Overview
- The 2025 technical report by Uriel de Jesús Mendoza Castillo recorded 252,659 detected sargassum polygons covering 382.7 square kilometres along the Mexican Caribbean coast over a 70-day window.
- Biomass estimates from the study range widely because of method uncertainty, with a conservative band of about 130,000–520,000 tonnes and a maximum estimate near 1.30 million tonnes.
- The report shows a strong seasonal pattern with the highest concentrations in July and August, which defines the predictable high-risk months for coastal communities and tourism.
- Roughly 70% of the reported sargassum area in 2025 lay more than 20 kilometres offshore, which makes beach cleanup ineffective and increases the need for at-sea interception and more vessels.
- Hoteliers say the repeated summer arrivals since 2011 have imposed rising, often permanent cleanup costs and have led some in Tulum to consider operating only outside sargassum season, while government plans now aim to expand offshore collection capacity.