Sea Lions Continue
by Steven Johnson
The migration season that attracts sea lions to gorge on endangered fish in the Northwest is over,
and this year's numbers are not pretty for the pinnipeds, salmon or ratepayers.
Sea lions consumed more than 8,700 chinook salmon and steelhead through May 31, wiping out about 5.5 percent of the migrating fish at Bonneville Dam between Oregon and Washington, according to the Army Corps of Engineers.
That is more than double the 10-year average for sea lion predation, the Corps said. It occurred even though wildlife managers trapped and euthanized 59 California sea lions under a federal permit designed to help stocks of endangered salmon and steelhead.
The Corps said its numbers are preliminary, but the trend shows that sea lions continue to congregate in the Northwest, where ratepayers invested $757 million in 2015 in fish and wildlife programs. About one-third of the wholesale power rates that Bonneville Power Administration charges electric cooperatives are tied up in wildlife efforts.
On May 4, for example, 66 California sea lions and 54 Steller sea lions, a larger species, hovered around the Bonneville Dam in search of salmon. That total of 120 observed sea lions is the highest on record, the Corps said.
In all, the Corps documented about 131 uniquely branded California sea lions through May 31, with 89 of those having been spotted in in previous years. It also recorded approximately 39 unique Steller sea lions, with all but three being returning visitors.
Observers also saw three California sea lions feasting on salmon at Dalles Dam on the Columbia River, about 50 miles east of Bonneville Dam and nearly 200 miles from the Pacific Ocean.
"One branded [California sea lion] has been observed in the Bonneville pool for multiple years," the Corps said in its Dalles Dam report. "Another branded [California sea lion] was last seen on May 4 by fisheries personnel at the Dalles Dam and was subsequently sighted by one of our observers on May 13 in the Bonneville Dam tailrace indicating that it moved back downstream voluntarily."
A federal authorization that expires this month allows wildlife managers to kill up to 93 sea lions annually under certain conditions. Northwest states are seeking a five-year extension.
The Corps did not assess the effect of hazing sea lions from boats and dams, which ran from March to May. It did note that wood panels placed on top of floating gates at Bonneville powerhouse helped to prevent sea lions from climbing over gates and entering the fishways.
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