Pepis, the bearded skipper of a small fishing boat, deftly picks up two lionfish caught in experimental traps off the coast of Cyprus, cuts off their venomous spines, guts them and tosses them into a bucket.
Around him, the Mediterranean looks like a pane of glass, its calm surface giving little hint of the dramatic transformation unfolding underwater.
Pepis' practiced routine is part of a wider effort by scientists to track and control the spread of invasive species, such as lionfish, in these waters. Here life is changing, caused by a combination of warming sea temperatures and the Suez Canal, which has eased access for fish from more tropical climes.
A new species is estimated to enter the Mediterranean every two weeks, according to a recent survey collated by the Cyprus Academy of Sciences, Letters and Arts, based on research by scientists based in 11 countries.
In all, there are more than 1,000 non-indigenous species in the Mediterranean, the report said, up from fewer than 800 counted in another study by the European Environment Agency in the 2012 to 2017 period.
The tropical newcomers from the Red Sea and beyond are displacing native species, reshaping food chains and threatening fisheries, experts said.
That is just another sign of the impact of climate change which has wreaked such havoc on land this summer in Europe, causing record heatwaves, wildfires and drought. And it's a big worry for environmentalists: Despite accounting for just 0.8% of the global ocean area, the Mediterranean supports a share of the world's marine species that some estimates place as high as 18%.
“Changes have been drastic, especially since 2000,” said Periklis Kleitou, a marine scientist at the Cyprus-based Marine and Environmental Research (MER) lab which is looking at ways to reduce the impact of invasive species.
“We see more and more non-indigenous species proliferating and dominating the marine environment and, unfortunately, fewer native species.”
NEW ARRIVALS TAKE OVER
The lionfish looks like an underwater punk, sporting a spiky mohican above a permanent scowl. It has no known predator in the Mediterranean and has a voracious appetite for native fish and crustaceans, scientists say.
Around Cyprus, MER is testing selective traps designed to attract lionfish and blue crabs while allowing other species to escape.
In Greece, increasingly common alien species are disrupting marine ecosystems.
More than 230 have entered Greek waters in recent decades, said Paraskevi Karachle, research director at the Hellenic Centre for Marine Research.
Newcomers disrupt the ecosystem in differing ways. Rabbitfish graze heavily on algae, creating barren areas underwater and competing with the Mediterranean's native herbivorous fish, said Karachle.
The Lagocephalus pufferfish, also known as silver-cheeked toadfish, a carnivore whose toxins can be fatal to humans, attacks other fish and is associated with reports of reduced octopus catches. Silver and speckled with black dots, it looks like a bruiser with bulging eyes and buck teeth.
Greek and Cypriot authorities have offered fishermen bounties on pufferfish hauls.
"Invasive species are taking over our seas, and that affects the local biodiversity as well as the economy," said Christina Kakoulli, a marine biologist at MER.
LOOKING AT WAYS TO ADAPT
Scientists are looking for ways to adapt. One option is to get consumers used to eating new types of fish. Lionfish is safe to consume once the spines are removed. Pepis the skipper advises dusting it with flour before frying.
"In the beginning people were afraid, but now they understand it's a high quality, delicious fish," said Petros Yiangou, a chef who works with MER on Life Prometheus, a European Union-funded project that looks at ways to reduce accidental capture of sharks and rays, while encouraging ways to harvest invasive species.
Markets are emerging in Lebanon and Türkiye, while Atlantic blue crabs have found customers in Tunisia.
Greek marine researchers have tested ways of removing toxins to turn pufferfish into fishmeal for farmed sea bass, Karachle said. Other research has explored possible uses for alien species in cosmetics, food supplements, leather products and pain relief.
Finding uses for the newcomers might be easier than finding one single trigger point for their spread and impact. Scientists say the situation needs sustained, long-term monitoring.
"The sea is very complicated," Kleitou said. "It has so many confounding variables interacting at the same time."
