In response to the discovery of a parasite infection in Chinook salmon in the lower Klamath River, the Bureau of Reclamation began today to release additional water from Trinity Reservoir.
On Monday, Sept. 15, scientists from the U.S. Fish and Wildlife Service’s Fish Health Center captured and examined 20 fish from the lower Klamath River mainstem. Of those 20, nine tested positive for Ich parasites, with six of those nine determined to be severe. Ich was the primary pathogen responsible for the fish die-off in 2002.
The Fish Health Center’s findings are well above the emergency response criteria described in an August 2013 joint memorandum from USFWS and NOAA Fisheries. The recommended response is an immediate doubling of the flow rate in the lower Klamath River for seven days. Accordingly, releases from Lewiston Dam were increased beginning at 10 a.m. today.
“This is the only possible means of preventing or reducing the severity of a parasite outbreak,” said Mid-Pacific Regional Director David Murillo. “We are greatly concerned about the impact today’s decision may have on already depleted storage levels, particularly the cold water pool in Trinity Reservoir. We must, however, take all reasonable measures to prevent a recurrence of the fish losses experienced in 2002.”
Today’s decision comes on the heels of Reclamation’s decision on August 22 to supplement flows in the lower Klamath River in an effort to stave off a large-scale fish die-off. While fish health had initially appeared to be improving following the August augmentations, Reclamation received reports late last week that fish in the river were exhibiting possible signs of Ich parasites, prompting further investigation.
Starting today and for the next seven days, the flow rate from Lewiston Dam will be increased to a maximum of about 3,400 cubic feet per second (cfs), which will provide a flow rate of approximately 5,000 cfs in the lower Klamath River. This is double the 2,500 cfs flow sustained since August 23. It will require approximately 35,000-40,000 acre-feet to accomplish the flow doubling. The public is urged to take all necessary precautions on or near the river while flows are high during this period.
Reclamation will continue to work with NOAA Fisheries and other federal agencies to comply with applicable provisions of the Endangered Species Act and the National Environmental Policy Act.
Reclamation is the largest wholesale water supplier and the second largest producer of hydroelectric power in the United States, with operations and facilities in the 17 Western States. Its facilities also provide substantial flood control, recreation, and fish and wildlife benefits. Visit our website at www.usbr.gov.
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