A toxic puffer fish species from the Red Sea has increasingly invaded Greek waters, posing a growing challenge to local fishermen. Known as Lagocephalus sceleratus, the silver-cheeked puffer fish has spread widely throughout the Mediterranean after migrating through the Suez Canal, a route that has long served as a biological corridor between seas.

Stathis Evangelou, a fourth-generation fisherman from the island of Astypalaia, recalls when the species was a rare curiosity, once encountering only a few in deeper waters. Now, two decades later, he reports that the fish are ubiquitous, causing substantial damage to fishing equipment and livelihoods. The puffer fish’s powerful "beaklike jaws," capable of slicing fishing nets and even metal objects, were highlighted by the Greek Red Cross earlier this year amid warnings about the potential for severe injuries.

This invasive species arrives amid existing pressures on the region’s small-scale fishing industry, which has contended with rising operational costs, depleted fish stocks, warming seas, and the long-term effects of overfishing. Fishermen like Evangelou and his 83-year-old colleague Kyriakos Chatzidakis describe how the puffer fish cut large holes in nets—damage that can take over a day to repair—and how the overall catch has declined significantly, with fewer traditional species available.

Scientists attribute the spread of the puffer fish and other invasive species such as lionfish to a phenomenon known as Lessepsian migration, facilitated by the continuous widening and deepening of the Suez Canal since its opening in 1869. Climate factors also play a role, as Mediterranean surface waters have warmed approximately 1°C over the past 30 years, with recent marine heatwaves pushing temperatures beyond historical levels.

Locals describe the puffer fish as a voracious predator that feeds on squid, octopus, cuttlefish, and juvenile fish, further undermining marine biodiversity. Evangelou recounts observing three puffer fish rapidly devouring a 4-kilogram bonito in minutes, underscoring their impact on marine life. Biologists estimate that fishermen lose on average at least €8,500 annually due to net damage, lost gear, and lost fishing days because of the species.

The puffer fish has expanded beyond traditional hotspots like the Dodecanese and Crete to other areas, including Attica. However, systematic monitoring of its population remains limited, with most data relying on fishermen's reports.

In response, the Greek government has initiated a €1.5 million pilot compensation program in Crete, offering professional fishermen up to €5.33 per kilogram of caught puffer fish. The project aims to incentivize removal of the invasive species, with coordination by regional authorities for collection and disposal. This approach follows Cyprus’s earlier but only partially effective bounty scheme targeting the same species.

Environmental organizations welcome measures to reduce puffer fish numbers but urge more nuanced strategies. Michalis Margaritis from WWF emphasized the need to determine appropriate timing and target age groups for removal efforts, cautioning that alien species invasions are complex phenomena exacerbated by human activity and climate change.

Despite the challenges, the government remains committed to supporting the fishing sector. Margaritis Schinas, minister responsible for rural development and food, affirmed the belief in the future of Greek fishing and pledged ongoing assistance to fishermen navigating these pressures.

For now, fishermen like Evangelou continue to persevere. While expressing deep attachment to their trade, they acknowledge the difficulties and uncertainty ahead. Evangelou lamented the decline of marine resources and the toll on his livelihood but remains hopeful that intensified removal efforts might reduce the puffer fish’s prevalence. Still, he warned that without significant change, many fishermen may be forced to abandon their work in favor of more stable employment.