Evaluation of two spawning induction methods and effect of stocking density and microalgal diet composition on larval growth and survival of Pacific clam, Asaphis violascens (Forsskål, 1775)

Abstract

AbstractPacific clam, Asaphis violascens is a benthic species present in the Indo‐pacific region. It is very much appreciated as food by the local community and its population is diminishing due to overfishing. The aim of this research is to establish suitable rearing conditions for its spawning and larviculture. Two different spawning induction methods were used, emersion and thermal shock. Two stocking densities of larvae were tested (10 and 20 larvae/mL) and three different microalgae diets, one consisting of Tisochrysis lutea as a single species diet and the other two with Ti. lutea combined with Nannochloropsis oculata and Tetraselmis suecica. Emersion of clams was established as a successful spawning induction method. Larval development of A. violascens is similar to other tropical bivalves, having a 10‐day planktonic period at 28°C. An initial stocking density of 10 larvae/mL showed significantly higher (p < .05) survival rate. No significant differences (p > .05) in growth and survival were found between the diets, proving that the use of Ti. lutea alone or mixed is suitable for their nutrition. The results presented could contribute to the implementation of restorative aquaculture farms in the region, helping to mitigate food security issues in the communities and collaborating with the establishment of healthier coastal ecosystems.