Artificial reproduction and embryonic development of surf clam Pseudocardium sachalinense

Artificial breeding techniques of the surf clam Pseudocardium sachalinense including broodstock culture,spawning induction,and larval rearing were investigated for the first time.At water temperature of 22~24 ℃ and salinity of 28~30,fertilized eggs began the first cleavage after 50 min,developed to D-shaped larvae after 20 h,and to the stage of metamorphosis characterized by the appearance of foot and siphon after rearing of 11 d.The larvae grew obviously faster after metamorphosis.Growth rates of shell height and shell length were 16.76 μm/d and 17.68 μm/d before metamorphosis,but became 22.49 μm/d and 23.15 μm/d after metamorphosis.The settlement of the larvae to three different substrata was compared.The highest setting rate was achieved for the barrel bottom without substratum followed by fine sand,plastic sheet and nets.