Washington and Oregon wildlife officials will resume their annual campaign to trap and euthanize salmon-munching sea lions at Bonneville Dam as soon as this week.
It could be a target-rich environment.
With a giant run of spring chinook salmon projected, California sea lions are likely to soon begin congregating en masse at the man-made bottleneck created by the dam. Four floating traps have been hauled into place on an island below the Washington-side powerhouse, and state officials said they expect to begin trapping animals sometime this week.
“Business as usual,” said Rick Hargrave, a spokesman for the Oregon Department of Fish and Wildlife.
Observers at Bonneville have already observed as many as 32 pinnipeds gathered at one time below the dam, although most of those are Steller sea lions. The Stellers, which primarily target sturgeon rather than salmon, are protected by the Endangered Species Act.
The National Marine Fisheries Service is permitting the lethal removal of relatively abundant California sea lions identified as having a “significant adverse effect” on imperiled wild salmon and steelhead.
About 60 sea lions have already been identified, by branding or naturally distinguishing marks, as nuisance animals eligible for lethal removal under the permit granted through the Marine Mammal Protection Act. Ten sea lions were euthanized last year by lethal injection, and four others were transferred to zoos in Chicago and Texas.
No zoos or aquariums have expressed interest in taking sea lions so far this year, Hargrave said.
Meanwhile, the 9th Circuit Court of Appeals is expected to render judgment any time on a lawsuit by the Humane Society of the United States.
The Humane Society contends that the proportion of wild salmon taken by sea lions does not come close to meeting the threshold described by the Marine Mammal Protection Act for killing nuisance sea lions. In 2009, observers with the Army Corps of Engineers estimated that sea lions consumed almost 4,500 salmon at the dam in the first five months of the year — about 2.4 percent of the total run. (Biologists estimate that ESA-listed wild fish account for about a quarter of the run moving through Bonneville during that time, with the rest raised in hatcheries).
That’s a fraction of the incidental kill rate on wild-spawning endangered salmon that fishery managers allow for fishermen primarily targeting hatchery-raised fish.
“Fishermen will be allowed to kill up to 16 percent of the listed fish,” said Sharon Young, marine issues field director for the Humane Society. “They’ve raised, yet again, the number the fishermen are allowed to take even as they’re killing sea lions for doing the same thing.”
The Humane Society contends that sea lions are being unfairly blamed for wild salmon driven to the brink of extinction by many decades of overfishing, dams and habitat degradation.
State and federal fishery managers, however, say the observed number of fish eaten by sea lions does not reflect what is certainly a much larger number of salmon being consumed beyond the dam itself. Officials believe they are having success by targeting the most prolific salmon predators at the dam.
“Our feeling was, if we could just deter those bad actors by either hazing them or removing them, we would certainly never eliminate foraging that goes on at Bonneville, but substantially reduce it,” said Brian Gorman, spokesman for NMFS in Seattle.
Officials acknowledge other factors have eradicated wild salmon, but they can’t ignore the effect of sea lions.
Erik Robinson: 360-735-4551, or firstname.lastname@example.org.