Nutritional value of microalgae-based diets for lions-paw scallop (Nodipecten subnodosus) juveniles reared at different temperatures

We studied the nutritional value of mono, binary, and ternary algal diets for the juvenile lions-paw scallop Nodipecten subnodosus reared at four temperatures: 16, 20, 24, and 28 °C. Live diets included one monoalgal (Isochrysis galbana), three binary (I. galbana + Pavlova salina, I. galbana + Chaetoceros muelleri, and P. salina + C. muelleri) and one ternary (I. galbana + P. salina + C. muelleri) mixtures of microalgae. Scallop responses were measured as survival, growth in shell height and wet and dry weight, and respiratory rate. Scallops grew significantly larger (6.81 mm; 39.75 g) and faster (0.13 mm d− 1; 1.11 g d− 1) and had higher respiratory rates (1326 mg O2 min− 1 mg− 1 dry weight of meat) when fed P. salina + C. muelleri and kept at 28 °C and 24 °C. In contrast, scallops grew significantly less (2.72 mm; 5.54 g) and slower (0.01 mm d− 1; 0.05 g d− 1), and had a lower respiratory rate (670 mg O2 min− 1 mg− 1 dry weight of meat) with a diet exclusively of I. galbana at 16 °C. Growth rates were significantly related to nutritional indices that include protein content. These results indicate the importance of this nutrient in juvenile growth, which is useful for optimizing culturing programs for this commercially important bivalve.

► Scallops fed P. salina + C. muelleri at 28 °C and 24 °C grew larger and faster.
► Scallop growth was poor at 16 °C with a monoalgal diet of I. galbana.
► Binary diets supported, at all temperatures, faster growth than the ternary diet.
► Growth was significantly related to nutritional indices that included protein content.