The European catfish (Silurus glanis) in large peri-alpine lakes: trophic ecology and impacts for resident species

• Main Author: Vagnon, Chloé
• Other Authors: Centre Alpin de Recherche sur les Réseaux Trophiques et Ecosystèmes Limniques (CARRTEL), Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Université Savoie Mont blanc, Jean Guillard, Victor Frossard (co-encadrant), Franck Cattanéo (co-encadrant)
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: HAL CCSD 2021
• Subjects: population dynamics; invasive species; trophic ecology; food webs; impact assessment; espèces invasives; écologie trophique; réseaux trophiques; estimation d’impacts; dynamiques de populations; [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; Burbot; Lota lota; lota
• Online Access: https://theses.hal.science/tel-03639076; https://theses.hal.science/tel-03639076/document; https://theses.hal.science/tel-03639076/file/VAGNON_Manuscrit_THESE_2021_FINAL.pdf

Invasive species represent a growing threat to biodiversity and ecosystems worldwide and predicting their impacts on invaded ecosystems represents one of the major current challenges, particularly in the context of global change, promoting displacement of species out of their native range. The European catfish (Silurus glanis), the largest European freshwater fish, native from Asia and Eastern Europe, has extensively been proliferating across the continent since the 20th century. Indeed, its wide physiological, trophic and behavioral plasticity represents a major asset for establishing a sustainable presence in various ecosystems. S. glanis recently invaded large peri-Alpine lakes (Lake Geneva and Lake Bourget) raising concerns about its impacts on resident species in these ecosystems. This PhD thesis falls within this context and consisted in investigating (i) the trophic ecology of the European catfish in peri-Alpine lakes and (ii) its impacts on food webs and on resident species at both species and multispecies levels. This work is part of the SILAC research program founded by the Region Auvergne-Rhône-Alpes.The study of the European catfish diet in peri-Alpine lakes highlighted its high reliance on littoral prey (e.g., speeny-cheek crayfish Orconectes limosus and roach Rutilus rutilus) but also on prey from habitats inherent to peri-Alpine lakes such as deep benthic (e.g., burbot Lota lota) and pelagic prey (e.g., whitefish Coregonus lavaretus).An allometric niche model (aNM), supporting the reconstruction of trophic interactions in peri-Alpine lakes, was then elaborated and applied to a body size gradient representing the European catfish ontogeny to infer its trophic interactions both as predator and prey toward resident species. This step underlined its apex position in the food web reached as soon as individuals measured 60 cm. In addition, the consideration of another exotic species (Hemimysis anomala) indicated their potential additive impacts in the ecosystem. Trophic interactions inferred by the aNM ...