PRODUCTION OF FUNCTIONAL MALE BROODSTOCK OF CORAL TROUT GROUPER (Plectropomus leopardus)

Fertilization rate of the first generation of c oral trout grouper, Plect r opomusleopardu s from wild broodstock in cultured tank was relatively low of 10 - 35%. Based on g onad histology analysis of 30 sample s, only one male was found in early stage maturation . Therefore, it is needed to increase functional male production to ensure an increase level of egg fertilization. The experiment w asconducted for 9 monthsusing coral trout broodstock, fromwild stockas control and selected F1 from culture as treatment . Broodstockswere reared in three tank s, each was 100 m 3 in volume with 54 fishes /tank. A ll selected cultured fish (F1) in tank C were implanted with 17 a -MT hormone at 50 m g/kg of body weight every month for 3 consecutive months. Wild stock f ish in tank A and selected cultured fish (F1) in tank B were not implant as controls . The result showed that the number of male  increased 6 times in implanted by 17 a -MT hormone compared to fish without implant only increased 2 times . Therefore, eggs fertilization and hatching rate were significantly increased by implanting F1 broodstocks with hormone1 7a-MT.Keywords: Functional male, broodstock, Coral trout ( Plectropomus leopardus )