Fisheries-enhanced pressure on Mediterranean regions and pelagic species already impacted by climate change

18 pages, 7 figures, 2 tables, supplemental files https://doi.org/10.1525/elementa.2022.00028.-- Data accessibility statement: The source data on which we base our findings are all open access and can be found at https://www.aquamaps.org/ and https://marine.copernicus.eu/. All of the generated TIF files will be available at the public repository https://digital.csic.es/ upon publication. All the code used in our analyses is stored in a dedicated GitHub repository and will be available upon request via the authors

Marine species are widely threatened by anthropogenic activities, including fishing and human-induced climate change. However, geographically broad and spatially explicit 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 representative 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 show how most of the studied Mediterranean pelagic species experienced a reduction in optimal habitat availability over the past decades. The few species that showed positive trends in optimal habitat availability expanded only to a small degree 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 regions. Similarly, fishing pressure was found to be higher in these regions, 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 distributions 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 would ensure food security and a healthy ecosystem in this highly impacted basin

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 No 869300 (FutureMARES project) and the Spanish project ProOceans (Ministerio de Ciencia e Innovación, Proyectos de I + D + I (RETOSPID2020-118097RB-I00). FR was supported by the Spanish government through the “Severo Ochoa Centre of Excellence” accreditation (CEX2019-000928-S) and the Ramón y Cajal programme (Spanish Ministerio de Ciencia e Innovación, RYC2020-030078-I). JO, FR and MC acknowledge the institutional support of the “Severo Ochoa Centre of Excellence” accreditation (CEX2019-000928-S). FR also acknowledges support by the Spanish government through the project SOSPEN (grant agreements Nº PID2021-124831OA-I00, Spanish Ministerio de Ciencia e Innovación)

Peer reviewed