Physioecology of Tropical Marine Copepods. I. Size Variations')

Size variations of two species of copepods collected off the west coast of Barbados were determined on an approximate fortnightly basis over a study period of two years. The observed variations were random rather than regularly recurring based on seasons and appeared not to be linked to temperature. Attempts were made to correlate prior food supply with present size. Some positive correlations between phytoplankton numbers and zooplankton dry weights and respective sizes of female Temora stylifera and Oncaea mediterranea were established. The male of the latter showed no size-food relationship. The results are discussed in the context of the theory of r and K selection. It was concluded that the reproductive strategies are a compromise between two conflicting demands, namely production of the largest possible clutch size (r selection) and achieving highest possible individual fitness (size) of the offspring (K selection).