alaska. We analyzed stable isotope ratios from serial sections of whiskers, estimated deposition date for each section, and used mixed models to determine if sex and body size influence stable isotope ratios. Seals were grouped by size (>1.4 m or ≤1.4 m curvilinear length) as a proxy for sexual maturity to describe isotopic differences between groups using standard ellipse corrected area. Mean carbon and nitrogen isotope ratios differed significantly between size classes (p < 0.005), with no effect of sex. Larger seals exhibited a broader isotopic niche in the fall, winter, and spring relative to smaller seals, but not in the summer. Our results suggest that seals using tidewater glacial habitat share common foraging behavior in the summer, while larger seals exhibit more diverse foraging throughout the rest of the year. These results highlight the importance of tidewater glacial habitat for this population of harbor seals during the summer. |
format |
Article in Journal/Newspaper |
author |
Smith, Justin Karpovich, Shawna Horstmann, Lara McIntyre, Julie O’Brien, Diane M. |
author_facet |
Smith, Justin Karpovich, Shawna Horstmann, Lara McIntyre, Julie O’Brien, Diane M. |
author_sort |
Smith, Justin |
title |
Seasonal differences in foraging and isotopic niche width related to body size in Gulf of Alaska harbor seals |
title_short |
Seasonal differences in foraging and isotopic niche width related to body size in Gulf of Alaska harbor seals |
title_full |
Seasonal differences in foraging and isotopic niche width related to body size in Gulf of Alaska harbor seals |
title_fullStr |
Seasonal differences in foraging and isotopic niche width related to body size in Gulf of Alaska harbor seals |
title_full_unstemmed |
Seasonal differences in foraging and isotopic niche width related to body size in Gulf of Alaska harbor seals |
title_sort |
seasonal differences in foraging and isotopic niche width related to body size in gulf of alaska harbor seals |
publisher |
Canadian Science Publishing |
publishDate |
2019 |
url |
http://dx.doi.org/10.1139/cjz-2019-0108 http://www.nrcresearchpress.com/doi/full-xml/10.1139/cjz-2019-0108 http://www.nrcresearchpress.com/doi/pdf/10.1139/cjz-2019-0108 |
geographic |
Gulf of Alaska |
geographic_facet |
Gulf of Alaska |
genre |
harbor seal Phoca vitulina Alaska |
genre_facet |
harbor seal Phoca vitulina Alaska |
op_source |
Canadian Journal of Zoology volume 97, issue 12, page 1156-1163 ISSN 0008-4301 1480-3283 |
op_rights |
http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining |
op_doi |
https://doi.org/10.1139/cjz-2019-0108 |
container_title |
Canadian Journal of Zoology |
container_volume |
97 |
container_issue |
12 |
container_start_page |
1156 |
op_container_end_page |
1163 |
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1785584432244064256 |