Defining yield policies in a viability theory approach
Définir des politiques de pêches en utilisant la théorie de la viabilité
Résumé
Within the Southern Benguela ecosystem, five different groups (detritus, phytoplankton, zooplankton, pelagic fish and demersal fish) were considered by (Mullon et al., 2004) in a dynamical model of biomass evolution. They studied this model in a viability perspective, trying to assess, for a given constant yield, whether each species biomass remains inside a given interval, taking into account the uncertainty on the interaction coefficients. Instead of studying the healthy states of this marine ecosystem with a constant yield, we focus here on the yield policies which keep the system viable. Using the mathematical concept of viability kernel (Aubin, 1991), we examine how yield management might guarantee viable fisheries. Numerical simulations are provided to illustrate the main findings.