The Garonne Dordogne watershed is one of the last basins in which all species of highly migratory amphihalins are still present. The main objective of the program is the preservation of migratory species such as aloses, lampreys and eel. Several axes of work are developed on the Garonne Dordogne Leyre basins, Médocain Lakes and tributaries of the Arcachon basin including actions to monitor reproduction and general status of the populations. The implementation of concrete actions to restore ecological continuity contributes to the improvement of habitats essential for their growth and development.