Overseas
The Mediterranean Sea has never been so warm and unpredictable. Marine heatwaves in the Mediterranean are becoming a new structural factor that affects ecosystems and human activities, particularly fisheries and aquaculture.
The Copernicus Ocean State Report 9, published in September, depicts a basin warming faster than the global average: +0.41 °C per decade since 1982, with even higher values in the Aegean, Levantine and Adriatic Seas. These are not just figures: behind them lie Italian production chains at risk of losing stability, profitability and future prospects.
From the Po Delta to Sicily: two emblematic emergencies
Between 2022 and 2023, the Mediterranean experienced the longest marine heatwave of the past forty years, with temperatures up to 4.3 °C above average. In the Po Delta, the impact was devastating: clam farming recorded production collapses of up to 100%. To make matters worse, the spread of the invasive blue crab took advantage of the new conditions to consolidate its presence.
In Sicily, another threat became concrete. The expansion of the bearded fireworm, favored by warmer waters, has affected biodiversity, small-scale fisheries, and even human health. Two emblematic cases that show how climate change is no longer a theoretical issue, but a factor altering the economic and social balance of the Mediterranean seafood sector.
Mediterranean aquaculture under pressure
While fisheries pay the price for ecological transformations, aquaculture is under equally strong pressure. In 2024, 17% of European shellfish farms were hit by extreme heatwaves. All ocean regions adjacent to countries producing more than 5,000 tons annually now show warming and acidification above the global average.
For Italy, where shellfish farming is a cornerstone of the sector, these figures mean direct risks for businesses, cooperatives and employment. Rising temperatures reduce yields and alter product quality, while acidification threatens bivalve life cycles.
Policy and management: the time to act is now
The message of OSR9 is clear: awareness is not enough, operational responses are needed. At the European level, the Restore Our Ocean and Waters 2030 Mission aims to strengthen monitoring, innovation and governance. For Italy, the challenge is to integrate this data into practical management, from aquaculture concessions to fisheries plans, and even climate risk insurance strategies.
The most innovative tool introduced by the report is the Starfish Barometer, a dashboard that will annually monitor the health of the ocean and human pressures. A useful basis for more informed policies, but also for businesses and associations that need to recalibrate their models.
Marine heatwaves in the Mediterranean are not a passing event, but a new context the Italian seafood industry must learn to live with. Ignoring them means leaving businesses and coastal communities exposed to increasingly frequent shocks. Facing them with data and strategies, instead, means transforming a crisis into an opportunity for adaptation and resilience.
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