This paper reports on embryonic and larval development of the giant clam Tridacna noae. Spawning was induced by serotonin injection into the gonad. Unfertilized eggs had a mean (±SE) diameter of 101.14 ± 0.47 mm and spermatozoa heads were 8.92 ± 0.09 mmlong. Embryonic development had progressed to the 8-cell and 16-cell stages by 3 h postfertilization and to the 32-cell stage by 4 h postfertilization. Rotating gastrulae accounted for 82% of developing embryos at 9 h postfertilization. Trochophore larvae accounted for 54% of embryos at 16 h postfertilization, and 98% of larvae at 20 h postfertilization. Straighthinged (D-stage) veligers comprised 74% of developing larvae at 22 h postfertilization with mean (±SE) anteroposterior measurement (APM) of 146.32 ± 0.58 mm, dorsoventral measurement (DVM) of 118.12 ± 0.74 mm, and hinge length of 77.46 ± 0.73 mmat 24 h postfertilization. At 96 h postfertilization, 74% of veligers had settled but had retained the velum without showing development of the foot and, by 120 h postfertilization, 78% of settled veligers had become pediveligers with a probing foot. The mean (±SE) APM of pediveligers at 144 h postfertilization was 176.50 ± 0.97 mm, DVM was 151.86 ± 1.01 mm, and hinge length was 63.50 ± 0.95 mm. Gills were first observed in settled individuals 11 days after fertilization, indicating completion of metamorphosis. The methods used in this study supported successful larval culture of T. noae and provide a basis for large-scale propagation of this species.
Journal of Shellfish Research / Vol. 35, No. 4, pp.777-783