The planktonic copepod community at Mahahual reef, western Caribbean

The species composition, distribution, and abundance of the copepods collec ted during a 4-d zooplankton survey across a Mahahual coral reef system of the Mexican Caribbean Sea were studied. Highest mean copepod abundance and diversity were observed in the fore-reef in daytime samples. Lowest abundan ces occurred in the reef lagoon and channel at daytime. Forty-five species were identified, with Temora turbinata, Undinula vulgaris, Subeucalanus sub crassus, and Calanopia americana as the most abundant. They belong to a gro up of planktonic copepods dominant in the Caribbean reefs. Cluster analysis revealed a primary (fore-reef) and secondary (reef lagoon, channel) oceani c group, showing the strong oceanic influence across the reef system which was attributed to the narrowness of the shelf and the effect of tidal curre nts and other hydrological features. Overall day-night differences were rel ated to the influence of near-benthic migrating forms. Acartia spinata, an abundant reef lagoon species in the Caribbean, was scarce at Mahahual due t o its breeding cycle. Its scarcity may be correlated with the relatively hi gh diversity in the reef lagoon, an oceanic predominance in the reef system , and relatively low overall copepod densities. The main features of the co pepod community at Mahahual are similar to those found in other regional re ef systems.