Management of an inshore fishery on the French Atlantic coast is a complex business requiring an understanding of how fishing enterprises work because of the impact they have on fisheries management. An acceptable management decision was reached through parallel changes in the rules concerning fishing licences and in the relative priorities of the objectives of the different parties and interests. An understanding of how fishing enterprises take their decisions is shown to be useful in negotiating towards an adaptive consensus conclusion. It allows management measures to be adjusted towards projected objectives, goals determined, and priority allocated. Following previous system studies in agriculture development, groups of fishing enterprises have to be defined on the basis of their present state and their (often long-term and unstated) objectives. This vision of public fishery management as a process of system regulation underlines the importance of shared information in facilitating desirable collective action.