A study of the offshore zooplankton of the tropical western Atlantic near Barbados

A series of 95 zooplankton samples from 400 m to the surface and 94 samples at the surface were collected over a period of 28 months at an offshore station near Barbados, West Indies, latitude BOI5'N, longitude 59°42'W. Average zooplankton wet volume of the oblique samples was 0.020 ± 0.001 ml per m3, dry weight 2.180 ± 0.143 mg per m3, and density 155 ± 14 per m3, Positive correlation coefficients of the oblique and surface samples were 0.379 for volume and 0.627 for dry weight. Seasonal variation of plankton biomass were not observed but the average amount of plankton from January to August, 1968.was significantly greater than at other times, probably caused by enrichment of the euphotic zone. The number of zooplankton species observed was 245 and the estimated number about 300. Copepods accounted for about half of the number of animals in most samples. 141 species of copepods were identified: 92 Calanoida, 38 Cyclopoida, 9 Harpactacoida and 2 Caligoida. Twelve species accounted for about 75% of all copepods. No seasonal variations were found in either the abundance or breeding periods of individual species. The biomass and composition of the zooplankton were in most respects comparable with other recent studies in the tropical western Atlantic Ocean.