Rising sea temperatures are fueling a surge in the numbers of a carnivorous lionfish (Pterois miles) in the Mediterranean, and they're preying on herbivorous fish species that are key to maintaining the seas ecosystem.
"The lionfish is an Indo-Pacific fish and it sits well in that ecosystem as there are predators that are used to eating it, so its population numbers don't explode out of control," Jason Hall-Spencer, paper co-author and a marine biologist at Plymouth University, told me over the phone.
"It's already caused havoc ecologically in the Caribbean as it eats the herbivorous fish that normally keep the algae down so that it doesn't choke the reefs there. It's worrying that it's spreading in the Mediterranean—it needs to be exterminated quickly."
In a study published Tuesday in the journal Marine Biodiversity Records, the researchers describe how the lionfish—a breed native to the Indo-Pacific sea—has colonised the entire southeastern coast of Cyprus, from Limassol to Protaras, in the space of just one year.
The research team used both existing government data, and their own data sourced from local fishermen and divers to determine the extent and speed at which lionfish were breeding in the area. They found at least 24 confirmed sightings of 19 individuals.
In the past ten years, these voracious fish with spiky, poisonous spines have successfully set up camp in the oceans surrounding the Caribbean and South America, causing havoc to reefs as their numbers multiply.
While Hall-Spencer attributed their rise in the Caribbean down to aquarium releases in Florida in the US, he suspects that with regards to the Mediterranean, the fish are being flushed through the Suez canal from the Red Sea.
"People used to think that this fish couldn't breed in the Mediterranean as it was too cold, but now we're seeing their breeding groups exhibiting courtship behaviours so that really shows that the invasion has begun," said Hall-Spencer.
Hall-Spencer said that the Caribbean example demonstrated how quickly lionfish populations can grow, and asserted that immediate action was necessary in preventing its numbers from swelling further in the Mediterranean.
"The flesh is actually very tasty and nice to eat, so that's one of the main ways we'll be able to catch and get rid of it," said Hall-Spencer, who hoped that fishermen in Cyprus would quickly diminish lionfish numbers by catching and bringing them to a dinner table near them soon.