Reproductive Patterns of Cayman Islands Nassau Grouper (Epinephelus Striatus) Populations

During five seasons (1987–1991, especially 1989), we monitored reproductive condition of Nassau groupers (Epinephelus striatus) from three major spawning sites near Grand Cayman. In January and February, groupers began aggregating between the first quarter and full moon and spawned between 2 days before and 10 days after the full moon, with high activity near the last quarter moon. The temporal relation between the full moon and spawning might vary by a few days from site to site and year to year. A review of available information indicates that Nassau groupers spawn over a wide range of daylength and with decreasing or increasing water temperature, but mostly at a temperature close to 26°C.