The decline of the semi-industrial purse seine fishery, in contrast to the growth of the small-scale fishery, has led the state authorities and professionals to call upon research to provide the objective reasons for the decline. After an assessment of the fishery, of the legal framework, and the economic aspects, the different levels of competition between the small-scale and semi-industrial fisheries were identified and the potential for cooperation between the two activities were analysed. (Résumé d'auteur