An algae is proliferating rapidly in the Callelongue cove in Marseille (Bouches-du-Rhône). Its size and green colour make it easy to spot, and its presence is a cause for concern.
Seaweed covers the whole area to a height of 60 cm, forming an opaque greenish carpet. Today, the Callelongue cove is far from the picture-postcard image. Local residents are wondering whether the algae is dangerous. A marine biologist has identified the invasive specimen. "It's a biological invasion, an introduced species from Japan called rugulopteryx okamurae", explains Thierry Thibaut, a teacher and researcher at the MIO.
Present since 2000
This Asian variety was first observed in the Mediterranean in the early 2000s. Since then, it has proliferated on the Spanish and French coasts. In the space of two years, the algae has colonised several kilometres of Marseille's coastline. This colonisation is a cause for concern for the Calanques National Park. A study has begun to assess the risks to flora and fauna.
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