The fishery for common sea bass (Dicentrarchus labrax) is the fourth most important French metropolitan fishery in value terms, with approximately 5 500 tons landed, and a total turnover of about 52 million euro in 2006. Given its high market value, sea bass is targeted by a range of métiers, resulting in interactions between a large number of fleets. The annual contributions to catches and landings of each of these fleets are highly variable, as are their level of economic dependence towards the species. Sea bass is also an emblematic species for recreational fishermen. Currently, there is no limitation on total allowable catch in this fishery, nor are catch allocations specified at the individual vessel level. The fishery thus faces the traditional difficulties of common-pool resource management, with a potential for the development of excess capacity and a risk of overexploitation. The nature and strength of externalities between fishing agents can thus be very different according to the fleets considered, and may lead to variable levels of potential support towards management decisions aimed at tackling these externalities. The aim of this paper is to simulate the response of French fishing fleets to the introduction of alternative management scenarios for the sea bass (Dicentrarchus labrax) fishery. The analysis is based on a bioeconomic model which includes and age-structured model of population dynamics and a detailed representation of the numerous fishing fleets which impact the stock, including the size distribution of catches per fleet and per fishing technique, and the economic status of fishing vessels. The main emphasis of the analysis is on the heterogeneity of commercial fleets in terms of both their harvesting capacity and their reliance on sea bass for their revenue; recreational fishing is also included in the analysis and adds to the heterogeneity of behaviors which are accounted for in the model. Simulation results emphasize the diversity of anticipated impacts of alternative management scenarios from both a short-term and a long-term perspective, and the associated heterogeneity of economic incentives for different fleets to support these management scenarios.