Development and metamorphosis in coral trout, Plectropomus leopardus: morphological, biochemical and physiological aspects

Studies were conducted on development and metamorphosis of coral trout Plectropomus leopardus. Rearing experiments were conducted at the Japan Sea Farming Association, Yaeyama Station, Okinawa in 1998 to 2000. The findings of this study show that coral trout experience two marked developmental changes related to metamorphosis. First phase is transformation from larva to juvenile at around 10-12 mm SL, when relative growth stabilized, functional digestive system differentiated, fins formation completed and vertebral column ossified. Juvenile in this phase is considered as pelagic juvenile. Second phase of marked changes occurred at around 20 mm SL. These changes include squamation, pigmentation, behavior (settlement and cannibalism) and physiology (surge of T4). This second phase of change is considered as true metamorphosis. In the sea inshore migration to the coral reef habitat is assumed to occur in this phase. It is concluded that coral trout displays a quite different early development from most common marine fishes, being characterized by largely delayed metamorphosis from larva-juvenile transformation.