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California sea lion eating a salmon

Non-lethal hazing is primarily done from a boat (sled) near the Willamette Falls. Willamette River

California sea lion eating a salmon
California sea lion eating a salmon
Willamette Falls
Willamette Falls
California sea lion eating a salmon
California sea lions have been feeding on threatened and endangered salmon and steelhead in the waters below Willamette Falls.

California Sea Lion Management

Restoring balance between predators and salmon

Columbia and Willamette river salmon and steelhead face serious threats from California sea lions that prey on fish waiting to move up the fish ladders at Bonneville Dam and Willamette Falls. Since the 1990’s, sea lions have consumed tens of thousands of migrating fish at these two locations, many from threatened and endangered runs protected under the federal Endangered Species Act (ESA).

The federal Marine Mammal Protection Act (MMPA) of 1972 specifies the actions States can/can’t take to manage California sea lions. Recognizing that predation by a growing sea lion population can jeopardize salmon and steelhead stocks at risk of extinction, the US congress amended the MMPA in 1994 to allow States to apply for limited lethal removal authority under a narrow set of circumstances (Section 120 of the MMPA).

In March 2008, fish and wildlife agencies in Washington, Oregon, and Idaho received federal authorization under Section 120 of the MMPA 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.

The Oregon Department of Fish and Wildlife is now pursuing similar authorization to begin removing California sea lions preying on threatened fish below Willamette Falls.

Removal of problem sea lions has proven to be the most effective means of protecting fish from predation. While exclusion gates keep sea lions out of the fishways, other non-lethal deterrents such as pyrotechnics and rubber buckshot fired at them have only a temporary effect. Wildlife managers from Washington and Oregon and federal and tribal partners have been chasing sea lions away from the area immediately below Bonneville Dam for over a decade. The Oregon Department of Fish and Wildlife conducted similar efforts below Willamette Falls in 2010-13. But these efforts have not proven effective in curbing salmon predation by robust populations of California sea lions.

Impact of removing California sea lions on population

The California sea lion population along the West Coast is no longer considered at risk and has likely reached its “optimum sustainable population” with the current population of an estimated 250-300,000 individuals, up from <75,000 individuals when the Marine Mammal Protection Act was adopted back in 1972. This means removing the relatively few sea lions necessary to reduce the immediate risk to salmon and steelhead at Bonneville Dam and Willamette Falls will have no impact on the California sea lion population. ODFW pinniped biologists believe California sea lions are now expanding beyond their historic range, to include Willamette Falls, where the first documented sighting was in the 1950s. Of note, all of the sea lions that migrate north of California are males.

The consequence of inaction

There has been an unprecedented effort among Northwest states, federal agencies, tribes, and private citizens to protect and recover salmon and steelhead. These efforts equate to hundreds of millions of dollars invested annually and billions over the past decades. The ongoing imperiled status of these fish is not only costing the region millions in direct investments, but also in opportunity costs associated with lost fisheries, restricted power generation, and constraints on land and water use. If predation by sea lions at these environmental pinch points is not addressed there is a high risk that these investments will fail and additional fish runs will be extirpated.

NOAA’s guidelines for sea lion deterrence

Willamette River

California sea lion predation on Upper Willamette River salmon and steelhead stocks has been a growing threat to these fish populations and is now at a crisis point.

The Upper Willamette River Winter Steelhead Population Viability Study, completed by ODFW scientists in 2017, concluded that upper Willamette River native steelhead are at significant risk of extinction due to predation by California sea lions. Sea lions are not native to the Willamette River and are predating on native runs of steelhead and salmon that are listed as threatened under the federal Endangered Species Act. In addition, CSL are eating native populations of white sturgeon and lamprey in the Willamette River.

In early October 2017, ODFW submitted an application to NOAA Fisheries for authorization to remove sea lions from below Willamette Falls under Section 120 of Marine Mammal Protection Act. A decision on the application is expected 12-18 months from the filing date, following a federal public involvement process and environmental analysis.

ODFW’s application for Section 120 authorization comes after 20 years of intermittent monitoring and non-lethal measures by staff to reduce sea lion predation at Willamette Falls. The lengthy period of data collection and nonlethal measures is necessary to ensure the application has sufficient rigor to satisfy the NMFS and potential legal challenges.

Sea lions at the Falls

Video of sea lion predation at Willamette Falls.

