Re-assessing abundance of Southern Hudson Bay polar bears by aerial survey: effects of climate change at the southern edge of the range
The Southern Hudson Bay polar bear (Ursus maritimus Phipps, 1774) subpopulation is considered stable but conflicting evidence lends uncertainty to that designation. Capture-recapture studies conducted 1984-86 and 2003-05 and an aerial survey conducted 2011/12 suggested abundance was likely unchanged...
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ftunivtoronto:oai:localhost:1807/90789 2023-05-15T15:12:35+02:00 Re-assessing abundance of Southern Hudson Bay polar bears by aerial survey: effects of climate change at the southern edge of the range Obbard, Martyn E. Stapleton, Seth Szor, Guillaume Middel, Kevin R. Jutras, Charles Dyck, Markus 2018-05-15 http://hdl.handle.net/1807/90789 http://www.nrcresearchpress.com/doi/abs/10.1139/AS-2018-0004 unknown NRC Research Press (a division of Canadian Science Publishing) N http://hdl.handle.net/1807/90789 http://www.nrcresearchpress.com/doi/abs/10.1139/AS-2018-0004 Article 2018 ftunivtoronto 2020-06-17T12:20:24Z The Southern Hudson Bay polar bear (Ursus maritimus Phipps, 1774) subpopulation is considered stable but conflicting evidence lends uncertainty to that designation. Capture-recapture studies conducted 1984-86 and 2003-05 and an aerial survey conducted 2011/12 suggested abundance was likely unchanged since the mid-1980s. However, body condition and body size declined since then, and duration of sea ice decreased by about 30 days. Due to conflicting information on subpopulation status and ongoing changes in sea ice, we conducted another aerial survey in 2016 to determine whether abundance had changed. We collected data via mark-recapture distance sampling and double-observer protocols. Results suggest abundance declined 17% from 943 bears (95% CI 658-1350) in 2011/12 to 780 (95% CI 590â 1029) in 2016. The proportion of yearlings declined from 12% of the population in 2011 to 5% in 2016, whereas the proportion of cubs remained similar (16% in 2011 vs. 19% in 2016) suggesting low survival of the 2015 cohort. In a warming Arctic, duration of sea ice is predicted to continue to decline in Hudson Bay affecting all ice-dependent wildlife; therefore, further monitoring of this subpopulation is warranted. We recommend a conservative approach to harvest management and repeating the aerial survey in 2021. The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author. Article in Journal/Newspaper Arctic Climate change Hudson Bay Sea ice Ursus maritimus University of Toronto: Research Repository T-Space Arctic Hudson Hudson Bay |
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Open Polar |
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University of Toronto: Research Repository T-Space |
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The Southern Hudson Bay polar bear (Ursus maritimus Phipps, 1774) subpopulation is considered stable but conflicting evidence lends uncertainty to that designation. Capture-recapture studies conducted 1984-86 and 2003-05 and an aerial survey conducted 2011/12 suggested abundance was likely unchanged since the mid-1980s. However, body condition and body size declined since then, and duration of sea ice decreased by about 30 days. Due to conflicting information on subpopulation status and ongoing changes in sea ice, we conducted another aerial survey in 2016 to determine whether abundance had changed. We collected data via mark-recapture distance sampling and double-observer protocols. Results suggest abundance declined 17% from 943 bears (95% CI 658-1350) in 2011/12 to 780 (95% CI 590â 1029) in 2016. The proportion of yearlings declined from 12% of the population in 2011 to 5% in 2016, whereas the proportion of cubs remained similar (16% in 2011 vs. 19% in 2016) suggesting low survival of the 2015 cohort. In a warming Arctic, duration of sea ice is predicted to continue to decline in Hudson Bay affecting all ice-dependent wildlife; therefore, further monitoring of this subpopulation is warranted. We recommend a conservative approach to harvest management and repeating the aerial survey in 2021. The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author. |
format |
Article in Journal/Newspaper |
author |
Obbard, Martyn E. Stapleton, Seth Szor, Guillaume Middel, Kevin R. Jutras, Charles Dyck, Markus |
spellingShingle |
Obbard, Martyn E. Stapleton, Seth Szor, Guillaume Middel, Kevin R. Jutras, Charles Dyck, Markus Re-assessing abundance of Southern Hudson Bay polar bears by aerial survey: effects of climate change at the southern edge of the range |
author_facet |
Obbard, Martyn E. Stapleton, Seth Szor, Guillaume Middel, Kevin R. Jutras, Charles Dyck, Markus |
author_sort |
Obbard, Martyn E. |
title |
Re-assessing abundance of Southern Hudson Bay polar bears by aerial survey: effects of climate change at the southern edge of the range |
title_short |
Re-assessing abundance of Southern Hudson Bay polar bears by aerial survey: effects of climate change at the southern edge of the range |
title_full |
Re-assessing abundance of Southern Hudson Bay polar bears by aerial survey: effects of climate change at the southern edge of the range |
title_fullStr |
Re-assessing abundance of Southern Hudson Bay polar bears by aerial survey: effects of climate change at the southern edge of the range |
title_full_unstemmed |
Re-assessing abundance of Southern Hudson Bay polar bears by aerial survey: effects of climate change at the southern edge of the range |
title_sort |
re-assessing abundance of southern hudson bay polar bears by aerial survey: effects of climate change at the southern edge of the range |
publisher |
NRC Research Press (a division of Canadian Science Publishing) |
publishDate |
2018 |
url |
http://hdl.handle.net/1807/90789 http://www.nrcresearchpress.com/doi/abs/10.1139/AS-2018-0004 |
geographic |
Arctic Hudson Hudson Bay |
geographic_facet |
Arctic Hudson Hudson Bay |
genre |
Arctic Climate change Hudson Bay Sea ice Ursus maritimus |
genre_facet |
Arctic Climate change Hudson Bay Sea ice Ursus maritimus |
op_relation |
N http://hdl.handle.net/1807/90789 http://www.nrcresearchpress.com/doi/abs/10.1139/AS-2018-0004 |
_version_ |
1766343247793225728 |