Effect of larval density on growth and survival of the Pacific oyster Crassostrea gigas in a recirculation aquaculture system

Abstract

The present study determined the effect of larval stocking density on larval yield (number of live larvae at the end of the experiment), competent larvae (number of live larvae at the end of the experiment retained on a sieve with mesh size of 236 μm (1st experiment) and 239 μm (2nd experiment)), and larval shell length of Crassostrea gigas in a recirculation aquaculture system (RAS). Two experiments were performed at different larval stocking densities: 50, 100 and 150 larvae mL−1 (1st experiment) and 50, 75 and 100 larvae mL−1 (2nd experiment). We used 250 L tanks and a randomized block design with three replicates per treatment (larval density). The physical and chemical parameters of the water were stable in all treatments during the experimental period. Our results demonstrated the feasibility of producing Crassostrea gigas larvae in a RAS at larval densities of 50 and 75 larvae mL−1; however, rearing larvae at densities of 50 larvae mL−1 resulted in the best growth and highest proportion of competent larvae. This RAS approach could be used to optimize larval rearing and improve both the resource efficiency and profitability of commercial hatcheries.