The zooplankton groups in general, and the copepoda group in particular, were determined and quantified. Changes were observed in their latitudinal distributions in the area between 6¿00' and 12¿38'S and up to 270 n. mi (513 km) off the coast during January and February 1983. The biomass fluctuated between 3 and 18 mL m-2, where the highest values are given by organisms typical of subtropical surface waters such as giltheads, appendicularians, and oceanic copepods. Because of the tropicalizing effect of the study area, a density decrease of larval stages of zooplankton typical for the area was observed, while prawn larval stages, unusual for the area, were found. Futhermore, there is a significant increase of carnivorous and omnivorous genera of the Copepoda group, such as Centropages, Candacia, Euchaeta, and Labidocera, all identified as predators of anchovy and sardine larvae. ¿ American Geophysical Union 1987