Invasive Marine Species Threaten Mediterranean Fisheries in Greece

Scientists link the warming of Mediterranean waters—projected to rise 2‑6 °C by 2100—to a rapid influx of non‑native marine organisms that are outcompeting native species. The rise in temperature and the open Suez Canal have facilitated the establishment of invasive fish such as puffer species and predatory newcomers, and the spread is now moving toward France and Spain.

In Greek coastal waters, the non‑toxic but highly aggressive blue crab (Callinectes sapidus) has proliferated over the past decade, dramatically reducing catches of traditional fish like anchovies. Fishermen report a drop from about 300 tonnes of anchovies to just five tonnes in recent years, and coastal cooperatives have called for targeted fishing measures and compensation. Marine biologist Ernestos Atzouro and oceanographer Ronan MacAdam warned that the Mediterranean is a “hot spot” of climate change, while Deputy Minister of Rural Development Athanasios Kavvadias met with fishing representatives to discuss possible mitigation.

Experts note that the blue crab arrived from the Americas in the 1950s and is among the 100 most dangerous invasive species in the basin. Its ability to thrive in the Mediterranean’s wide temperature range (3‑37 °C) and to damage nets and other marine life makes it a pressing ecological and economic concern for Greece and neighboring coastal nations.