10,000 Walruses Gather on Shore as Ice Retreats

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If you see a walrus in the wild, chances are you’ll see other walruses with it. A lot of other walruses. And it doesn’t matter if the ice floe that they have chosen as the spot on which to rest is seemingly far too small to accommodate such a massive quantity of blubber and tusk: Like a Great Dane that doesn’t know it isn’t supposed to be a lap dog, they will somehow squeeze their collective bulk onto it. It can be, candidly, an amusing sight: a floating platform of ice barely visible beneath a mound of giant pinnipeds.

The strategy is not without its risks: Walruses can be spooked, and sometimes it only takes one of the throng to twitch in response to some anticipated danger for the rest of the crowd to hurtle into the water — leaving pups in particular of being crushed beneath the tumult.

VIDEO: Ice Disappears, Walruses Head for Land

But there is method in such evident madness. For one, the potential risk is outweighed by the doctrine of safety in numbers, and the fact that so many walruses in one place provides protection against polar bears. But the reason they seek out ice floes in the first place is not only to rest, but also because they need a platform from which to dive to the shallow seabed and feast on the clams, snails, worms and other benthic animals that are their preferred prey.

However, as is well known, Arctic sea ice is diminishing in extent — and, in places such as the north of Alaska, is retreating farther from the shore over summer. That means that instead of being over the shallow areas of the continental shelf, it is now in deeper waters, too deep for walruses to repeatedly make dives. And so instead, they swim back to shore, where they gather in massive haulouts. Scientists with the National Oceanic and Atmospheric Administration (NOAA) have documented just such a haulout on a barrier island near the village of Point Lay in northwest Alaska. Using aerial photographs, scientists estimated that the area initially contained 1,500 to 4,000 animals on Sept. 12. The number of walruses had increased to 5,500-8,000 when sighted on Sept. 22, and on Sept. 27, biologists estimated that there were approximately 10,000 walruses. (Awesome zoomable photograph here).

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Such massive haulouts are a recent occurrence in the region, as NOAA noted in a press release:

The first large beach haulout in this region formed in 2007 near Pt. Lay, coinciding with an unprecedented loss of sea ice across the Chukchi Sea. Subsequent haulouts formed in northwestern Alaska near Icy Cape and Cape Lisburne in 2009, and near Pt. Lay in 2010, 2011 and 2013. During 2008 and 2012, remnants of sea ice offshore in the Chukchi Sea were sufficient for walruses to rest on between foraging bouts.

The U.S. Fish and Wildlife Service notes that increased reliance on such vast shore-based haulouts run the risk of exposing “all individuals, but especially calves, juveniles, and females, to increased levels of stress from depletion of prey, increased energetic costs to obtain prey, trampling injuries and mortalities, and predation.”

 

Photo: Government scientists spy a massive walrus gathering in northwest Alaska. Credit: NOAA

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