Effect of stocking density on the growth and survival of spotted sand bassParalabrax maculatofasciatus larvae in a closed recirculating system

The effect on growth and survival of the initial stocking density (50, 100, 150, and 700 larvae/L) in larval rearing of spotted sand bass was evaluate d over 30 d in a closed recirculating system. Larvae were fed with rotifers . copepods. nauplii and adult Artemia. and spotted sand bass yolk-sac larva e. Water quality was monitored daily. The notochordal or standard length of sampled larvae was measured by image analysis, Specific growth rates at ea ch density were corn pared by covariance analysis. Survival was estimated f rom day 15 to the end of the experiment, when a resistance test was used to evaluate the juvenile quality amt,ng densities. At the end of the experime nt, mean standard length of larvae at lower densities was significantly lar ger (P < 0.05) than at higher densities. Higher specific growth rates were found at lower densities. Significantly higher survival (P < 0.051 was reco rded for the lowest density, bur the highest number of harvested fish was o btained with the highest densities (150 and 700 larvae/L). The lowest densi ty also showed the significantly (P < 0.05) higher survival after using a r esistance test. We conclude the highest density can be used in larval reari ng of spotted sand bass. However, better survival, growth, and seed quality are obtained at the lowest density. To recommend an optimal density for th is specie, it is necessary to improve the water quality in the culture syst em and to make a cost-benefit study.