Quantitative and qualitative aspects of the zooplankton and breeding patterns of copepods at two Caribbean coral reef stations

Abstract

Zooplankton samples collected in inshore waters overlying similar coral reef areas at Barbados and Jamaica are compared. Although a good correlation exists between zooplankton numbers, wet volumes and dry weight the fluctuations of these variables appear random with no signs of seasonality at either site. Evidence of an ‘island mass’ effect, expressed in terms of zooplankton biomass, is manifested for both islands. The zooplankton quantitative data, plus nutrient and phytoplankton data from previous studies at the same stations, indicate a similar scale of energy conversions at different trophic levels. A species list of the total zooplankton collected off the two islands is presented. Copepods constitute the major faunal component accounting for 84.4% and 76.0% of the total inshore zooplankton at Barbados and Jamaica, respectively. The differences in the order of importance of zooplankton species common to both stations suggest that unknown factors may place constraints on population sizes of these organisms at either locality. Breeding patterns of various copepods are determined. Reproductive activities of the selected species lack synchronization and seasonal regularity. The copepods investigated are classified into two main groups: (a) continuous breeders and (b) sporadic breeders with or without protracted periods of activity. Only one species, Farranula gracilis, is a continuous breeder at both sites, while Clausocalanus furcatus and Paracalanus aculeatus, numerically the most important organisms at Barbados and Jamaica respectively, are sporadic breeders. Miracia efferata is the only copepod expressing any kind of recognizable periodicity. It is suggested that data on egg production may be used as an index to the biotic potential (BP) of a given species.