Highlights
Scientists in the Arctic are reporting a ra
re mass migration of thousands of walrus from the ice floes to dry land along Alaska’s coast.
Researchers from the US Geological Survey (USGS), who have been tracking walrus movements using satellite radio tags, say 10,000 to 20,000 of the animals, mainly mothers and calves, are now congregating in tightly packed herds on the Alaskan side of the Chukchi Sea, in the first such exodus of its kind.
“It’s something that we have never seen before in this area,” said Geoff York, of the WWF’s global Arctic programme. “As the ice decreases, the walrus are abandoning it earlier and earlier. They are having to swim ashore, or to linger on less suitable drift ice for long periods of time.”
The flight of the walrus, first reported by the Alaska Dispatch, has reinforced warnings from scientists that the lumbering animal may be headed for extinction because of climate change.
Arctic sea ice dropped to its third lowest level in recorded history this month. The USGS study noted that the entire Chukchi shelf could be completely ice-free during August, September and October by the end of the century.
Meanwhile, local residents in Point Lay told the Dispatch the numbers of walruses coming ashore could be much higher than government estimates.
The rare onshore mass sightings have raised fears of a grisly repeat of last summer when some 130 of the beasts, mainly calves, were trampled to death as the herd foraged for food.
“Walrus mums and calves need the sea ice to rest,” said Shaye Wold of the Centre for Biological Diversity. “When the sea ice disappears they are forced to come to shore and their calves are extremely vulnerable to being trampled in a stampede as you can imagine with 10,000 to 20,000 walruses on shore trying to forage in a limited area.”
Because of their huge girth, walrus are relatively clumsy in water. During their annual migration, they rely on large floating patches of ice as resting stops or mobile fishing platforms as they make their voyage cross the shallow frigid waters between Alaska and Russia.
In 2007 and again last year “thousands of walruses hauled out along the coast of north-western Alaska and tens of thousands of walruses hauled out along the coast of northern Chukotka when ice disappeared,” the USGS report said. “These events led to the trampling and death of hundreds of walruses in Alaska and thousands in Alaska,” the report said.
Increased concentrations of carbon dioxide in the ocean was also depleting the walruses’ food supply, making the waters too corrosive for the clams and other shellfish that are their staple.
The source article Scientists investigate massive walrus haul-out in Alaska | Environment | guardian.co.uk .
