USVI Sargassum
Working Group
What is Sargassum?
Sargassum is a genus of marine brown algae with over 600 species.
Most species are anchored to the ocean floor, similar to kelp found on the Western Coast of the United States.
Sargassum natans and S. fluitans are the only two pelagic Sargassum species, meaning they are free-floating for their entire lifecycle!
These two species are found in the Sargasso Sea, an area of the North Atlantic that provides an essential habitat for a variety of marine species, including fish, sea turtles, mobula rays, dolphins, and seabirds.
Sargassum in the Caribbean
When ocean currents had an unpredictable change around 2009 - 2010, pelagic Sargassum became more prevalent in the Caribbean. This increase has led to the naming of a new region in the equatorial Atlantic Ocean, the Great Atlantic Sargassum Belt (GASB).
Sargassum continues to bloom each year in the Caribbean due to favorable nutrient concentrations, temperatures, and light availability. Since 2011, the inundation of Sargassum in bays and on beaches has caused issues for residents, business owners, and tourists.
Top Photo: https://www.miamidade.gov/global/recreation/sargassum.page
Bottom Photo: Sargassum natans, left, and Sargassum fluitans, right – photo by GCRL https://roffs.com/2014/10/sargassum-identification-guide/
Contact Us
Interested in working together? Want to learn more about Sargassum? Fill out some info, and we will contact you shortly. We can’t wait to hear from you!

