science environment

Sea Lions Put Willamette River Steelhead At Risk Of Extinction

By Cassandra Profita (OPB)
Oregon City, Oregon Aug. 7, 2017 11:38 p.m.
Sea lions have been eating steelhead and other fish at Willamette Falls in ever greater numbers.

Sea lions have been eating steelhead and other fish at Willamette Falls in ever greater numbers.

Courtesy of ODFW / Courtesy of ODFW

Oregon officials say Willamette River steelhead are on the verge of extinction because they’re getting eaten by sea lions at Willamette Falls.

They're asking Congress for permission to kill some of the sea lions this year to protect the fish.

Native winter steelhead are already on the Endangered Species List because they're threatened by the impacts of dams and habitat loss.

But with more and more sea lions feasting on fish below Willamette Falls, new data show the steelhead now face about a 90 percent chance of being wiped out altogether.


In a recent study, the Oregon Department of Fish and Wildlife counted the number of fish being eaten by sea lions at Willamette Falls and compared it to the number of fish passing over the falls.

They found the sea lions ate more than a quarter of the entire steelhead run this year.

Shaun Clements, a senior scientist with the agency, said the steelhead population has been on a downward spiral for the last 15 years as sea lion numbers have grown. Their numbers have dropped from a run of 15,000 in the early 2000s to around 500 this year.

Trees flank a broad river with wide cascading waterfalls in the middle.

Willamette Falls from the site of the former Blue Heron Paper Mill.

Lucila Cejas Epple / OPB

"The situation is a lot worse than we ever thought it could be," he said. "They've have had a home here in Oregon for thousands of years, and we want them to continue to have a home. We don’t want to see fish winking out on our watch.”

Sea lions are protected under the Marine Mammal Protection Act, and their population has grown from around 30,000 in the 1960s to around 300,000 today. As their numbers have grown, they've expanded their range into areas like Willamette Falls, a natural barrier to fish migration and a perfect place for sea lions to catch their prey.

Officials with the state wildlife office support a bill sponsored by U.S. Reps. Kurt Schrader, D-Oregon, and Jaime Herrera Beutler, R-Washington, that would change the Marine Mammal Protection Act to make it easier for mangers to kill sea lions in the Columbia River Basin.

The agency also plans to ask the National Marine Fisheries Service for permission to kill sea lions under the Marine Mammal Protection Act, Clements said, but it could take years to get approval under that process.

About 40 sea lions were seen at Willamette Falls last year, according to the state, and about a dozen of them are doing about 70 percent of the damage to the fish.

"So we could remove those six to 12 to start and see what the behavior of the other animals is after that," Clements said. "Ultimately our goal is to get to where we don't have sea lions habituating here and the fish can pass freely."

Without sea lions around, he said, there's only a 5 percent chance the steelhead will become extinct.