- July 2025 saw record Mediterranean surface temperatures (26.68°C average)
- Water at 30m depth in Turkey reached 29°C—near Red Sea levels
- Invasive species like lionfish and rabbitfish are thriving in warm waters
- Native fish are vanishing due to heat and competition
- Scientists warn the western Mediterranean will soon follow the same trend
- Some species are now spotted as far as Malta, 1,700km from Suez
- Ecosystem disruption is advancing without native predators
When the Sea Boils, the Red Sea Arrives
It was bound to happen. But not this fast.
Off the coast of Antalya, scuba divers now swim through what feels like the Red Sea with a Mediterranean accent. Temperatures at 30 metres deep have touched 29°C, and on the surface, 32°C is becoming the new norm. For Murat Draman, a local diving instructor, the change is not subtle—it is a full-scale ecosystem upheaval.
“We used to see one or two lionfish. Now there are 20 per dive,” says Draman. “And the small native fish? Gone.”
Draman is not exaggerating. This summer, the Mediterranean officially broke heat records for both June and July, according to Mercator Ocean International. The consequences are swimming all around us—armed with venomous fins and no natural predators.
Lionfish with No Lions to Fear
The beautifully dangerous lionfish (Pterois miles) has settled in like a tourist overstaying their welcome. With no sharks or barracudas to keep it in check, the predator is multiplying across the eastern basin—gorging on gobies, groupers, and anything unlucky enough to get in its way.
And it is not alone.
- Rabbitfish (Siganus rivulatus) has been spotted off Malta—over 1,700 km from the Suez Canal.
- Over hundreds of Red Sea species have colonised warm waters along Turkey, Lebanon, and Israel.l
- Many native species have vanished due to heat stress and invasive competition.
Professor Gil Rilov from Israel’s IOLR warns that the problem is not limited to the east.
“What is happening here will happen in five, ten, twenty years in the north and west of the Mediterranean,” he says. “This is a warning.”
Rilov traces the invasion back to the Suez Canal’s opening in 1869. But it is the 2015 canal expansion and climate change that have turned the migration into a stampede.
A Sea in Peril
In April 2024, a study published in PNAS painted an unsettling picture:
- Even in moderate warming scenarios, species from West Africa may enter the western Mediterranean by 2050
- In worst-case predictions, the sea could be entirely tropicalised by 2100
The Mediterranean, one of the fastest-warming seas on Earth, is becoming unrecognisable. With native species disappearing and invaders settling in, scientists and locals alike are calling for action—particularly in marine protected areas.
“We need to keep these species out of biodiversity hotspots,” says Draman. “Without natural predators, their numbers are exploding.”
Learn More About Another Invader:
Read about the rise of the Lagocephalus sceleratus (silver-cheeked toadfish) in Chania:
Venomous Lagocephalus Invades Crete
