SUMMER STEELHEAD RESISTANCE TO 


CERATOMYXA shasta BY STOCK


IN WILLAMETTE RIVER





						Percent Deaths


Stock Crosses					Due to C. shasta


										                








Skamania X Skamania


(Native to Columbia R.)				3





Umpqua X Umpqua


(Coastal native)				99





Siletz X Siletz


(Coastal native)				97





Umpqua X Skamania


(hybrid cross)					49





Skamania X Umpqua


(Hybrid cross)					47





Siletz X Skamania				67


(Hybrid cross)		





Skamania X Siletz


(Hybrid cross)					68


                                                                 


Source:  ODFW 1982





NOTE:Certatomyxa shasta is a disease indigenous to 


the Columbia River basin.  This research tests the 


resistance of steelhead derived from native 


Columbia R. stock (Skamania Hatchery stock) to 


this disease relative to resistance of non-native 


stocks (Umpqua and Siletz). This data shows that 


native stock has a high resistance to C. shasta 


while non-native stocks do not.  In addition, 


crosses between native and non-native stocks 


resulted in an intermediate level of resistance to 


this disease.