Stronger Together: Fisheries Enhance Pressure on Mediterranean Regions and Pelagic Species Already Impacted by Climate Change

VIII International Symposium on Marine Sciences, 6-8 July 2022, Las Palmas de Gran Canaria, España

Marine species are widely threatened by anthropogenic activities, including fishing and human-induced climate change. However, geographically broad and spatiallyexplicit assessments of the simultaneous impacts of these major threats at regional scales are mostly lacking due to the practical challenges of surveying vast geographical areas and obtaining adequately resolved data. Yet, these assessments are key for identifying highly and cumulatively impacted areas and species that should be prioritized for conservation through knowledge-based management strategies. Here, we analysed a 26-year (1993-2018) time series of highly-resolved remotely sensed environmental data to evaluate changes in optimal habitat availability (i.e., extent of marine areas encompassing optimal environmental conditions) for 15 species of small, medium and large pelagic fish inhabiting the Mediterranean Sea Large Marine Ecosystem. We then combined spatial and temporal data on fishing pressure and changes in optimal habitats to identify areas of high risk of cumulative impacts. Overall, results showed how most of the Mediterranean pelagic species went through a reduction of optimal habitat availability over the past decades. The few species that showed positive trends in optimal habitat availability did not expand largely and hence were unlikely to compensate for the loss of key functional roles at the group level. Habitat loss concentrated in the western and central basins. Similarly, fishing pressure was found to be the highest in both basins, thus overlapping with the areas experiencing a higher reduction of optimal habitat. Small and large pelagic fish were the most impacted groups, having a larger proportion of their distribution in highly, cumulative impacted areas. Redistributing fishing pressure and reducing it in highly impacted areas may alleviate the overall cumulative pressure on pelagic stocks, contributing to the necessary shift to sustainable and resilient fisheries that allow ensuring food security and achieving a healthy ecosystem in this “sea under siege”

JO was supported by Universitat de Barcelona through the PREDOCS-UB grant (2021). MC received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement N° 869300 (FutureMARES project). FR was supported by the Spanish government through the 'Severo Ochoa Centre of Excellence' accreditation (CEX2019-000928-S)

Peer reviewed