Walruses proposed for threatened list

ANCHORAGE — Pacific walruses are not protected under existing regulatory mechanisms, according to a conservation group, so it turned Thursday to the Endangered Species Act.

The Center for Biological Diversity on Thursday petitioned the U.S. Fish and Wildlife Service to list walruses as threatened because their sea-ice habitat could disappear in summers due to global warming and drastically shrink in winter.

"The Pacific walrus is an early victim of our failure to address global warming," said Shaye Wolf, a biologist for the conservation group in San Francisco and the principal author of the petition. "As the sea ice recedes, so does the future of the Pacific walrus."

Bruce Woods, a spokesman for the U.S. Fish and Wildlife Service in Anchorage, said the law calls for a review to determine whether the petition contains "substantial information" within 90 days, if practicable.

If the petition passes that first hurdle, the agency would have nine months to perform a status review on walruses.

Oil and gas development off the Alaska and the Russian Far East coasts also threatens the animals, according to the petition.

Walruses use sea ice as a platform to dive to the ocean bottom to feed on clams, snails, crabs, shrimp and worms. They cannot swim indefinitely, and females and their young traditionally ride the ice north in spring and summer over offshore foraging areas, first in the northern Bering Sea, then into the Chukchi Sea. An adult walrus can eat 200 pounds of clams in a day.

Sea ice last summer receded to 1.65 million square miles, the lowest level since satellite measurements began in 1979, according to the National Snow and Ice Data Center at the University of Colorado. In September, sea ice was 39 percent below its long-term average from 1979 to 2000.

Sea ice in the Chukchi Sea receded well beyond the shallow outer continental shelf over water too deep for walruses to dive to reach clams. Rather than staying on ice, many walruses congregated on Alaska's northwest shore and in Chukotka on the Russian side.

Wolf said she became interested in the threat to walruses as she worked on a petition to list ribbon seals as threatened. She said action must be taken to stop the loss of sea ice.

"I'd like to see a national strategy to immediately and drastically cut our greenhouse-gas emissions," she said.

The center's petition contends that walruses would be harmed eight ways from global warming:

• Lost access to foraging grounds. Without a summer platform, animals would not reach rich offshore feeding areas. With less ice in winter, the population would have access to progressively smaller areas of the Bering Sea.

• Increased physiological stress. Without summer ice, walruses would expend more energy reaching feeding areas from shore and escaping when threatened by land predators.

• Increased calf mortality. Calves would have less time to rest and nurse if based on shore and would face a higher likelihood of abandonment.

• Increased mortality due to stampedes and predation. Russian observers estimated 3,000 to 4,000 mostly young walruses died in stampedes in late 2007 when herds on shore rushed into the water at the sight of a polar bear, hunter or low-flying aircraft.

• Interruption of breeding activities. A reduction of winter sea ice would interrupt the timing and success of breeding, birthing and nursing.

• Decreased prey availability. The petition cites research that concludes warming and sea-ice loss are shifting the northern Bering Sea from an ecosystem dominated by benthic creatures — creatures that live near the bottom of a body of water — to one dominated by fish.

• Changing interactions with predators and disease. Walruses forced to haul out on shore could be at risk from polar bears, grizzly bears and wolves. Concentration on shore could create conditions for disease.

• Increased human disturbance. More shipping, oil and gas exploration, tourism and commercial fishing are expected to accompany more ice-free days.

Scientists at the National Snow and Ice Data Center have said they do not expect summer sea ice to bounce back without changes in current warming trends. Mark Serreze, senior research scientist, said in December that summer sea ice could disappear by 2030.

Two scientists at the Naval Postgraduate School in Monterey, Calif., said last month the Arctic Ocean could be entirely ice-free during the summer months by 2013. Wieslaw Maslowski, research associate professor in the Navy school's Department of Oceanography, and researcher Jaclyn Clement Kinney modeled and monitored Arctic ice melt.

The petition also said walruses are likely to be affected by petroleum development. The U.S. Minerals Management Service on Wednesday accepted high bids on 2.76 million acres of Chukchi Sea ocean bottom.