Epipelagic copepod assemblages in the western Caribbean Sea (1991)

Zooplankton samples were collected on a four-month schedule (February, Marc h, May, August 1991) off the eastern coast of the Yucatan Peninsula, wester nmost portion of the Caribbean Sea. Taxonomic analysis of the pelagic Copep oda yielded 89 species, Undinula vulgaris, Temora turbinata, and Farranula gracilis being the overall dominant forms. They represented more than 60% o f the copepod numbers during the four months surveyed. The faunistic influe nce of the surface Caribbean water was evident during the entire period in the surveyed area. Mean diversity was moderate and did not show relevant mo nth-to-month variations during the surveyed period. Station clustering with the Bray-Curtis Index suggests the absence of a definite coast-ocean gradi ent in the local copepod community, stations being sorted mainly by density differences. Coastal species were recorded well inside the oceanic zone, a nd oceanic and even mesopelagic forms occurred very near the coast or over the shelf. These effects may result from continuous mixing of coastal and s helf waters with oceanic water because of (1) the narrowness of the contine ntal shelf off the Mexican Caribbean coast, and (2) the effect of local mes oscale circulation patterns. It is suggested that these processes favour th e homogeneity of the local copepod community.