Monday February 27, 2023
The Spokesman-Review —
Decadeslong efforts by state and tribal agencies have slowly curbed sea lion populations in the region, yet officials still consider the pinnipeds a threat to at-risk salmon populations in the Columbia River.
Between August 2021 and May 2022, officials estimate, more than 7,000 fish in the Bonneville Dam tailrace were killed by Columbia River sea lions, according to the Portland U.S. Army Corps of Engineers’ 2022 predation report. This totals about 12.4% of the salmon run accounted for during the agency’s observation period.
Dozens of sea lions congregate at the dam in the fall, winter and spring. They feast on chinook, steelhead and coho salmon, as well as sturgeon and other fish. Spring chinook salmon were disproportionately affected, accounting for roughly 4,400 of the 7,000 fish killed.
Predation samples vary depending on the dam’s tailraces and seasons studied, leading the report to note that total predation at the Bonneville Dam may be higher than its estimates.