Yurok fisheries crews detected an alarming level of a parasite that can be deadly to salmon Thursday on the Lower Klamath River.
The parasite ichthyophthirius multifiliis, commonly known as ich (pronounced “ick”) was detected at levels many times higher than the 30 ich per gill arch threshold designated as “severe.”
“Four out of seven chinook had very heavy infections,” said Michael Belchik, senior fisheries biologist for the Yurok Tribal Fisheries Program. “It was over 1,000 ich per gill arch.”
Bureau of Reclamation Public Affairs Officer of the Mid-Pacific Region Shane Hunt said U.S. Fish and Wildlife Services’s California-Nevada Fish Health Center will conduct additional testing to confirm the Yurok crew’s findings.
Ich is the primary pathogen responsible for the infamous 2002 fish kill on the Klamath River which saw more than 35,000 adult Chinook salmon die during the fall run.
Ich attacks a fish by attaching itself to the gill, causing the host to slowly swell and suffocate. Testing requires a lethal sampling by removing the first gill arch on both sides of the salmon and examining it under a microscope.
Since 2002, Yurok fisheries crews have conducted routine testing of salmon in the river through the late summer and fall to check for early signs of the parasite. All seven of the chinook salmon taken for the sample on Thursday came from near the mouth of Blue Creek on the mainstem of the Klamath River.
“Right now, with the water temperature so warm that is really the only place you are going to find salmon, either there or right at the lip of the estuary,” Belchik said. “The ich doesn’t survive in salt water, so we aren’t that interested in fish that have just come in from the ocean. We have been concentrating on Blue Creek but when the water temperatures cool down and the run commences we will diversify our sampling places.
“Even now,” he said, “we are going to look at the estuary to see if we find any down there.”
While finding ich in the Klamath is always concerning for the tribe, Belchik said the effect the parasite may have on the 2016 fall run, already predicted to be one of the smallest in recent years, is still unknown.
“I think right now we are trying to assess exactly what it means, I am not ready to just sound the alarm bells,” Belchik said. “It is never good news when you find ich here, but there are not all that many fish in the river yet. We are conducting sampling to figure out the extent of it and what it means. The take home message is that we are going to work with our Federal, state and tribal co-managers to figure out what our next steps should be.”
In the past, ich infections have been battled by increasing flows on the Klamath River. In the late summer and early fall that means securing releases from the Lewiston Dam on the Trinity River.
The U.S. Department of the Interior Bureau of Reclamation is currently working on an environmental assessment entitled “2016 Lower Klamath River Late-Summer Flow Augmentation From Lewiston Dam,” released for public review on Aug. 2, which aims to address this very issue.
The environmental assessment’s proposed action would kick off with a preventative base flow, starting on Aug. 22, of up to 24,000 acre feet of water from the Lewiston Dam over the course of approximately 30 days, with the intent of meeting a target flow of 2,800 cubic feet per second on the Lower Klamath River.
On Friday the Lower Klamath was flowing at 2,100 cfs according to the U.S. Geological Survey gauge on the Klamath River near Klamath.
Belchik said the Yurok Tribe will be encouraging the Bureau of Reclamation to follow that plan.
In addition to a potential preventative base flow, the environmental assessment also calls for potential preventative pulse flows (bringing the river up to 5,000 cfs over the course of three days) and emergency flows (a target 5,000 cfs on the Klamath for no more than five days) later in the run, if specific qualifying criteria are met.
An unrelated release from the Iron Gate Dam for the Yurok boat dance in Weitchepec, scheduled to be held on Aug. 21, began on Friday. While the release for the boat dance will help to increase flows on the Klamath, the timing is completely coincidental.
“This will provide additional water to the lower Klamath River for several days,” Hunt said in an email to the Triplicate. “At the same time, we will be working with our Federal, State, and Tribal partners to evaluate the severity of the Ich outbreak and risk to a die-off of adult fall run salmon as our next steps to potential implementation of a flow augmentation release from Lewiston Dam on the Trinity River. The final EA and a decision document are expected to be released soon and additional monitoring information gathered over this weekend will be used to help inform our decision.”
The Bureau of Reclamation’s environmental assesment can be viewed in its entirety at http://www.usbr.gov/mp/nepa/nepa_projdetails.cfm?Project_ID=26477.
Reach Michael Zogg at firstname.lastname@example.org.