Exploring spatial-based management scenarios to protect the seafloor in different areas of the Mediterranean Sea

In recent years, European policies aimed to regulate bottom trawling activities, given the significant environmental damage they cause. Trawling represents a considerable source of income for the economies of many Mediterranean countries. Therefore, it is essential that management measures, including spatial closures, consider the potential long-term consequences of their implementation. This study investigated the impact of different spatial management scenarios on reducing the environmental footprint of bottom otter trawling in four distinct sectors (Western, Southern, Adriatic, and Ionian) of the Mediterranean Sea. Using vessel monitoring systems and logbook data, the study identified core fishing grounds and modelled the effects of various spatial restrictions, including depth-based fishing bans and fishery-restricted areas (FRAs). The results indicate that in all the sectors, the adoption of FRAs does not lead to significant variations in the economic performance of fleets, and the application of the ban over 800 m would allow the protection of a significant portion of the deep-sea bottom with relatively little economic impact. On the contrary, other spatial-based measures lead to different, sector-specific effects. In fact, restricting shallow coastal areas (<6 nm) significantly affects the profitability by reallocating effort to other fishing grounds, with noticeable differences between fleets operating in the same sector (i.e. the Adriatic Sea); meanwhile, bans over 600 or 700 m would determine very different economic effects in the four sectors. Overall, these results suggest that a sole fishery management measure approach is inadequate. Tailored region-specific measures are instead essential to balance ecological sustainability and economic outcomes across different Mediterranean regions.