I am primarily interested in the distributions, abundances and interactions of pelagic marine organisms. The open sea is a vast three-dimensional environment, seemingly homogeneous and thinly populated when compared to benthic or terrestrial habitats, yet pelagic animals everywhere routinely occur in local aggregations at densities that exceed by far the population sizes estimated by traditional oceanographic techniques. Most of the interesting events in the sea occur within or near these aggregations, and we attempt to understand the causes for their formation and the subsequent dynamics of the organisms. My research concerns both physical and behavioral factors that generate and maintain these aggregations. 1.We investigate fine-scale physical and chemical structure of the sea in order to understand how pelagic animals respond to subtle differences in the water column. In particular we examine how eddies, fronts, shear zones, thermoclines, Langmuir cells and odor trails generate patchy distributions of pelagic organisms. Currently we are investigating these phenomena off the coast of southern California via UCLA research vessels and in the isolated marine lakes of Palau in the western tropical Pacific. 2.We examine the ecological role of behavior in plankton and in fishes in the open ocean via SCUBA in the upper ocean and via submersibles and remotely operated vehicles (ROVS) in the deep sea. We have conducted behavioral studies in the Antarctic, the Gulf of California, the Caribbean, and the Pacific. In situ research is supplemented with laboratory studies of planktonic animals and fishes maintained in specially designed aquariums.