Heat suffocates shellfish as blue crab population explodes in Italy

Italy's coastal ecosystems are facing a dual crisis: extreme heatwaves are devastating native shellfish populations like mussels and clams in lagoons and ponds, while the invasive blue crab continues its unchecked proliferation. Confcooperative Agroalimentare e Pesca reports an escalating emergency from the Upper Adriatic to the Tyrrhenian Sea, with the blue crab's presence now stable along the Tyrrhenian coast, including Orbetello lagoon and the Arno river mouth, as well as in Sardinia, Sicily, and Calabria.

The situation is particularly dire in Friuli Venezia Giulia, where catches of the blue crab in the first four months of 2026 reportedly equaled the entire catch for 2025. The invasion is no longer confined to lagoons but extends to open sea areas up to four miles offshore. In Orbetello, extreme heat has led to large concentrations of blue crabs reappearing.

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The Delta del Po is the ideal habitat for the blue crab to proliferate. It's a perfect habitat for the reproductive cycle: males move towards fresh water during molting, while females stay near the mouth to reproduce multiple times during their lives.

Giuseppe Castaldelli, a professor of Ecology at the University of Ferrara, explains that the Po Delta serves as an "ideal habitat" for the blue crab's reproductive cycle. Males move towards freshwater during molting, while females remain near the estuary to reproduce multiple times. Castaldelli points to 2017 as a turning point, with annual catches per boat soaring from less than 1.5 kg to 9,124 kg by 2023. While climate change contributes, the Po Delta's specific ecology, with Adriatic currents feeding phytoplankton and thus the mollusks the crab preys on, is a major factor.

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Thanks to the resilience of fishermen and the use of enclosures and nets, we manage to carry out a small production of clams, but we have losses of 70%.

Researchers like Anna Gavioli from the University of Ferrara suggest that capture alone is insufficient. While humans are the primary predators of adult crabs, recovering native species such as sea bass, sea bream, eel, striped red mullet, and goby is crucial for controlling juvenile populations and restoring ecosystem balance. Commercial and recreational fishing of these native species is encouraged.

Vadis Paesanti, vice president of Confcooperative Agroalimentare e Pesca Emilia Romagna, notes that despite fishermen's resilience and the use of traps and nets, they face a 70% loss in clam production. In response to the overwhelming catches and to avoid disposal costs, some organizations, like the Consorzio Cooperative Pescatori del Polesine, are adopting a new strategy: commercializing the blue crab. President Paolo Mancin announced the launch of blue crab products in three varieties, claws, fillet, and pulp mix, aiming to turn an ecological threat into a culinary resource.

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We have decided to change strategy by commercializing it.