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"Juvenile Klamath River Chinook salmon (Oncorhynchus tshawytscha) experience high incidence and severity of infection with the myxosporean parasites Ceratomyxa shasta and Parvicapsula minibicornis during the spring and summer outmigration period (True et al. 2009). From the beginning of May until the week of August 16th 2010, staff from the Yurok Tribal Fisheries Program (YTFP) collected juvenile Chinook salmon (Oncorhynchus tshawytscha) from the Lower Klamath River for an evaluation of the severity and occurrence of fish disease. The project was conducted in cooperation with staff from the U.S. Fish and Wildlife Service (USFWS) California Nevada Fish Health Center, located in Anderson, California. The primary function of YTFP staff was to collect juvenile Chinook salmon specimens, while the USFWS staffs primary function was to analyze the samples for signs and severity of disease. The Trinity division of YTFP has been participating in this study since 2006, while USFWS has had some monitoring of infection rate in place since the 1990’s (Foott et al. 1999).

 

"In the 2010 sampling season for the first time YTFP staff collected samples of unmarked juvenile Chinook in the month of May. This earlier sampling effort was conducted in addition to the hatchery focused sampling that occurs from early June until mid-August, after volitional releases of juvenile Chinook by the hatcheries in the basin. A fraction of juvenile hatchery Chinook salmon are marked in the Klamath Basin yearly. Starting in 2009, 25% of both Iron Gate Hatchery (IGH) and Trinity River Hatchery (TRH) juvenile Chinook were to be marked with an adipose fin clip (ad-clipped) and coded wire tag (CWT). Marked Chinook are of particular interest to USFWS staff because the hatchery of origin is able to be determined using the CWT. Using this information a comparison of vulnerability to disease could be conducted for the two hatcheries’ stocks, increasing understanding of when, where, and to what extent juvenile Chinook salmon become infected with various pathogens including Ceratomixa Shasta ( C. Shasta). Hopefully this information can help identify what role different parts of the basin play in juvenile fish health during outmigration."