Canada’s western Hudson Bay polar bear population in decline. Climate change to blame.
Polar bears in the western Hudson Bay rely upon annual sea ice for access to their primary prey, ringed seals. During the summer months, when Hudson Bay is ice-free, bears remain on land where they make little use of terrestrial food sources.
In the past 30 years rising temperatures have increased the duration of this ice-free period – and the bears’ seasonal fast – by three weeks. Scientists say this indicates the decrease in population size appears to have been initiated by earlier summer ice break up in the Hudson Bay, which caused the bears' body condition to decline.
It also may explain why the town of Churchill, on Hudson Bay, like many communities in the Canadian Arctic, has experienced an increase in the number of bear occurrences in and around town. Apparently, a larger number of nutritionally-stressed bears are visiting the Churchill area each year in search of alternative food sources.
Because western Hudson Bay is near the southern limit of the polar bear’s range, the scientists’ findings may foreshadow how more northerly populations will respond to projected warming in the arctic ecosystem.
In February, the US Fish and Wildlife Service announced that it is opening the formal process to list polar bears as officially "threatened" due to the unprecedented meltdown of their sea-ice habitat caused by global warming. There are between 20,000 and 25,000 polar bears in the Arctic.
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WWF International Arctic Programme
*The Population Decline of Polar Bears in Western Hudson Bay in Relation to Climatic Warming
Regehr, Eric V.12; Lunn, Nick J.3; Amstrup, Steven C.1; Stirling, Ian3
(1) U.S. Geological Survey, Alaska Science Center, 1011 E. Tudor Rd., Anchorage, AK, 99503, USA
(2) Department of Zoology and Physiology, University of Wyoming, 1000 E. University Ave., Laramie, WY, 82071, USA
(3) Environment Canada, Canadian Wildlife Service, 5320 122 St., Edmonton, AB, T6H 3S5, Canada