The Mediterranean Sea is one of the most heavily exploited marine areas in the world. Due to its semi-enclosed nature and the long history of human use, ecological pressures and socio-economic demands are tightly interlinked (Rick et al., 2020). Fishing is an important activity throughout the sea, supporting local economies and culture, yet it causes significant pressures on marine ecosystems (Fiorentino and Vitale, 2021; FAO, 2023). In the Mediterranean, the activity takes place throughout the region from depths ranging 50–1000 m and in 2016 to 2018, it was responsible for 27.0% of Mediterranean landings through just 7.9% of the vessel segment (FAO, 2020). The 1000 m depth trawling limit was set by the General Fisheries Commission for the Mediterranean and Black Sea (GFCM) and intended to protect deep-sea ecosystems, which are particularly vulnerable to fishing pressure and slow to recover (EC, 2006). Among fishing methods, bottom trawling is the most pervasive and destructive activity for the seabed due to its direct contact with the benthic environment (Kaiser, 1998; Foden et al., 2011). As well as direct removal of benthic and demersal species, bottom trawl gear reshapes benthic community structure, reduces habitat integrity, and affects the biodiversity and overall resilience of marine ecosystems (Eigaard et al., 2016; Tiano et al., 2019; Bradshaw et al., 2024; Agnetta et al., 2025). In Europe it is the most widespread marine activity with varying levels of intensity and impact across almost all shelf areas (Hiddink et al., 2026).

Until recently, scientific and policy debates about Mediterranean fisheries focused on whether fish stocks were overexploited and if so how to best reduce this pressure, neglecting the ecological impacts of fishing on benthic habitats (Bahamon et al., 2024; Bastardie et al., 2025). For example, the GFCM 2030 Strategy proposes to establish effective area-based conservation measures based on the mapping of essential fish habitats and vulnerable marine ecosystems (VMEs) (FAO, 2021). However, it pays little or no attention to other benthic habitats that cover most of the seafloor and offer invaluable services to humans, such as carbon sequestration (Porz et al., 2022). Yet, growing evidence highlights that all benthic ecosystems are highly sensitive to bottom-contacting fishing (Tiano et al., 2019; Pitcher et al., 2022). In addition, recent policy and legislation in the European Union has incorporated not only biodiversity but also seafloor integrity as key descriptors of good environmental status (GES in EU, 2008 – Marine Strategy Framework Directive, MSFD), placing benthic habitats at the heart of marine sustainability objectives. More recently and in accordance with the MSFD, the Nature Restoration regulation (EU, 2024) sets specific restoration targets for degraded benthic habitats. In this context, policy around fisheries should also consider seafloor ecological status. To achieve this, mapping the spatial footprint, i.e. the extent and intensity of seafloor disturbance caused by bottom trawls and also assessing benthic status are essential steps for identifying sensitive areas and areas of high pressure, guiding more effective, spatially explicit management strategies (Bona et al., 2025).

The Eastern Ionian Sea offers a valuable case study for examining the dynamics and trade-offs between bottom trawling and benthic ecological impacts. This region hosts a mosaic of habitats—ranging across multiple MSFD broad habitat types from infralittoral to deep bathyal zones, each supporting distinct benthic assemblages with varying sensitivity to disturbance (Smith et al., 2023). This area includes Patraikos Gulf, one of Greece’s main fishing grounds. The Gulf is also adjacent to a marine protected area (MPA), Zakynthos national park, and therefore this area illustrates the tension between ecological protection and extractive fishing industries. Few studies have tested the impact of different spatial management scenarios on reducing the environmental footprint of bottom trawling, mainly focusing on the fisheries themselves, i.e. bycatch, fish stock assessment, nursery-ground protection, and on the economic outcomes (Bastardie et al., 2017, Bastardie et al., 2025; Sbrana et al., 2025), with even less providing evidence on how benthic status is influenced (Bastardie et al., 2020; Zupa et al., 2025).

In this context, our study aims to evaluate the ecological outcomes of various management measures and fishing restrictions on the benthic ecosystem and to explore the implications of these findings for regional fisheries governance. This is in accordance with the objectives of the EU Biodiversity Strategy to achieve GES in at least 30% of the habitats in the EU marine waters by 2030 (EC, 2021) and aligns with the recent goals of the GFCM, which among others promotes sustainable fisheries through the protection of vulnerable marine ecosystems (FAO, 2021). By integrating ecological assessments with management scenarios, this research contributes to the advancement of ecosystem-based fisheries management in the Mediterranean. It provides insights into the trade-offs and co-benefits between marine habitat conservation and resource exploitation, offering evidence-based guidance for environmental and fisheries policymakers seeking to align marine ecosystem health with socio-economic sustainability. This approach has been to anticipate the impacts of different protective management strategies by modelling scenarios of alternative spatial allocations of bottom trawling effort on seabed ecological status.

