Since 2010 the city has suffered major strandings of sargasses algae on the southern shoreline. Are severely affected and recurrently: the marina of St François, the nautical base, the beach of the pies, the beach at the top of the town, the beach of the former meridian, the beach of light grapes. Regular strandings have been reported for almost 8 years with a peak during the months of April to July. Today, the installation of floating barriers would protect the most sensitive and hard-hit areas and, in a second step, direct sargasse algae to the point of recovery only (clear reasons in particular)