Abstract

Visual census of three coral reef fishes communities of South Mexican Caribbean were made from March to July 1997. Those reefs are subject to different levels of exploitation. Fishing and eco-tourism are the most widespread human activities in the litoral in Mexican Caribbean Sea. Composition, biomass and trophic structure of one hundred and thirty-four species of reef fishes associated with five reef habitats were analized at 60 sites sampled. Fifty-three percent of species recorded were present at Boca Paila Reef (in the north zone of Sian Ka’an Biosphere Reserve), 50 % at Tampalam Reef (in the south of the same reserve), and 76% at Majahual Reef (out of the protected area). The divertsity of species was higher at Majahual’s fishing site (0.948 Simpson’s index) than the protected reefs, Boca Paila (0.924) and Tampalam (0.928). There was not a significant difference (P>0.05) between the mean fishes’ biomass in the three reefs. The same thing happened with the mean sire comparaison at the three reefs. The relation of fish species from different trophic groups was approximately the same for the three zones. The generalized carnivorous was the major feeding category (25%). followed by plant and detritus feeders (20%) and “shelled” invertebrate feeders (15%). Canonical correspondence analysis between fifteen environmental variables and the more representative species (abundance, biomass and trophic structure) was carried out to visualize and describe the differential habitat preferences (niches) of fish species via an ordination diagram. The environmental factors that determine significatively the community structure were, in the order of importance: topographic complexity, depth, algal cover, current direction, and coral seagrass and gorgonias cover.

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