Concerned about increasing predation by sea lions on salmon and steelhead in the Columbia River, the Council supports bipartisan legislation introduced in the United States House and Senate to provide state agencies and Indian tribes more effective emergency options for protecting fish and fisheries from the small number of aggressive, individually identifiable sea lions.

Full text of letter

September 14, 2017

The Honorable James E. Risch
United States Senate 
Washington, DC 20510

Dear Senator Risch:

The Northwest Power and Conservation Council strongly supports S.1702, the Endangered Salmon and Fisheries Predation Prevention Act. After witnessing the alarming increase in sea lion predation on salmon, steelhead, sturgeon, and lamprey in the Columbia and Willamette rivers in recent years, we believe that it is incumbent upon Congress to provide the Northwest’s state and tribal fish and wildlife agencies more effective options for protecting our fish and fisheries from these aggressive predators. Failure to do so risks the extinction of some of our most precious and important fish species, including at-risk populations of spring Chinook salmon. Thank you for taking the initiative to introduce this legislation and raise the visibility of this increasingly serious issue.

The California sea lion population has grown to a current level of about 300,000 animals, rebounding from a low of about 10,000 in the 1950s. Marine biologists conclude that the population is currently at its carrying capacity. The number of sea lions counted at the east mooring basin in Astoria, Oregon, which is a favorite resting spot for these marine mammals, has increased dramatically over time. According to the Oregon Department of Fish and Wildlife, in the spring of 2004 the peak count was 206; in the spring of 2014 it was 1,420; in the spring of 2016 it hit an all-time high of 3,834.

There are 32 populations of ESA-threatened and endangered spring Chinook salmon being significantly harmed by the increasing sea lion population, including Snake River spring/summer Chinook, which were listed as a threatened species in 1992. The observed consumption of Spring Chinook salmon by sea lions is on the rise, reaching a high of 9,800 at Bonneville Dam in 2015, over five times the 2012 number of 1,750. In 2016, the observed consumption was 9,525 salmon, an estimated 5.8 percent of the run. In 2017, the preliminary estimate by the Corps of Engineers is 4,759 to 5,227 fish, about 4.5 percent of the run.

Between 2004 and 2016, California and Steller sea lions are estimated to have taken about 68,000 adult salmon and steelhead in the Columbia River near Bonneville Dam, the first dam salmon and steelhead encounter when they return from the ocean to spawn. In addition, between 2006 and 2016, Steller sea lions are believed to have consumed approximately 12,500 white sturgeon below Bonneville Dam. Sea lion predation on Pacific lamprey has also increased in recent years with 85 taken in 2014, 196 in 2015, and 501 in 2016.

These numbers, however, reflect only the fish observed being consumed within 1/4 mile of Bonneville Dam. State and federal researchers who have studied predation in the entire 146 miles between the ocean and the dam believe that a significant portion of the annual spring Chinook salmon run is lost to marine mammal predation. State researchers estimate that about 20 percent of the spring Chinook run is lost to sea lions, while a NOAA Fisheries researcher, Dr. Michelle Wargo-Rub, believes it is far higher.

According to her study, as much as 45 percent of the spring Chinook run disappeared in 2016, and much of that loss is likely attributed to sea lions. This translates into a potential loss of between 34,000 and 78,000 spring Chinook salmon in 2016.

Meanwhile, wild Upper Willamette River steelhead, listed as a threatened species under the Endangered Species Act in 1999, are considered at high risk of extinction, according to the Oregon Department of Fish and Wildlife (ODFW).

Continuing a decade-long downward trend, the number returning to the upper Willamette in 2017 was the lowest on record, with only 512 fish passing above the Willamette Falls. ODFW scientists estimate sea lions consumed at least one quarter of the run and warn that if sea lion predation continues at these levels, there is a probability of up to 90 percent that at least one population of these fish will go extinct. The agency believes that the near-term risk of wild steelhead extinction can be significantly reduced or avoided by limiting sea lion access to Willamette Falls.

While some critics of sea lion removal have argued that in the long term it would be more effective to boost declining salmon and steelhead populations by, for example, improving fish habitat, reducing fishing, addressing the impacts of ocean conditions on fish survival, and removing the four federal dams on the lower Snake River, we note that with the exception of dam removal all of those concerns are being addressed effectively already, and improvements at the dams, such as the installation of removable spillway weirs, is boosting dam-passage survival. As well, those are long- term problems with long-term solutions, but predation by sea lions is an immediate problem that needs an immediate solution – one that already is being pursued and, we believe, needs to be strengthened through the actions your bill would authorize.

If predation is not controlled, populations of endangered wild Columbia River spring Chinook and threatened Upper Willamette steelhead could be lost in the coming years. We have seen it before. In the 1980s and 1990s, California sea lions feasted on wild Lake Washington steelhead at the Ballard Locks in Seattle. Attempts to resolve the problem by transporting several sea lions back to the California coast failed because they returned in a matter of days. In relatively short order, sea lions left the population of steelhead functionally extinct. Where there were once thousands returning, only four returned in 2012.

Fortunately, Congress took notice and enacted Section 120 of the Marine Mammal Protection Act, which enabled limited lethal removal of individual sea lions provided they were from a healthy population and were causing significant harm to a population of salmon or steelhead listed under the Endangered Species Act.

Washington and Oregon have implemented this action at Bonneville Dam since 2008, and it has slowed the increase in predation at that location. However, the number of sea lions choosing to forage throughout the lower Columbia has soared to the point where Section 120 is no longer an effective option. Section 120 was designed to deal with a few problem sea lions in a small area like what occurred at the Ballard Locks in Seattle. Unless Congress steps in again and amends the Act, the number of endangered salmon consumed by sea lions in the lower Columbia River and tributaries will continue to increase.

Again, thank you for introducing this important bill and for being an advocate for the Columbia River Basin’s precious fishery resources. Please do not hesitate to contact the Council if you need additional information or have any questions.

With best regards.


Henry Lorenzen Chair

cc: Northwest Senate Delegation

Related links: 2017 Congressional tour of sea lion predation at Bonneville Dam