The final report summarizes research on the bioassay aspects of aquatic toxicology conducted during the period 1 December 1961 - 30 November 1962. The report presents research findings and conclusions, together with descriptions of new apparatus to the extent that their descriptions are judged useful to researchers and others interested in this approach to the study of living organisms. The experiments reported herein were designed to test the amenability of a specific behavioral or physiological parameter of toxic response to quantitative bioassay procedures. Only those aspects which clearly demonstrated features permitting quantification of biologically significant response mechanisms were carried beyond a cursory examination.