Biologists with the U.S. Army Corps of Engineers (USACE) estimate that two different species of sea lion have eaten a total of 4,858 threatened or endangered salmon and sturgeon near the Bonneville Dam between January and June of this year, according to a report issued by the Corps.
California sea lions regularly eat salmon at the dam that borders Oregon and Washington in the Columbia River Gorge. California sea lions are not listed on the U.S. Fish and Wildlife Service Endangered Species List. Steller sea lions arrive to the dam site earlier in the year and typically feast on both salmon and the threatened North American green sturgeon until the spring salmon run starts. While Oregon and Washington have permission to remove and kill California sea lions, Steller sea lions are listed as threatened in the northwest and may only be harassed to keep away from the fish.
This year, sea lions ate 2,360 sturgeon, the second highest number since 2006, while the salmon feast was at 2,498 fish. To compare, the highest recorded number of salmon eaten at Bonneville Dam was 6,321 in 2010.
Oregon and Washington are allowed to to cull up to 30 California sea lions with a permit from the National Marine Fisheries Service. Since Steller sea lions are threatened, there is no such permit, but the governments of Oregon, Washington and Alaska have requested that the eastern population of Steller sea lions be removed from the threatened list. The USACE have observed that for the past two years, Steller sea lions have outnumbered California sea lions at Bonneville.
At this time, the Humane Society of the United States has a lawsuit pending to stop the sea lion removal from the dam. Final arguments are to be heard Friday in U.S. District Court in Portland.