A perspective for the Caribbean Sea and Gulf of America* by the University of South Florida Optical Oceanography Lab – (bbarnes4@usf.edu, yuyuan@usf.edu, huc@usf.edu)

The map above shows the average Sargassum abundance for the month of May 2026, with warm colors representing higher abundance. The top color (red) indicates that 0.4% of the ocean surface is covered by Sargassum, meaning that Sargassum clumps and mats are scattered here and there in the location. The Sargassum abundance for each region is compared with historical values in the same month of 2011 – 2025 in the whisker box plot below, where horizontal bars in each vertical box indicate minimal, 25%, 50%, 75%, and maximal historical values, respectively. As predicted last month, total Sargassum amount in most regions continued to increase in May, with every but the West Atlantic region continuing to show record-high Sargassum amount for the month of May. The three separate large masses, as shown in the dashed outlines on the map, also continued. The transport of Sargassum to the Gulf also continued, resulting in record-high amount at this time of year. Major beaching events have been reported around the Caribbean and Lesser Antilles islands as well as along the Florida Keys and east coast of Florida.

Looking ahead: Sargassum amount in most regions is likely to increase in June. Beaching events around the Caribbean and southeast coast of Florida will continue and likely increase. Some beaching events may also occur around Louisiana and Texas coasts. The year of 2026 is set to be another major Sargassum year (i.e., Sargassum amount exceeds 75% of the historical values), and possibly to be a record year by summer 2026. All previous monthly bulletins as well as daily imagery can be found under the Sargassum Watch System (SaWS). Meanwhile, high-resolution Sargassum maps for selected coastal regions are also available in near real-time under “Satellite Data Products => High Resolution” of the OOL Website.