Influence of habitat on grouper abundance in the Florida Keys, USA

There was a significant inshore to offshore pattern in grouper species comp osition and density on Florida Keys coral reefs. Red grouper Epinephelus mo rio and black grouper Mycteropercu bonaci were most abundant on inshore pat ch reefs. Graysby Cephalopholis cruentata was most abundant on offshore ree f types. Density among sites ranged from 0 to 0.43, 0 to 0.26 and 0 to 1.23 100m(-2) for red grouper, black grouper, and graysby, respectively. Groupe r density exhibited no consistency among sites within similar reef types. T he densities of red and black grouper were correlated significantly with ei ther physical or biotic habitat parameters. Graysby were observed in microh abitats with whose benthic features differed significantly from the surroun ding habitat. This species was observed in high-relief areas with significa ntly less octocoral species and colony densities. Larger graysby were obser ved in areas of higher relief and less octocorals than smaller graysby. Hab itat was one of several important factors influencing the distribution of g roupers among coral reefs types in the Florida Keys. (C) 2001 The Fisheries Society of the British Isles.