When the Oregon Department of Fish & Wildlife (ODFW) modeled “Extinction Risk” of winter steelhead in the Willamette River in 2017, it was a whopping 90%. Following the removal of just 33 California sea lions preying on steelhead at Willamette Falls, ODFW estimates that the year-end extinction risk will fall to between 10-15%.
Before the permitted removal began, about 25% of the steelhead population was consumed by sea lions. Predation on winter steelhead dropped to 9% this year. Just 512 winter steelhead spawned above Willamette Falls in 2017, rising to 3,118 in 2018.