Aspects of the reproduction of two groupers, Epinephelus guttatus and E. striatus in the West Indies

Epinephelus guttatus aggregated and spawned along the shelf edge off southwestern Puerto Rico around the full moon in January and February 1979. Males patrolled territories containing several females. Two spawnings were observed low in the water column shortly before sunset 1 day after full moon. Eggs were 0.97 × 0.96 mm, and hatched in 27 h at 26.5°C and about 31 h at 25.5°C. E. striatus aggregated and almost certainly spawned at the eastern ends of the Cayman Islands around the full moon in January 1978. There was no distinct size-sex differentiation among individuals of both species from commercial catches. The importance of aggregations to spawning success in Epinephelines is poorly known. Larvae from the Puerto Rico spawning area could potentially reach at least to Hispaniola, Jamaica, Cuba, Turks and Caicos Islands and the southeastern Bahamas. This population is almost certainly not self-recruiting, but other populations of E. guttatus elsewhere may be. E. striatus is believed to locate aggregation sites in the Cayman Islands by moving upcurrent along the shelf edge to the eastern ends of the islands. Downcurrent ends of islands may not be feasible aggregation sites. Currents in the Cayman Sea are complicated, but the Cayman Islands' populations are potentially self-recruiting. The full moon may be a superior (to the new moon) aggregation and spawning cue, particularly in areas of weak tidal currents. Timing and location of spawning by groupers may be due to the needs of adults rather than oceanographic conditions favoring survival of the young.