Artisanal fisheries in the Amazon are probably as dispersed and variable as those in any hydrographic basin. Diversity is of a biological nature (presence and abundance of species), as well as of an economic and social nature (proximity of markets, cultural habits, etc). An initial study of biological aspects of Amazonian fisheries conclude that there was significant and widespread under exploitation of resources, although for some species, indications of possible over exploitation existed. A reevaluation of this first assessment given in this paper, shows that the total yield was probably underestimated previously. Nevertheless the general under exploitation of resources, although for some species, indications of possible over exploitation existed. A reevaluation of this first assessment given in this paper, shows that the total yield was probably underestimated previously. Nevertheless the general under exploitation is confirmed. A tentative approach is made to apply the global Maximum Sustainable Yield model. The result is not compatible with the previous conclusion, probably because the overall effort does not apply uniformly to the different species. Further investigations appear to be necessary, particularly those dealing with environmental influences on capture. (Résumé d'auteur)