Dead Kokanee fingerlings possibly killed by Trinity Dam’s intake shafts

Kokanee Salmon Die-off Prompts Questions; No Official Explanation


By Bill Siemer August 31, 2014 

Thousands of dead and dying Kokanee salmon were floating on the upper end of Lewiston Lake this week after increased flows were initiated to save this fall’s run of adult Chinook salmon in the lower Klamath River.

Thousands of dead Kokanee salmon float on Lewiston Lake. Photo by Bill Siemer.

The dead Kokanee fingerlings, floating belly side up, were killed by the rapid change in pressure which occurred when they were sucked into Trinity Dam’s intake shafts when water was released downstream into Lewiston Lake, according to a knowledgeable source who asked not to be named.

The four-to-six inch Kokanee were washing up on the Lewiston Lake shore for a quarter of a mile on Tuesday evening when this reporter kayaked by. Early estimates, given to the Trinity Journal, had the losses between 200 to 400. The source estimated the die-off at 2,000. However, dead fingerlings were scattered on the Lake’s bottom and caught in the marshy grasses. Eagles, buzzards and crows dined from the shore. It was a smelly mess.

Vultures and other creatures feast on the dead fish at Lewiston Lake. Photo by Bill Siemer.

Kokanee need cold water to survive and the land-locked Kokanee are forced deeper into Trinity Lake as the water is released downstream. The Lake dropped 5.84 feet during the week ending August 25, according to the U. S. Bureau of Reclamation, which made the decision to increase the flows last week.

The Bureau’s website reported that releases from Lewiston Dam began at 7 a.m. on August 23.

Initially, the release was raised from 450 cubic feet per second (cfs) to 950 cfs. At 7 a.m. on August 25, releases from Lewiston Dam were increased to 2,450 cfs for a period of 24 hours, then dropped to 950 cfs. The goal, according to the Bureau, is to keep the lower Klamath at approximately 2,500 cfs until September 14.

Trinity Lake’s depth, as of August 25, was 316.27 feet, according to the Bureau’s website, with the Lake being 29 percent full. As of the end of that week, the average release to Whiskeytown and the Carr Powerhouse, was 2,119 cfs, while the Trinity River release averaged 1,650 cfs.

The Bureau’s decision to increase the flow of water for the lower Klamath salmon was met immediately by lawsuits from several water districts in the Sacramento Valley. A federal judge denied their request.

Thousands of dead fish litter Lewiston Lake in Trinity County. Photo by Bill Siemer.

Calls to the California Department of Fish and Wildlife in Redding, and the U.S. Bureau of Reclamation, seeking answers to questions regarding how many Kokanee are actually dying and whether the die-off is expected to have an impact on the Kokanee fishery, were not returned.

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