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California sea lion eating a salmon
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| California sea lion eating a salmon |
Weekly Updates
August 28, 2009
On August 24, wildlife managers conducting research in Astoria captured an additional California sea lion that met the criteria for removal. That animal was euthanized in accordance with federal protocols because no zoological facility could be found to take it.
Wildlife managers will continue to trap and mark California sea lions for identification in Astoria, and plan to resume efforts to remove animals that prey on ESA-listed salmon and steelhead below Bonneville Dam next spring.
May 19, 2009
State efforts to remove California sea lions below Bonneville Dam have ended for 2009 because very few animals remain near the dam. During the 2009 trapping and removal operations, 20 California sea lions were trapped. Six were not on the list for removal. They were branded, acoustic tags were attached and they were released.
Four of the animals were relocated – two to the Shedd Aquarium in Chicago and two to Gladys Porter Zoo in Brownsville, TX.
Ten animals were found unacceptable for transfer to a zoo or aquarium due to health reasons and were euthanized.
Routine trapping and marking operations in Astoria are continuing.
May 11-15
Five California sea lions were trapped this week – three at Bonneville Dam and two at Astoria. Two of the animals trapped at Bonneville were unmarked and not on the list for removal. Two were branded, acoustic tags were attached and they were released. The remaining three animals underwent health assessments, were found to be unacceptable for transfer due to health reasons, and were euthanized.
May 4-8
No California sea lions were trapped or transported this week.
April 27-May 1
No California sea lions were trapped or transported this week.
April 20-24
No California sea lions were trapped or transported this week.
April 13-17
Two California sea lions were trapped on April 16 but neither was on the list of animals to be removed. Both were branded and/or fitted with an acoustic monitoring tag and released.
April 5-11
On Sunday, two California sea lions trapped the week of March 30 were safely transported to the Point Defiance Zoo for eventual transfer to the Gladys Porter Zoo in Brownsville. No other California sea lions were trapped this week.
March 30-April 3
Eight California sea lions were trapped on Wednesday morning. Six of the sea lions were on the list of animals authorized to be transfered or euthanized. The other two were branded and released.
One sea lion will be transported to Point Defiance Zoo for eventual transfer to the Gladys Porter Zoo in Brownsville, TX. Four animals were euthanized – three when health assessments revealed they suffered from the same viral infection found in other sea lions trapped at the site and one for other health reasons. The final animal has undergone a health assessment and final lab results are expected in the next few days.
March 23-27
No sea lions were trapped this week.
March 16-20
Three sea lions were trapped this week and, as of Friday, March 20, were being held in a secure location on site pending results of the health exam. UPDATE, Posted Monday, March 23: Two of the sea lions trapped earlier in the week were transported to the Point Defiance Zoo near Seattle on Sunday, March 22. There they are in quarantine awaiting final transfer to the Shedd Aquarium in Chicago. A third sea lion trapped this week was euthanized on Friday when the health exam revealed in suffered from the same viral infection found in two sea lions trapped the week before.
March 9-13
Two sea lions were trapped and euthanized after a health exam revealed the animals had lesions of a viral origin that were indicative of cancer. The condition is potentially contagious to other animals in captivity.
For more information about this issue visit
Related news releases
For images of sea lion trapping
The effort to remove California sea lions is intended to protect threatened and endangered fish runs from a growing number of the animals. The sea lions feed on spring chinook and steelhead below Bonneville Dam as the fish attempt to navigate the dam’s fish ladders to spawn upriver.
According to the U.S. Army Corps of Engineers, 103 sea lions last year consumed 4,243 salmon and steelhead—the highest number on record—in a quarter-mile area immediately below the dam.
Since January, state and federal biologists have been using underwater firecrackers, rubber buckshot and other non-lethal deterrents to “haze” sea lions away from fish—primarily sturgeon—congregated below the dam.
Wildlife managers will continue removing specific California sea lions under authority granted to Washington, Oregon and Idaho last year by NOAA-Fisheries, the federal agency responsible for managing marine mammals. That authority allows the three states to use lethal or non-lethal means to remove individual California sea lions that have been documented feeding on salmon or steelhead below Bonneville Dam.
Only those animals that the states have identified as persistent predators on threatened salmon and steelhead can be relocated or removed.
Like last year, the states’ first priority will be to place those animals in federally approved zoos and aquariums. This year the Shedd Aquarium in Chicago has requested two California sea lions and the Gladys Porter Zoo in Brownville, Tex. has requested five. Animals that are trapped and eligible for transfer will be held at a secure location on site and undergo a health exam that includes blood and urine tests. If approved for transfer they will be transported to Point Defiance Zoo near Seattle for eventual placement. Last year, state wildlife managers relocated six California sea lions to SeaWorld facilities in Orlando, Florida and San Antonio, Texas, where the animals are all reported to be in good health.
Animals that are trapped and cannot be placed will be euthanized on site under the supervision of an ODFW veterinarian and an interagency Animal Care Committee.
The removal of specific sea lion predators from the Columbia River will not affect the overall sea lion population, biologists say. 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. population of California sea lions is estimated at some 300,000 animals, all on the Pacific coast. A population survey conducted in 2006 by WDFW documented 1,200 California sea lions near the mouth of the Columbia River alone.
Since 1972, when the California sea lion came under the provisions of the Marine Mammal Protection Act, its population has rebounded from a low of 50,000 to about 300,000. In fact, today the number of sea lions in the northwest has increased so significantly that their predation on threatened and endangered salmon and steelhead has officials in Oregon, Washington and Idaho concerned for the future viability of these fish populations.
Since 2003, the Army Corps of Engineers has documented approximately 100 California sea lions annually consuming an average of 3,000 spring chinook salmon and steelhead at the Dam, some 145 miles upstream from the Columbia River mouth.
As permitted under the federal law, Oregon and Washington fish and wildlife agencies, NOAA Fisheries, U.S. Army Corps of Engineers, and the Columbia River Indian tribes have attempted to control predation through non-lethal measures. Although used aggressively, the hazing techniques have been largely ineffective.
As a result, Oregon, Washington and Idaho fish and wildlife agencies sought federal approval to employ lethal methods against individual sea lions to protect wild fish populations, many of which are listed under the Endangered Species Act (ESA).
The agencies submitted an application under Section 120 of the Marine Mammal Protection Act, which allows lethal removal of individual California sea lions that negatively impact federally-protected salmonid stocks.
On March 18, 2008, the National Oceanic and Atmospheric Administration gave Oregon and Washington Departments of Fish and Wildlife and Idaho Fish and Game federal authority to remove – through lethal or non-lethal means – California sea lions preying on salmon and steelhead listed for protection under the Endangered Species Act (ESA).
The affected fish include upper Columbia River spring chinook, which are listed as endangered under the federal ESA, lower Columbia River chinook and steelhead, middle Columbia River steelhead, Snake River spring/summer chinook, and Snake River Basin steelhead, which are all listed as threatened under the ESA.
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