ANCHORAGE, Alaska (AP) — The absence of vast swaths of summer sea ice is changing the behavior of Pacific walrus, federal scientists said Wednesday, but added that more research will be needed to say what the final effects might be.
"There is a definite concern for the population," said Chad Jay, a U.S. Geological Survey research ecologist who studies patterns of walrus distribution.
Since 2008, Jay, USGS researcher Anthony Fischbach and colleagues in Russia have used crossbows to attach temporary radio collars to walrus so their movements can be tracked.
In a paper published last month, they concluded that walrus in late summer will increase their use of coastal resting areas, called haul-outs, and feed in nearshore foraging areas because sea ice will continue to diminish. The consequences for the population, they said, was not known.
A decade ago, the future of walrus was hardly a consideration. Their habitat in in a hostile locale off a remote state provided natural protections.
Warming has opened up the Arctic for ecotourism, petroleum development and possibly cargo transport and commercial fishing. Like polar bears, walrus have seen their primary habitat melting beneath their feet or flippers.
Walruses cannot swim indefinitely. They use ice, rocks or beaches as resting platforms.
Walrus females give birth in the Bering Sea, and as temperatures warm each summer, live on the sea ice edge as it moves north through the Bering Strait and into the Chukchi Sea. The ice provides a sanctuary for nursing walrus calves and an ever-changing diving platform for females that hunt along the ocean floor for clams, snails and marine worms. Biologists compare the ice edge to a conveyor belt that carries walrus north and south as ice melts and re-forms with the seasons.
A wakeup call for U.S. scientists came in 2007, when several thousand walrus appeared on Alaska's northwest coast in late summer. Ice had receded beyond the shallow continental shelf to the Arctic Basin, where the ocean floor is 10,000 feet down and too deep to reach by walrus. Thousands more hauled out on the Russian side.