Strain evaluation of striped bass (Morone saxatilis) cultured at different salinities

Abstract

Striped bass (Morone saxatilis) and their hybrids have been well studied and are widely cultured in freshwater ponds as food and gamefish. Recent industry expansion has generated an interest in strain-specific broodstock development for marine netpen and pond culture. In this effort, Atlantic and Gulf coast striped bass strains were cultured in recirculating aquaculture systems (RAS) at different salinities for up to two years and production and morphometric parameters (specific growth, feed conversion, fillet yield, condition factor and stripe patterns) were compared. Striped bass juveniles produced from wild-caught broodstock from rivers in Nova Scotia, Delaware, Virginia, North and South Carolina, Florida, Texas and a selected, domesticated strain were reared in triplicate fresh (0 ppt), brackish (5 ppt) and saltwater recirculating (30 ppt) systems. After one year of age, a subset of fish were implanted with passive integrated transponder (PIT) tags, combined into a larger, “common-garden”, saltwater, recirculating system and monitored over an additional year. Parental broodstock and cultured offspring were fin-clipped and genotyped to identify juvenile family origin. Final weights of fish after one and two years averaged approximately 0.5 and 2.5 kg, respectively and did not differ by water salinity. Growth rates and condition factors differed by strain, but condition factor was not correlated with fillet yield. Consistent with other studies, juvenile fish from South Carolina and Nova Scotia were found to be slow growing compared to migratory Atlantic and Gulf strains. Mixed model analyses showed that family, and family by strain interactions were significant, but accounted for less growth variance than strain alone. These results indicate that family-based selection by strain may be useful in striped bass broodstock development programs.