GROWTH AND DEVELOPMENT OF ATLANTIC MUD CRAB LARVAE FED NATURAL ZOOPLANKTON PREY

Atlantic mud crab larvae (Panopeus herbstii H. Milne Edwards) were fed either brine-shrimp nauplii or natural zooplankton in the laboratory and in large, field-deployed enclosures. Larvae developed fastest in 1 440-1, field-deployed enclosures. By 9 days post hatching, more than 9 0% of the enclosure larvae had reached zoea Stage IV compared to only 50% of the larvae that were fed brine shrimp in small bowls. Larvae fe d natural zooplankton in either 40-1 tanks developed more slowly and w ere still in zoea Stage II after 9 days. Larvae that were fed natural zooplankton in small bowls lost weight during the course of the experi ment. Even though larvae developed most rapidly in field-deployed encl osures, there was no significant difference between the rate of dry-we ight growth of larvae fed brine shrimp in 50-ml bowls and larvae fed n atural zooplankton in enclosures. The greater stage-specific dry weigh t of larvae fed brine shrimp may have been related to the relative ene rgy content of the two diets, while differences in the rates of develo pment may have been related to the respective spatial scales of the di fferent culture techniques. Diel cycles in temperature within the encl osures may have also had an effect on the rate of development.