Abstract
<jats:p>The ocean is increasingly being used by new human activities, fueled by an expansion of the “blue-economy” adding new pressures to the marine environment. These changes are happening fast, and balancing biodiversity conservation and present and future uses of the marine space needs to be done in an equitable way for human and ecological communities. Here, we used a systematic conservation planning approach to generate five different scenarios to inform the extension of marine protected areas using the Balearic Sea as a case study of a region with conflicting high fishing activity and new human uses. These scenarios were designed to (1) maximize biodiversity protection, (2) balance biodiversity and socio-economic costs, and (3-5) ensure fishing fleet equity for 10%, 20% and 30% of area extent. Our results show protecting 30% of the Balearic Sea in line with European commitments of 30x30 (i.e., 10% of fully no-take MPAs and 20% demersal no-take MPAs) through our ‘Equitable’ scenario would require an overall cost of 13% of annual fishing revenue in the area. However, scenarios differ in the final areas selected and the total costs of protection; supporting flexibility in the marine spatial planning process. These differences underscore the importance of evaluating multiple scenarios and objectives to reach biodiversity conservation targets while limiting socio-economic and inequitable costs. Regionally informed systematic conservation planning is key to accommodate human uses and biodiversity conservation in the marine environment. We show a transferable and equitable approach that could be implemented to achieve 30x30 throughout European marine waters.</jats:p>