Growth and survival of Pinctada martensii (Dunker) postlarvae under concurrent variation in temperature, algal ration and stocking density

Abstract

The growth and survival of pearl oyster postlarvae (Pinctada martensii) were studied under laboratory conditions. A face-centered central composite experimental design was used with 3 factors, temperature (18―34 °C), algal ration (5―100 cells μL―1) and stocking density (0.2―3.0 in.. mL―1). Pearl oyster postlarvae were fed with a 1: 1 mixture of Isochrysis zhanjiangensis and Pavlova viridis during the experiment. Temperature, algal ration and stocking density exerted significant effects on postlarvae growth and survival. Temperature was the most dominant factor, followed by algal ration. Significant interactions among the 3 factors were inhibitory (negative) to growth and survival. Within the ranges of 3 factors tested, growth and survival increased with 3 factors up to a pinnacle, beyond which they began to decrease. The conditions required for the optimal growth could also ensure the optimal survival. Through simultaneously maximizing the reliable models of postlarvae growth and survival, the optimal trifactor culture conditions of 27.86 °C/50.85 cells μL―1/1.60 in.. mL―1 were obtained. These optimal culture conditions resulted in the greatest specific growth of 8.95 % d―1 (95 % confidence interval, 8.73―9.18 % d―1) and survival of 21.5 % (95 % confidence interval, 21.06―21.94 %), with desirability as high as 99.6 %. Due to practical feasibility, the optimal trifactor culture conditions were recommended to apply to practice to maximize growth and survival of the pearl oyster P. martensii postlarvae martensii. This study provides valuable new insights into refining the production efficiency of the pearl oyster postlarvae.