California sea lions are returning from their breeding ground in Southern California to Willamette Falls earlier every year and staying longer. Sea lions are now arriving as early as August, well before the first of the ESA-listed upriver wild Willamette winter steelhead are showing up at the falls. In 2017, the single day maximum number of California sea lions was 41, up from the 2-4 observed in the late 1990s and early 2000s. ODFW estimates sea lions consumed an estimated 25 percent of the Willamette River wild winter steelhead population in 2017.

Hazing and monitoring programs

ODFW conducted non-lethal hazing of sea lions in 2010, 2011, and 2013 in an attempt to deter sea lions from foraging near the fish ladder entrances at Willamette Falls. After hazing proved to be unsuccessful, ODFW began a rigorous monitoring program, tracking sea lion abundance and predation to document the extent of the problem. The results of these monitoring efforts can be found in these reports: 2014, 2015, 2016 and 2017. Monitoring will resume in January 2018 and continue through May.

2018 sea lion trapping below Willamette Falls

In February 2018, ODFW began relocating California sea lions from the lower Willamette River to the Oregon Coast in an attempt to reduce extinction risk to wild Willamette steelhead.

On Wednesday, Feb. 7, ODFW biologists captured the first California sea lion on the Willamette. This male has been coming to Willamette Falls to feed almost every year since 2009, including every year for the past five years. Following his release on a beach south of Newport, he was back at Willamette Falls in three days, a swim of more than 200 miles. A second sea lion was relocated Thursday, Feb. 8 and returned in six days.

Capturing sea lions on the lower Willamette is the latest attempt by ODFW to reduce pinniped predation on the lower Willamette. The agency also tried non-lethal hazing of sea lions for three years starting in 2010 but concluded those efforts were ineffective.

ODFW now considers sea lion predation one of the greatest threats to the survival of wild winter Willamette steelhead as well as native Chinook, lamprey and sturgeon. Last year, the number of wild steelhead that crossed Willamette Falls fell to an all-time low of just 512 adult fish, while marine mammals were responsible for taking an estimated 25 percent of the run. So far this year’s steelhead are tracking slightly better but are still far below the ten-year average.

ODFW is trying to avert a situation similar to the one at Ballard Locks in Seattle in the 1980s where a small group of California sea lions wiped out the Lake Washington native steelhead population by preying on them while they congregated in a concentrated area that made them susceptible to predation.

To preserve and protect wild salmon and steelhead populations, ODFW has federal authorization to euthanize sea lions with a documented record of killing salmon and steelhead in the Columbia River around Bonneville Dam. On Wednesday, Feb. 14, ODFW captured a male sea lion that was authorized for removal under this federal authorization and this sea lion was euthanized Feb. 15. Other sea lions with a documented record of killing salmon and steelhead in the Columbia River around Bonneville Dam that move into the Willamette and are captured in ODFW’s traps may also be taken back to a secure facility at Bonneville and euthanized.

Columbia River

Since 2008 the Oregon Department of Fish & Wildlife and Washington Department of Fish & Wildlife have staffed a branding and removal program to reduce predation at Bonneville Dam problem California sea lions.

From 2008 to 2017 a total of 190 California sea lions were removed from the Columbia River: 15 were placed in permanent captivity, 7 died in accidents incidental to trapping, and the remainder were chemically euthanized.

Learn more about why California sea lions are being removed from the Columbia River (pdf)

Summaries of sea lion trapping

Summary of 2018 California sea lion trapping operations at Bonneville Dam (pdf)
Summary of 2017 California sea lion trapping operations at Bonneville Dam
Summary of 2016 California sea lion trapping operations at Bonneville Dam (pdf)
Summary of 2015 California sea lion trapping operations at Bonneville Dam (pdf)
Summary of 2014 California sea lion trapping operations at Bonneville Dam (pdf)
Summary of 2013 California sea lion trapping operations at Bonneville Dam (pdf)
Summary of 2012 California sea lion trapping operations at Bonneville Dam (pdf)

Current Section 120 Authority to remove sea lions

In March 2012, NOAA Marine Fisheries issued a letter authorizing (pdf) the states to remove California sea lions that are eating threatened salmon and steelhead in at Bonneville Dam. That authorization expired in June 2016 but was renewed for another five years until June 30, 2021. 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) AND
  • Have been observed eating salmonids in the Bonneville Dam area between Jan. 1 and May 31 of any year AND
  • 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  AND
  • 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 (pdf)


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