Effect of algal diet and temperature on survival, growth and biochemical composition of spat of the lion's paw scallop Nodipecten subnodosus

Abstract

To find the best conditions for production, spat of the scallop Nodipecten subnodosus were grown for 10 weeks at 23, 26 or 29 °C, and fed with 2:1 mixtures (cell:cell) of Chaetoceros calcitrans with Pavlova lutheri or Isochrysis sp. (diets M1 and M2) or with a 1:1 mixture of P. lutheri and Isochrysis sp. (diet M3). Mortality was 100% after 4 weeks at 29 °C. Survival was significantly higher with diet M1 than with the other diets, and was 51 and 46% at 23 and 26 °C, respectively. With diets M2 and M3, the respective percentages of survival were 39.39 and 33.84% at 26 °C and 23.03 and 19.85% at 23 °C. The best growth in shell height was with diet M2, but there were no differences in final organic weight between diets M1 and M2; diet M3 gave the lowest spat growth. The highest protein content was with diet M1 at 23 °C. This diet gave the lowest carbohydrate contents of the spat at both temperatures, and the lowest spat lipid content at 23 °C. The fatty acid composition of spat was related to that of the respective diets, and there was no evident relation between dietary fatty acids and spat growth. Our results indicate that N. subnodosus spat should be kept at 26 °C and fed a mixed diet containing C. calcitrans and either P. lutheri or Isochrysis sp.