Thanks Kain , Capitol Press recently had an article about research on sea-lion predation on sturgeon in the Columbia river, I was amazed at the high percentage.
Dec. 6 th Capital Press
"We don't have the tools to make an accurate estimate," said Cindy LeFleur, Columbia River policy coordinator for the Washington Department of Fish and Wildlife. "We know what we see happening at Bonneville Dam. We feel 10,600 is a reasonable number to put in our sturgeon population model to account for predation riverwide and across all age classes."
That estimate includes about 750 oversize sturgeon, the spawning portion of the population.
LeFleur first unveiled the 10,600 figure at the Washington Fish and Wildlife Commission meeting Friday in Olympia and reiterated it Monday night at a joint Washington-Oregon sturgeon meeting in Longview.
The U.S. Army Corps of Engineers has been observing marine mammal predation on spring chinook and sturgeon in the Columbia immediately downstream of Bonneville Dam since 2005.
Predation by sea lions at the dam has jumped from an estimated 413 in 2006 to 2,172 in 2010.
"Sea lion predation has been increasing (at Bonneville)," she said. "Both the total catch and catch per hour have been increasing basically since 2006."
Oregon's draft Lower Columbia White Sturgeon Conservation Plan, more than in year in preparation, estimates marine mammal predation at 6,700 sturgeon and increasing to 10,600 next year, said Brad James, Washington's sturgeon program manager.
