Cooperative Ecosystem Studies Unit, Pacific Northwest CESU

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The USGS Alaska Science Center is offering a funding opportunity to a CESU partner for research on ¿Seasonal and diurnal activity patterns of polar bears in the Chukchi and southern Beaufort Seas¿. This research will advance our understanding of the mechanisms by which polar bears may be responding to changes in the availability of sea ice habitat. One of the primary mechanisms by which sea ice appears to be affecting polar bear populations is via reduced body condition and associated effects on reproduction and cub survival. This is hypothesized to be largely attributed to declines in foraging opportunities resulting from a decline in the duration of sea ice cover over productive habitats where the primary prey of polar bears, ice seals, occur. One way in which polar bears might cope with reduced foraging opportunities, particularly during the annual sea ice minimum, would be to reduce energy expenditure through reduced activity. This may occur primarily during the annual sea ice minimum when the net cost of continued searching for prey could exceed the cost of foregoing foraging opportunities by resting until prey become more accessible. Alternatively, polar bears might increase activity levels in order to reach key resting or denning habitats on land or to find more disperse food resources over a fragmented sea ice landscape. In an attempt to gain insight into potential responses in polar bear activity to sea ice loss, this study proposes to use long-term activity sensor data from satellite collars deployed on adult female polar bears in the Chukchi and southern Beaufort Sea between the 1980s and 2000s to examine seasonal, population-level, and habitat-associated differences in activity patterns. This dataset represents one of the largest, long-term activity data sets available for polar bears providing a unique opportunity to explore temporal and spatial variation in activity patterns.

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