Denis J. auteur aut IRD Rabhi K. auteur aut IRD Le Loc'h François auteur aut IRD Lasram F. B. auteur aut IRD Boutin K. auteur aut IRD Kazour M. auteur aut IRD Diop M. auteur aut IRD Gruselle M. C. auteur aut IRD Amara R. auteur aut IRD text journalArticle eng text/pdf reformatted digital access 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. delta N-15 and delta C-13 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 delta C-13 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 delta C-13 values showed significant enrichment from upper to lower along the estuaries while the delta N-15 values showed an inverse effect, with the lowest values in the lower part and highest in the upper part. Higher variability in delta C-13 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. delta N-15 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. specialized FRANCE MANCHE SLACK ESTUAIRE WIMEREUX ESTUAIRE LIANE ESTUAIRE CANCHE ESTUAIRE AUTHIE ESTUAIRE SOMME ESTUAIRE 034 032 040 17 7 [23 p.] 2022 1932-6203 https://www.documentation.ird.fr/hor/fdi:010085957 10.1371/journal.pone.0270348 1932-6203 [F B010085957] https://www.documentation.ird.fr/hor/fdi:010085957 https://horizon.documentation.ird.fr/exl-doc/pleins_textes/2022-09/010085957.pdf IRD - Base Horizon / Pleins textes 2022-09-28 2025-02-24 fdi:010085957 fre