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Walruses Forced To Dry Land

(CLIMATE CHANGE) ALASKA —  Walruses are crowding along the Alaskan shoreline instead of breeding during their summer months on ice sheets in the Chukchi Sea, recent documentation reveals. This relocation caused by climate change is resulting in calves being crushed by forced proximity and dangerously deep waters for feeding, further threatening the endangered walrus species.  Read on why walruses need ice and the prospects for the mammals’s future. — Global Animal

 

L.A. Times

U.S. scientists have unveiled new video documentation of what they say is another stunning effect of the world’s steadily warming oceans: the unusual haul-out of up to 20,000 walruses off the coast of Alaska.
 
The video compiled by the U.S. Geological Survey’s Alaska Science Center, together with data collected from radio collars affixed to some of the animals, could help scientists learn more about the problems posed by shrinking sea ice for the creatures that call the distant Arctic home. The ice has been documented this year as among the lowest in recorded history. 

Walruses normally spend summers far offshore in the Chukchi Sea, foraging for food on the relatively shallow continental shelf and resting on floating ice. But much of the ice isn’t there this year.  So the animals are forced either to dive unusually deep off the continental shelf looking for food or to choose — as many apparently have — to lumber ashore and try to find food there.

This is the fourth recent year that the barren coast near Point Lay, Alaska, has hosted the massive walrus gathering.

 Walruses Forced To Dry Land

Walruses forced onto dry land off Alaskan shores. Photo credit: WWFblog.org

For an animal being considered for listing under the Endangered Species Act, the unusual behavior is problematic. Most of the animals clustered onshore are females with calves, and calves can be trampled to death when so many animals crowd together, said Chad Jay, walrus project leader for the USGS’ Alaska Science Center.

Moreover, scientists aren’t sure there is adequate food for the animals so near shore. Adult walruses consume more than 100 pounds of food a day, mainly clams, snails and marine worms foraged from the ocean floor. That’s why they prefer not to venture into deep water off the continental shelf, now the only place left with sea ice during the summer.

“They become a little more restricted in the areas they can forage, because they now can only access what’s available from shore,” Jay said in an interview with The Times.

Walruses have been swimming as far as 40 miles offshore from the haul-out to find food, he said.

There’s more. Although similar haul-outs in Alaska were documented in 2007, 2009 and 2010 (in 2008 there was remnant sea ice and the walruses stayed offshore), this is the first year many  walruses have left the Point Lay haul-out and begun venturing north.

Where are they going? There’s no sea ice there. How will they manage?

“We’re wondering what they’re going to do, because they’re spending their time in the water while they’re out there,” said Jay. He said radio-collared animals have been tracked to about 120 miles north of Point Lay, still in the Chukchi Sea.

“If the weather gets up, it could exhaust the animals,” he said. “The concern is more for the very young animals. The calves are totally dependent on the mother for protection, and the calves are also hitching a ride on the mother when they’re traveling, and sometimes the mother and calf can get separated.”

Two dead walruses were among the animals seen during an aerial sighting of the haul-out on Aug. 26. Last year, several dead calves were left behind on land, Jay said.

The numbers have been dwindling in recent days. An estimated 20,000 walruses were seen during the August over-flight, but the numbers are down now to 5,000 to 10,000, scientists say.

No one knows how many walruses remain in the Bering and Chukchi seas between Russia and the U.S. The last full census, conducted in 2006, put the number at about 130,000, and concerns are growing that their numbers, like those of polar bears, could be threatened.

Walruses forced to Alaskan shores 400x300 Walruses Forced To Dry Land

Walruses and their calves on the shores. Photo credit: WWFblog.org

The National Snow and Ice Data Center last month reported that the Arctic ice sheet was 25% below a 31-year average, a deficit of 625,000 square miles and approaching the record-low set in 2007.  Scientists at the University of Bremen in Germany said they documented even greater shrinkage that exceeded 2007 levels.

The summer sea ice has shrunk to about half what it was in 1972, the Bremen scientists said, and some of their U.S. contemporaries have predicted that summer sea ice could be gone by 2030.

“Climate change has forced Arctic sea ice into a downward spiral with disastrous results: Polar bear litter sizes are dwindling, walruses are crowding ashore and Alaskan communities are relocating due to extreme erosion and storm surges,” Lou Leonard, climate change director for the World Wildlife Fund, said in a statement about the walrus haul-out.

http://latimesblogs.latimes.com/nationnow/2011/09/walrus-haulout-arctic-alaska-chukchi.html

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