K. E. Kulzer

Two bluegill subspecies (common bluegill Lepomis macrochirus macrochirus and coppernose bluegill L. m. purpurescens) were subjected to cold tolerance tests in the laboratory. Juvenile and adult bluegills were exposed to water temperature decreases of 1°C/hour from acclimation temperatures of 20° and 30° C until loss of equilibrium. Response temperatures of both subspecies were similar; temperatures at which 50% oftest fish lost equilibrium were usually <1.0° C lower for common bluegill and overlapping occurred in fiducial limits. Bluegill acclimated to 20° C lost equilibrium at 0.6...

Natural reproduction of hybrid striped bass (Marone chrysops x M.saxatiUs) was documented in Lake Palestine, Texas. Electrophoresis and isoelectric focusing analysis indicated 29% of the sampled Marone spp. were non F-l hybrids. These individuals apparently resulted when F-l hybrids reproduced with white bass and/or F-l hybrids. Age analysis revealed the non F-l hybrids were from years when hybrid striped bass were not stocked.