Developing coral trout, Plectropomus leopardus larviculture technology: application of floating skimmer

Abstract

Abstract Coral trout Plectopomus leopardus seed production has not been established well compared to other popular groupers such as tiger and hybrid grouper. Thus, the research has been focusing on the protocol construction of larviculture to improve survival and productivity. This study aimed to evaluate the application of floating skimmer to encourage swim bladder inflation in order to increase survival. Coral trout eggs were stocked in 5,000 L concrete tanks. Rotifer fed started on Day 2 (D2) afternoon and copepods nauplii on D4. Oil was dropped on the rearing water surface from D1 to D5 for without application of floating skimmer (control) and to D3 for with the application. A floating skimmer was installed on the surface of rearing water from D3 afternoons to D10. The survival rate was determined on D50. The results showed that application floating skimmer had a significantly higher survival rate (6.18±1.4 %) than without application (5.28±1.64%) (p<0.05). Observation under a microscope confirmed that swim bladder inflation first noticed on D4. The application of floating skimmer promoted a higher swim bladder inflation rate than without skimmer. From an economical aspect, application of skimmer in coral trout larviculture resulted in higher profit.