Anguille argentée (Copyright : ©MNHN CRESCO & AAPPBLB, Proust & Bourillon, 2019)

Life history traits of catadromous fish species

The project « Life history traits of catadromous fish species » studies the life history traits of the eel and flounder, two migratory species that live in rivers and reproduce at sea, before the restoration of the Selune river continuity, in order to anticipate its effects later.

The project in short…

ThemeBiocenosis, functioning and evolution
Full titleEffect of dam removal on the life history traits of catadromous species: the case of the European eel and flounder on the Selune River
Objectives1. To characterise the life history traits of eels and flounders during their recolonization phase. 2. To provide feedbacks to anticipate the consequences of future actions on these species.
Study subject(s)European eel (Anguilla anguilla) ; Flounder (Platichthys flesus)
Methods usedScientific fisheries; Microstructure and microchemistry of otoliths; Stable isotopes; Microbiome sequencing; Parasitic procession; Dissection; Fish biometrics.
Project length2019-2021
Coordinator(s)Eric Feunteun and Nils Teichert
Laboratories involvedMuséum national d’histoire naturelle, Station marine de Dinard UMR BOREA – Biologie des Organismes et Ecosystèmes Aquatiques UMR Ecosystèmes, Biodiversité, Evolution (ECOBIO), Rennes
Funding sourceAESN

Scientific context

Restoring the continuity of the Selune river by the removal of its dams is expected to promote the recolonization of the upstream watershed by many species, and in particular by migratory fish species. This will potentially modify the life history traits of migratory species, which will therefore be able to go up or down the river to live or reproduce. This is the case of the European eel and flounder, two migratory species that live in rivers and reproduce at sea. In fact, the restoration of continuity in the Selune river will potentially have two effects on these fish populations:

  1. The recolonization of upstream habitats should induce a decrease of intra-specific competition, as well as change in life history traits (growth, size, fecundity and age at reproduction) and sanitary conditions, particularly for eels.
  2. Sediment and nutrient fluxes will be modified, resulting in the modification of habitat quality, especially in the estuary, with a potential impact on nursery function for flounder juveniles.

Study subject(s)

The project studies two migratory fish species that are catadromous, i.e. that live in rivers and reproduce at sea: the European eel and flounder.

Objectives and methodology

The main goal of this research project is to investigate the restoration process of the Selune River by studying the evolution of life history traits of two catadromous fish species. Hence, the project aims at studying the life history traits (dynamics) of these fish species, which translates into their use of the different habitats found in the river. As a result, the observed modifications will help quantifying the influence of dam removal on fish stocks, such as that of the eel, and to draw lessons to guide future restoration measures of ecological continuity.

The simultaneous study of flounders and eels provides a relatively inclusive view of the effects of river continuity restoration through the removal of dams. Indeed, the flounder is mainly sensitive to the modification of downstream areas at the sea-river interface (estuarine nursery), whereas the eel will be responsive to changes in accessibility and quality of habitats distributed in the whole watershed. This project studies the relationships between: • Life history traits of individuals (age, height, weight, fat percentage, condition, growth rate, etc.), • Life history (growth habitat, estuary dependence), • The trophic position (stable isotope analyses of d13C and d15N) • The health status of silver eels (condition indices, study of the gut microbiome and parasite communities).

Results and conclusions

This project is ongoing. Results and conclusions will be elaborated later.

Publications and reports

This research project is ongoing. Here you will find the list of reports and publications.

The project “Life history traits of catadromous fish species” is part of the second phase of the Selune scientific program. Find all the research projects here.