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Columbia River salmon and steelhead face a serious threat from California sea lions that prey on fish waiting to move up the fish ladders at Bonneville Dam in early spring. Each year since 2002, sea lions have consumed thousands of migrating fish, many from threatened and endangered runs protected under the federal Endangered Species Act (ESA).
The federal Marine Mammal Protection Act recognizes that predation by a growing sea lion population can jeopardize salmon and steelhead stocks at risk of extinction. For the past seven years, wildlife managers from Washington and Oregon have worked with federal and tribal partners to chase sea lions away from the area immediately below Bonneville Dam. But these efforts, alone, have not proven effective in curbing salmon predation by a robust population of California sea lions.
In March 2008, fish and wildlife agencies in Washington, Oregon and Idaho received federal authorization to remove California sea lions that have been observed preying on salmon and steelhead below Bonneville Dam. The federal authorization allows wildlife managers to use lethal measures to remove sea lions that meet specific criteria, although the states’ first priority has been to relocate them to zoos and aquariums.
Through 2012, wildlife managers removed a total of 54 California sea lions – 11 of which were sent to zoos and aquaria – that met the federal criteria. The number of salmon consumed by sea lions below the dam has declined in the past two years, but predation rates are still in the thousands and it is too early to assess the long-term effectiveness of those efforts.
In 2013, the Washington Department of Fish and Wildlife and partnering agencies will mark their ninth straight year in the ongoing effort to manage sea lions preying on protected Columbia River salmon runs.
Learn more about why California sea lions are being removed from the Columbia River (pdf)
Trapping operations at Bonneville Dam will begin once sufficient numbers of California sea lions are observed at the dam. Updates will be posted here.
Section 120 Authority to remove sea lions
In March 2012, NOAA Marine Fisheries issued a letter authorizing (pdf) the states to remove specific California sea lions eating threatened salmon and steelhead in the Columbia River. The authorization stays in effect until June 1, 2016. The authorization allows the states to remove up to 93 California sea lions a year; these animals must meet the following criteria:
- Must be individually identifiable through natural or applied features (usually a brand)
- Have been observed eating salmonids in the Bonneville Dam area between Jan. 1 and May 31 of any year
- Have been observed on a total of any five days (consecutive days, days within a single season, or days over multiple years) between Jan. 1 and May 31
- Have been subjected to but not responded to non-lethal hazing
Visit the NOAA Marine Fisheries Website for more information about the Section 120 application and authorization.
Pinniped Branding on the West Coast
ODFW has been conducting a pilot program to see if hazing the sea lions can be effective in moving them away from the falls where salmon and steelhead congregate before entering the fish ladders. This pilot program does not include removing or trapping operations.
California sea lion predation has been identified as a concern in the Draft Upper Willamette River Salmon and Steelhead Recovery Plan, which describes the many factors having a negative impact on salmon and steelhead populations in the basin. ODFW is conducting the hazing program under the authority of and consistent with the policies set in the Marine Mammal Protection Act.
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