Thursday June 11, 2026
KOBI 5 —
Low winter snowpack and warmer-than-average spring temperatures have triggered elevated levels of the Ceratonova shasta parasite in the Klamath River. This has been leading to recent die-offs of juvenile salmon. Oregon State University researchers monitoring the river say that the warmer water accelerates both the ecosystem’s metabolism and parasite proliferation. Water samples taken through out the spring have been showing dangerous parasite levels at multiple lower basin sites. By June, water sampling detected the parasite at all six sites
The complex life cycle of the C. shasta parasite involves a worm host and the salmon host, with the parasite multiplying rapidly and returning to the water as temperatures rise. Sascha Hallett, a research associate professor at OSU’s Parasite Host Interactions Lab, explained that this year’s winter precipitation primarily fell as rain rather than snow. This has resulted in a lack of cool snowmelt and consequently lower river flows and warmer water. These conditions have proven fatal for some juvenile salmon, particularly recent hatchery releases, whose bodies have been observed by California Department of Fish and Wildlife washing up along the river’s shores over the last two weeks.