REPRODUCTION IN AN AGGREGATING GROUPER, THE RED HIND, EPINEPHELUS-GUTTATUS

We examined the reproductive pattern of an aggregating grouper, the re d hind, Epinephelus guttatus, in Puerto Rico. Macroscopic and histolog ical examination of gonads confirmed that, although mature, ripe ovari es are found over a three-month period, spawning activity is limited t o about 2 weeks each year. Females are determinate spawners and indivi duals are able to spawn more than once during the course of the annual spawning season. The red hind is protogynous and 50% maturity is atta ined at 215 mm fork length. In western Puerto Rico, spawning occurs in aggregations at several sites within loosely defined areas located to wards the edge of the insular platform. Sex ratios of individuals take n by hook and line at one of the aggregation areas over a consecutive six-year period, suggest considerable intra- and inter-annual variatio n most likely attributable to a combination of differential ingress an d egress by males and females during the course of an aggregation and to fluctuations in recruitment, differential mortality by sex and sex change among years. A comparative assessment of the reproductive patte rns of seven western Atlantic Epinephelus spp. suggests that aggregati on-spawning is associated with medium- to large-sized groupers, while smaller groupers do not aggregate. Mating systems vary among congeners in association with trends in male-female size dimorphism, sexual pat tern and sperm competition. The short-term, localized, nature of spawn ing aggregations renders species with this reproductive mode particula rly vulnerable to fishing pressure at spawning sites. Aggregating spec ies, therefore, may require special management consideration.