1. The seawater hard clam Meretrix lusoria is an important aquaculture species in Asian countries. Its diet comprises mainly microalgae species from the culture ponds. Because of the benefits of n-3 highly unsaturated fatty acids, such as eicosapentaenoic acid and docosahexaenoic acid, toward cardiovascular disease, many cultured aquatic animals are enriched with these fatty acids through dietary treatments to increase their nutritional values. This practice can be applied to bivalve culture using microalgae as the dietary fatty acid provider. (25%)