Refining Broodstock, hatchery and weaning strategies: Key to the Commercial Culture of the Imperiled Giant Grouper

Giant Grouper (E. lanceolatus) is one of the most desirable marine fish in the world. Its robust nature, tremendous growth rate, superb quality flesh and high value make it ideal for open ocean aquaculture. Phase I research marked the first time this species has been reared in the hatchery outside of Southeast Asia. Broodstock nutrition, spawning seasonality and lunar periodicity were defined. Around 6.5 million viable eggs were obtained from four induced spawns. Several dozen larvae were raised to metamorphosis in one tank, but weaning cannibalism was heavy. Further research is needed to define the critical criteria for commercial-scale hatchery culture and growout of this species. Phase II research addressed this need. Broodstock manipulation will strive to extend the natural spawning season and, increase spawn viability. Larval rearing trials will evaluate stocking densities and feeding regimes, and improve overall survival to metamorphosis. Refined diets and passive larval grading mechanisms will be tested to reduce cannibalism around weaning. Growout feed trials will compare affects of commercial diets on growth rates and feed conversion ratios. Fish from selected cohorts and size class will be tested to determine parentage, leading to better understanding of spawning behavior, larval fitness and genetic diversity of offspring.