Role of estuarine habitats for the feeding ecology of the European eel (Anguilla anguilla L.)

International audience This study aims to characterize and compare the feeding ecology of the European eels ( Anguilla anguilla L.) during the continental phase (i.e. yellow and silver) along a salinity gradient (i.e. lower, middle and upper) in six northern France estuaries (i.e. brackish water). T...

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Published in:PLOS ONE
Main Authors: Denis, Jérémy, Rabhi, Khalef, Le Loc’h, François, Ben Rais Lasram, Frida, Boutin, Kévin, Kazour, Maria, Diop, Mamadou, Gruselle, Marie-Christine, 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 des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Parc Naturel Marins des Estuaires Picards et de la Mer d’Opale (DECISION N ̊2018-28 09/03/2018), Région Hauts de France (PFEA621220CR0310022), European Project: PFEA621220CR0310022
Format: Article in Journal/Newspaper
Language:English
Published: HAL CCSD 2022
Subjects:
Online Access:https://ulco.hal.science/hal-03716404
https://ulco.hal.science/hal-03716404/document
https://ulco.hal.science/hal-03716404/file/journal.pone.0270348.pdf
https://doi.org/10.1371/journal.pone.0270348
Description
Summary:International audience This study aims to characterize and compare the feeding ecology of the European eels ( Anguilla anguilla L.) during the continental phase (i.e. yellow and silver) along a salinity gradient (i.e. lower, middle and upper) in six northern France estuaries (i.e. brackish water). The diet and stable isotopic (i.e. δ 15 N and δ 13 C values) compositions of eels collected with a fyke net in six estuaries (Slack, Wimereux, Liane, Canche, Authie and Somme estuaries) located along the French coast of the eastern English Channel per season over a year were described by combining gut content and stable isotope analyses. Eel guts were dominated by typical BW prey, Malacostraca and Actinopterygii (54% and 40%, respectively), with the gammare Gammarus zaddachi and the green crab Carcinus maenas (38% and 14%, respectively), and smaller yellow eels of A . anguilla and juvenile European flounder, Platichthys flesus (19% and 14%, respectively) being the most frequently found in their guts. The δ 13 C values of a majority of eels confirmed the sea- and brackish water-specific carbon resources. Dietary and isotopic niche revealed no clear change between total length, silvering stages and seasons, but a significant difference between salinity gradients and estuaries. Eels δ 13 C values showed significant enrichment from upper to lower along the estuaries while the δ 15 N values showed an inverse effect, with the lowest values in the lower part and highest in the upper part. Higher variability in δ 13 C values in larger estuaries suggested that eels feed on a wide range of food sources than in smaller estuaries. While eels in the smaller estuaries fed mainly on Actinopterygii prey, eels in the larger ones had a lower trophic level (i.e. δ 15 N values) and fed mainly on Malacostraca prey. This spatial difference in dietary and isotopic niche is discussed in relation to biological structure of eel and environmental variables.