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Table 1. Summer (mid April - mid September) and winter (mid 

 September - mid April) mortality rates (%) for age 

 II and older trout in study sections of the 

 Madison and Gallatin rivers (unpublished data from 

 R. Vincent, Fisheries Biologist, MDFWP, Bozeman). 



Rainbow Trout - Durnam Study Section - Gallatin River 



Year 



1980-81 



Mortality 



Summer 



17 



Winter 



53 



Annual 



61 



Brown Trout - Varney Study Section - Madison River 



Rainbow Trout - Snoball Study Section - Madison River 



Year 



1980-81 



Mortality (%) 

 Summer Winter 



28 



34 



Annual 



52 



