Projet scientifique - Dispersion et recolonisation du cours de la Sélune et de ses affluents: état de référence pour les poissons migrateurs amphihalins et anticipation de l'expansion spatiale de l'écrevisse de Californie -

In a nutshell: Restoring the connectivity of inland water bodies is one of the key measures of the Water Framework Directive, and must be achieved either by modifying existing barriers or by removing them entirely. This second solution was chosen for the Sélune River as part of an operation that is subject to scientific monitoring. The goal of this monitoring, within the context of studying biocoenoses, is to help us understand the consequences of this removal on migratory and invasive species. The removal of dams and the restoration of river connectivity can have both positive and negative consequences. Objectives This project aims to provide answers to the following interconnected questions: Which species are taking advantage of the removal of dams to (re)colonize the Sélune and its tributaries? What are the consequences of restoring river continuity on species distribution and their demographic and genetic structure at the watershed scale? What are the consequences of (re)colonization dynamics on the traits of the species concerned? Methods: scientific fishing; hydroacoustic camera monitoring; DNA analysis; demographic analysis Data - Trout fishing (IAT) - Eel fishing (IAA) - Lamprey fishing (IAL) - All-species fishing (PTE) - Crayfish fishing (IAE) - Identification of upstream-migrating Atlantic salmon - Otolith sampling from smolts - Counts of lamprey and salmon spawning grounds - Inventories of aquatic plant communities - Crayfish detection