This invasive species native to the Red Sea was discovered off Port-Cros this week. Its presence, a sign of warming waters, is a threat to the Mediterranean ecosystem.
Article written by
Posted
Reading time : 1 min.
Lophocladia lallemandii, a type of invasive red algae, was spotted by chance by a researcher during a dive between five and twenty meters deep, off Port-Cros (Var). This discovery, announced Tuesday, January 25is nothing to cheer about, explains Thierry Thibaut, professor at the Mediterranean Institute of Oceanography: “It’s always bad news to discover an introduced species. It’s a new biological pollution. Especially this one, Lophocladia, is a very invasive species. There may be some impacts on the Mediterranean ecosystem.”
This seaweed is a great traveler. Native to the Red Sea and the Indian Ocean, it was first spotted in the eastern part of the Mediterranean in the 1980s. Then in Corsica two years ago, before being identified this January near the mainland. It gradually goes up the Mediterranean taking advantage of the significant warming of the waters. The Lophocladia lallemandii entered through the Suez Canal which became, according to Thierry Thibault, the door of invasive species.
“It’s a highway. There is no physical or chemical barrier that allows many species to be stopped. There are a lot of introduced species in the Mediterranean.”
Thierry Thibaultat franceinfo
>>>Environment: Brittany distraught in the face of the invasion of green algae
The red algae has no predator. Spanish and Italian researchers have also found that it has an impact on Posidonia meadows, which constitutes a form of aggression. These meadows indeed play an essential role for biodiversity, specifies Thierry Thibaut: “Posidonia is the main ecosystem of the Mediterranean. It is said that it is the place of life of a quarter of the species, it is a bit exaggerated, but there are a lot of species that are associated directly to the herbarium. It is a spawning ground [lieu où les poissons déposent leurs oeufs], photosynthesis, respiration, that is to say that it produces oxygen in quantity. And above all, it is also a gigantic carbon sink for the Mediterranean.”
There are already 150 algae introduced into the Mediterranean Sea, of which 17 have been observed in the Calanques National Park.