Sargassum Seaweed: Turning a Problem into A Business

Sargassum seaweed, originally beneficial to the marine ecosystem, has been spreading through the Atlantic Ocean and Caribbean for many years with record blooms recorded in June 2022 and again in June 2025.   When it reaches a country’s coastline it decomposes and decimates fauna, flora and coral, with serious consequences for the environment, the economy and health according to the Citizen Science based Sagassum Monitoring website.

Affecting many islands of the Caribbean as well as parts of Central America and the US State of Florida, the severity can vary greatly, with some places experiencing intense seaweed build-up and others being relatively unaffected depending on currents and clean-up efforts.

For sailors crossing the Atlantic, Sargassum weed can be a real problem, snagging on rudders and keels and creating drag as well as providing a hazard to navigation.

Transforming a Problem into A Sustainable Business

But now, a UK-based ocean farming company is providing the technology to transform the Caribbean’s sargassum seaweed problem into a sustainable business.

If the project works, it could provide a long-awaited solution to the region’s tourism that has taken a hit due to the seaweed’s yearly visit.

UK company Seafields Solutions Ltd has teamed up with Private Refuse and Garbage Disposal (PRGD) in St. Vincent and the Grenadines (SVG) to launch the second phase of a Sargassum Beach Clean-Up Project. The project is being funded by the World Bank and the OECS and will run from September 2025 to April 2026.

Seafields will provide ocean-harvesting technology while PRGD will provide clean-up services as they work to convert sargassum into products such as bio-stimulants and biochar for agriculture.

The project is expected to create jobs and new revenue streams for communities in SVG.
Seafields CEO John Auckland said the goal is to prove that sargassum can be “transformed from a costly environmental burden into a valuable resource,” laying the groundwork for long-term commercialisation.

Grenada Also Tackling the Problem

Some hotels on the Caribbean island of Grenada are already using sargassum as a clean energy source. Benjamin Nestorovic and Renatta Fielden, from the Grenada-based bioenergy company SarGas, have proved the technology works and have installed a biodigester, which uses micro-organisms to break down the seaweed into biogas and fertiliser, to fuel the ovens at the True Blue Bay Resort’s House of Chocolate bakery in St George’s.

“You can eat chocolate with a good conscience,” Nestorovic says. “Our process produces clean energy and digestate – a valuable organic fertiliser – giving us two products in one.” The company recently secured government approval to construct a large-scale biogas facility to help provide electricity to the island.

Grenada’s prime minister, Dickon Mitchell, held a conference in 2024 to explore innovations around sargassum weed. Speaking at the event, he said: “We believe that we have a unique opportunity in Grenada and in the Caribbean basin to turn the tide on what is viewed as a problem into a solution – and into a solution that can have ripple effects to all of the stakeholders that it has thus far negatively impacted.”

TransAtlantic Sailors Be Aware

• Drag & speed loss: Thick carpets of sargassum can drastically reduce speed – going from 6 knots to 1-2 knots in dense patches. Rudders, bulb keels, hull bottoms suffer.

• Snagging & fouling: Propellers, rudders, keels, struts, hydro-generators, water intakes, and cooling intakes get clogged. Vigilant cleaning needed.

• Hydrogenerators / energy systems especially vulnerable: They may lose output or stop working altogether due to weed entanglement and drag. ARC reports that boats had to stop, clear, or lift the device to clean.

• Monitoring & routing helpful: Satellite tools like the USF Sargassum Watch Project help you see where big patches are, so you can try to avoid or plan crossings around them. [See Sargassum bulletins by month here].

• DIY maintenance / gear readiness: Boat hooks, strainers, intake cleaning equipment, possibility to dive or partially haul out or stop to clean; ability to clear around rudders/prop manually.

• Flexible route & timing: You may need to deviate or change sail plans, or adjust expectations of speed/time when going through sargassum belts.

• Health & smell & coastal impact: When large mats reach shore, the decaying seaweed may cause bad smells (hydrogen sulphide), affect reefs, beaches, ecosystem, tourism, etc. Useful to know once arriving.

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Related News:

• UK Firm Finds Sargussum Solutions in the Caribbean Sea (BVI News)
• From Foul to Fuel:  How a Seaweed Problem Could Power the Caribbean (The Guardian)
• North Atlantic:  Record Sargassum Bloom
• Huge Seaweed bloom can be seen from space (Skynews website)
• Sargassum Belt snakes around Florida (NPR website)
• Seaweed Mass Expands, Reaches Record Tonnage (Sargassum Monitoring)
• Why Sargassum poses a threat for Sailors (Yachting World)
• University of Southern Mississippi – Sargassum Threat
• University of the West Indies – Sargassum Outlook Bulletin

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Related Noonsite Reports:

• Tracking Sargassum Blooms by Satellite
• Major Seaweed Invasion Underway

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Related Links:

• Sargassum Monitoring – Twitter
• Sargassum Monitoring Website
• University of South Florida Optical Oceanography Laboratory
• Florida Atlantic University Harbor Branch Oceanographic Institute
• The University of the West Indies at Cave Hill, Barbados