These algae pose risks to marine biodiversity but will not be dangerous to swimmers, according to the municipality.

Since it was identified three years ago, this algae has proliferated in the streams of Marseille. green color, Rogolopteryx Okamurai Visible on the surface and encircling the sea floor with the risk that it “replaces all other plants and becomes the only plant that can exist” explains Didier Reault, Head of the Calanque National Park at BFM Marseille.

To combat the invasion of this algae, the municipality of Marseille relies on scientific research that will make it possible to better understand this species and is committed to Aix-Marseille University.

“To work on its spread, it is necessary first and foremost to better understand this species, study its evolution, and assess its impact on local flora and fauna,” Aurélie Biancarelli-Lopes, deputy mayor of the municipality, wrote in a press release.

Harmless to swimmers

The City of Marseille is also asking for the support of other communities and in particular the City of Aix-Marseille-Provence Metropolis to “intensify the collection measures that have already been implemented” on the beaches.

In fact, this phenomenon is not specific to Marseille and the algae could cover the entire Mediterranean coast from Montpellier to Nice within three years if no solution was found.

If this algae had consequences for marine biodiversity, it would not be dangerous to swimmers and boaters, according to the Marseille Marine Fire Brigade ordered by the city council. The latter, however, maintains the ban on bathing in the ports so as not to “exacerbate the phenomenon associated in particular with marine pollution” justify the city council.