Sensitivity of megabenthic invertebrate communities to bottom trawling in the Mediterranean based on biological traits

Bottom trawling has major impacts on the structure of the seafloor and on the composition and functioning of benthic communities. Reduction in benthic biomass has particularly been observed on the soft bottoms of the Mediterranean Sea, where the highest trawling pressures in European waters are recorded. Assessing the sensitivity of benthic taxa to trawling disturbance is therefore essential to develop effective conservation strategies. Although some taxa have already been identified as indicators of Vulnerable Marine Ecosystems based on expert knowledge, a broader quantitative evaluation is now required to support conservation planning. In this study, a trait-based approach was applied to a large dataset of megabenthic invertebrates collected during the MEDITS survey to assess two components of sensitivity: the resistance of taxa (their likelihood of being captured or damaged by trawls) and their resilience (their ability to recolonize the seafloor after disturbance). Spatial patterns of biomass for the most sensitive taxa were mapped, and these metrics were then aggregated at the community level to provide an integrated measure of sensitivity across northern Mediterranean shelves and slopes. Most invertebrates caught by the scientific trawl exhibited biological traits associated with high sensitivity to trawling. Biomass maps of the 30 most sensitive taxa revealed fragmented distributions across the basin, with species-specific and heterogeneous hotspots. At the community scale, low resistance to trawling was observed throughout the basin, while resilience levels tended to be higher overall. The main hotspots of highly sensitive communities occurred along the shelf breaks of the Gulf of Lion and the Catalan Sea, on the northern shelf and southern slopes of the Adriatic Sea, and in the western Strait of Sicily, areas generally subjected to lower fishing pressure. The persistence of low-resistance taxa in other heavily exploited zones may reflected some degree of resilience that enables them to support the disturbance. These findings provide valuable insights for identifying and prioritizing areas most sensitive to bottom trawling within Mediterranean conservation networks.