Towards a spatially explicit risk assessment for marine management: Assessing the vulnerability of fish to aggregate extraction

Management of human activities in the marine environment increasingly requires spatially explicit risk assessments that link the occurrence and magnitude of a pressure to information on the sensitivity of the environment. We developed a marine spatial risk assessment framework for the UK continental shelf assessing the vulnerability of 11 fish and shellfish species to aggregate extraction. We calculated a sensitivity index (SI) using life-history characteristics and modelled species distributions on the UK shelf using long-term monitoring data and indicator kriging. Merging sensitivity indices and predicted species distributions allowed us to map the sensitivity of the selected fish to aggregate extraction. The robustness of the sensitivity map was affected primarily by widespread species with a low to medium level of sensitivity, while highly sensitive species with more restricted distributions had a limited effect on the overall sensitivity. The highest sensitivity in the case study occurred in coastal regions, and where nursery and spawning areas of four important commercial species occur. To test the framework, we overlaid the estimated sensitivity map with the occurrence of aggregate extraction activity in inshore waters, including sediment plume estimations, to describe species vulnerability to dredging. We conclude that our spatially explicit risk assessment framework can be applied to other ecosystem components and pressures at different spatial scales and it is therefore a promising tool that can support the sustainable development of marine spatial plans.