PORTLAND -- Two Washington congressmen introduced a bill Thursday to allow killing of the more aggressive sea lions who prey on Columbia River salmon, which just now are heading upriver to spawn.

"Unfortunately, the news this year isn't any better than last; California sea lions are already setting their sights on this year's salmon run," said Democratic Rep. Brian Baird.

The sea lions, protected by the 1972 Marine Mammal Protection Act, gather at the base of Bonneville Dam to wait for and feed on the migrating salmon.

Wildlife officials have tried harassing the sea lions with large firecrackers and rubber bullets, but with little effect.

"After trying every trick in the book, this is the only option left to stop the sea lions," said Republican Rep. Doc Hastings.

The districts of both Baird and Hastings border the Columbia. Democratic Rep. Norm Dicks of Washington and Republican Rep. Greg Walden of Oregon are co-sponsors.

Hastings said taxpayers pay millions of dollars a year to protect salmon while the sea lions gorge themselves on the fish. The bill would create a temporary fast-track process for Oregon, Washington and the four Columbia River treaty tribes to get permits to kill a limited number of the sea lions when nonlethal harassment has failed.

In recent years, the U.S. Army Corps of Engineers says, the sea lions have killed thousands of returning salmon, mostly at Bonneville Dam. The fish and the sea lions began entering the river in large numbers in the 1990s, and many sea lions return year after year.

About a dozen salmon and steelhead runs that enter the Columbia River are listed as threatened or endangered under the Endangered Species Act. The sea lions are protected but are not listed as threatened or endangered.

Oregon, Washington and Idaho applied last year for federal permission to kill some troublesome California sea lions. That approval process could take five years.

In 1995, NOAA Fisheries gave Washington state permission kill sea lions eating endangered steelhead swimming through Ballard Locks in Seattle, but before the executions, Sea World in Florida took the three worst offenders.

Wildlife officials say they can identify problem animals by brands placed on some of them or by distinctive markings or scars.

The spring chinook and the sea lions have just begun to enter the river.

By some estimates, the sea lions eat about 3 percent of the fish that arrive at the dam, where the salmon school up and are most vulnerable to the sea lions. Eventually, the salmon climb fish ladders to get around the dam Animal rights activists say the sea lion issue takes attention from the larger problems of pollution, destruction of habitat and spawning areas, the dams themselves and other factors that reduce the size of the runs.

Hastings and Baird say the bill has safeguards to make sure the overall California sea lion population is not affected.