This 2017 applied research operation carried out by the LOGRAMI association aims to obtain information on fish habitat, population dynamics and catch pressure and 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 2017 call for projects on research, experimentation, acquisition and valorisation of knowledge on amphihalin migratory fish populations in the Loire basin.