This project assesses the impact of restoring connectivity between fish populations following the removal of dams on the Sélune River. It is based on the calculation of a genetic fragmentation index for five fish species.

The aim of this project is to understand the exchanges between the groundwater and the water in the Sélune river. This knowledge will help prevent the physical, chemical, and biological changes that restoring continuity will cause to the water quality of the Sélune.

This project establishes a baseline, including dams, for trophic interactions between aquatic biocoenoses present on the Sélune, ranging from microorganisms to fish, in tributaries and the river itself from its source to its entry into the estuary.

This project aims to develop and apply a non-invasive method for monitoring migratory fish flows in the Sélune River. The development of this method is based on the analysis of images and videos taken by a hydroacoustic camera positioned in the watercourse.

The spawning grounds of the sea lamprey Petromyzon marinus are located within the perimeter of the Sélune Observatory. As this species is migratory, its colonisation of the Sélune river and its tributaries will probably be influenced by the removal of the Sélune dams. The spawning grounds are characterised by a depression accompanied by a sediment ejection dome immediately downstream. The stones returned to the dome are lighter, making the nests easily visible and identifiable for up to several weeks after spawning. This data is available for the years 2015, 2019, 2020, 2021, 2022, 2023, 2024 and 2025. The Sélune Observatory's activity reports (see attached links) give details of the prospecting conditions.

This project assesses the impact of dams on aquatic animal and plant communities in relation to water quality (zooplankton, macroinvertebrates, phytoplankton, periphyton, macrophytes).

The opening of the dams will have a significant impact on fish populations in the Sélune. Restoring the ecological continuity of the river will alter population flows by allowing certain amphihaline species to migrate further upstream and other species to move downstream and upstream of the dams. For many years now, as part of the ORE DiaPFC (Observatory for Research into the Environment of Diadromous Fish in Coastal Rivers), the SOERE OLA (Observation and Experimentation System for Environmental Research in Alpine Lakes) and the OFB-INRAE-Institut Agro-UPPA cluster, various INRAE units (U3E, UMR ECOBIOP and UMR CARRTEL) and OFB (DRAS) have been taking samples from numerous aquatic specimens. These samples, usually otoliths, scales, and/or fins, are then used by the scientific community to carry out various analyses and research. These samples are also collected as part of the Sélune observatory. Certified as a Biological Resource Center (BRC) by GIS IBISA, Colisa is part of the BRC4Env environmental pillar (network of Biological Resource Centers for the Environment) of the RARe infrastructure. Our catalog references these different hard tissue samples and offers a module that allows you to query our database and select the types of data that may be of interest to you. You can then export this data. This dataset does not contain any specific data, but provides a link to the COLISA (COLlection of Ichtyological SAmple) application, which allows the storage of collected samples. The COLISA application requires the creation of a user account to access the entire collection.

This project defines the initial state prior to the removal of dams with regard to diadromous fish and invasive crayfish. This will enable the (re)colonization of these species throughout the watershed to be monitored after removal.