A federal appeals court handed an animal rights group a partial victory in a dispute over the fate of California sea lions in the Columbia River, allowing some to be trapped but none to be killed this spring.

The Humane Society of the United States sought an emergency order last week to contest federal authorization for Oregon and Washington to trap or kill up to 85 sea lions annually for five years because of the amount of salmon they eat at the base of Bonneville Dam.

A lower court had denied the society's bid for a preliminary injunction to halt the authorization, pending a full court hearing on the merits of its lawsuit seeking to protect the sea lions. The defendants are the National Marine Fisheries Service and the states of Oregon and Washington.

In denying the request, U.S. District Judge Michael Mosman noted the Humane Society was likely to prevail under an amendment to the Marine Mammals Protection Act of 1972, which requires proof of "significant negative impact" on salmon before the sea lions can be killed.

On Wednesday, a three-judge panel of the 9th U.S. Circuit Court of Appeals in San Francisco granted the emergency order, saying: "The lethal taking of California sea lions is, by definition, irreparable. This logic also applies to the salmon consumed by the sea lions."

The court said the reprieve applies only to the spring chinook run and that it expects the case to be resolved before next year's run. The sea lions typically leave the dam by late May.

The full appeals court is scheduled to hear arguments on the merits of the case on May 8 in Pasadena, Calif. A ruling could come months later.

The states estimate the sea lions eat up to about 4.2 percent of the salmon as they pass through the dam's fish ladders en route to spawning grounds upriver. The federal authorization recommended an annual take of about 30 sea lions.

Brian Gorman, a fisheries service spokesman in Seattle, said about 30 sea lions were seen at the dam Wednesday, but that 63 were counted one day two weeks ago and the run has yet to reach its peak.

He said attorneys must examine the ruling before the agency can comment.

"It's too bad this thing is being held up," Gorman said. "We're seeing 50 to 100 adult salmon eaten every single day at Bonneville."

The Oregon Department of Fish and Wildlife said trapping would begin Thursday.

Gorman said plans called for sending the sea lions to zoos or marine parks, if those facilities meet health standards.

Humane Society spokeswoman Sharon Young said the group remains opposed to trapping and relocation, but is pleased the court will hear the case and that no animals will be killed.

Copyright 2008 Associated Press