Known as the Great Atlantic Sargassum Belt (GASB), it has reached extraordinary proportions in 2026, about 5,000 miles in length.Satellite measurements showed 37.5 million metric tons of sargassum across the Atlantic in May, while researchers at the University of South Florida (USF) recorded 33.6 million metric tons across the monitored Atlantic basin in June. Within a year, about 1 million metric tons were recorded across the region in 2011, compared with approximately 40 million in 2025. Consistent ocean currents then helped establish the recurring belt extending towards northern South America, the Caribbean and the Gulf of Mexico. Around 1 million metric tons of sargassum were already present in the western Caribbean in January, approximately 10 times the usual amount for that month. By late July, authorities had collected approximately 100,000 metric tons of sargassum in 2026, already surpassing the roughly 92,783 metric tons removed during the whole of last year.A round-the-clock defence is underway against the invasion in the country's tourism hub, including boats, barriers and manual beach cleaning teams.