The Saint-Louis marine protected area (MPA), located between the former mouth of the Senegal River (before 2003) and the fishing district of Guet-Ndar (Saint-Louis), is the largest of the 5 MPAs created in Senegal in 2004. Its biodiversity, studied by crossing various sources of data (scientific campaigns, field surveys, baseline, etc.), reveals 437 fish species and 83 bird species whose viability is confronted with natural, anthropogenic, institutional and political threats. This inventory, the first of its kind for the St. Louis MPA due to the number of data sources (5 in total) is, however, to be deepened for poorly documented taxa such as cetaceans. Pre-requisites are specified, followed by the proposal of 8 indicators of good governance and monitoring of biodiversity so that the MPA meets the expectations placed on it when it was created.