ON THE LARVAL REARING OF THE WHITE‐SPOTTED GREEN GROUPER, Epinephelus amblycephalus (BLEEKER), WITH A DESCRIPTION OF LARVAL DEVELOPMENT

Abstract

ABSTRACTThe white‐spotted green grouper, Epinenephelus amblycephalus (Bleeker), a popular and cmercially important marine food fish in Hong Kong, has been used for intensive cage culture in coastal water for many years. The major constraints to its large‐scale development are, however, the shortage and uncertain supply of fingerlings from the wild. Research efforts have therefore been directed at producing large supplies of fingerlings, either for culture to marketable size or for restocking.Larvae of E. amblycephalus were reared through metamorphosis in 1000‐liter rectangular tanks covered with a large translucent roof. The newly hatched larvae measured 2.0 mm in total length and possessed a large yolk sac. Effects of temperature and salinity on the yolk sac larvae were examined in laboratory experiments. Recommended temperature and salinity for rearing of the early larvae are 24°C and 25–32 Ppt. In the laboratory larvae were fed fertilized oyster eggs, rotifers, Artemia nauplii, copepods and shrimp meat. The developnent stages from hatching through metamorphosis are described. Three mortality peaks were observed during the experiment. The highest larval survival rate through metamorphosis (i.e., 40 days) after hatching was 25%.