Mapping regional trawling activity and benthic ecological status are valuable policy tools, enabling effective spatial management by identifying sensitive or marine areas at high risk to disturbance (Bona et al., 2025). Insufficient knowledge of fisheries distribution and sensitive areas can lead to incorrectly placed closures that will not only result in a reduction of economic profit but may also fail to provide benefits to maintain or improve the benthic ecological status (Vaughan, 2017; Sbrana et al., 2025). Based on the benthic status (RBS) estimated with recent trawling effort in the area by Pitcher et al. (2022) and Smith et al. (2023), this study explores how different fisheries spatial management scenarios would change RBS. Trawling intensity and benthic sensitivity are linked across different habitat types and alternative management measures. Our findings suggest that the selection of specific management measures is critical, since different measures have yielded different outcomes. While bottom trawling closures in shallow waters (<150m) offered the most substantial improvement in RBS, deeper bathymetric closures and the displacement of effort from protected areas resulted in negligible or mixed effects.

Techniques for reconciling fisheries’ economic performance and minimization of their impacts on the seafloor are of growing interest to policymakers now that environmental targets are pursued (within the GFCM, the MSFD, and the Nature Restoration Regulation). In this context, this study aimed to evaluate the performance of different management scenarios to reduce the ecological impact of bottom trawling on the seafloor. This study prioritized seafloor integrity in the management scenarios tested, with the expectation that preserving benthic habitats will, in turn, promote the long-term sustainability of the fisheries sector. Among the scenarios examined, four of them were based on a bathymetric ban of trawling where fishing pressure is removed from the system entirely. The outcomes of these scenarios indicated that reducing trawling effort does not always improve benthic status. Specifically, restricting trawling down to 150 m depth yielded the strongest improvements, while closures of trawling in areas deeper than 600 or 800 m had negligible changes in the benthic status. The latter has been suggested as a sustainable measure that would allow the protection of the deep-sea including several deep-water coral species and vulnerable marine ecosystems, with relatively little economic impact (Sbrana et al., 2025). Nevertheless, the negligible difference in RBS between the 800 m and 600 m scenarios suggests that for the Eastern Ionian Sea, the ‘ecological gain’ is relatively small, indicating that targeted, habitat-specific interventions rather than broad bathymetric shifts may be more beneficial. In contrast, the implementation of a drastic management plan that would offer protection to the shallower habitats (to 150 m depth) delivered significant ecological benefits in the model, first explained as these habitats host the core fishing grounds in the area and also host the most sensitive benthic communities (Smith et al., 2023). However, as maximum trawling intensity is generally observed at 50–200 m depth, this scenario may have significant economic costs to fishers, particularly if no “reserve effect” is to be expected. For example, if this ban leads to increased productivity or redistribution of species that could benefit fisheries outside the closed area, this can offset some short-term economic losses. Thus, reducing trawling entirely in a core fishing ground may not be realistic, and anticipating effects without accounting for likely effort displacement may overestimate ecological improvements (Bastardie et al., 2014; Vaughan, 2017).

Spatial closures of trawling may be insufficient if effort is redistributed rather than reduced (Bastardie et al., 2025; Binch et al., 2025). Hence, a dynamic scenario was implemented to predict the effects of closing all MPAs in the study area and the consequent redistribution of trawling effort. This scenario is policy relevant as the Greek government is currently in the process of implementing a trawling ban in all MPAs². This scenario yielded minimal benthic ecosystem benefits. This is because many of the MPAs in the study area were established to meet Natura 2000 conservation objectives, i.e., the protection of habitats and species included in Natura 2000’s annexes, rather than as fisheries management tools designed to maintain or restore seafloor integrity. Our results show that the Greek government’s policy, while well-intentioned, may produce unintended ecological consequences if implemented without complementary management measures. Specifically, we found that MPA closures resulted in localized RBS declines in already heavily fished areas, particularly in Patraikos Gulf. In certain grid cells within this area, our model predicted RBS values falling below 0.8 - the proposed threshold for GES - as displaced fishing effort concentrated in the remaining accessible grounds. This result is concerning given that Patraikos Gulf represents one of the most economically important fishing grounds in the region, where increased effort intensity could simultaneously compromise both ecological status and long-term fishery sustainability. The displacement effect we observed complements the findings by Bastardie et al. (2025), who showed through bioeconomic simulations that spatial restrictions can have unexpected negative outcomes when effort is reallocated to adjacent areas. Similarly, Binch et al. (2025) concluded that trawling effort displacement can transfer ecological impacts beyond protected areas and influence whole food webs in the North Sea. Despite the ecological risk, spatial restrictions and fishing effort redistribution also impose significant economic trade-offs. For example, Sbrana et al. (2025) noted from a modelling scenario, restricting fishing in shallow coastal areas (<6 nm) in Italian waters, significantly affects fleet profitability by reallocating effort to other fishing grounds.

