Migration behaviour of silver eels (Anguilla anguilla) in a large estuary of Western Europe inferred from acoustic telemetry

• Published in: Estuarine, Coastal and Shelf Science
• Main Authors: Bultel, Elise, Lasne, Emilien, Acou, Anthony, Guillaudeau, Julien, Bertier, Christine, Feunteun, Eric
• Other Authors: Muséum national d'Histoire naturelle (MNHN), Centre Alpin de Recherche sur les Réseaux Trophiques et Ecosystèmes Limniques (CARRTEL), Institut National de la Recherche Agronomique (INRA)-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry ), Groupement d'Intérêt Public Loire Estuaire, Partenaires INRAE, Muséum d'Histoire Naturelle de Genève, French Ministry of Environment, European Project: 212133,EC:FP7:ENV,FP7-ENV-2007-1,EELIAD(2008)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2014
• Subjects: silver eel; spawning migration; conservation; escapement; biological traits; European Eel Management Plan; Loire estuary; [SDV]Life Sciences [q-bio]; Anguilla anguilla
• Online Access: https://hal.inrae.fr/hal-02630562; https://doi.org/10.1016/j.ecss.2013.11.023

International audience Despite intensive research on eels, the behaviour of silver eels in estuaries during their migration remains poorly documented which creates serious gaps in planning the restoration of the European eel population. Estuaries are complex environments that can be exposed to large human pressures which could impede, delay migration or impact fish reproductive potential. This study investigated the estuarine migration of female silver eels in the Loire River using an acoustic telemetry system. An array of 31 hydrophones was deployed in the Loire estuary and 51 female seaward migrants were tagged with acoustic transmitters and released 20 km upstream of the estuary, at 100 km from the river mouth. 94% of the silver eels could be followed down to the river mouth. Mean global estuarine speed was 4.5 km days(-1), i.e., 0.05 m s(-1) and residence times varied significantly between upstream and lower compartments. Mean directional migration speed was found to be 48.6 km days(-1), i.e., 0.56 m s(-1), and appeared correlated with total length and body weight. Also, daily escapement rate was highly influenced by river flow.