Abstract:
Population of giant clam has been decreasing severely in many regions due to
harvesting and stress-induced bleaching. Mariculture studies have been directed to
focus on artificial spawning induction, rearing of larvae and relationship of
zooxanthellae to host nutrition. However, data for this purpose is specifically lacking
in Malaysia especially for Tridacna maxima. This study was done to describe the
artificial spawning induction events in broodstocks using Serotonin and the early life
development from embryo to larvae morphologically. Furthennore, was to detennine
the physiological behaviour of adults as a response to temperature in tenns of
photosynthesis and respiration. Three trials were conducted using 1 ml of 2 mM
serotonin honnone to induce spawning in four different broodstocks. Sperm were
released after 1-2 min after injection and lasted for about 10 min while eggs released
took place after about 13 min and lasts about 45- 75 min. After fertilization, the
survival and growth of larvae collected were followed until pre-metamorphosis stage.
Larval survival was 21.62 % at day 2 and 0.11 % at day 4. On day 6 whole batch of
culture collapsed because of bacterial contamination. Size of unfertilized eggs was
102.78 ± 2.78 µm and reached larvae size of 145.56 ± 8.08 µm on day 6. Increase in
total shell length and width length is more noticeable compared to hinge length.
Morphological study was carried out using light compound microscope.
