Joel Garlich-Miller, a walrus expert with the U.S. Fish and Wildlife Services in Anchorage, said Thursday animals began showing up on shore in late July, a month earlier than usual.
By August, several thousand animals - far more than normal - were bunched up in haulouts in a stretch of coastline from Barrow, America's northernmost community, to Cape Lisburne, about 300 miles to the southwest on the Chukchi Sea, as first reported by The Arctic Sounder.
"It's raising a bunch of conservation issues for us," Garlich-Miller said.
The agency's immediate concern is that groups of walruses congregated on land are susceptible to additional human contact, whether a low-flying airplane or a hunter's boat, that could can panic the group, setting off a deadly stampede to the water.
But having animals concentrated on land instead of the vast expanse of the Arctic ice pack also raises stress issues, said Chad Jay, a U.S. Geological Survey biologist.
Walruses on shore may be forced to swim farther to forage, expending more energy. Researchers would expect increased mortality to calves, Jay said, if they try to stay with their mothers during feeding rather than resting on a platform of sea ice over feeding grounds.
"You can imagine access to traditional foraging areas is diminished," Garlich-Miller said. "That is cause for concern."
The Fish and Wildlife Service has no evidence that the walruses have suffered nutritional stress or disease, said Bruce Woods, an agency spokesman.
The agency has received anecdotal information from hunters that some animals appear thin but not emaciated or endangered, Garlich-Miller said. As has happened in the last few years, the agency has receive reports of orphan calves.
Walruses also have been spotted at Kaktovik 325 miles southeast of Barrow on the Beaufort Sea, far east of their normal range, Garlich-Miller said.