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California Sea Lion Questions and Answers sealion eating salmon

Why are California sea lions a concern on the Columbia and Willamette Rivers?

In the Columbia and Willamette Rivers, a growing number of habituated California sea lions are preying on endangered and threatened stocks of salmon and steelhead that are listed for protection under the federal Endangered Species Act (ESA). Sea lion predation is occurring throughout in the lower river system, but the problem is especially acute below Bonneville Dam and Willamette Falls where returning salmon and steelhead congregate as they prepare to move up the dam’s fish ladders to spawn upstream. 

Fish managers are also concerned about increasing predation by sea lions on mature sturgeon below Bonneville Dam and on listed salmon and steelhead runs in the Willamette River and other tributaries to the Columbia River. Human safety is also a concern. In recent years, there have been numerous reports of these powerful animals swamping boats and biting people along the Pacific coast.

What fish are at risk from sea lions in the Columbia River?

Thirty-two wild salmon populations bound for the upper Columbia and Snake rivers are vulnerable to predation by sea lions immediately below Bonneville Dam. The population of greatest concern is the Upper Columbia Spring Chinook run, which is listed as endangered under the Endangered Species Act (ESA). Snake River Spring/Summer Chinook, listed as threatened under the ESA, are also highly vulnerable to predation by sea lions feeding in spring immediately downriver from Bonneville Dam. Other ESA-listed salmon and steelhead populations passing through the lower Columbia River when sea lions are feeding include Lower Columbia River Chinook, Lower Columbia River steelhead, Middle Columbia River steelhead, Snake River Basin steelhead, Upper Willamette River Chinook and Upper Willamette River steelhead. All are listed as threatened under the ESA.

How do fish managers know that California sea lions are preying on protected fish? 

Since 2002, the Army Corps of Engineers has recorded the number of salmon and steelhead consumed by California sea lions annually from January through May immediately below Bonneville Dam. In 2005, for example, the Corps watched sea lions consume 3,023 fish in a year when ESA-listed upriver chinook stocks made up 14.5 percent of the run.

Besides recording the number of fish taken, the U.S. Army Corps of Engineers also documented a sharply increasing number of sea lions foraging at the dam. That number has grown from six sea lions in 2001, to 31 in 2003, to approximately 100 sea lions annually since 2004. Until the mid-1970s, California sea lions were seldom seen anywhere on the Columbia River.

The Corps’ data only includes observations of fish taken by sea lions above water immediately below Bonneville Dam. A biometric model, based on California sea lions’ metabolic needs, indicates that 100 animals feeding in that area may consume as many as 13,000 salmon each spring. In addition, sea lions are foraging in the other 140 miles of the lower river, and in tributaries.

Are sea lions native to the Columbia River?

California sea lions are found all along the west coast of the North America from Mexico to southeast Alaska including the mouth of the Columbia River. However, in recent years their numbers and distribution have increased significantly in the Columbia River system all the way upriver to Bonneville Dam. Until the early 1980s, it was uncommon to see a California sea lion in the Columbia River. Since then, migrant animals from California and Mexico have appeared in the river seasonally from January to late May in dramatically increasing numbers – first in the river estuary, then in the tributaries and finally upriver to Bonneville Dam, 145 miles from the river mouth. A 2006 survey conducted by the Washington Department of Fish and Wildlife (WDFW) estimated up to 1,200 California sea lions and 1,000 Steller sea lions in the lower Columbia River.

What steps have been taken to deter sea lions from preying on salmon?

In the spring of 2005, 2006 and 2007 the Washington Department of Fish and Wildlife (WDFW), the Oregon Department of Fish and Wildlife (ODFW) and other partners made a concentrated effort to drive California sea lions away from the area below Bonneville Dam. Partners in this effort included the Columbia River Inter-Tribal Fisheries Commission (CRITFC), National Marine Fisheries Service (NMFS) and the U.S. Army Corps of Engineers (USACE). Despite hazing tactics that included underwater firecrackers, acoustic devices and boat hazing, the sea lions returned to the area within a short period.

How do the live traps work?

Sea lions naturally haul out of the water and rest on structures such as jetties and docks. They will also haul out into floating cages, which are used by wildlife biologists to capture these animals. In a typical operation, a biologist leaves the door to the trap open until one or more animals are inside, then trips the door shut using a remote, short-range trigger system. 

