Zusammenfassung: The paper discusses the links between fish stock assessment and economics of fisheries, as perceived by a fisheries biologist. It focuses on the type and format of data required from the biological side as well as the economic side, to merge the biological and the economic methodologies into a bio-economic methodology. The biological methodology in question derives from the analytical approach, which operates with cohorts and size distributions of several stocks exploited by several fleets fishing on several fishing grounds. The economic methodology comprises costs and earnings analysis of the harvesting and the processing sectors, and computations of indicators for the economic performance of the sub-sectors. The paper is based on applications of bio-economics to tropical fisheries (targeting at shrimps). The methodology has been applied during a series of workshops and seminars organized by the Fisheries Department of FA0. The paper addresses both biologists and economists.