Stocking Density Effects on Production Characteristics and Body Composition of Market Size Cobia, Rachycentron canadum, Reared in Recirculating Aquaculture Systems

Culture density in excess of a critical threshold can result in a negative relationship between stocking density and fish production. This study was conducted to evaluate production characteristics of juvenile cobia, Rachycentron canadum, reared to market size in production-scale recirculating aquaculture systems (RAS) at three different densities. Cobia (322 +/- 69g initial weight) were reared for 119d at densities to attain a final in-tank biomass of 10, 20, or 30kg/m3. The specific objective was to determine the effects of in-tank crowding resulting from higher biomass per unit rearing volume independent of system loading rates. Survival was 96% among all treatments. Mean final weight ranged from 2.13 to 2.15kg with feed conversion efficiencies of 6566%. No significant differences were detected in growth rate, survival, feed efficiency, or body composition. This study demonstrates that cobia can be reared to >2kg final weight at densities 30kg/m3 under suitable environmental conditions without detrimental effects on production.