Integrated ecosystem analysis in Irish waters; Providing the context for ecosystem-based fisheries management

Fishing has long been considered the most impactful human activity on the marine ecosystem. To adopt ecosystem-based fisheries management (EBFM) requires consideration of all human impacts, not just those of fishing. The ODEMM (Options for Delivering Ecosystem-based Marine Management) approach provides an integrated ecosystem assessment that is a flexible, cost-efficient and expert-based. The framework traces the sectors affecting the marine environment, the pressures they create, and the ecological characteristics affected. This research presents the first application of the ODEMM framework outside of the ODEMM project, completed for Ireland's marine waters. The assessment places fishing in the context of other anthropogenic pressures and highlights areas of threat to Marine Strategy Framework Directive (MSFD) descriptors. From 1874 impact chains, just 59 (44 of which were attributed to the fishing sector) account for 64% of the Total Risk score, highlighting areas for management action with a high risk-reduction return. Of the sectors, The analysis showed Waste Water to have the highest average risk of all sectors, followed by Land-based Industry, Fishing and then Shipping. In terms of total risk, Fishing was the most important sector, due to its high connectance to many ecosystem components and widespread influence, even though many of the impacts are relatively low and the components impacted show a high degree of recoverability. Litter was identified as the pressure with the highest total risk scores (average and summed) due to its persistence, and widespread reach. Among the ecological characteristics, deep water habitats that have low resilience to pressures showed the highest average total risk, yet the highest impact risks were for ecological characteristics that were closer to land and were impacted more frequently. These conclusions highlight the importance of context and interpretation in the analysis. The impact chains were further linked through to the MSFD environmental status descriptors, indicating Biological Diversity and Food Webs as the descriptors most at risk, followed by Sea-floor Integrity. As the first independent application of the method, issues arose with interpretation of some categories and definitions, and some modifications are discussed. Overall, this has proven a valuable exercise for helping to identify management priorities. The analysis presented provides useful context for EBFM and a basis for decision making and trade-off analysis for Ireland. The ODEMM framework employed offers a comprehensive, adaptable, globally-applicable tool to guide ecosystem management and the decision-making process, by highlighting risk areas and priorities for management action and research.