Laboratory Evaluation of Post-Impingement Survival of Juvenile and Adult Fish With a Rotary-Disc Screen

The Electric Power Research Institute (EPRI) sponsored a laboratory study to gather biological performance data for the Passavant-Geiger Rotary-disc screen.  In particular, the effect of approach velocity, screen mesh, and fish length were evaluated for their effect on species-specific  fish survival, injury, and scale loss with juvenile and adult fish.  Species tested included: golden shiner (Notemigonus crysoleucas); channel catfish (Ictalurus punctatus); hybrid striped bass (Morone chrysops × M. saxatilis); bluegill (Lepomis macrochirus); largemouth bass (Micropterus salmoides); and common carp (Cyprinus carpio).  Fish were impinged at 0.3, 0.6, or 0.9 m·s^-1 approach velocity using a screen with either 2.0-mm woven wire or 9.5-mm perforated plastic mesh.  Mortality, injury, and scale loss were generally low (<10%), but varied by species.  For most species, survival was significantly correlated to velocity, with a decrease in survival as velocity increased.  For most combinations of species and mesh type, survival was significantly correlated to fish length, with larger fish surviving better than smaller fish.  In some cases, there were differences in survival associated with mesh type.  In all cases when this was true, survival was higher with the 2.0-mm mesh than the 9.5-mm mesh.