As the Sea Ice Retreats, Walruses Come Ashore in Alaska
There’s nothing quite like the sight of a walrus emerging slowly out of the ocean and dragging its 2,000 pound body up onto a beach for a rest. It’s exhausting just to watch — and when a whole gang of walruses do it at once, the combined effort is so enormous that there’s a special, and very apt, term for it: a “haulout.”
But what’s happening on the northwest coast of Alaska could more aptly be called a mega-haulout. For a couple of weeks now, something like 10,000 or 20,000 of the blubbery creatures have been parked on the beach just outside of Point Lay, on the Chukchi Sea.
“It’s hard to count them,” says Tony Fischbach, a biologist with the U.S.Geological Survey (USGS), “because they’re all squished together. The haulout we’re talking about here has a linear extent of about a mile — but we don’t have good model for how many walruses you can pack into a mile.”
This isn’t the first time Alaska has seen such a thing; there were big haulouts in 2007 and 2009 as well, although this one appears to be larger, and they’re not uncommon in Russia. But historically, says Fischbach, the Alaskan variety tends to involve tens or hundreds of animals, not thousands or tens of thousands.
The driving force behind the haulouts, he says, is almost certainly the summer melting of sea ice in the Arctic Ocean, which in turn is almost certainly exacerbated by anthropogenic climate change. Sea ice loss has been particularly extensive this year in the Chukchi Sea northwest of Alaska.
Archipelago, Norway, August 2009.
Credit: Michael D. Lemonick
What biologists want to know, naturally enough, is how increased sea ice loss will affect the walruses. The huge mammals feed mostly on shellfish from the continental shelf, and normally the ice still overlaps the shelf, even at the end of summer. Not so in recent years: “If you can just roll off a piece of ice to forage,” says Fischbach, “that’s one thing. But if you suddenly have to commute several hundred miles, it may not be worthwhile.”
In order to track how the walruses move in response to changing ice conditions, and try and figure out if diminishing ice will reduce populations, USGS biologists have been tagging the creatures with radio transmitters (the scientists have created an animation showing this summer’s movements).
The most immediate problem, says Fischbach, is that walruses love to be next to other walruses. “When they come ashore,” he says, “they pile on top of each other, shoulder to shoulder.” It works great for big walruses, but the calves weigh in at only 200 to 400 lbs. “The little guys,” says Fischbach, “can get squished. We’re seeing some of that this year, but the big walruses are still there, so we don’t know what’s underneath them.”
But in the long run, unless climate projections are very badly off, the summer ice isn’t likely to recover, and could disappear entirely by later this century. Once they have a better idea of how the beasts respond to diminishing ice — that could take a couple of years — they’ll finally be able to say something meaningful about how significantly climate change may impact walrus populations throughout the Arctic.