Tuesday, January 10, 2012

Thin Ice Jeopardizes Polar Bears in Manitoba: CBC News

Hundreds of polar bears in northeastern Manitoba may face an increased risk of starvation due to delayed ice formation along the western coast of Hudson Bay, conservationists say.

Higher-than-normal temperatures have prevented ice from forming in the region, putting it three to four weeks behind schedule, according to the Canadian Ice Service, a division of Environment Canada. As a result, minimum ice cover there is the lowest since 1971, Canadian Ice Service forecaster Luc Desjardins said.

Formation of sea ice is critical for polar bears, which use it as a platform for catching seals and other marine mammals.

While a recent aerial survey of 333 polar bears along the bay's western coast showed the bears to be in good condition, conservationists worry the animals' health will deteriorate quickly if ice does not form in the next few weeks.

"The conditions that are occurring are indicative of the ice coverage that we would see probably in the mid-October time frame, rather than the mid-November," Desjardins told CBC News last month.
Normally by late November, a thin layer of ice up to 15 miles long would have formed, stretching seaward from the bay's western and southern coastlines, he said.

"The ice is almost non-existent this year, compared to our long-term normal," Desjardins said.
Where there is ice, "it's very patchy in terms of formation and it's not a distinct pattern that affects the entire length of the coast of Hudson Bay."

Desjardins stressed that the amount of ice has fluctuated in recent years and 2010 levels are not "significantly different" from those of the last five or six years.

What is different, however, is temperature: the region's air temperature is “consistently warmer" than in recent years, he said.

In Nunavut's Foxe Basin, the temperature is 14 degrees above normal.

Winter is the polar bear's feasting season. From November until early summer, they fatten themselves on ringed seals, bearded seals and other mammals. In the summer, during what's called a "walking hibernation," the average polar bear loses 1.6 kilograms of weight per day.

Ideally, the slow, heavy predators have enough weight by the end of the summer to make it back onto the ice platforms and hunt anew for fatty mammals.

"The longer that ice is in forming, the longer the polar bears have to survive on the fat reserves they put down in the spring and conserved right through the summer," said Peter Ewin, an Arctic specialist for the World Wildlife Fund.

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