Challenges for Diadromous Fishes in a Dynamic Global Environment

Assessing Management Plans for the Recovery of the European Eel: A Need for Multi-Objective Analyses

Daniele Bevacqua, Paco Melià, Alain Crivelli, Marino Gatto, and Giulio A. De Leo


Abstract.—The European eel Anguilla anguilla stock has been declining since the early 1970s and is currently considered to be outside safe biological limits. In June 2007, the Council of the European Union approved a regulation establishing measures for the recovery of the European eel stock. Each member state is required to develop eel management plans (EMPs) in order to achieve an escapement of at least 40% of the potential spawner biomass (with respect to undisturbed conditions) from each river basin. A reliable estimate of the potential spawner output of local stocks is crucial for the development of EMPs. Given the complexity of the eel life cycle, the use of mathematical models explicitly accounting for specific demographic traits and incorporating fundamental socioeconomic information is necessary to thoroughly assess the effectiveness of alternative management strategies. Here, using a case study approach, we show how mathematical modeling, based on sound field data, can contribute to the assessment of potential spawning stock and to the development of sound management plans. Then, we discuss how a multi-objective approach can be used to examine trade-offs between conservation and fishery goals and to help decision makers identify effective management policies.