This paper analyses the possible economic consequences of the development of ecotourism on fishing communities of poor countries from two complementary points of view: an empirical survey of a case study, and a bioeconomic model. It is divided into three parts. The first part of the paper is dedicated to the case of the Saloum delta, Senegal, an area where demographic pressure and an agriculture crisis have led to a sharp increase in fishing effort resulting in overfishing, and where attempts have been made to provide alternative income to the local population through ecotourism. The second part of the paper presents a two-sector bioeconomic model, where the link between artisanal fishing and ecotourism relies on their common use of the same natural resource. According to this model, developing ecotourism may help to overcome the dilemma between the need for long-term resource conservation and the immediate necessity to provide jobs and income to the local population. However, due to the negative externality exerted by fishing on ecotourism, the model suggests that this development is likely to be non-optimal if it is left to the initiative of market forces. The last section of the paper discusses the practical significance of these conclusions, with reference to the Saloum delta case. It underlines the major limits of the model, including the assumed non-extractive character of ecotourism, and its lack of spatial dimension. Keywords: ecotourism; fisheries management; Saloum delta