Studies towards advancing reproductive development in giant grouper (Epinephelus lanceolatus Bloch) using recombinant hormone manipulation

Abstract

Groupers are an economically significant commodity owing to the major portion they occupy in the live reef fish trade (LRFT). The giant grouper E. lanceolatus is one of the most sought-after grouper species in the LRFT, and is also a favoured culture species due to its fast growth rate. Captive breeding of giant grouper, however, is challenging due to its large size at sexual maturation, where females mature at 20 kg while males can reach more than 100 kg body weight. Thus, handling is complicated and operational cost is more expensive due to larger facility and additional food and labour required. Giant grouper matures at a late age (~4 years) hence a long period of broodstock conditioning is required before spawning is achieved. In addition, being protogynous hermaphrodites, initially maturing as female and then changing into male, securing broodstock of both sexes is challenging. This thesis is aimed at inducing early sexual maturation in giant grouper using recombinant hormone manipulation so that captive breeding could be done with a younger and smaller broodstock.