Relationship between habitat use and individual condition of European eel (Anguilla anguilla) in six estuaries of the eastern English Channel (North-eastern Atlantic ocean)

• Published in: Estuarine, Coastal and Shelf Science
• Main Authors: Denis, Jérémy, Mahé, Kélig, Tabouret, Hélène, Rabhi, Khalef, Boutin, Kévin, Diop, Mamadou, Amara, Rachid
• Other Authors: Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 (LOG), Institut national des sciences de l'Univers (INSU - CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD France-Nord ), Université du Littoral Côte d'Opale (ULCO), Laboratoire Ressources Halieutiques de Boulogne (LRHBL), Unité Halieutique Manche Mer du Nord (HMMN), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Institut des sciences analytiques et de physico-chimie pour l'environnement et les materiaux (IPREM), Université de Pau et des Pays de l'Adour (UPPA)-Institut de Chimie - CNRS Chimie (INC-CNRS)-Centre National de la Recherche Scientifique (CNRS), Parc Naturel Marins des Estuaires Picards et de la Mer d’Opale (DECISION N◦2018–28 9 March 2018), Région Hauts de France (PFEA621220CR0310022), European Union (ERDF), the French Government, the Reégion Hauts-de-France and IFREMER, in the framework of the project CPER MARCO 2015–2020 (https://marco.univlittoral.fr/), ANR-21-EXES-0011,IFSEA,Transdisciplinary graduate school for marIne, Fisheries and SEAfood sciences(2021), European Project: PFEA621220CR0310022
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2023
• Subjects: Lipid content; Health status; Hepatosomatic index; Otolith microchemistry; Environmental history; Fulton condition factor K; [SDV]Life Sciences [q-bio]; [CHIM]Chemical Sciences; [CHIM.ANAL]Chemical Sciences/Analytical chemistry; [SDE.BE]Environmental Sciences/Biodiversity and Ecology; Fulton; Anguilla anguilla; European eel
• Online Access: https://hal.science/hal-04174448; https://doi.org/10.1016/j.ecss.2023.108446

International audience Brackish habitats are considered important for the facultatively catadromous European eel, but knowledge of eel habitat use strategies and the consequences on their condition, particularly in the estuaries areas, is limited and yet necessary for understanding some features such as growth and maturation in the different habitats that eel inhabit during the continental phase, that might also support assessment and management of local stocks, and contribute to the stock-wide assessment of this panmictic species. This study aimed to characterise and compare the condition of European eels according to their habitat use strategies and local estuarine characteristics. Eels were collected along the salinity gradient in six small and medium-sized estuaries located along the French coast in the eastern English Channel (i.e. the Slack, Wimereux, Liane, Canche, Authie and Somme estuaries). Four condition indices (i.e. Fulton condition factor K, lipid content, hepatosomatic index and health status) were measured on 119 individuals to explore variation with habitat characteristics at the small geographical scale and their habitat use strategies. Eel condition showed clear spatial differences between the six estuaries, with better condition in smaller estuaries. The spatial differences in eel condition appear to be related to variations in their diet composition, corresponding to different availability of macrozoobenthos prey among sites, in turn due to the local hydro-morpho-sedimentary characteristics. Environmental history and movements were reconstructed from the Sr:Ca and Ba:Ca ratios of otoliths from eel samples (N = 37) in both small- and medium-sized estuaries. The Sr:Ca and Ba:Ca ratios were used to distinguish the habitat use strategies and showed that both estuaries had a high proportion of resident eels (81%). Within each estuary, the Sr:Ca and Ba:Ca ratios were sufficiently contrasted to track movements of estuarine resident eels between three resident sectors (i.e. upper, middle and lower ...