Overall, most habitat types in the GSA20 are currently in good condition (with RBS values higher than 0.9 in every habitat), even though some areas, particularly in circalittoral and offshore circalittoral mud habitats, exhibit higher impact from bottom trawling pressure. This is due to two reasons, firstly the Eastern Mediterranean, with the exception of some localized trawling hotspots, is not under intensive trawling pressure compared to other regions of Europe; maximum SAR in Northern European waters and the Adriatic Sea can reach values of more than 10 or 40, respectively (van Denderen et al., 2020; Zupa et al., 2025). Secondly, our benthic assessment was based on the macroinvertebrate community that tend to have lower longevity (and therefore less sensitive) than the larger sized epifaunal species that are used in other Mediterranean assessments (Zupa et al., 2025). The use of infauna-based sensitivity may be a source of underestimation of trawling impact. However, highly mobile larger epifaunal species are usually not effectively sampled by the grab devices, while trawl caught epifauna used for sensitivity estimation in other European assessments may not represent near pristine communities required for the analysis. Additionally, the spatial resolution of our study, which had C-squares of around 25 km² (resolution), may make it difficult to capture the very localized effects of bottom trawling, requiring higher resolution in habitat, sensitivity and trawling pressure maps. While this assessment is effective at characterizing impacts across broad spatial scales, they are less effective at detecting impacts on VMEs that are highly localized.

Together, these comparisons between the scenarios raise the question of whether large-scale spatial restrictions are necessary for seafloor integrity in areas where the baseline benthic status is already high, such as in the case of Eastern Ionian Sea. Instead, more targeted measures may be more effective, such as protection of the most sensitive habitats (e.g., maerl beds, Posidonia meadows, VMEs), reduction in overall fishing effort (which is also important for fish stocks management), gear improvements to reduce physical impact, and the use of management frameworks that minimize harmful effort displacement. These alternatives may better support the EU’s 30 by 30 targets and Restoration Regulation objectives by focusing on ecologically valuable or vulnerable habitats.

Our study provides useful insights for fisheries governance in the Eastern Ionian Sea. Integrating benthic quality indicators such as RBS into spatial planning can improve alignment with EU legislation objectives, while coupling ecological assessment with socioeconomic analyses will provide a more comprehensive basis for decision-making. In this context, future research should combine RBS modeling with fleet economics, fuel consumption, carbon emissions, and target species distribution modeling at high resolution to more accurately quantify trade-offs and co-benefits, supporting sustainable fisheries management in the entire Mediterranean Sea.

Our study indicated that spatial management can meaningfully improve benthic status in the Eastern Ionian Sea, but the effectiveness of closures depends on the area characteristics and habitat sensitivity. Closures down to 150 m depth produced the largest improvements in benthic status, particularly in infralittoral and circalittoral habitats that host sensitive communities, but the economic costs of this type of closure might be significant since this zone has the highest concentration of bottom trawling activity (from 50 to 200 m depth). Moving the already established boundary of 1000 m maximum fishing depth to 800 or 600 m depth had negligible effects on the benthic state given there are no targeted bottom trawling activities in that zone compared to other areas in the Mediterranean Sea. In contrast, when the effort displacement triggered localized declines in the benthic status in heavily fished areas, spatial protection alone may be insufficient without complementary measures to control effort.

These comparisons highlighted that in regions like the Eastern Ionian Sea, where a high proportion of benthic habitats are in good status, additional ecological gains require measures that either target the most sensitive habitats (e.g. infralittoral sand, maerl beds, Posidonia meadows or vulnerable marine ecosystems) or reduce overall fishing effort. Closures at intermediate depth or minimal area restrictions are unlikely to produce measurable improvements. In addition, failure to predict displacement risks may compromise MSFD objectives and its socioeconomic benefits. Thus, future work should compare optimized management scenarios that integrate: (1) targeted protection of the most sensitive habitats or species, (2) graduated effort reduction targets coupled with spatial closures, and (3) socio-economic impact assessments to identify solutions that maximize benthic status while minimizing economic loss of fisheries.