Substrate effect on growth and survival of the rock oyster Striostrea prismatica (Gray, 1825) cultured in suspended systems in two different ecosystems

The interest in developing a more diverse mollusk aquaculture in the tropical eastern Pacific has increased in recent years. In this region, the rock oyster Striostrea prismatica is being extracted and consumed massively. The species lives attached to large rocks, which offer firmness and stability in their high-energy environment. For aquacultural research purposes, we seek to simulate those natural conditions through artificial fixation of spat with an epoxy adhesive. Spat (initially metamorphosed on pieces of shell of 0.5 mm(2)) with a size of 14.00 +/- 1.85 mm in dorso-ventral length were artificially fixed on substrates: shells, stones, and plastics. In addition, individual non substrate animals from de same cohort were also grown and used as a control. The performance of these spat in suspended culture at sea and estuarine area, together with the environmental variables of each growing site were registered. In the two culture sites and for all treatments, the animals were confined in black polypropylene culture systems. After 12 months, artificially fixed animals (regardless of substrate) had significantly higher lengths (asymptotic to 80 mm) and dry tissue masses (asymptotic to 3 g) compared to non-substrate animals (asymptotic to 46 mm and asymptotic to 0.90 g, respectively). ANOVA did not show significant differences between the sites (blocks) for survival, shell and tissue increases, despite the different environmental conditions characteristic of both areas. Therefore, our study shows that the strategy of artificially fixing the spat is a necessary activity to ensure the good performance of S. prismatica for its cultivation in the sea or in estuarine areas.