Over the past week, the Yurok Tribe has discovered a total of approximately 65 dead adult Chinook salmon in the lower Klamath River.
In the past three days, Yurok Fisheries Department monitoring crew observed approximately 30 dead salmon. Last weekend, the Department discovered approximately 35 disease-killed adult salmon and many other sick fish on a 40-mile segment of river from Blakes Riffle to Weitchpec, according to a press statement from the Tribe.
The Fisheries Department continues to monitor the Klamath River for sick and dying salmon. The Tribe said the current quantity of dead fish does not yet constitute a “major fish kill event,” which is characterized by 50 fresh dead salmon in a 20-kilometer reach. The Tribe’s team of fisheries experts said they expect more fish to die, but it is too early to tell if there will be a catastrophic disease outbreak.
The fish died from Columnaris, also known as gill rot. In addition to surveying for dead fish, the department is capturing and analyzing fish for the presence of Columnaris and Ichthyophthirius multifiliis or Ich.
“Many of the sampled salmon have tested positive for both diseases, but the Ich infections are not yet severe enough to kill the fish and it appears that all of the mortalities have been caused by Columnaris,” the Tribe stated.
The Tribe said Ich is the primary pathogen responsible for killing more than 60,000 adult salmon on the Klamath in September of 2002. The 20th anniversary of the historic fish kill, when over 60,000 salmon perished in low, warm water conditions on the river, is in less than a month.
“The number of dead fish is alarming but not surprising given the poor river conditions,” said Yurok Fisheries Department Director Barry McCovey Jr. “We are keeping a close eye on the river and will continue to monitor for disease and deceased fish until the conclusion of the fall run. We will be working closely with the Karuk and Hoopa Valley Tribes and our federal and state partners to assess fish health and to strategize on any necessary response."
McCovey said the sick and dead fish are believed to have staged in cooler water located at creek mouths for a long period of time. This is due to the unusually high water temperatures the river experienced during the month of August.
“Pathogens can spread quickly when large numbers of fish congregate in small pockets of water. The Tribe is working with the Karuk and Hoopa Valley Tribes as well as state and federal partners to determine the best course of action if disease rates spike,” added MCovey.
“Earlier this month, the Yurok Fisheries Department’s fish disease monitoring crew confirmed the presence of Columnaris and Ich in the Klamath. To improve conditions, the Yurok and Hoopa Valley Tribes successfully advocated for additional water to be released from the Lewiston Reservoir on the Trinity River, the Klamath’s largest tributary,” McCovey said.
The Tribe said the Bureau of Reclamation is releasing enough water to keep Klamath flows at 2,800 cfs until September 21. This management strategy aims to cool the river and encourage salmon to disperse throughout the system.
“A new pulse of migrating salmon has entered the river. Hopefully, these fish will spread out and migrate upstream, rather than concentrate at creek mouths,” the Tribe continued.
The Tribe said it remains concerned about the fish run and will continue to monitor the Klamath until the salmon spawning migrations concludes. In order to successfully reproduce, many of these salmon must travel more than 100 miles and remain healthy for a month or longer.
“Due to water quality issues caused by the Klamath dams, fish that spawn in the upper reaches of the river — above the confluence with the Trinity River — will have to contend with even worse conditions,” the Tribe concluded.