Dr. Michael Blouin (OSU Integrative Biology), Dr. Jerri Bartholomew (OSU Microbiology), and ODFW Fish Health Services studied hatchery effects on disease resistance in rainbow trout. Oregon has over 30 fish hatcheries that protect and propagate fish. ODFW worked with OSU to answer two overarching questions on the interactions between hatchery and wild fish: (1) What is their comparative fitness (regarding disease resistance)?
(2) Are pathogens transferred between hatchery and free-ranging fish? Different salmonid species and stocks were studied using sentinel fish exposures and lab experiments.
There were no differences between hatchery and wildfish on disease resistance in rainbow trout. Sentinel fish held downstream of hatcheries undergoing epizootics developed infection with the same pathogen but effects depended on distance, dilution and the specific pathogen.