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1 November 2012 Bounding the Southern Hudson Bay polar bear subpopulation
Martyn E. Obbard, Kevin R. Middel
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Polar bears (Ursus maritimus) are managed by the 5 nations where they occur (Canada, Greenland/Denmark, Norway, Russia, United States) using discrete subpopulations. In Canada, polar bears are harvested throughout their range, and several subpopulations are managed by more than one jurisdiction; therefore, recent management focused on ensuring sustainable polar bear harvests. Consequently, the subpopulation from which harvested bears are removed and the geographic boundaries of that subpopulation must be correctly identified. However, boundaries of the Southern Hudson Bay (SH) subpopulation have not been verified using satellite radio-telemetry data. Sea ice duration has already declined in Hudson Bay and James Bay, and both the duration and distribution of sea ice are predicted to decline greatly in the next century; therefore, it is important to document current habitat use patterns to assess the potential impacts of climate change. We used a probabilistic approach to describe the utilization distribution for the SH subpopulation based on data from 1997–2003 from 26 adult female bears fitted with satellite collars and assessed whether the currently accepted boundaries represent the population utilization distribution. We conclude that the SH boundaries do reflect the current spatial distribution of adult female bears in this subpopulation. Our analysis provides a benchmark to compare to the future distribution and habitat use of this subpopulation in response to effects of climate change and identifies future research needs to investigate polar bear distribution in James Bay and in the area near the boundary between the SH and Western Hudson Bay management zones.

International Association for Bear Research and Management
Martyn E. Obbard and Kevin R. Middel "Bounding the Southern Hudson Bay polar bear subpopulation," Ursus 23(2), 134-144, (1 November 2012).
Received: 2 December 2011; Accepted: 1 August 2012; Published: 1 November 2012

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