Sargassum Tracker

USF OOL Long Term Outlook

Mar 31, 2025
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Since 2011, large amounts of Sargassum seaweed 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 (https://optics.marine.usf.edu/projects/saws.html)

Looking ahead: April is expected to see continued increases. More Sargassum is expected to enter the Caribbean Sea through the Lesser Antilles, and to enter the Gulf through the Yucatan. Sargassum inundation will likely occur in most of the Caribbean nations and islands as well as in the Florida Keys. The year of 2025 will be another major Sargassum year. All previous monthly bulletins as well as daily imagery updates can be found under the Sargassum Watch System (SaWS). Finally, a NOAA-funded effort led to the development of higher-resolution Sargassum maps for the lower Florida Keys and upper Florida Keys. These new maps will be combined with circulation models to have a short-term forecast of Sargassum transport, and such a capacity will be expanded to other regions in the near future. . .

SARGASSUM ABUNDANCE INTENSITY

Details

As predicted last month, the Sargassum amount in each of the 5 regions increased in March, with most increases in the eastern Caribbean Sea and tropical Atlantic. Such increases are due to both local growth and physical transport. What is noteworthy is that the total Sargassum amount in the tropical Atlantic as well as for all regions combined reached a new historical record for the same month of March. The amount in the Gulf is still low but there are signs that some of the Sargassum will be transported to the Straits of Florida in the coming weeks. There is a relatively large amount in offshore waters east of Florida, but the probability of this Sargassum reaching the east coast is low because the strong Gulf Stream may serve as a barrier. (SaWS, https://optics.marine.usf.edu/projects/saws.html).

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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.