Is European catfish a threat to eels in southern France?

• Published in: Aquatic Conservation: Marine and Freshwater Ecosystems
• Main Authors: Martino, Aurelia, Syväranta, Jari, Crivelli, Alain Jean, Céréghino, Régis, Santoul, Frédéric
• Other Authors: Laboratoire Ecologie Fonctionnelle et Environnement (LEFE), Institut Ecologie et Environnement - CNRS Ecologie et Environnement (INEE-CNRS), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT), Leibniz-Institut für Gewässerökologie und Binnenfischerei (IGB), Leibniz Association, Station Biologique de la Tour du Valat
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2011
• Subjects: European eel; Conservation; European catfish; Stable isotope analysis; Gut contents; Camargue; [SDE.BE]Environmental Sciences/Biodiversity and Ecology; [SDV.BA.ZV]Life Sciences [q-bio]/Animal biology/Vertebrate Zoology; [SDV.EE.IEO]Life Sciences [q-bio]/Ecology; environment/Symbiosis; Anguilla anguilla
• Online Access: https://hal.science/hal-03469135; https://hal.science/hal-03469135/document; https://hal.science/hal-03469135/file/Martino_10155.pdf; https://doi.org/10.1002/aqc.1177

International audience European eel (Anguilla anguilla) is recognized as a critically endangered species in the northern hemisphere. Threats such as overfishing or pollution are well known as risks for eel populations. However, much less is known about the impact of introduced fish on European eels. In particular, introduced large-bodied predators could become new predators to eels.The potential impact of European catfish (Silurus glanis L) on an eel population in the Camargue, southern France was studied using a combination of stable isotope and gut content analyses.Only large bodied catfish (> 500 mm) can consume numerous fish prey. However, catfish mostly consumed crayfish (Procambarus clarkii), these prey items being found in 79% of the guts of the largest individuals. Eel was absent from the dissected catfish guts. A mixing model based on Bayesian inference revealed that catfish diet included only 5% (0-8.5%) of marine sources (both eel and mullet).While local economic interests prompted ecological studies to assess whether catfish exerted a new and strong predatory pressure on eel, this study found that European catfish behaved as an opportunistic omnivore, and as such was not a direct threat as a predator on eel populations in the Camargue.