Sargassum Tracker

USF OOL Long Term Outlook

May 31, 2025
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In June 2025, as expected, the total Sargassum amount in the western Caribbean and eastern Caribbean regions continued to increase, but decreased slightly in the central West Atlantic, and dropped substantially in the East Atlantic. Such a disparity indicates that most increases in the Caribbean regions were due to physical transport, while Sargassum growth in the tropical Atlantic lost momentum. Nevertheless, most regions still reached their historical highs.

Looking ahead, June 2025 appears to be the month of a turning point for the tropical Atlantic, after which the total Sargassum amount will decline, although the absolute amount will continue to be higher than most previous years. The amount in the Caribbean Sea may remain stable as local decreases may be compensated by physical transport. Sargassum inundation of variable degree will continue to occur in most of the Caribbean nations and islands. However, whether a beach or small region receives a large amount of Sargassum depends on local factors that are difficult to predict, including winds and ocean currents.

SARGASSUM ABUNDANCE INTENSITY

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Since 2011, large amounts of Sargassum seaweed have appeared in the Caribbean Sea every summer except 2013, creating many environmental, ecological, and economic problems in many regions. The seaweed originated from the tropical Atlantic and is believed to be a result of climate variability and other natural and unnatural processes. Based on satellite observations and statistics of historical events, in early February 2018, the Optical Oceanography Lab developed the first 1-page Sargassum outlook bulletin for the Caribbean Sea. Since then, the bulletins have been generated and distributed to subscribers by the last day of the month. These monthly bulletins are also made available at the bottom of the SaWS page.

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Disclaimer

The information bulletin is meant to provide a general outlook of current bloom condition and future bloom probability for the Caribbean Sea. By no means should it be used for commercial purpose, or used for predicting bloom conditions for a specific location or beach. The authors of this bulletin, as well as Caricoos, USF and NASA, take no responsibility for improper use or interpretation of the bulletin. Any use of the image, data, or graph from this bulletin page in reports or publications should obtain permission from the USF OOL group.