Comparison of Hatchery Performance Between a Whirling-Disease Resistant Strain and Tensleep Strain of Rainbow Trout

Salmonid species vary substantially with respect to both susceptibility and pathology when challenged with Myxobolus cerebralis (O’Grodnick 1979). Even within a species, strain differences in susceptibility have been demonstrated (Densmore et al. 2001). Rainbow trout are generally accepted to be one of the most susceptible species to M. cerebralis infection, yet are one of the most popular sport fish. A resistant rainbow trout strain would provide the sport fish benefits that anglers are accustomed to, while reducing myxospore concentrations in the environment and potentially reducing mortality and deformity among naturally infected fry of susceptible salmonids.