Annual structure of the copepod community and its associated pelagic environment off Discovery Bay,Jamaica

Monthly samples were collected in oceanic waters off Discovery Bay, Jamaica, in 60- and 200-m vertical hauls, using 200- and 64-m mesh plankton nets, from June 1989 to July 1991. Sixty-nine species of copepods were identified: nauplii, copepodites and adults were separately enumerated. Total copepod abundances (all stages) ranged from 695 to 4120 m^-3 in the upper 60 m, and from 483 to 3319 m^-3 in the 200-m water column, without any clear seasonal pattern. With the exception of temperature, no seasonal variations in physico-chemical (chlorophyll a, S, particulate organic carbon, particulate protein) or biological variables were evident. Nauplii, adults and copepodites of selected taxa, and two chaetognath species, showed no significant variations in body length. Significant variantions in reproductive index were detected for several species, but without seasonal trends; many species appear to be continuous or intermittent breeders. There was no evidence of seasonal pattern in overall community composition or diversity, or evidence of changes due to water mass advection. The copepod community can be divided into a recurrent group of 13 (at 60 m) to 17 (at 200 m) perennial species, present year-round, and associated ephemeral groups of 1 to 3 species, present randomly for 1 to 4 consecutive months. The most plausible explanation of these patterns is that broad areas of the Caribbean Sea are dominated by the community of perennial species, while the ephemeral species represent the superimposed influence of local mesoscale gyres.