Stranded Walrus Are A ‘New Phenomenon’ And We Don’t Know How Bad It Will Get

http://thinkprogress.org/climate/2014/10/01/3574540/walrus-stranding-adaptation-questions/

by Katie Valentine Posted on October 1, 2014

The gathering of 35,000 walrus on a beach in northwest Alaska this week after they couldn’t find their preferred resting grounds of summer sea ice was a notable occurrence in terms of its sheer size, but it wasn’t an isolated event.

Walrus have been gathering on Alaska’s shore in huge numbers almost every year since 2007, a relatively new phenomenon that has scientists working to determine how this change in resting grounds affects the walrus’ behavior, food supply, and health. Typically, Pacific walrus, which don’t have the stamina to swim indefinitely and depend on sea ice for places to rest periodically, follow sea ice in the Bering Sea as it recedes north in the summer, ending up in the Chukchi Sea off the coast of Alaska. This year — and every year since 2007 besides 2008, when there was just enough sea ice left for the walrus to make use of — all the summer sea ice disappeared, causing a record 35,000 walrus to convene on an Alaska beach.

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“The massive concentration of walruses onshore — when they should be scattered broadly in ice-covered waters — is just one example of the impacts of climate change on the distribution of marine species in the Arctic,” Margaret Williams, managing director of the World Wildlife Fund’s Arctic program, said.

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Under normal conditions, during their fall migration, walrus rest briefly on sea ice before returning to the sea to forage for food and continue on their way South. But Fisbach said that these huge groups of walrus can remain on the Alaska shore for three to five weeks at a time, with individual walrus entering the sea to forage and returning to the beach to rest periodically. Fisbach said this behavior raises “lots of questions” about whether the walrus will run out of food in the surrounding area, due to the high numbers of walrus competing for food.

“Occupying these areas and foraging these areas concentrates tens of thousands of walruses in a smaller area that is already known to be less rich than their off-shore foraging ground, and there is a concern that they could deplete the resources,” he said. “We don’t have a good measure of that — these are simply hypotheses or concerns we have.”

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