Use of species genetic resources in Morone breeding programs

Abstract

The goal of this research project was to determine optimal breeding strategies for improving important traits of Marone species hybrids reared in recirculating aquaculture systems (RAS). Effects of hybridization and backcrossing among striped bass (Marone saxatilis), white bass (M chrysops) and yellow bass (M mississippiensis) on important traits were determined. This dissertation is described in four studies. In the first study, performance of striped bass female x white bass male (SBxWB) and striped bass female x yellow bass male (SBxYB) fingerlings reared in RAS was evaluated. SBxWB were superior to SBxYB for overall mean growth rate and feed conversion. Survival was higher for SBxYB than for SBxWB. Time x hybrid interactions for growth rate indicated that growth rate of SBxYB improved through time relative to that of SBxWB. Time x hybrid interactions for growth may have been due to differential responses ofSBxYB and SBxWB to deterioration of water quality. The slow growth of SBxYB limits its use for aquaculture. In the second study, relationships among total weight, body shape, visceral components and fillet yield were examined in SBxWB and SBxYB in order to evaluate strategies for improving fillet yield. Fillets were heavier (5g per fish) for SBxYB than for SBxWB. Relative increase of fillet weight was slightly greater than total weight in both hybrids indicating that small increases in fillet yield can be achieved by rearing fish to a larger size. Low variation in fillet weight (SD ± 9.6 to 11.3g) and poor predictability of fillet weight from body shape (models with r2s of .27 to .43) in both hybrids indicated that potential for improving fillet yield within hybrids is limited. Identification of superior species or strain crosses appears to be the best strategy for improving fillet yield of Morone hybrids.