Performance of domesticated striped bass Morone saxatilis, palmetto bass and backcross hybrid striped bass (sunshine bass female X striped bass male) raised in a tank culture system

摘要

Grow-out performance of striped bass, palmetto bass (Morone saxatilis female X M. chrysops male) and backcross hybrids [sunshine bass female (M. chrysops female X M. saxatilis male) X M. saxatilis male] was examined in a 2-part study. During part 1fish (mean weight = 20.1 g) were stocked at a density of 56 fish/m3 in 1.8-m3 cylindrical fibreglass tanks connected to a central biological filter. Fish were fed a 38%-protein trout ration daily and the study duration was 273 days. At harvest, no differences (P>0.05) in mean weight or feed conversion were detected among the fish types. There were differences in specific growth; the striped bass had a significantly higher growth rate than the palmetto bass and the backcross hybrids had intermediate rates. The condition factor for striped bass was also significantly lower (1.2) than that recorded for either of the other 2 groups (P<0.05). Survival of striped bass (91%) was significantly (P<0.05) higher than that of backcross hybrids (74%), while survival of palmetto bass (87%) was intermediate. The survival of backcross hybrids was adversely affected by an infestation of dinoflagellates Amyloodinium sp. During part 2 of the study stocking density in each tank was reduced to 19 fish/m3. The study lasted104 days. At harvest, no differences were detected in weight, survival or feed conversion. There were significant differences in specific growth, length and condition factor. Striped bass and backcross hybrids gained weight faster than palmetto bass. Length and condition factor were inversely related, all groups being significantly (P<0.05) different. Striped bass had the largest total length and the lowest condition factor; palmetto bass were the shortest and had the highest condition factor.