RESUMO
Under hatchery conditions (temperature, 23.5-24.0 degrees C; salinity, 29.5-30.0), effects of microalgal diets on growth and survival of the juvenile ark shell, Scapharca broughtonii, were investigated for 24 days by feeding with diets made of single or combinatory use of four different microalgae, Isochrysis galbana, Chlorella sp., Chaetoceros muelleri and Nitzschia closterium. The results showed that the survival rates were over 95% in all diet groups with no significant difference among them. When feeding with single microalgae, the best feeding effects on growth were observed in I. galbana, while the worst effects occurred in Chlorella sp. When feeding with various combinations of microalgae, the optimal effects on shell length and specific growth rate were observed in diets containing I. galbana compared to the other diets. The diet composed of I. galbana and Chlorella sp. (1:1) provided the best effects for S. broughtonii juveniles, resulting in a specific growth rate of 5.6% x d(-1) in shell length and 6.4% x d(-1) in shell height. These results should be valuable to direct the technique optimization of artificial breeding for the hatchery production of S. broughtonii seeds.