Precautions are taken to ensure that no animals are inadvertently shut inside the cage traps, or that doors are closed when animals are not all the way in the trap. Doors to the traps are locked open to prevent them from closing accidently when the traps are unattended. The Corps has updated its surveillance systems at Bonneville Dam and monitors the entire area where the traps are set up.

Have the state’s efforts to remove California sea lions been effective?

There are some positive signs, but it is too soon to assess the success of the states' efforts. The good news is that the number of California sea lions feeding in the tailrace area has declined from a high of 104 animals in 2003 to 39 in 2012, and a low of 19 in 2019. The percentage of protected salmon and steelhead runs consumed by California sea lions has also declined in recent years, although that trend is partly due to larger salmon runs. Run timing and river conditions also affect predation rates, complicating an assessment of the states' efforts.

Will removal of specific California sea lions from the Columbia River impact the overall sea lion population?

No. California sea lion numbers have grown rapidly since the 1970s and the species is now at "carrying capacity" - near the highest level the environment can sustain - according to wildlife biologists. The U.S. Stock of California sea lions is estimated at some 300,000 animals, all on the Pacific coast. By comparison, the entire Pacific coast population of California sea lions was down to 10,000 in the 1950s. An aerial survey conducted in 2011 by the Washington Department of Fish and Wildlife documented over 2,000 California sea lions on the South Jetty at the mouth of the Columbia River alone.

Why can't sea lions be relocated from the Columbia River?

Previous efforts to relocate sea lions have been largely unsuccessful because sea lions frequently navigate back to the site of capture. The experience with sea lions at Ballard Locks in Seattle in the late 1980s is a prime example. In 1988 and 1989, resource managers captured a total of 39 California sea lions that had been foraging at the Ballard Locks and transported them to the outer Washington coast near Long Beach where they were released. Within a few weeks, 29 of those animals returned to the Locks to resume preying on salmon and steelhead in Shilshole Bay. The result was much the same the following year, when resource managers transported six California sea lions back to their breeding area off the coast of southern California. Three of those animals returned to Puget Sound within 45 days and a fourth was sighted in the Columbia River.

Three California sea lions that had been foraging near the Locks were captured and transferred to SeaWorld in Orlando, Fla., in 1996. Resource managers have initiated contact with accredited zoological facilities about the possibility of taking additional animals, but it is unlikely that demand will be sufficient to ease predation on protected salmon and steelhead populations on the Columbia River. A final determination on whether any California sea lions could be moved to captivity would be made by NMFS, based on the federal agency's assessment of the adequacy of captive facilities as well as the risk of possibly exposing healthy captive animals to diseases carried by wild animals.

What would happen if California sea lions were allowed to continue foraging in the lower river?

Left unchecked, California sea lions could undermine the recovery of threatened and endangered salmon and steelhead runs moving through the lower Columbia River. For some stocks, recovery efforts involving reduced fishing opportunities have been under way for decades. Since the 1990s, recovery efforts have expanded to include mitigation efforts and billions of dollars in public investment.

Previous experience with California sea lions at Seattle’s Ballard Locks demonstrates the risk these animals can pose to vulnerable fish stocks. From the early 1980s through the mid-1990s, resource managers tried a variety of methods to deter sea lions from preying on Lake Washington winter steelhead. Those efforts were unsuccessful, and sea lion predation continued until the run was effectively destroyed. Today, Lake Washington winter steelhead remain at critically low levels and the population is not expected to recover. With sea lion numbers and predation increasing on the lower Columbia River, fish managers fear some Columbia and Snake River stocks could meet the same fate.

Are other impacts to ESA-listed salmon and steelhead being addressed?

Yes. There has been an extraordinary and growing effort in this region to protect and recover salmon and steelhead populations. Recovery plans are being developed in every watershed to restore important habitat, improve dam passage survival, reform hatchery programs to assist wild fish populations, and reshape fisheries by focusing on selectively harvesting healthy, hatchery fish. The people of the Northwest have supported restoration efforts, and borne the costs, because of the importance of salmon to our heritage, the cultural value to Native Americans, and the economic value of salmon to our fishing communities.

Why are the states trapping and branding California sea lions in Astoria?

The states have been trapping and branding California sea lions in Astoria since 1997 as part of long-term study to monitor the movement, feeding habits and migration patterns of the animal in the Columbia River and along the Pacific Coast in collatoration with NOAA. By being able to resight individual animals throughout their lives, we can learn about age-specific survival, habitat use, age at sexual maturity, reproductive rates and longevity.  All of this information is crucial to understanding sea lion life history in order to insure the overall health and well-being of the population, and brands are the only method established thus far that are a life-long marker and can be applied to large numbers of animals.

