Identification of the inland population dynamics of the European eel using pattern-oriented modelling

We propose a process-based model (GlobAng) for the population dynamics of the continental phase of the European eel based on an ecological pattern derived from knowledge in the existing literature. This model simulates ageing, recruitment, sexual differentiation, silvering, natural mortality and, for the first time, movement within a watershed. It demonstrates that it is possible to simulate the pattern of density-dependent mortality, density-dependent sexual determination and diffusive movements. The downstream part of the watershed appears to be the area of maximum production for both males and females and where sexual differentiation takes place, especially when recruitment is low. The quality of the pattern is discussed in relation to the modelling results and field observations. The consequences of our findings for primary management are to advise concentrating mitigation efforts on the downstream part of the catchment area.