This applied research operation carried out by the association LOGRAMI aims for the year 2018 to obtain information on fish habitats, population dynamics and catch pressure and information on population support in order to establish a common knowledge base on amphihalin migratory fish in the Loire basin. This data will enable managers to guide and take effective management actions. This operation is submitted as part of the 2018 call for projects on research, experimentation, acquisition and valorisation of knowledge on amphihalin migratory fish populations in the Loire basin.