Alternative spatial management configurations to balance conservation objectives and sustainable exploitation of marine resources in the Western Mediterranean Sea

Abstract

The Mediterranean Sea is under multiple threats due to intense human activities and climate change. Spatial management actions are essential tools to improve this situation. We used an ecological modelling approach to assess the historical contribution of marine protected areas and other spatial management measures, and to investigate the plausible impacts that alternative configurations of spatial protection could have in the future. We used the Ecopath with Ecosim (EwE) food web modeling approach to develop a spatial-temporal regional model covering the Western Mediterranean. The model was fitted to historical data, and was used for spatial-temporal analyses of historical (1990 to 2017) and future trajectories of change (2018 to 2050) under different IPCC scenarios of C02 emissions. Several proposed spatial management configurations were tested, such as elevation of partially protected areas (such as Natura 2000 sites) to highly protected or fully protected areas, establishment of proposed new protection schemes (such as the protection of Ecologically or Biologically Significant Marine Areas or Consensus areas), and seasonal or temporal fisheries closures (such as Fisheries Restricted Areas, protection of Essential Fish Habitats or Vulnerable Marine Species). To assess the impact of protection scenarios at local and regional scales, we used the biomass emitter concept to transfer local benefits of protection to corresponding regions in larger scales. Results illustrated that current spatial management efforts have contributed modestly to a good environmental status and fisheries sustainability at the regional scale, but plausible modifications to current management schemes can have positive impacts to both. We identified important trade-offs between protection and exploitation. This work can serve as a baseline for defining and assessing future management scenarios of MPA networks in the Mediterranean