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NOAA Fisheries Proposes Delisting Eastern Stellar Sea Lions; Growing Numbers In Columbia River
Posted on Friday, April 20, 2012 (PST)

NOAA Fisheries announced Thursday that it is proposing to remove the “eastern” Steller sea lion population, currently deemed "threatened," from the list of endangered wildlife.


In recent years, an increasing number of Steller sea lions have congregated below the Columbia River’s Bonneville Dam to feed mostly on white sturgeon.


A status review conducted by agency biologists found the species is recovering sufficiently to be dropped from the Endangered Species Act list of imperiled species


"This proposal reflects the continued recovery of the eastern population of Steller sea lions and the strong conservation partnership among NOAA Fisheries, the states, the fishing industry, and other stakeholders," said Jim Balsiger, NOAA's Fisheries Alaska regional administrator.


The Federal Register Notice of the decision can be found at


NOAA Fisheries began a draft status review of the eastern population, which ranges from southeast Alaska's Cape Suckling to southern California's Channel Islands, in June 2010, and opened a 60-day public comment period. Within a few days, NOAA received two petitions, one from the states of Washington and Oregon, and the other from the state of Alaska, asking that the eastern Steller sea lion be removed from threatened status under the Endangered Species Act.


The draft status review, which was completed in March 2012, shows the eastern Steller sea lion population has met the recovery criteria outlined in the recovery plan, which was developed by NOAA Fisheries in 1992 and revised in 2008.


There were approximately 34,000 eastern Steller sea lions in 1997, when the eastern and western stocks were found to be genetically different from each other. Estimates in 2010 put the eastern population at about 70,000.


The western stock, which ranges from Alaska as far as the Russian Pacific coast, will retain its endangered status.


The 2010 petition signed by the directors of the Oregon and Washington departments of fish and wildlife said that the eastern Steller population is robust. And the eastern population has increased even since 2002, when a NOAA report said a 3.1 percent growth rate had been experienced over the previous 25 years.


“… the Oregon Department of Fish and Wildlife has conducted abundance surveys from northern California to Washington that demonstrate continued population growth at nearly 4 percent through 2008,” the states’ delisting request says. “In addition, Washington Department of Fish and Wildlife has conducted Steller sea lion surveys along the Washington coast that show both increasing Steller sea lion numbers at haul out areas as well as increasing numbers of newborn pups at several locations over recent years. These data, demonstrating continued population growth in the area of the primary Steller sea lion rookeries in U.S. waters south of Alaska, add an additional six years to the 25-year record of population growth previously documented.”


“Of particular concern to state fish and wildlife management agencies are the increasingly negative interactions that the growing Steller sea lion population is having with other very important marine and anadromous fish resources,” the states said in their August 2010 letter to NOAA Fisheries.


Of growing concern is the predation of Steller sea lions on white sturgeon that are known to huddle together in midwinter below the lower Columbia River’s Bonneville Dam. Stellers have long lived in the lower river but have until recent years seldom ventured as far as far upriver as Bonneville (river mile 146) in any great number. Sturgeon, while not ESA listed, are a popular game fish that have shown marked population declines in recent years in the lower river.


Since 2002 when research began to evaluate Californina sea lions impact on, primarily, migrating salmon and steelhead spawners, no Stellers were seen in the neighborhood and only three individuals were seen in each of the next two years.


But the number of Steller sea lions that congregate at the dam each winter and spring has grown steadily through the years.


In 2011 the total number of individually identifiable Steller sea lions at the dam reached 89 and they ate, according to observers keeping a tally, more than 3,000 white sturgeon in the area immediately below the dam. That’s the most white sturgeon taken by sea lions since the researchers have been keeping track.


Estimates are that more than 98 percent of the predation on white sturgeon below the dam was by Steller sea lions, while the California sea lions concentrated on salmon.


The most recent state estimates of legal size -- 3 ½ to 5-feet long -- sturgeon in the lower Columbia declined steeply, from 131,700 fish in 2007 to an estimate of 66,400 fish in 2010. The Oregon Department of Fish and Wildlife initiated an additional survey in 2010 using research setlines during July-August to recover white sturgeon tagged in May and June. The “in-year” approach produced an estimate of 87,000 fish in 2010 and a preliminary estimate of 80,500 for 2011.


The maximum number of Stellers seen any day so far this year has been 20. Average numbers of Steller and California sea lions present per day this year is now lower for both than last year. The U.S. Army Corps of Engineers researchers have documented approximately 56 different Stellers visiting the dam so far this year. They’ve taken more than 1,300 sturgeon during daytime observation hours, which is slightly more than the record total through mid-April a year ago.


Most of the sturgeon seen taken have been in the 2- to 4-foot range.


“This year there seems to be more of the larger sturgeon taken than previous years, however there are also many more with no recorded size associated with them,” according to the April 13 weekly update report prepared by the Corps.


“It’s a huge concern to the states,” the ODFW’s Conservation and Recovery Program manager, Charlie Corrarino said of white sturgeon predation issue. The two states have sought and received permission to remove California sea lions that have been showing up each spring to feed on spawning salmon, many of which are protected under the ESA. But state management of Stellers at this point is restricted to non-lethal hazing in an attempt to dissuade the big predators.


“We’ll be looking to explore some creative options” for reducing the Steller sea lion predation on white sturgeon, Corrarino said.


Steller sea lions were first added to the endangered species list in 1990 because of steep declines in their population, largely the result of indiscriminate shooting by people who felt the sea lions were competing for available fish. Through education and outreach, the shooting has been reduced.


With the decrease in shootings, increased public awareness, laws protecting the sea lion, and improved population survey data, scientists now believe the eastern population actually has been increasing at an average rate of 4.3 percent each year since the late 1970s.


NOAA seeks public comment on the proposal to delist the eastern population. The 60-day comment period began Thursday.


After the public comment period closes June 18, comments will be evaluated. A final decision on whether to delist will be made within one year of publication of the proposed rule in the Federal Register. If the agency proceeds with a delisting, NOAA will issue a post-delisting monitoring plan to guide monitoring activities for the eastern Steller sea lions for the next 10 years.


The comment period will allow the public to give their views on the proposed delisting, the draft status review, and the draft post-delisting monitoring plan, which are all available at


For more information, see CBB, March 4, 2011, “ESA-Listed Steller Sea Lions Munching Away On Non-Listed White Sturgeon; Management Options Few”


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