Evaluation of five microalgal species for the growth of early spat of the Japanese pearl oyster Pinctada fucata martensii

To estimate the food value of five microalgal species, early spat of the Ja panese pearl oyster, Pinctada funcata martensii, were fed five algal specie s separately; Pavlova lutheri, Chaetoceros calcitrans, Tetraselmis tetrathe le, Nitzschia closterium, and Nannochloropsis oculata. The food value of ea ch microalgal species was estimated from the growth rate of hinge length: d ry whole spat, dry shell weight, and dry flesh weight of spat fed each micr oalgal diet over 19 days in the laboratory. C. calcitrans produced the best growth of the pearl oyster spat. P. lutheri and T. tetrathele supported mo derate growth of the spat. However. growth rate of the spat fed Nitzschia c losterium was very low and spat fed Nannochloropsis oculata showed negligib le growth. These results indicate that C. calcitrans is an appropriate micr oalgal diet for rearing pearl oyster spat. P. lutheri and T. tetrathele are also suitable diets for rearing early spat of pearl oysters.