Guadeloupe sargassum algae threaten beaches and public health

The Caribbean islands of Guadeloupe and Martinique are grappling with massive influxes of sargassum brown algae, now arriving year‑round. The seaweed releases hydrogen sulfide gas when it decomposes, causing headaches, respiratory irritation and nausea among residents and visitors. In Guadeloupe, the phenomenon has even forced the relocation of national baccalaureate exams away from affected beaches.

Authorities and locals now rely on a dedicated forecast bulletin from Météo‑France and the crowd‑sourced Fangass app to identify at‑risk beaches in real time. The annual haul reaches 30,000‑50,000 tonnes per island, prompting projects to turn the waste into economic opportunities. As Frédérick Mandine, environmental director for Petit‑Bourg, warned, “Each year it gets worse… volumes are increasing, people write to complain.”