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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.

Video of sea lion predation at Willamette Falls.

Sea Lion Management

Restoring balance between predators and salmon

Columbia and Willamette river salmon and steelhead face serious threats from California and Steller sea lions that prey on fish waiting to move up the fish ladders at Bonneville Dam and Willamette Falls and other pinch points. Since the 1990s, a small number of habituated male sea lions have consumed migrating fish at these locations, many from threatened and endangered runs protected under the federal Endangered Species Act (ESA).

Data shows that sea lions can consume significant numbers of fish—up to 44 percent of the Columbia River spring Chinook run and 25 percent of the Willamette winter steelhead run each year.

The federal Marine Mammal Protection Act (MMPA) of 1972 specifies the actions States can/cannot take to manage California sea lions. 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 December 2018, the US Congress again amended the Marine Mammal Protection Act to provide regional fish and wildlife managers more flexibility to remove sea lions at these environmental pinch points.

Sea lion management in the Columbia River Basin is nothing new and has been ongoing for over a decade—since fish and wildlife agencies were first given Section 120 authorization to remove California sea lions observed preying on salmon and steelhead below Bonneville Dam in 2008 and years later at Willamette Falls. But before 2020, the States were only able to remove California sea lions at these two locations—and only then after spending years documenting predation, meeting multiple criteria for removal of individual sea lions, as well as expending considerable effort with non-lethal methods such as relocation and hazing that have largely proved futile.

In August 2020, under the more recently amended MMPA, the National Marine Fisheries Service issued a permit to the three NW States and six regional Tribes that were co-applicants to lethally remove Steller as well as California sea lions in the Columbia River basin. The new permit issued by NMFS creates “safe zones” for fish by giving managers from the Tribes and States the authority to remove, via humane euthanasia, both California and Steller sea lions that attempt to prey on fish in certain areas. These safe zones include locations where ESA listed salmon and steelhead, sturgeon, lamprey and eulachon are especially vulnerable to sea lion predation because they are either spawning, or temporarily holding in their spawning migration at the mouth of smaller tributaries or below barriers like Willamette Falls and Bonneville Dam.

Removal of problem sea lions has proven to be the most effective means of protecting fish from predation—and was a significant factor in 2020 being the best return of wild Willamette steelhead in years after biologists believed they were on the verge of extinction in 2017 due to increasing sea lion presence at Willamette Falls. Removal occurred after ODFW was granted authorization to begin removing California sea lions preying on threatened salmon and steelhead below Willamette Falls in 2018.

A variety of other nonlethal methods were first attempted to manage California sea lions at Willamette Falls including: exclusion gates to keep sea lions out of the fishways, multiple years of hazing including pyrotechnics and rubber buckshot, and even long-distance relocation only resulted in temporary mitigating effects. Wildlife managers from Washington and Oregon and federal and tribal partners have also been deterring predatory sea lions in the area immediately below Bonneville Dam for over a decade. Unfortunately, all of these efforts have not proven effective in curbing salmon predation by robust populations of California and Steller sea lions.

Impact to Sea Lion populations

The California sea lion population along the West Coast (the ‘U.S. Stock’) is no longer considered at risk. According to experts at NOAA, the U.S. Stock of California sea lions has likely reached its “optimum sustainable population (OSP)”- also known as Carrying Capacity- with an estimated 250-300,000 individuals, a drastic increase from <75,000 individuals when the Marine Mammal Protection Act was adopted back in 1972. Female California sea lions do not migrate north as far as Oregon or Washington, so all California sea lions in these regions are generally subadult or adult males.

Similarly, the Eastern stock of Steller sea lion stock is considered healthy and has no special designation under ESA or MMPA. The population has been growing annually since the 1980’s and the most recent population estimate was 52,139 non-pups and 19,423 pups. NOAA has concluded that the stock is likely at its Optimum Sustainable Population. Like California sea lions, the Steller sea lions that migrate up[river into the Columbia Basin are all male.

As of August 2020, the States and Tribes estimate that there may be up to 290 California sea lions and 130 Steller sea lions using these areas in the Columbia Basin which is less than 0.1 percent and 0.18 percent of the total population, respectively. This level of take will have no impact on the population health of either species.

