The region of the ocean called the mesopelagic, of midwaters, lies in the depths between -200 and -1000 meters. It covers virtually the entire extent of the world's ocean excepting the continental shelves and small areas around ocean islands; therefore it represents one of the world's largest types of environments. The mesopelagic is characterized by cold, dark waters with ususual life forms but, in general, our knowledge of this huge region is minimal, We know of the accounts of strange fishes and the prevalence of bioluminescent organisms, but little of the distribution, abundance, and behavior of the living things that occupy these depths. Now, with the advent of some extremely sophisticated submersibles that make open water observations very sucessful, our understanding of this ocean region is starting to expand greatly. Dr. Harbison and colleagues have contributed greatly to our initial progress studying the ecology and behavior of animals in the mesopelagic world. They have proposed to conduct some preliminary investigations into the responses of mesopelagic fishes to environmental stimuli (visual and acoustic); they will also make comparisons of traditional vs. submersible sampling techniques using comparisons of traditional vs. submersible sampling techniques used in the midwaters. These studies will provide exciting new findings from this poorly known region and will yield some important information about how effective our past sampling efforts have been in this environment. The Biological Oceanography Program recommends a one-year award at $54,736.