Alert from a lifeguard at Camagüey beach: “The pile of seaweed is over a meter high.”

A lifeguard from the famous Santa Lucía beach in Nuevitas, Camagüey, alerted to the presence of a "mound of seaweed" more than a meter high.

Armando León, a lifeguard at Santa Lucía beach, warned that due to the presence of sargassum, they have lost visibility of "people sitting on the shore or children."

On behalf of all the lifeguards at the Residencial hotel, León requested assistance: “We are afraid of what might happen to a child who gets tangled in the sargassum and we don’t see it,” he said.

Record this summer

A historic record in the accumulation of sargassum in the Caribbean Sea, the western and eastern Atlantic, and the Gulf of Mexico has raised alarms in the region and is directly impacting several coastal areas, including parts of Cuba.

According to a report from the Optical Oceanography Laboratory at the University of South Florida, cited by the AP, in May 2025, 38 million metric tons of sargassum were recorded, the largest amount documented since studies on the Atlantic's Great Sargassum Belt began in 2011.

The previous record of 22 million tons was reached in June 2022, the news agency specified.

The current accumulation has already led to temporary closures of schools in the French Caribbean, citizen protests on islands like St. Maarten due to odors and pollution, and special operations with heavy machinery in tourist areas.

In the island Caribbean, hotels have had to bear the cleaning costs, while in places like the Dominican Republic, barriers have been set up to contain the spread of the algae.

The impact also extends to marine ecosystems: sargassum blocks sunlight, suffocates reefs and seagrass meadows, and upon reaching the shore, it kills the organisms it carries. It also releases toxic gases such as hydrogen sulfide and ammonia that affect human health.

Impact in Cuba

In Cuba, the phenomenon has hit the eastern part of the country particularly hard, especially in Guantánamo province. According to the newspaper Venceremos, in Baitiquirí Bay —one of the most affected areas— hundreds of decomposing macroalgae are causing unpleasant odors and have led to discomforts such as headaches and nausea among the local residents.

Local authorities have conducted public hearings and are conducting active investigations in the surrounding communities.

Iroel Cantillo Cartaya, a specialist from the Ministry of Science, Technology, and Environment (CITMA) in San Antonio del Sur, explained that the phenomenon is linked to climate change, which has raised sea temperatures and altered ocean currents, facilitating the proliferation of sargassum.

Although accumulations are expected to decrease starting in July, CITMA acknowledged that there are no technical resources available to remove the large concentrations in areas like Baitiquirí, where intervention is unfeasible due to its magnitude.

In other Guantanamo beaches such as Sabanalamar, El Guanal, Los Siguatos, and Yateritas, partial cleanups are expected to take place before the summer. However, the management of sargassum remains a challenge at the municipal level due to the lack of technology for its final disposal or utilization.

Authorities recommend not swimming or walking in areas with high concentrations of algae, avoid direct contact, refrain from consuming fish caught near these hotspots, and use a face mask as a protective measure against gases.

In Cuba, the Civil Defense has already classified sargassum as a potential risk within its Directive 1 for disaster reduction, due to its complexity and its impact on public health, the local economy, and the coastal environment.

Frequently Asked Questions about Sargassum on the Beaches of Cuba