Copepod assemblages in surface waters of the western Gulf of Mexico

Composition, distribution, and abundance of the pelagic copepods collected in surface waters of the western Gulf of Mexico during the EMOAPI cruise (May, 1993), were determined. A total of 55 species were identified. The most abundant were Temora turbinata, Clausocalanus furcatus, Paracalanus aculeatus, and Corycaeus speciosus; together they constituted more than 50% of the copepods in numbers. From cluster analysis (Bray-Curtis Index) using the 12 most abundant copepod species, four faunistic assemblages were recognized. Their arrangement in the surveyed area followed the conditions of the coastal-oceanic gradient. Resulting assemblages were compared with previous surveys and constitute a detailed description of faunal variations of the copepod community in the area. The structure of the local copepod community was related to the prevailing hydrographic conditions dominated by heavy land effluents and by the intrusion of an oceanic front into the shelf area mainly related to the presence of an eddy derived from the Loop Current. Differences in copepod community structure seem to be related mainly to variations within the coastal-oceanic gradient.