Sargasso Seaweed in Sight

Local stakeholders, citizens and tourists missing white sandy beaches can now consult the evolution of these seaweed mats in the Caribbean online.

Sargasso mats have serious impacts on tourism, fishing and the health of citizens. The coastal regions deeply affected by mass strandings have seen the annual cost of cleaning beaches soar. The restoration of the beaches in the Caribbean has been estimated at an incredible 120 million dollars per year! Fishermen immobilized at the quay are becoming increasingly frequent, their propellers getting entangled in these algae infesting the fishing ports. Citizen health is also threatened. The decomposing Sargasso seaweed fumes release gases that are sources of intoxication.

sargasso on a beach

We are currently in the middle of the stranding season. CLS’s Earth observation and space oceanography experts have placed the affected areas under high-level satellite surveillance. Thanks to the development of an operational capacity to detect and forecast Sargasso drift, CLS provides strategic information to local stakeholders from space: maps of the presence of algae and drift forecasting based on the use of optical and radar satellite sensors.

This monitoring, at an altitude of several hundred kilometers, can cover the overall state of Sargasso mats throughout the Caribbean, the Gulf of Mexico and the African coast. Local stakeholders, citizens and tourists in need of a destination found in postcards can now consult the evolution of these banks online. This reliable satellite solution was developed with the support of the European Space Agency and chosen by Météo-France in 2019 on behalf of the French government, whose confidence in this solution was renewed this year.


SAMtool platform2021 Season: A resurgence of Sargasso mats

The borders are slowly opening after being closed due to the pandemic. Travelers are already imagining turquoise waters and white beaches. That’s why CLS is now providing weekly updates on the sargassum situation throughout the Atlantic region. Anyone can access this information:

  • Local governments looking to stay alert and mitigate impacts to their economies and citizens.
  • Tourism stakeholders who seek to reassure their customers.
  • And the customers themselves who would like to choose their destination according to these new criteria.


CLS’s sargassum detection and monitoring tool, SAMTool, is a scalable solution available through a secure web portal, with no local software installation needed.

The first screenshot represents the weekly detections made available, the second screenshot in the middle represents the daily Sargasso detections. The last screen shows the yellow, black and red dots representing the probable drift positions of the Sargasso rafts, with forecasts valid up to five days.

For more than 5 years now, CLS has been working on the development of an operational solution to help solve the problem caused by massive Sargasso strandings. As an expert in space-based solutions, the company has devised a solution based on optical and radar satellite sensors that can detect Sargasso, day or night and regardless of cloud cover.

More information about SAMtool


Sentinel-3 Satellite

As an expert in spatial oceanography, the company has also developed a drift model that can now be used to predict future strandings. Faced with an increasing number of strandings, CLS has been able to test its solution on numerous cases and thus perfect its predictions. CLS provides an operational service supported by analysts, based on a unique combination of Earth observation satellite data from 6 optical instruments and 2 synthetic aperture radar (SAR) instruments.

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