Larval rearing and production of spat of the oysterCrassostrea madrasensis (Preston) in anExperimental hatchery

The Indian backwater oyster, Crassostrea madrasensis, was spawned in the laboratory at Tuticorin. The larvae were reared and the spat settled in 15-20 days. Two species of jihytoflagellates, Isochrysis galbana and Pavlova sp. were isolated from the natural environment, cultured in mass scale and given as food throughout the larval period. Early stages of the development of fertilized egg, successive stages of developing larvae, and metamorphosis to the spat have been described. The methodology of the production of cultchless spat and rearing the post-set oysters are discussed.