The Consequences of Inaction

Recent decades have seen unprecedented effort and collaboration 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 of dollars over the past several decades. The ongoing imperiled status of these culturally and economically important 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 as a tipping point, there is a high risk that these investments will fail, many efforts will be negated, and additional and irreplaceable native fish runs will be extirpated at increasing rates.

Ports, Marinas, Private Property Owners and Vessels Actively Fishing have the right to deter sea lions to protect personal property and safety. NOAA has established guidelines for this deterrence that can be found here:
NOAA’s Guidelines for Sea Lion Deterrence

Managing Pinnipeds on the Willamette River

California sea lion predation on native Upper Willamette River salmon and steelhead stocks has been a growing threat to these fish populations in recent years, and has now reached 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 preying on native runs of steelhead and salmon that are listed as threatened under the federal Endangered Species Act. In addition, California and Steller sea lions are preying on native populations of white sturgeon and lamprey in the Willamette River.

Video of sea lion predation at Willamette Falls

Willamette Falls is a natural barrier to salmon migration found 26 miles (42 km) upstream from the confluence of the Willamette and Columbia Rivers. Therefore, animals must travel 128 miles (206 km) from the ocean just to reach this relatively isolated destination. Most of this is learned behavior, resulting from animals following others upstream to this location.

California sea lions are returning from their breeding ground in Southern California to Willamette Falls earlier every year in summer, resulting in longer consecutive stays at this area. Individuals 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. A larger number of animals naturally results in increased probability that other animals will find their way to the Falls. For example, in 2017, the single day maximum number of California sea lions was 41, up from 2-4 individuals 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 at Willamette Falls

ODFW conducted non-lethal hazing of sea lions at Willamette Falls in 2010, 2011, and 2013 in an attempt to deter sea lions from foraging near the fish ladder entrances. 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: 201420152016 , 2017 and 2018. Monitoring resumes annually in January through May.

Removing sea lions is the latest attempt by ODFW to reduce pinniped predation on the lower Willamette in order to prevent Oregon’s iconic Upper Willamette native steelhead from going extinct. Relocation of sea lions at Willamette Falls failed to work, as all the marked sea lions returned the 210 miles from the coast back to Willamette Falls within 4-6 days.

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. In 2017, 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. 2018 and 2019 steelhead numbers 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.

California Sea Lion Removal Summaries

Removals at Willamette Falls conducted/permitted via ODFW MMPA §120 Authorization
Removals at Bonneville Dam conducted/permitted via ODFW, WDFW, IDFG MMPA §120 Authorization

Individual Sea Lions Permanently Removed from CRB Management Area
Month Of Willamette Falls Bonneville Dam
  Cal. Sea Lions Steller Sea Lions Cal. Sea Lions Steller Sea Lions
April 2021* 5   7 7
March 2021*   1    
November 2020*       3
October 2020*       3
May 2019 8   18  
April 2019 12   1  
March 2019 5      
February 2019 3      
January 2019 2      
December 2018 3      

*Total sea lions removed under new (14 August 2020) NMFS MMPA Authorization and Permit:
14 Steller sea lions (13 as of 4/21)
12  California sea lions (12 as of 4/21)
(26 total)

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. The Idaho Department of Fish and Game also began assisting with this program in 2019.

From 2008 to present, a total of 232 California sea lions have been 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)

See above table for 2019 operations at both Bonneville and Willamette Falls.

Annual report: 2020 Columbia River Basin Research and Management Activities (pdf)
Annual report: Pinniped management at Bonneville Dam 2020 (pdf)
Annual report: Pinniped monitoring at Willamette Falls 2020 (pdf)
Annual report: Pinniped management at Willamette Falls 2020 (pdf)
Annual report: Pinniped monitoring at Willamette Falls 2018-2019 (pdf)
Annual report: Pinniped management at Willamette Falls 2018-2019 (pdf)
Annual report: Pinniped management at Bonneville Dam 2019 (pdf)

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)

Visit the NOAA Marine Fisheries Website for more information about the Section 120 application and authorization.
Pinniped Branding on the West Coast (pdf)

Media Contact: Michelle Dennehy, (503) 947-6022,


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