Marine conservation of multispecies and multi-use areas with various conservation objectives and targets
Marine spatial management is an important step in regulating the sustainable use of marine resources and preserving habitats and species. The systematic conservation planning software “Marxan” was used to analyse the effect of different conservation objectives and targets on the design of a network of marine protected areas around two islands of the Azores archipelago, Northeast Atlantic. The analyses integrated spatial patterns of the abundance and reproductive potential of multispecies, the vulnerability of fish to fishing, habitat type, algae biotopes, and socio-economic costs and benefits (including fishing effort and recreational activities). Three scenarios focused on fisheries-related objectives (“fisheries scenarios”, FSs) and three on multiple-use and biodiversity conservation objectives (“biodiversity scenarios”, BSs), respectively. Three different protection targets were compared for each set, the existing, minimum, and maximum levels of protection, whereas conservation features were weighted according to their biologically/ecologically functioning. Results provided contrasting solutions for site selection and identified potential gaps in the existing design. The influence of the conservation objective on site selection was most evident when minimum target levels were applied. Otherwise, solutions for FSs and BSs were very similar and mostly shaped by the protection level. More important, BSs that considered opportunity cost and benefits achieved conservation targets more cost-efficiently. The presented systematic approach ensures that targets for habitats with high fish abundance, fecundity, and vulnerability are achieved efficiently. It should be of high applicability for adaptive management processes to improve the effectiveness of existing spatial management practices, in particular when fishing and leisure activities coexist, and suggest that decision-makers should account for multiple users’ costs and benefits when designing and implementing marine reserve networks.