Friday, 15 May 2015

waiting for walrus

Last summer, the sudden shrinking of sea ice and subsequent haul-outs of thousands of walrus caught scientists somewhat off guard. summer, they were ready.
Chad Jay, a research ecologist with the USGS in Anchorage, had lined up a hunter in Point Lay and was ready to tag walrus there and in Cape Lisburne to help figure out how the walrus survived when they couldnt rely on ice.
"Basically we were all set, ready to go, tags in hand and just kind of waiting for the walruses to come to shore," Jay told me today. "But they never did."
A few reports have trickled in of walrus hauling out, but nothing like last summer, when walrus lined the beaches and caused scientists to worry about potential stampedes. year, the lack of haul-outs came as something of a surprise.
And not because the sea ice didnt shrink. The ice did what scientists expected and disappeared far to the north, Jay said. Its just that bits of ice remained.
"There were some small oases -- micro bits of ice -- that were enough to sustain animals in offshore waters," said Joel Garlich-Miller, a walrus expert with the U.S. Fish and Wildlife Service. Satellite images couldnt pick up the ice chunks, but people passing in boats could.
"We were wondering," Garlich-Miller said, because walrus the USGS had already tagged were showing up in places satellite images showed to be ice-free. "We were wondering what was holding them there."
The lesson, or one lesson anyway, is that its not just the size and location of the main ice pack that matters, but the quality of the ice there and elsewhere. (Sea ice extent measures the area of water covered by a certain density of ice.) UAFs David Atkinson stressed this point to me last year; this drove it home.
Generally speaking, 2008 was another grim year for sea ice. For the month of September, the average extent was 1.8 million square miles, the second-lowest figure in the 30-year satellite record and only about 9 percent more than last summers record low, according to the National Snow and Ice Data Center in Colorado. The drop in 2008 made it harder to see 2007 as an anomaly.
Mark Serreze, the oft-quoted NSIDC scientist, said last year the Arctic was "screaming." In a news release posted today, his language was less colorful but no less urgent. "Both within and beyond the Arctic, the implications of the decline are enormous," he said.
And while there was more ice cover than in 2007, scientists suspect there was less ice volume, as the proportion of thick, multi-year ice continued to shrink, according to the release.
Dwindling sea ice was the main justification for the Interior Departments decision in May to list the polar bear as threatened under the Endangered Species Act. Conservation groups are pushing for similar designations for walrus and four species of ice-dependent seals.
As the ice shrinks, scientists expect bears and walrus to spend more time on land, where finding enough food becomes an issue. Thats what Jay was trying to figure out -- how and where the walrus feed when the do have to haul out. But hes doubtful any big haul-outs will happen this year.
"Its good for them," he said, "not good for us, looking to learn about their behavior.
"Well try again next year," he added.
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