Evaluation of two sizes of hybrid striped bass for introduction into smallponds

Private recreational fisheries in small impoundments provide a potential ne w market for the growing industry producing hybrid striped bass Morone saxa tilis. We estimated growth, condition, and survival of hybrid striped bass (female striped bass x male white bass M. chrysops) in two small ponds with established fisheries for largemouth bass Micropterus salmoides and bluegi ll Lepomis macrochirus that eventually experienced severe weather-induced f ish kills 266 d and 348 d after stocking. Both ponds were stocked with 40 p hase 2 (120-169 mm total length, TL) and 22 phase 3 (241-344 mm TL) hybrid striped bass/ha. Growth and condition were monitored from introduction unti l the occurrence of fish kills. Fish collections immediately following the kills allowed minimum estimates of survival for time at large before each e vent. Mean growth rates were near 0.35 mm/d for phase 2 hybrids and ranged from 0.13 to 0.21 mm/d for phase 3 hybrids. Mean relative weight (W-r), whi ch at the time of stocking was optimal (100), decreased to near 85 for phas e 2 hybrids and near 75 for phase 3 hybrids after 300 d at large. Adjusted annual survival estimates over the period from stocking until initiation of the fish kills were 42.3% and 58.6% for phase 2 hybrid striped bass and 56 .0% and 66.6% for phase 3 fish. Based on purchase price and relative surviv al of the two size-groups, phase 2 hybrid bass are the more economical choi ce for stocking recreational ponds that have established sport fish communi ties.