Sargassum Season Begins: What You Need to Know about Quintana Roo’s Seaweed Alert

Sargassum, a type of seaweed, has begun to appear on the shores of the Solidaridad municipality in Quintana Roo, Mexico. This indicates the onset of the 2025 sargassum season, which is expected to intensify during spring and peak between May and August, according to Estevan Amaro, director of the Quintana Roo Sargasso Monitoring Network.

The Network continuously monitors the coastlines of Quintana Roo, with a particular focus on areas identified as "red foci" in previous years. These include parts of Cozumel, Tulum, the southern zone of Punta Nizuc bordering the Puerto Morelos municipality, and especially the Mahahual area.

Sargassum is a natural occurrence that has been exacerbated by climate change, with factors such as rising surface water temperatures and increased nutrient levels in oceans contributing to its growth. These nutrients, which originate from rivers in Africa and North America, combined with high solar radiation in the tropics, promote the proliferation of this macroalgae.

In the past two years, ocean currents have diverted much of the sargassum away from Quintana Roo, primarily affecting Caribbean islands like Puerto Rico, Cuba, and the Dominican Republic. There is hope that this pattern will continue in 2025, but an increased presence of sargassum on Mexican coasts cannot be ruled out.

Amaro warns that, aside from the visual and tourism impact, sargassum poses potential health risks. Recent studies suggest that decomposing sargassum releases gases such as carbon dioxide, hydrogen sulfide, and ammonia, which can be toxic in high concentrations, particularly for individuals with respiratory conditions.

He emphasizes the need for proper procedures during the sargassum collection process to avoid skin contact with the liquid produced by the seaweed and the toxins it releases.

Amaro remains hopeful that marine conditions will favor Quintana Roo this year, minimizing the impact of sargassum on its shores.