Laboratory Evaluation of Effects of Distance and Debris Exposure On Survival and Injury of Juvenile Fish Within a Fish Return System

The Electric Power Research Institute (EPRI) sponsored a laboratory study to determine the effect of fish return length and presence/absence of debris on the survival, injury, and scale loss of juvenile and adult fish.  Two fish return lines of different length (60 m and 305 m) were evaluated.  Species tested included: alewife (Alosa pseudoharengus), 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).  Two fish length groups (25 mm and 50-76 mm) were evaluated during testing to determine if fish length was an important factor in the likelihood of survival, injury, or scale loss.  Injury and scale loss were generally low, but varied among species.  Survival, with the exception of alewife (25 mm size class) and small (25 mm size class) hybrid striped bass, was greater than 90% regardless of fish return length or presence/absence of debris.  In general, there was no consistent pattern demonstrating debris or fish return length effects on survival, injury, and scale loss.