The agreement approved this month by a federal court judge settles a court case brought by the Center for Biological Diversity, which sued in December to force a decision.

This May 18 2006 photo provided by the U.S. Fish and Wildlife Service shows walrus on an ice flow in the northern Bering Sea off of Alaska. Changes in ice sheet due to warming in the Arctic could change how walruses feed. Females use sea ice as a resting area for their calves and as a platform for diving to the ocean bottom to feed. Biologists fear sea ice will recede beyond the continental shelf where the water is too keep for nursing mothers to reach feeding areas. (AP Photo/U.S. Fish and Wildlife, Liz Labunski )

The group petitioned the agency in February 2008 to list walrus because of the loss of walruses' sea ice habitat due to global warming.

The Endangered Species Act requires a decision by the agency within 90 days on whether the listing petition has merit. It requires a preliminary decision on listing within 12 months. Neither deadline was met.

Under the agreement approved by U.S. District Court Judge John Sedwick in Anchorage, the Fish and Wildlife Service must make the initial "90-day" finding on the walrus petition by Sept. 10.

If the agency determines the petition presents substantial information that a listing is warranted, the agency would have until Sept. 10, 2010, to complete a walrus status review and its "12-month" finding. The law calls for a final decision after public hearings and consideration of additional data.

The Fish and Wildlife Service routinely says limited resources force it to miss deadlines and that agency decisions on endangered species listings are driven by litigation, forcing the agency to rank actions by court order rather than species need.

"It's just been a matter of funding, like every other Endangered Species Act listing," said Bruce Woods, agency spokesman in Anchorage, on Monday.

Rebecca Noblin, an attorney for the Center for Biological Diversity, said the agreement was a good first step.

"We hope that they will go ahead and determine that a listing is warranted," she said.

Unless drastic action is taken to reduce greenhouse gas pollution, she said, walruses will be forced into a land-based existence for which they're not adapted.

Listing would require federal agencies to consult with the Fish and Wildlife Service to ensure that any action they authorize will not jeopardize walruses or adversely modify their critical habitat.

The Center for Biological Diversity and other groups successfully petitioned for protection of polar bears using the same global warming argument. It has also filed petitions to protect other ice-dependent species, including Arctic seals.

According to the National Snow and Ice Data Center at the University of Colorado, summer sea ice in 2008 reached the second lowest level, 1.74 million square miles, since satellite monitoring began in 1979. The loss was exceeded only by the 1.65 million square miles in 2007.

Walrus depend on sea ice to breed and forage. The animals dive from ice over the shallow outer continental shelf in search of clams and other benthic creatures. Females and their young traditionally use ice as a moving diving platform, riding it north like a conveyor belt as it recedes in spring and summer, first in the northern Bering Sea, then into the Chukchi Sea off Alaska's northwest coast.

Sea ice in the Chukchi Sea, shared with the Russian Far East, for the last two years receded well beyond the outer continental shelf over water too deep for walruses to dive to reach clams. In fall 2007, herds congregated on Alaska and Siberia shores until ice re-formed.

Conservation groups predict that if walrus are repeatedly forced to shore, they will over-hunt areas within short swimming distances and their population will crash.

Conservation groups also hope a listing could slow plans for offshore petroleum development.