The Oregon Department of Fish and Wildlife’s plan to remove problem California sea lions from the Willamette River Falls using lethal force has been approved by the National Marine Fisheries Service.
The sea lions are protected by the Marine Mammal Protection act, but the federal agency approved the plan because the pinnipeds have put runs of salmon and steelhead in the river in jeopardy of extinction.
ODFW filed the application because analyses showed that high levels of predation by sea lions (25 percent of the steelhead run in 2017) meant there was an almost 90 percent probability that one of the upper Willamette steelhead runs could go extinct.
The level of predation on spring Chinook, although lower at 7 to 9 percent annually, was still enough to increase the extinction risk by 10 to 15 percent.
Although the predators kill more spring Chinook than steelhead, the smaller size of the steelhead runs puts them in greater danger of being extirpated.
NMFS reached its decision after considering public comment on the application as well as the recommendations of a 14-member stakeholder panel.
“This is good news for the native runs of salmon and steelhead in the Willamette River,” said Dr. Shaun Clements, the ODFW policy analyst 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. We did put several years’ effort into non-lethal deterrence, none of which worked. 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.”
Clements said that there are 12 animals in particular that are causing most of the problems.
“They are the same sea lions we have seen here for the past five or 10 years,” said Clements. “They have been getting here earlier every year.”
Clements said the timing of the decision will allow the department to address the problem before the runs of imperiled steelhead and salmon start to arrive in early spring.
ODFW has been working with Oregon’s congressional delegation on a legislative solution that would give wildlife managers broader authority to deal with conservation problems if they arise elsewhere in the Columbia Basin.
There are currently almost 300,000 California sea lions along the west coast.