The DPNR Sargassum Blueprint was created in 2023 and can be found here: https://dpnr.vi.gov/wp-content/uploads/2023/05/Sargassum-Blueprint-FINAL5.2023.pdf
See sargassum predictions here: https://www.caricoos.org/sargassum
Native sargassum is a floating brown alga primarily comprised of two species: Sargassum fluitans and S. natans. It forms dense mats up to 3 meters deep in the open ocean, held to the water’s surface by bladders filled with air. The seaweed is named after the Sargasso Sea, an approximately 5 million km2 area of the North Atlantic between the Caribbean and the Azores. Characterized by calm, still waters, the Sargasso Sea is covered by giant mats of floating seaweed and other surface debris. Although itself calm, the sea is surrounded by major ocean currents, including the Gulf Stream, which transport these surface mats to other locations. While the giant seaweed mats were, up until recently, fairly rare in the Caribbean, they are a common feature of the Gulf of Mexico and off the U.S. South Atlantic Coast, where they attract large numbers of fish, including highly migratory species such as tuna and marlin, and are highly valued by the lucrative sportfishing industry. The floating mats in the Gulf of Mexico typically show a seasonal pattern of originating in the northwest Gulf of Mexico in the spring of each year and moving into the Atlantic (Gower and King 2011).
Sargassum has been included as a habitat type in the USVI SWAP because of the value the natural system provides to larval fish, juvenile sea turtles, pelagic fish, seabirds, and host of other marine and coastal organisms. However, in recent years sargassum has shifted from a pelagic habitat towards a coastal nuisance. These mats are areas of high primary productivity and are the equivalent of nearshore seagrass beds and coral reefs, offering a floating habitat in an otherwise largely uninhabitable environment. The floating mats provide food and shelter for many oceanic organisms that would not otherwise be able to inhabit the open ocean: juvenile fish and sea turtles that float with the mats until they reach a size where they are safe from predators, crabs and other invertebrates that nestle among the seaweed and feed off the detritus the mats collect, specialized fish that have evolved to resemble their seaweed home, and large migratory fish, like tuna and marlin, that are attracted to the teeming mass of life associated with the sargassum mats. The seaweed that accumulates on beaches provides important habitat for beach and intertidal invertebrates, and for the organisms that eat them, such as seagulls and shorebirds. Beach wrack offers an important invertebrate food source for native reptiles like Pholidoscelis polops lizards on St. Croix’s offshore cays.
In 2011, the Caribbean saw its first major Sargassum influx (Schell et al. 2015). An unprecedented amount of seaweed accumulated in bays and on beaches throughout the Caribbean. The seaweed floated in and accumulated, forming piles up to five feet tall in some places. Bays and inlets were clogged with it, and as it decomposed it gave off noxious hydrogen sulfide fumes.
The Sargassum Information Hub has more information on non-native sargassum and tracking: https://sargassumhub.org/monitoring/
NOAA policy analysis is here: https://library.oarcloud.noaa.gov/noaa_documents.lib/Sargassum_Policy_Management_Assessment_2024.pdf
Report sargassum you see here: https://five.epicollect.net/project/sargassum-watch
Permits for sargassum collection on beaches can be done through the USVI DPNR Coastal Zone Managment Division with concurrence from DPNR Fish and Wildlife. The wildlife guidelines can be requested from DPNR DFW.