Robust viable management of a harvested ecosystem model

The Word Summit on Sustainable Development (Johannesburg, 2002) encouraged the application of the ecosystem approach by 2010. In this perspective, we propose a theoretical management framework that deals jointly with i) ecosystem dynamics, ii) conflicting issues of production and preservation and iii) robustness with respect to dynamics uncertainties. More specifically, we define the robust viability kernel as the set of initial species biomasses such that at least one harvesting strategy guarantees minimal production and preservation levels for all times, whatever the uncertainties. We apply our approach to the anchovy-hake couple in the Peruvian upwelling ecosystem. We find that accounting for uncertainty significantly reduces the robust viability kernel compared to the deterministic one (without uncertainties). We observe that, when we increase the set of uncertainties, the robust viability kernel very slightly decreases, expressing a moderate sensibility with respect to refining the set of uncertainties. We comment on the management implications of comparing robust viability kernels (with uncertainties) and the deterministic one (without uncertainties).