A demographic model for the conservation and management of the European eel: an application to a Mediterranean coastal lagoon

• Published in: ICES Journal of Marine Science
• Main Authors: Bevacqua, Danièle, Melià, Paco, Schiavina, Marcello, Crivelli, Alain, De Leo, Giulio, Gatto, Marino
• Other Authors: Unité de recherche Plantes et Systèmes de Culture Horticoles (PSH), Institut National de la Recherche Agronomique (INRA), Dipartimento di Elettronica, Informazione e Bioingegneria (DEIB), Politecnico di Milano Milan (POLIMI), Institut de recherche de la Tour du Valat, Department of Biology Pacific Grove, CA, USA (Hopkins Marine Station), Stanford University
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2019
• Subjects: stock assessment; Anguilla anguilla; density dependence; European eel; fish population dynamics; life history variation; plasticity in vital traits; size-dependent demography; stochastic demographic models; [SDE.BE]Environmental Sciences/Biodiversity and Ecology; [SDE.IE]Environmental Sciences/Environmental Engineering; [SDV.EE.ECO]Life Sciences [q-bio]/Ecology; environment/Ecosystems
• Online Access: https://hal.archives-ouvertes.fr/hal-02467800; https://hal.archives-ouvertes.fr/hal-02467800/document; https://hal.archives-ouvertes.fr/hal-02467800/file/Auteur_Benvaqua.pdf; https://doi.org/10.1093/icesjms/fsz118

International audience We present a general size and age-structured demographic model of the continental phase of catadromous eels' life cycle, allowing for the incorporation of (i) fluctuations of juvenile recruitment, (ii) density-dependent settlement and sex determination, (iii) plastic body growth and sexual dimorphism, and (iv) vital rates driven by body size rather than age. The model can be used to assess (i) standing stock, (ii) fishing yield, and (iii) spawner production under different recruitment and management scenarios. We demonstrate the model by applying it to a European eel stock (Camargue lagoons, southern France) that was continuously monitored for 17 years (1993-2009). Results indicate that the upper limit to settlement in the Camargue water system is ~419 eels ha ─1 per year. A balanced sex ratio occurs for a settlement of ~94 eels ha ─1 , shifting towards males at higher densities. Catchability is higher in adult silver eels than in sub-adult yellow eels, possibly due to behavioural differences. Estimated standing stock ranged between 7 and 19 kg ha ─1. Fishing yield was 5-7 kg ha ─1 per year, while spawner escapement ranged between 0 and 13 kg ha ─1 per year (<30% of what would occur in the absence of fishing and obstacles to migration). How to cite : Bevacqua D., Melià P., Schiavina M., Crivelli A.J., De Leo G.A., Gatto M. 2019. A demographic model for the conservation and management of the European eel: an application to a Mediterranean coastal lagoon.