Cooperative Fish and Wildlife Research Units Program: Cooperative
Education, Research and Technical Assistance for Managing Our Natural Resources

Aquaculture is one of the fastest growing industries worldwide and Bacterial Coldwater Disease (BCWD), caused by Flavobacterium psychrophilum (Fp), is one of the most important hatchery diseases. Outbreaks of BCWD can result in economic losses to producers of salmon and Rainbow Trout. Antibiotics are used for treatment for BCWD and concerns exist about the development of antibiotic resistance. The US Department of Agriculture (USDA) developed a selection program to create a Rainbow Trout strain that was genetically resistant to BCWD (the PRR strain in Colorado’s state hatchery system). BCWD resistant fish provide another management tool to reduce loss of Rainbow Trout due to BCWD outbreaks in aquaculture. A similar approach has been used to manage Rainbow Trout in the presence of whirling disease (WD). Colorado Parks and Wildlife (CPW) have developed WD resistant strains of Rainbow Trout that retain important wild characteristics, such as the ability to survive and breed in the wild. The state of Colorado has been using WD resistant Rainbow Trout to reestablish populations in the presence of Myxobolus cerebralis (Mc), the parasite that causes WD. Monitoring indicates that natural Rainbow Trout reproduction and recruitment are occurring. We are proposing to produce Rainbow Trout that are genetically resistant to both BCWD and WD. This would minimize the use of antibiotics to control BCWD and produce a fish capable of resisting WD. We propose to develop and evaluate a cross between Rainbow trout that are genetically resistant to BCWD and WD for managing both diseases concurrently.