Sargassum in Dominica

Sargassum is a type of floating brown macroalgae, primarily comprising Sargassum natans and Sargassum fluitans. It often washes onto Dominica’s east coast, favoured by the warm waters of the Atlantic Ocean, though west coast beaches on the Caribbean Sea are also affected when blooms drift across, impacting coastal habitats and nearby coastal communities. Unlike seamoss, which is cultivated red algae such as Gracilaria and Eucheuma harvested for nutrition and commerce, Sargassum blooms arrive from oceanic drifts. These influxes have grown more frequent with climate change, affecting Dominica’s Coastline, fisheries, and community livelihoods, and are addressed by government units and international partners.

Scientific Background and Key Distinctions

Sargassum belongs to the family Sargassaceae, forming large floating mats that drift across the Atlantic Ocean. Unlike seamoss, which is deliberately farmed and processed, Sargassum influxes are uncontrolled natural phenomena. In Dominica, mats sometimes bring in organisms such as the Plagusia depressa (Sargassum Crab), linking these events to changes in the island’s marine biodiversity. The distinction between edible seamoss and nuisance Sargassum is crucial for local economies, conservation policy, and the Ecosystem Approach to Fisheries Management (EAFM) Plan for Dominica.

Distribution and Impacts on Coasts and Communities

Most strandings occur on the windward coast, particularly near Castle Bruce, Marigot, and other Atlantic-facing communities. These accumulations obstruct fishing gear, reduce fish catches, and hinder small vessels operating out of coastal villages. Local businesses such as CJ’s Seafood and Fishing Service and the Fond St Jean Fisheries Cooperative are directly impacted by Sargassum, as entangled nets and reduced access to fishing grounds create financial strain. Although tourism beaches on the leeward coast are less affected, east coast residents must contend with cleanup and the odor of decomposing algae.

Climate Change Drivers and Ecological Role

Rising sea surface temperatures, nutrient enrichment, and altered ocean currents linked to climate change contribute to increased bloom events. Floating Sargassum mats provide temporary shelter for juvenile fish and invertebrates but threaten nearshore marine ecosystems by smothering seagrasses and corals, releasing methane during decomposition, and affecting marine conservation priorities. These ecological pressures also interact with enforcement measures under the Forestry and Wildlife Act and the National Parks and Protected Areas Act, 1975, both of which guide the management of coastal and marine habitats.

Government and NGO Responses

The Ministry of Environment and the Parliamentary Secretary in the Ministry of Agriculture, Fisheries have initiated plans for a national Sargassum Action Committee to coordinate responses. The Fisheries Division emphasizes monitoring and data collection to strengthen climate resilience. Partnerships with regional bodies, including the UWI Centre for Resource Management and Environmental Studies (CERMES) under the SargAdapt project, support adaptation strategies. NGOs such as Resilify Inc. have provided research to shape a Strategic Preparedness Plan, while enforcement of the Forestry and Wildlife Act ensures ecological safeguards. By aligning with Protected Areas in Dominica, the government integrates Sargassum management into broader sustainability and resilience goals.