Mediterranean Jellyfish Bloom: Why is Pelagia noctiluca back and so soon?

Our 2025 records show an early and intense bloom of the Purple Jellyfish (Pelagia noctiluca) across the coasts of France, Spain, Italy, and the Adriatic Sea, echoing the infamous summer outbreak of 2020, but starting earlier than expected.

🟣 Comparison with 2020:
In 2020, Pelagia blooms peaked around late June to August, particularly along the Tyrrhenian and Ligurian coasts, Catalonia, and southern France. This year, observations are already flooding in by early May – a significant shift forward.

📈 Why Is It Happening Earlier?
Unlike the typical 12-year cycle theorized for large-scale blooms, recent patterns show Pelagia populations can surge in shorter intervals due to:

🔥 Rising sea temperatures in the Western Mediterranean in some areas already exceed 21°C in May.

🌬️ Weak winter storms and early spring calm seas, allowing jellyfish polyps to mature undisturbed.

🧪 High nutrient levels from spring river outflows, fueling zooplankton, their primary food source.

France: Reports along the Provence and the Côte d'Azur, particularly dense near estuaries.
Spain: Sightings are increasing along the Costa Brava, Almeria, and Valencia.
Italy: Strong presence already confirmed around Tuscany.

📊 We are now mapping the bloom in real time. Early intervention through citizen science is crucial for monitoring and public safety.

📍 View our Mediterranean heatmap.