Luc DOYEN

Research Director, CNRS, GREThA.

Luc Doyen, Doctor in applied mathematics, has received an education in control theory, optimisation and mathematical economics. He currently holds a permanent position of Director of Research at the CNRS (Centre National de la Recherche Scientifique), where he is especially involved in bio-economic modelling, viable management of biodiversity and mathematics of sustainability. He is now affiliated to the GREThA (Research Group Theoretical and Applied Economics) at the University of Bordeaux where he is the leader of the team II devoted to ‘ecosystems dynamics’. His publications (70 in international peer-reviewed journals, 1 book Springer, H-index=28, 2500 citations), his international network of collaboration, his supervision and teaching activities (10 doctorates) emphasise both the scientific excellence, the international dimensions and the interdisciplinarity of his work at the interface between economics, ecology, mathematics and computer sciences. The applied component of his research relies on contracts and grants pointing out the transfer of the theoretical results toward international or national institutions such as CSIRO, RMIT, CGIAR, INRA, IFREMER, IRSTEA regarding the sustainable management of ecosystems and biodiversity through fisheries and land-use. In particular, Luc Doyen is the leader of the international SEAVIEW network funded by the Belmont Forum regarding the scenarios of biodiversity and ecosystem services and bringing together researchers from Germany, Norway, France, Brazil, Australia and South Africa. He also participates to different European programs including GEO-SAFE (H2020-MSCA-RISE-2015). Luc Doyen is the current president of the Resource Modelling Association (RMA) and member of the Scientific Advisory Board of SIAG-MPE, a SIAM Activity Group devoted to Mathematics of Planet Earth. Luc Doyen recently organised several international events including the 2015 World Conference on Natural Resource Modeling in Bordeaux. Luc Doyen is also member of the editorial board of the journals 'Environmental Modeling and Assessment' and  'Natural Resource Modeling'.

> Ecoviability boundaries for fisheries management and resilience

Reconciling the conservation of marine biodiversity with the maintenance of economic performances of fisheries and coastal ecosystem services (ES) is a key international challenge in particular facing demographic growth and climate change (CC). In this ecological-economic perspective, marine scientists advocate an ecosystem approach to identifying sustainable and resilient management strategies for fisheries and marine biodiversity. However operationalizing such an ecosystem-based fisheries management (EBFM) is difficult, in particular in terms of ecological-economic quantitative methods, models, indicators and scenarios. We propose a methodological framework— ecoviability modelling —to do so. Accordingly, we first remind the generic features and interest of this ecoviability framework. We then show how ecoviability modelling can be applied to fisheries using different contrasted case-studies in South America, Pacific, Europe and Australia. Results show to what extent the ecoviability risks associated with status quo strategies are relatively high and challenge the implementation of EBFM. In contrast, ecoviability strategies, that aim at satisfying both biodiversity, profitability and food security  constraints, reduce significantly these ecological and economic risks and promote EBFM. The gains associated with those ecoviability strategies, however, decrease with the intensity of regulations imposed on these fisheries