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Martinique is a French overseas region and an island located between the Dominican Republic and Saint Lucia. Like most Caribbean territories, the Atlantic and North Atlantic coast of the island is regularly confronted with massive Sargassum events, especially since 2011- the year the groundings became more important. The Prefecture coordinates various services set up by the State, from seaweed monitoring to storage. The DEAL (Department of the Environment, Planning and Housing) manages satellite image monitoring of algae slicks to be able to predict Sargassum strandings. The Regional Health Agency works in collaboration with Madininair on a network to monitor hydrogen sulfide and ammonia concentrations in urbanized areas that are impacted by groundings. This network makes it possible to inform in real time about gasses concentration and alert authorities of dangerously high levels, in order to act for concerned populations. The collection of algae falls within the competence of mayors of affected municipalities, who can count on technical, financial and even human assistance in their mission, which can be provided by communities of municipalities, the general council, the Region and ADEME. Storage is also the responsibility of municipalities. Today, 99% of the seaweed collected is stored on backshore sites. Several private companies offer valorization solutions in the area. In August 2022, during an extraordinary committee about the national plan to combat Sargassum set up by the French government, the Minister in charge of Overseas France announced the creation of an anti-Sargassum public service. The Territorial Collectivity of Martinique (CTM) has opted for a Public Group of Interest (GIP) which will rely for its operational part on a trade union cooperation structure or on the group of affected communities.

Comparison of seaweed events between 2018 and 2022 in Martinique

Baie de Fonds d’Or (Marigot) par le satellite Sentinelle 2 en mars 2018
Fonds d’Or Bay (Marigot) by the Sentinelle 2 satellite in March 2018
echouements algues entre 2018 et 2022 en Martinique
Fonds d’Or Bay (Marigot) by the Sentinelle 2 satellite in February 2022

The groundings of 2011 and 2018 were particularly intense, but 2022 broke records with quantities of Sargassum never recorded before. The Club Sentinelle, a Guadeloupe monitoring network, studies these groundings using satellite data and local data.

Source: Club Sentinelle, Guadeloupe


Retention and collection of Sargassum in François in Martinique: the example of the Net DROM

Alexis de Jaham, a fisherman from Martinique, tells us how Sargassum transformed his daily life, and how over time, he reoriented himself to work on the installation and maintenance of networks of floating anti-Sargassum barriers in Martinique. A long and challenging journey that started in François Bay.

Collecting seaweed while cleaning the beaches

At Le Diamant, Martinique, the municipality tasked Kevin Saint-Louis-Augustin to daily pick up the Sargassum washed up on the beach. A routine collection for the greater good of the saleswomen and men of the beaches.

Sargassum invasion and the impact of H2S on health

In Vauclin in Martinique, Dr. Dalle has an appointment with one of his patients who is suffering from H2S fumes. Far from being an isolated case, many coastal inhabitants have been affected.

What if Sargassum seaweed was a good fertilizer?

In François, Martinique, a company is working on the valorization of Sargassum making it into a 100% natural fertilizer, clear of any chemical input addition. A Sargassum-based fertilizer therefore, whose properties allow the micro-organisms naturally present in the soil to be more active in decomposition.

Thematic sheet



Explaining Sargassum, a guide answering all your questions about this phenomenon

Explaining Sargassum is a guide published by ADEME, the Prefecture and ARS Martinique which allows you to understand what Sargassum is, where it comes from, the health hazards of Sargassum events, the management of the phenomenon in Martinique and the scope of research.

Comic Sargassum - Story(ies) of a brown tide

(Cf Alliance Française)


Sargassum: Story(s) of a Brown Tide

“Sargassum: Story(s) of a Brown Tide” was written in the style of a role-playing game. Researchers are invited to come out of their laboratories to meet citizens, illustrators to return to the benches of the university to question the research, screenwriters to immerse themselves in the reality of fieldwork.

Led by the Alliance Française of Santo Domingo, the creation of this Caribbean and international documentary comic strip is intended to become a space for discussion and reflection on the environmental issue of Sargassum.

The planet Sargoss

The astral adventures of the Taïnautes couple Dwayne and Keyssa. In this Afrofuturist tale, the mission is to save the Caribbean from extinction with the help of planets Sargoss and N’2A.

Writer: Henri Tauliaut
Cartoonist: Stéphanie Destin
Scientist: Constance Chevalier


Net DROM – Alexis de Jaham – +596 696 82 29 44 –

Madininair – +596 596 60 08 48 –

ARS Martinique
+596 596 39 42 43 –

Anti-Sargassum Association of Fregate in François – Gérard THOMAS (President)
+33 6 65 33 42 94 –

Mélanie Cueff – Collection and recovery engineer – ADEME – +596 596 63 51 42

Holdex environnement
+596 596 50 36 58

Procap – Manufacture of floaters for Net DROM – 0596 57 10 23

Public Health France

Territorial collectivity of Martinique
+596 596 59 63 00 –

Professor Dabor Résière – Intensive care physician, toxicologist at Martinique University Hospital – +596 696 20 31 84

Department of the Environment, Planning and Housing