Atlantic salmons abundance (IAS) - Selune Observatory

The opening of the dams should impact the functioning of Atlantic salmon populations migrating up the Sélune River and its tributaries. Restoring the river's ecological continuity will alter population flows by allowing amphihaline sea trout to migrate further upstream and native trout to move downstream and upstream of the dams. The trout population is monitored at a network of stations covering the entire Sélune basin using an abundance index, which is carried out every two years before 2021 and every year since then.

Field campaigns comply with the fishing protocol developed by INRAE and OFB. The aim of this method is to estimate the abundance of juvenile Atlantic salmon (Salmo salar) at a station (or sector). This protocol targets juveniles of the year (aged 0+) whose abundance reflects the renewal of generations within the population (or recruitment) and survival after the embryonic development phases under gravel and the first months of life in the open environment. Field campaigns are carried out by INRAE and the Manche and Ille-et-Vilaine Federations for Fishing and the Protection of the Aquatic Environment (FDAPPMA50 and FDAPPMA35).

This dataset provides abundance data for Atlantic salmon (0+, 1+, 2+ and cumulative) as well as the salmon abundance index (IAS) by station and fishing session.

Date (Publication): 2025-08-05T00:00:00

Edition: Mise à jour 2025

Identifier: fr-18007003900276-umrsas-selune-v_bioc_ias_ab_ias

Purpose: The purpose of this data is to estimate changes in juveile atlantic salmon abundance as part of the Sélune Observatory.

Status: Completed

Point of contact

INRAE UMR DECOD - Jean-Marc Roussel ( )

65 rue de Saint-Brieuc - CS 84215 , Rennes , 35042 , France

+33 2 23 48 57 73
https://programme-selune.com/fr/

Point of contact

INRAE U3E - Frédéric Marchand ( )

65 rue de Saint-Brieuc - CS 84215 , Rennes , 35042 , France

+33 2 23 48 57 86

funder

AESN - ( )

1, rue de la Pompe - BP 70087 , HEROUVILLE SAINT-CLAIR Cedex , 14203 , France

02 31 46 20 20

Maintenance and update frequency: Annually

Theme

Open data
atlantic salmon
capture data
Dam removal

Place

Selune river
France
Normandy

INSPIRE themes

Installations de suivi environnemental

Thésaurus INRAE

poisson migrateur amphihalin
dam

Use limitation: Unrestricted use subject to the following compulsory wording on all distribution documents: "Source: INRAE - U3E".

Use limitation: Open license: https://www.etalab.gouv.fr/licence-ouverte-open-licence

Access constraints: Other restrictions

Use constraints: License

Other constraints: No public access restrictions

Spatial representation type: Vector

Denominator: 25000

Metadata language: fre

Topic category

Environment

Begin date: 2012-09-02

End date: 2027-12-31

Reference system identifier: RGF93 / Lambert-93 (EPSG:2154)

Geometric object type: Point

Distributor

Distributor

UMR 1069 SAS INRA - Agrocampus Ouest - Pole GéoSAS

65 rue de Saint-Brieuc , Rennes cedex , 35042 , France

Name: ESRI Shapefile

Version: 1.0

OnLine resource

v_bioc_ias_ab_ias ( OGC:WMS )

Abondances en saumons atlantiques (IAS) - Observatoire Sélune

OnLine resource

Abundance of Atlantic salmon (IAS) - Observatoire Sélune ( WWW:DOWNLOAD-1.0-http--download )

Download "Abundance of Atlantic salmon (IAS) - Observatoire Sélune" in Shapefile format

OnLine resource: Observatoire Sélune ( WWW:LINK-1.0-http--link )

OnLine resource

Abundance of Atlantic salmon (IAS/SAI) - Observatoire Sélune ( WWW:DOWNLOAD-1.0-http--download )

Download "Abundance of Atlantic salmon (IAS/SAI) - Observatoire Sélune" in CSV format

OnLine resource: Dispersion and (re)colonization of the Sélune and its tributaries ( WWW:LINK-1.0-http--link )

OnLine resource: Activity report on the Sélune aquatic biocenoses observatory 2019-2021 ( WWW:LINK-1.0-http--link )

OnLine resource: Observatoire des biocénoses aquatiques de la Sélune - 2022 activity report ( WWW:LINK-1.0-http--link )

OnLine resource: Sélune aquatic biocenoses observatory - 2023 activity report ( WWW:LINK-1.0-http--link )

OnLine resource: Indice d'abondance saumon (IAS) ( WWW:LINK-1.0-http--link )

Hierarchy level: Dataset

Conformance result

Date (Publication): 2013-12-10

Explanation: Non évalué

Pass: No

Statement: Monitoring of amphihaline fish populations in the Sélune is carried out on the main river and its tributaries, both upstream and downstream of the old dams. This allows us to understand the dynamics of these populations before, during, and after the dams are demolished. Brown trout, Atlantic salmon, European eel, and lampreys (marine, river, and Planer) are species of high conservation importance. The populations are monitored using various inventory protocols (electrofishing, trapping, DNAe) supplemented by sampling aimed at better characterizing the populations (genetics, scalimetry).

The objectives of this monitoring are:

- to estimate the level of recruitment in 0+ and 1+, the evolution of cohorts, and the abundance and density of trout (Salmo trutta);

- to monitor biometrics (measurements, scale sampling, and scalimetry) at reference stations;

- to study intra- and inter-population genetic structure and the impact of migratory individuals and the movement of sedentary trout downstream and upstream of dams on the entire population (fin sampling).

Sampling has been annual since 2022 and biannual before that.

The protocol implemented is the “Gaétan Pottier, Frédéric Marchand, Sabrina Servant, Etienne Prévost. Indice d’abondance saumon

(IAS). Collection Guides et Protocoles. La pêche scientifique à l’électricité dans les milieux aquatiques

continentaux, INRAE; OFB, 2022. ffhal-03757386".

The stations (also called study areas) were located using a hiking GPS (expected planimetric accuracy <= 20 m).