The coastal communities of Martinique, particularly those on the Atlantic coast, face a new phenomenon, which is the recurrent invasion of sargasse algae. The failure of these algae has now known consequences for health, property and biocenosis. From a sanitary point of view, the H2S gas released by the putrefaction of these algae is toxic at a high dose. Prolonged exposure to this gas with consequences for humans. From a material point of view, movable and immovable property is adversely affected by this gas. From an environmental point of view and more specifically in terms of biodiversity, there is rapid and significant degradation. Mortality of animal species is observed in particular fish, crustaceans, turtles, but the marine flora is also impacted: corals, grasslands, mangroves... Fighting solutions on earth after stranding are ineffective. The City of Robert has thus opted for the collection of sargasses algae at sea by taking two options: the realisation of dams at sea and the acquisition of boats designed for harvesting at sea. The aim is to couple these different ways to minimise grounding on the coast. Several dams are being considered in view of the extent of the coastline and the impacted sites. These include Pontaléry, Pointe-Savane, Pointe-Lynch, Sable-Blanc, Pointe-la-Rose and Pointe Jean-Claude.