U.S. federal marine mammal experts in Alaska studying how global warming affects walrus, polar bears and ice seals warn there are limits to the protections they can provide. They can restrict hunters, ship traffic and offshore petroleum activity, but that may not be enough if sea ice disappears.
Experts on summer sea ice say it's not likely to suddenly reappear. Arctic sea ice this summer plunged to its lowest levels since satellite measurements began in 1979, according to the National Snow and Ice Data Center at the University of Colorado.
"Ultimately it's beyond my scope," said Joel Garlich-Miller, a walrus expert for the U.S. Fish and Wildlife Service in Anchorage. "I can't make ice cubes out there."
Garlich-Miller said 3,000 to 4,000 mostly young walrus were trampled to death this year in stampedes on land on the Russian side of the Chukchi Sea, the body of water touching Alaska and Russia just north of the Bering Strait. Instead of spending the summer spread over sea ice, thousands of walruses were stranded on land in unprecedented numbers for up to three months.
If current ice trends continue, and walrus have to stay on coastlines every summer, they may put too much pressure on nearby foraging areas instead of feeding in the rich waters offshore, said U.S. Geological Survey biologist Tony Fischbach.
The U.S. Fish and Wildlife Service will decide within weeks whether to list polar bears as "threatened" under the federal Endangered Species Act because of the loss of sea ice from global warming. Polar bears hunt and breed on sea ice and are poor candidates for survival if they are based on land, where grizzly bears dominate.
Polar bears' primary prey are ringed seals, the only seals that thrive under sea ice. They dig breathing holes with their thick claws and create lairs on top of the ice where they birth their young. With warming, those lairs collapse earlier in springtime, leaving hairless pups susceptible to freezing, foxes, polar bears and even ravens and gulls.
The Pacific walrus faces at least three problems: Their ocean habitat may be changing, they may be forced to shore for long periods, and their weakest members are in danger when crowded on land.
"I suspect they won't do very well as totally shore-based animals," said Vera Alexander, one of three members of the U.S. Marine Mammal Commission.
Source:Xinhua/Agencies
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