Fish, up to 75% of which is supplied by small-scale fisheries, provide well over 30% of the animal protein intake in many African and Asian countries. According to the Food and Agricultural Organization, the annual growth rate of developing country marine food fish production can be increased 35-50%. Small-scale fisheries thus have an obvious potential for alleviating developing world hunger problems, especially given the new opportunities for fish production opened up by the international acceptance of the extended marine economic zone during the 1970's. To help provide decision makers with the extensive information base they need to plan and develop small-scale fisheries, A.I.D. financed a 4-year investigation of small-scale fisheries in Costa Rica, El Salvador, and Guatemala. This study, the results of which are presented in this report, was multidisciplinary in nature, involving specialists in fish biology, food science, resource economics, anthropology, and development administration. To establish the context of the research, the initial section of the report describes the structure and role of information systems, the general nature of developing country small-scale fisheries, and the research setting in the above-named countries. The next two sections contain, respectively, the data collected by specific discipline field tests of various fishery sectors and the analyses of these data. Included are biological surveys of fisheries resources, economic and anthropological surveys of the harvesting sector, food science and technology surveys of handling and processing methods, economic surveys of marketing and consumption, and a survey of fisheries administrators in government. A final section makes recommendations regarding data collection, with emphasis on specifying the quantity and quality of data to be collected in advance; and discusses policy implications in the areas of resource assessment, the fish capture sector, marketing and distribution, fish handling, fish consumption, and fisheries development administration. Included are 380 Spanish and English references (1934-79), plus diagrams, maps, and questionnaires.