Isn’t there a more humane way than branding to mark animals?

Branding is the only permanent way to mark a California sea lion. All of our capture and marking procedures have been reviewed and approved by our Institutional Animal Care and Use Committee, which includes experience veterinarians, species experts, and unaffiliated members of the general public, as dictated by the federal Animals Welfare Act.
The hot brand is applied for 2-3 seconds to burn the hair and the very top layer of skin so the hair can’t grow back. While the process and the brand itself may look painful and raw to us, the skin of a California sea lion is very different that than of a human. It’s thicker and tougher, and has few nerve endings. 
Since 1997 we have branded nearly 1,400 California sea lions in Astoria. In that time, we have never had an animal die due to branding. In fact, most sea lions react very little to the branding event.

What does Section 120 mean?

Under the authority granted under Section 120 of the Marine Mammal Protection Act, states can apply for limited management authority of marine mammals under very specific sets of circumstances. In this case, state resource managers from Oregon, Washington and Idaho are allowed to remove a limited number of California sea lions annually that have been identified as preying on salmon and steelhead in the areas below Bonneville Dam and Willamette Falls. Visit this page for more information.

How much does it cost to protect salmon and steelhead from sea lions below Bonneville Dam?

Washington and Oregon fish and wildlife departments have each received annual grants of $100,000 to $150,000 from the Pacific States Marine Fisheries Commission to support their work with pinnipeds, including state wide food habits studies, capture and marking at Astoria, capture and marking at Bonneville, boat survey of pinnipeds in the Columbia River, field work for all the different tasks, equipment, supplies, maintenance, office time for data analysis and presentations.

The Columbia River Inter-Tribal Fish Commission has assumed a majority of responsibility for early season hazing efforts.

The Army Corps of Engineers provides approximately $150,000 per year to document predation, haze sea lions and conduct fieldwork related to sea lion predation. This is in addition to the Corps' $3 million investment to install heavy bars and sonic devices to keep sea lions out of fishways and ladders at Bonneville Dam.

What are the ultimate goals of this management program?

State managers hope to act quickly to remove habituated sea lions in an effort to not only protect imperiled salmon runs, but also to prevent additional animals from learning these behaviors by following other animals upstream. Animals present in the East Mooring Basin of the Columbia River (Astoria) have approximately 7% chance of finding their way upriver to Willamette Falls or Bonneville Dam. Sea lions that have previously been upriver often revisit in subsequent years, sometimes followed by other individuals. When habituated animals are removed, the chance of other animals arriving at the Dam and Falls by chance falls significantly. Therefore, quicker action results in less animals that will have to be lethally removed over the longterm, and provides the greatest benefit to fish runs.

What does the new legislation, SB 3119, mean for pinniped management?

Senate Bill 3119 (the “Endangered Salmon Predation Prevention Act”) was passed by both the U.S. Senate and House of Representatives, and signed into law in December 2018. This law allows for management of both California and Steller sea lions (after a permit application process, comment period, task force meeting, and recommendations by NOAA and the Task Force) upriver of River Mile 112 in the Columbia River as well as tributaries of the Columbia River. This will prevent lengthy application periods in the future if animals show up at other pinch points for salmon migration, and in turn reduce the possibility of growing numbers of animals at these sites as was seen at both Bonneville Dam and Willamette Falls.

The permits associated with this law will likely not go into effect until mid-to-late 2020 due to the process involved with the States’ applications and federal approval of the permits. An additional set of population assessments and approved protocols for Steller sea lions must also be approved. Senate Bill 3119 will also allow for management of animals that are preying on sturgeon, lamprey and other fish besides threatened and endangered salmonids, a problem that has grown in prevalence since the arrival of pinnipeds at these two sites.

What can anglers do to deter problem sea lions that try to take their fish?

Under the Marine Mammal Protection Act, regulatory authority over sea lions rests exclusively with the federal agency, NOAA Fisheries. NOAA Fisheries’ Northwest Regional Office has posted a website that answers many of the questions anglers may have about protecting themselves from aggressive sea lions while fishing. ODFW encourages anglers to visit NOAA Fisheries’ Deterring Problem Seals & Sea Lion page.



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