|Abstract or Summary
- Oregon Department of Fish and Wildlife trout broodstocks from Alsea, Cole Rivers, Klamath, Leaburg, Oak Springs, Roaring River and Willamette Fish Hatcheries were examined for the presence of myxosporidans. Wild fish collected from waters above these hatcheries were also examined. Seven species of myxosporidans were observed in the hatchery broodfish: Chloromyxum sp., Chloromyxum majori, Hennequya sp., Myxidium minteri, two Myxobolus sp. and Myxosoma squamalis. Two of the above species, Chloromyxum sp. and Hennequya sp., were not seen in the wild fish samples. Two myxosporidans not observed in hatchery fish, Myxobolus insidiosus and Myxobolus kisutchi, were found in wild fish. Chloromyxum majori was present in fish from Alsea and Leaburg Fish Hatcheries and the North Fork of the Alsea and Roaring Rivers. Chloromyxum sp. was observed from fish at Cole Rivers and Klamath Fish Hatcheries. Broodfish from Cole Rivers and Roaring River Fish Hatcheries hosted Hennequya species. Myxidium minteri was found at Alsea, Leaburg, Oak Springs and Roaring River Fish Hatcheries and in the North Fork of the Alsea River, Roaring River and Salmon Creek. Myxobolus insidiosus was observed in wild fish from the McKenzie River, the North Fork of the Alsea River, Roaring River and Salmon Creek. A Myxobolus sp. similar to M. insidiosus in morphology and size was observed in fish from Roaring River and Willamette Fish Hatcheries and from the McKenzie River, the North Fork of the Alsea River, Roaring River and Salmon Creek. Myxobolus kisutchi was noted at only one location, the North Fork of the Alsea River, while a Myxobolus sp. resembling M. kisutchi in morphology and tissue specificity was observed in fish from Cole Rivers Fish Hatchery and the Rogue River. Broodfish from Cole Rivers Fish Hatchery and wild trout from the North Fork of the Alsea River hosted Myxosoma squamalis. The ratio of infected to uninfected fish examined at each location ranged from 12-56% in the broodfish and from 20-76% in the wild fish. Forty-one out of the 47 infected hatchery broodfish hosted coelozoic myxosporidans, while seven broodfish were infected with histozoic species. All 48 infected wild fish hosted at least one histozoic form; only four wild fish carried coelozoic myxosporidans. Three out of the 175 broodfish examined hosted more than one myxosporidan; seven multiple infections were noted in the 107 wild trout examined.