First published 1984. The intent of the authors in organizing a AAAS symposium and this subsequent volume was to integrate the findings of aquatic ecologists whose research spans the first three trophic levels (algae, zooplankton and fish) of both marine and freshwater environments. Major topics (phytoplankton, zooplankton, fish and community interactions) are presented as, at least, two trophic-level associations by scientists who have distinctly differing perspectives. The format of papers varies from review to research and was chosen by authors on the basis of suitability to their specific topic.