Ages of black sea bass. Cenropristis striata, from the South Atlantic Bight were determined from otoliths. Analysis of marginal increments showed that annulus formation occurred in April and May. The von Bertalanffy growth equation derived from back-calculated mean standard lengths at age was It = 341 (1 - e-O.23f.l9(I+O.3010. where t is age in years and It = standard length at age. The oldest fish was age 10. Centropristi8 striata is a protogynous hermaphrodite that undergoes sex succession at ages 1 through 8. The process of sex succession is described from histological examination of the gonads. The major spawning period is from March to May, and a minor spawn occurs in September-October. Mature males and females were encountered at age 1. Fecundity estimates ranged from 17,000 in a 108 mm SL female to 1,050.000 in a 438 mm SL fish, and were significantly related to length, weight, and age. The instantaneous rate of total mortality of C. striata from catch curve analysis, ranged from 0.721 in 1978 to 1.320 in 1981 for commercial fish traps and 0.726 in 1979 to 1.430 in 1981 for hook-and-Iine gear. Petersen mark-recapture techniques were used to determine the population size of C. striata. on two shallow-water patch reefs. Conversions of these estimates to densities gave 14-125 individuals per hectare.