Effects of Stocking Density on Fry Survival and Growth of Asian Sea Bass (Lates calcarifer)

Survival rate and growth were determined on Asian sea bass Lates calcarifer larvae using stocking densities of 20, 40, 60, 80 larvae/liter. Temperature, pH and dissolved oxygen values were within the favorable levels for the Asian sea bass larvae, as well as unionized ammonia (NH3) and nitrite (NO2) maximum values in all the larval tanks may have affected the overall larval survival. Fry production after 20 days of rearing showed that survival rate of 28% was significantly higher at a stocking density of 20 larvae/l, which was 2-3 times better than at higher larval densities (P 0.05) however there were no significant differences among survival rates 40, 60 and 80 larvae/L with 14.68%, 8.89% and 8.67%, respectively. Significant exponential correlation of R2 = 0.8879 between average survival rate and larval density was observed as increasing larval density resulted in decreasing survival rate. Reduction in survival of about 2% with density was highly significant (P 0.0002), based from the computed relationship of SR = 35.109 e¬¬?0.0197D. Significant differences in larval length were only detected on day 5, however, at higher densities larval density started to decline beginning after day 5, particularly when their number became much less after day 15. Growth rates may have increased such that no significant size differences detected at the end of the larval culture period. A very poor linear relationship (R2 = 0.0806) was obtained between the final larval length at 20 days and larval density.