Evaluating the efficacy of closing the current European network of marine protected areas to mobile bottom-contacting fishing gears

The European Natura 2000 (N2000) network aims to protect Europe's most valuable habitats and species. As the EU advances its “30% by 2030” target, prohibiting bottom trawling within all N2000 sites has been proposed. We evaluated the effectiveness of such closures for seafloor protection by quantifying network coverage across benthic habitats and ten mobile bottom-contacting fishing métiers in four northeast Atlantic regions, and by assessing ecological implications under multiple fishing-redistribution scenarios. N2000 coverage and its overlap with fishing grounds varied strongly across habitats, métiers, and regions. The network covered 23% of the assessment area and contained 22% of annual average fishing effort (2016–2020), with particularly high values in the Bay of Biscay & the Iberian Coast (44% coverage; 43% effort). Nearshore habitats were disproportionally represented in the network, whereas deeper offshore habitats were underrepresented. Several métiers relied heavily on N2000 sites, especially beam trawls targeting crustaceans (85% of effort), followed by otter trawls for small pelagic fish (41%), Danish seines (40%), and beam trawls for molluscs (38%). Ecological outcomes of N2000 closures varied across displacement scenarios. Habitat quality increased within closures, but regional declines occurred outside them under certain redistribution strategies, particularly in habitats with limited N2000 coverage. Consequently, some scenarios yielded habitat-specific net losses. Closing all N2000 sites could contribute to the EU's 30 × 30 target, but would still yield uneven habitat protection and disproportionate consequences for specific fisheries. The dependence of net conservation gains on displacement dynamics highlights the need for strategic MPA design and active redistribution management.