Zooplankton aggregations such as copepod swarms and mysid schools represent one end of a continuum of plankton patchiness from those controlled mainly by the behavior of the organisms to those controlled mainly by physical concentrating mechanisms. By achieving a better understanding of the factors influencing behaviorally controlled zooplankton aggregations, the range of potential contributions of behavior to other forms of patchiness will become clearer. By understanding the adaptive value of swarming and schooling behavior in zooplankton, the potential effects of patchiness on plankton trophic dynamics will be revealed. This study will focus on several unanswered questions regarding copepod swarms and begin studies of schooling behavior of mysids. In mangrove prop root habitats there are two excellent examples of aggregative behavior in zooplankton: the swarming behavior of the copepod Dioithona oculata and the schooling behavior of the mysid Mysidium columbine. One objective of this study is to determine the sensory information used by D. oculata to find its way back to the mangrove habitat at dawn. D. oculata swarms are also found near coral reefs, where environmental and optical conditions are quite different from mangrove habitats. Swarms near coral reefs will be studied in situ, and the factors affecting swarm formation and maintenance in these environments will be quantified. Mysidium columbine is a holoplanktonic mysid that schools in shaded areas near mangroves. It's well developed compound eyes are thought to have limited visual acuity but highly developed movement perception. The role of vision in the schooling behavior of this species will be investigated by determining the visual threshold and visual acuity of this mysid. The adaptive value of schooling as an anti-predation device and metabolic costs of schooling behavior will also be investigated.
