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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)
April 16, 2013
One California sea lion was trapped and euthanized at Bonneville Dam today. A physical exam by ODFW veterinarians showed the presence of precancerous lesions* that made the animal ineligible for transfer to a zoo. The Queens Zoo in New York has offered to take up to two qualified California sea lions.
*Veterinarians estimate California sea lions with this condition have very short life-spans – about 1.5 years.
April 23, 2013
Two California sea lions were trapped today; neither was on the list for removal. Both animals were branded, fitted with GPS tags and released.
April 30, 2013
Nine California sea lions were trapped today. Six were branded and released. Three are on the list for removal and are undergoing health exams for possible transfer of up to two animals to the Queens Zoo in New York.
ODFW is working with a scientist from National Geographic to test a new remote release system for the group’s “critter cams.” Two steller sea lions have been fitted with video cameras using the remote release system. This will allow scientists to recover the cameras and view the footage.
May 3, 2013
Of the three California sea lions on the removal list that were trapped on April 30, two are being transferred to the Queen’s Zoo in New York and one has been euthanized.
May 7, 2013
Nine California sea lions were trapped today. None were on the list for removal. Three were branded and released. Six were already branded and were released.
May 8, 2013
Two California sea lions, not on the list for removal, were trapped and released.
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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