Temporal ecotrophic impacts of fisheries and climate change in the Aegean Sea

Mediterranean fisheries face a crisis with rapidly depleting stocks due to overexploitation, exacerbated by various stressors, including climate change, alien species and pollution. To address these challenges, modelling tools like ECOPATH with ECOSIM (EwE) are being used to assess marine ecosystems within the context of the ecosystem-based fisheries management (EBFM). In this study, an ECOSIM model was developed for the Aegean Sea based on a previously developed ECOPATH configuration (calibration period: 2006-2021; projection period: 2022-2050), to assess the current state of the food web and predict future conditions. Forecast scenarios incorporating fisheries and climatic stressors were explored to propose management measures that will ensure fisheries sustainability. The baseline simulation demonstrated a decline in biomass and catch in most functional groups (FGs). Fishing effort reduction scenarios led to biomass increase in several FGs, but resulted in lower catches. Climate scenarios with sea surface temperature time series from the Intergovernmental Panel on Climate Change triggered varied responses among FGs, with biomass gains observed in the demersal compartment, while the most negatively affected pelagic groups were mackerels and horse mackerels. Combined fisheries and climatic scenarios revealed synergistic effects, emphasizing the complex ecological interactions in the Aegean Sea. Ecological indicators from the ECOIND analysis highlighted losses in the demersal compartment in relation with the fisheries and climate scenarios, while trophic-based indices exhibited the most notable variations, suggesting cascading effects in the food web. The findings of this study will provide valuable insights for fisheries management and climate adaptation strategies in the Aegean Sea.