Reducing fisheries impacts on the seafloor: A bio-economic evaluation of policy strategies for improving sustainability in the Baltic Sea

摘要

Under the European Union's Marine Strategy Framework Directive (MSFD) and Common Fisheries Policy (CFP), management organisations are directed to evaluate measures for reducing the footprint of fishing on the seafloor. We applied a spatial modelling platform to evaluate the effects of spatial fishery management measures on the Baltic Sea. The evaluation includes restricting areas for fishing with the dual goal of reducing the impact on benthic habitats and minimising negative effects on fishery catch and profit. To redistribute the fishing effort realistically, the model simulates individual-vessel agents and behavioural rules. The model integrates benthic community dynamics by combining gear-specific depletion rates from fishing agents with habitat-specific traitbased recovery rates for the benthic communities. Our simulations showed that closing areas in the central Baltic Sea and condensing the fishing efforts into core fishing areas did not improve the relative benthic status (RBS). In addition, the fisheries were adversely affected by reduced fishing opportunities, further impacting their economic performance. The potential for improving the overall RBS with spatial management is dubious in the central Baltic, given that the area is dominated by relatively short-lived and rapidly recovering benthic species. By contrast, the Kattegat showed a substantial improvement in the RBS, as determined by measures combining the protection of long-lived benthic communities with the mitigation of high-impact fisheries. Our results and investigations provide different bio-economic scenarios on benthos and fisheries dynamics resulting from specific management measures. The developed knowledge base and modelling tool is expected to assist policymakers in identifying the most appropriate measures to achieve both a Good Environmental Status (GES) of the seafloor according to the MSFD and to maintain sustainable fisheries and stocks according to the CFP.