Officials from the National Marine Fisheries Service have approved an application from the Oregon Department of Fish and Wildlife to kill California sea lions at Willamette Falls in an effort to try to save the state’s beleaguered winter steelhead and spring Chinook.

Protected under the Marine Mammal Protection Act, the state needed federal approval to take lethal action against the pinnipeds, which have been observed gorging themselves on endangered fish at the foot of the iconic waterfall.

“This is good news for the native runs of salmon and steelhead in the Willamette River,” said Shaun Clements, a policy analyst for the state on the sea lion issue. “Before this decision, the state’s hands were tied as far as limiting sea lion predation on the Willamette River.”

The agency said that sea lions were responsible for consuming roughly 25 percent of the steelhead run in 2017. The state applied to kill the sea lions “because their analyses showed that the high levels of predation by sea lions meant there was an almost 90% probability that one of the upper Willamette steelhead runs would go extinct,” the wildlife agency said in a statement.

Predation was lower for spring Chinook, between seven and nine percent, but the predators still increased the species’ chances of extinction by 10 to 15 percent, the agency said.

Clements said lethal removal was only looked at as a last resort.

“We did put several years’ effort into non-lethal deterrence, none of which worked,” he said in a statement. “The unfortunate reality is that, if we want to prevent extinction of the steelhead and Chinook, we will have to lethally remove sea lions at this location.”

After decades of hunting, the estimated number of California sea lions dipped as low as 10,000 in the 1950s, a sparse population inhabiting the waters stretching from Mexico to Alaska. In 1972, President Nixon signed the Marine Mammal Protection Act, which barred the killing of sea lions, among other pinnipeds and cetaceans, except under very specific circumstances.

Fast forward to 2018 and California sea lions have seen a resounding recovery throughout their range. Some 300,000 of the animals now swim in the waters of the Pacific and haul out on beaches, outcroppings and public docks from the Channel Islands in Southern California to Pier 39 in San Francisco to the fish processing plants in Astoria at the mouth of the Columbia River, often numbering in the thousands.

Shea Steingass, marine mammal program lead for the state, said that, at their peak, there are between 50 and 100 sea lions that congregate at Willamette Falls.

“Removal of these sub-adult and adult males will have no impact on viability of the sea lion population but will greatly improve the outlook for threatened upper Willamette winter steelhead runs,” she said.

Steingass said there are roughly a dozen sea lions that have become habituated to the falls and return every year.

Critics of the plan have long said that salmon runs have been declining on the Willamette and Columbia rivers for a variety of reasons including degrading water quality, sea lions and numerous dams that impede the natural migration of salmon.

Sharon Young, marine issues field director for the Humane Society of the United States, said killing more sea lions fixes nothing and is a "draconian solution."

“It’s a complete distraction from dealing with the actual problems facing the fish,” Young, who has participated in marine mammal protections workgroups since 1992, told The Oregonian/OregonLive last year.

To kill a sea lion, the state must meet one of two criteria mandated by the federal government. The animals must be observed between the falls and the mouth of the Clackamas River or be seen preying on salmonids.

When either of those criteria are met, “will be transported to a secure facility and humanely euthanized by a veterinary staff,” the state said in a news release. The agency “requested and was granted authority to remove up to one percent of the population’s ‘potential biological removal’ level, a metric that translates to a maximum of 93 animals a year on the lower Willamette.”

-- Kale Williams

kwilliams@oregonian.com

503-294-4048

@sfkale