Must be eaten

Poisonous lionfish are making the Mediterranean unsafe

It is increasingly entering the Mediterranean via the Suez Canal - where it eats up the native species: the Indian lionfish.

(Bild: APA/AFP/Ibrahim CHALHOUB)

It's a veritable invasion: Indian lionfish are arriving in the Mediterranean from the Indian Ocean via the Suez Canal - and displacing the local biodiversity. Researchers have a rather unusual recommendation to get the problem under control.

The predatory fish are not picky and also munch on rare species that only occur in the Mediterranean and would be worthy of strict protection, explains Austrian zoologist Alexander Kotrschal, who now warns of the spread of the invaders in the specialist journal "NeoBiota".

It is increasingly entering the Mediterranean via the Suez Canal - and eating up the native species there: the Indian lionfish.

(Bild: APA/AFP/Ibrahim CHALHOUB)

Climate change causes further spread
The invasion of the lionfish (Pterois miles) into the Mediterranean began around ten years ago, according to Kotrschal, who conducts research at Wageningen University in the Netherlands. The fish originate from the warm Indo-Pacific Ocean and, according to genetic studies, made their way into the Mediterranean via the Red Sea and most likely the Suez Canal.

They are now permanently present in the eastern part of the Mediterranean and are spreading into areas of water that were thought to be too cold for them. Due to the rise in temperature caused by climate change, they can now obviously cope with the once cooler Mediterranean climate.

The lionfish does not like to be caught, but is said to taste delicious:

Constant supply from the Indian Ocean
In addition, lionfish larvae can nowadays swim through the Suez Canal, and not just travel in the "ballast water" of ships as they used to. This is because the "soda lakes" through which it passes could not be swum through by marine animals, and freshwater flushing caused by annual Nile floods hindered the advance of marine animals, explained the researcher.

"The diversion of almost all freshwater for irrigation eliminated freshwater flushing, and the widening and deepening of the Suez Canal salinized the soda lakes with water from the Red Sea." The lionfish population in the Mediterranean can therefore be constantly replenished.

Mediterranean fish an easy target
This largest sea, almost entirely enclosed by land, is home to a unique diversity of species. More than 11,000 animal species live in the Mediterranean, some of which are found nowhere else in the world, reports Kotrschal. Many of the fish that live there are not used to lionfish and do not flee from them.

This makes them easy prey for the predators with no particular dietary preferences. "It is always impressive to see how such an extravagant and, for us, enormously conspicuous predator can approach its prey unnoticed," said the researcher.

Clear recommendation: "Taste excellent"
The best way to stop the lionfish invasion in the Mediterranean is probably to remove the invaders, says Kotrschal: "To do this, they would have to be marketed as edible fish," says Kotrschal: "Lionfish are really easy to hunt and taste excellent."