Warming Mediterranean Sees Invasive Species Reshape Marine Life
Rising sea temperatures and the Suez Canal are fueling a surge of non-native marine species in the Mediterranean, disrupting ecosystems and fisheries.
Off the coast of Cyprus, a fisherman carefully removes the venomous spines from a lionfish before tossing it into a bucket. The routine is part of a scientific effort to track and control invasive species that are rapidly transforming the Mediterranean Sea.
A combination of warming waters and the Suez Canal has opened a pathway for tropical fish to enter the region. A recent survey collated by the Cyprus Academy of Sciences, Letters and Arts, based on research from scientists in 11 countries, estimates a new species arrives every two weeks. The Mediterranean now hosts more than 1,000 non-indigenous species, up from fewer than 800 recorded between 2012 and 2017.
These newcomers are displacing native species, altering food chains, and threatening local fisheries. The changes have been particularly pronounced since 2000, according to Periklis Kleitou, a marine scientist at the Cyprus-based Marine and Environmental Research (MER) lab. "We see more and more non-indigenous species proliferating and dominating the marine environment and, unfortunately, fewer native species," he said.
The lionfish, with its spiky appearance and no known predator in the Mediterranean, feeds voraciously on native fish and crustaceans. In Greece, more than 230 alien species have entered waters in recent decades, said Paraskevi Karachle, research director at the Hellenic Centre for Marine Research. Rabbitfish graze heavily on algae, creating barren underwater areas, while the toxic silver-cheeked toadfish attacks other fish and has been linked to reduced octopus catches. Greek and Cypriot authorities have offered bounties on pufferfish hauls.
Scientists are exploring ways to adapt, including encouraging consumption of these new species. Lionfish is safe to eat once spines are removed, and chefs are beginning to feature it. Markets are emerging in Lebanon, Turkey, and Tunisia. Researchers are also testing methods to convert toxic pufferfish into fishmeal for farmed sea bass and investigating uses for alien species in cosmetics, supplements, and leather products.
Experts stress that the sea's complexity requires sustained, long-term monitoring to understand the full impact of these changes.