Towards the 30x30 target: data-driven planning is needed to achieve a win-win strategy for conservation and fisheries sustainability

As the 2030 deadline for the “30 by 30” conservation target approaches, the challenge of determining where to fish—or not to fish—remains critical, particularly in overexploited regions like the Mediterranean Sea where less than 1% of its waters are highly protected. To advance conservation efforts in this ecologically significant region, we developed a novel framework, combining a spatially-explicit multi-species ecosystem model with regional climate and biogeochemical models, to evaluate six configurations of no-take marine protected area (MPA) networks, progressively expanded to achieve 30% coverage. These networks included one based on the expansion of existing MPAs, two randomly distributed designs (across the entire basin and at country level), and three science-informed networks proposed in the literature. As climate change is projected to significantly alter the effectiveness of MPAs through shifts in species distributions, we assessed the conservation and fisheries outcomes of these networks both under current and future conditions (2071-2100 period) considering a high emission scenario (RCP8.5). To enhance applicability, we further optimized the networks by incorporating ecological, socio-economic, and feasibility criteria. Our results underscore the need for data-driven, adaptive planning to achieve global conservation targets while minimizing negative impacts on fisheries. This study provides a robust foundation for policymakers to strategically optimize MPA placements in the Mediterranean Sea, ensuring both ecological resilience and socio-economic benefits in the face of a changing climate.