AGE, GROWTH, AND REPRODUCTION OF BLACK GROUPER, MYCTEROPERCA-BONACI, IN FLORIDA WATERS

We examined 1166 black grouper ranging from 155 to 1518 mm TL collecte d in South Florida waters from 1994 to 1996. Among all black grouper t hat we sexed, females ranged from 155 to 1310 mm in length (mean = 696 , n = 834), and males ranged from 947 to 1518 mm (mean = 1255, n = 54) . Ages of 927 black grouper ranging from 155 to 1518 mm TL were estima ted from thin-sectioned otoliths (sagittae). Marginal-increment analys is of grouper 1-7 years old suggested that a single annulus was formed each year during May-June. Black grouper appear to reach a maximum ag e of at least 33 years, but ages of fish older than 7 years are unvali dated. Growth of the black grouper in our study was rapid until an age of about 10 years and then slowed considerably. The von Bertalanffy g rowth equation for black grouper was TL = 1306.2(1-e((-0.169(Age+0.768 )))). Black grouper are protogynous hermaphrodites. We estimated that 50% of the females in the population bad reached sexual maturity by 82 6 mm and an age of 5.2 years. By a length of 1214 mm and an age of 15. 5 years, 50% of the females in our sample had transformed into males. The presence of large females in the population suggests that some fem ales may not transform into males. The scarcity of transitional groupe r (n = 1) in our sample suggests that transition occurs quickly. Black grouper appear to spawn year-round, but peak spawning occurs during w inter and early spring. Vitellogenic oocytes and oocytes in the final stages of maturation were most common during January-March.