The climate crisis is causing significant physical changes in marine systems, including warming, ocean acidification, thermal stratification, and more extreme weather events. The Eastern Mediterranean, a climate change hotspot, is expected to see heat waves occur seven times more frequently and last three times longer by the century’s end. These changes can directly affect farmed species, such as when sea temperatures exceed their thermal limits, or indirectly through eutrophication and species invasions. Impacts on aquaculture include reduced growth, widespread die-offs, increased disease risks, reproductive cycle disruptions, and infrastructure damage.
Experimental studies show that the thermal tolerance for key species in the Mediterranean is narrow. E. seabass performs best around 26°C and above this, performance drops while the lethal limits for the species is at 33°C. Gilthead sea bream presents reduced growth above 28°C, stop feeding above 32°C and has lethal limits at 34°C. While generalized models have been developed, gaps remain regarding the effects of combined stressors in real-world production, where multiple factors in open sea environments may lower these tolerance thresholds. Climate change is exacerbating bacterial and parasite issues in Mediterranean aquaculture. Warmer waters favor pathogen growth while stressing aquatic organisms, weakening their immune systems. Cascarano et al. found that rising temperatures extend the transmission period of key pathogens, increasing disease outbreaks from spring to autumn. This presents a major challenge for fish health management, alongside the risk of new pathogens invading the warming Mediterranean.
Mitigation strategies for the sector in the Mediterranean ought to focus on enhancing sustainability, scientific innovation, regulatory frameworks, and investment. Sustainable production systems are crucial, and together with novel feed ingredients may promote economic and social sustainability. Data collection on the current state for timely monitoring, combined with robust forecasting tools, and prediction models targeting small geographical areas, is essential for adaptive management. Collaboration between the industry and the scientific community is vital to improving animal health, developing alternative fish-feed raw materials, promoting species diversification, and advancing selective breeding. Regulatory action at the EU and Member State levels is necessary for the planning and design of adaptation strategies, implementing mitigation actions. Supporting mechanisms, at European (CFP, EMFAF) and regional level (GFCM) also play a critical role. Investment in climate-adapted engineering, robust insurance schemes, business model diversification, risk mitigation, and innovation—especially in energy transition—is essential to strengthen the sector’s resilience and ensure its sustainable future in the region.