Sargassum in Saint Barthelemy: Understanding and Anticipating This Natural Phenomenon
Everything you need to know about sargassum seaweed: origins, arrival periods, affected areas, and local management
Understanding to better plan your stay in St. Barth
Sargassum regularly makes headlines in Caribbean media, sometimes creating apprehension among travelers. However, this natural phenomenon does not affect the entire island uniformly and local authorities have implemented effective management and prevention systems.
What exactly is sargassum?
Sargassum are brown pelagic algae, meaning they live and reproduce in the open sea, primarily in the Sargasso Sea located in the North Atlantic. They form floating rafts that drift with currents and winds.
Since 2011, exceptional quantities of sargassum have been arriving in the Caribbean, a phenomenon linked to several environmental factors: climate change, increased ocean nutrients (nitrogen, phosphorus), changes in ocean currents, and Amazon deforestation.
Important note
In moderate quantities, sargassum is beneficial for the marine ecosystem: it shelters rich biodiversity (juvenile fish, shrimp, turtles) and serves as a natural nursery. The problem only arises during massive arrivals on the coasts.
When does sargassum arrive in St. Barth?
Understanding seasonality to plan your stay with full knowledge
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Peak season
May to August
Period of most intense peaks. Frequent arrivals, especially at Grand Cul-de-Sac and Lorient.
Intermediate period
April and September
Occasional arrivals possible, generally smaller in volume.
Calm period
October to March
Very few arrivals. The peak tourist season (December to April) is generally spared.
Good news for peak season travelers: the main tourist period (December to April) coincides with the season least affected by sargassum. If you are traveling between May and September, regularly check sargassum alerts issued by the Collectivity of Saint Barthelemy.
Which areas are most affected by sargassum?
Identify risk areas to avoid discomfort related to sargassum
Grand Cul-de-Sac
Most exposed area, protected lagoon
Lorient
Moderate exposure depending on currents
St-Jean
Can be affected during major episodes
Toiny
Exposed coast, little accumulation
Gouverneur
Rarely impacted
Colombier
Protected by its configuration
The origin of sargassum in St. Barth
The scientific factors behind the arrival of sargassum in St. Barth
Sargassum are brown pelagic algae that develop in the open sea, primarily in the Sargasso Sea. They are carried to the Caribbean by ocean currents and winds.
Factors contributing to sargassum arrival
Ocean currents play a crucial role in moving sargassum toward the Caribbean.
Climate change increases sea surface temperatures, promoting sargassum proliferation.
Increased nutrients in the ocean (nitrogen, phosphorus) stimulate their growth.
Amazon deforestation releases nutrients into the ocean, promoting their proliferation.
What are the impacts of sargassum on St. Barth?
Discover the positive and negative effects of sargassum on the island
Positive impacts
Sargassum serves as a natural nursery for many marine species.
It promotes marine biodiversity by sheltering juvenile fish, shrimp, and turtles.
Negative impacts
In excess on beaches, its decomposition releases hydrogen sulfide, a gas with a characteristic rotten egg smell.
It can prevent beach access, affecting tourist and local activities.
What actions does the St. Barth Collectivity take?
Discover the measures taken to manage sargassum
- 1
Satellite monitoring
Tracking sargassum banks at sea to anticipate arrivals
- 2
Preventive collection
Teams mobilized to clean beaches before decomposition
- 3
Floating barriers
Installation of nets to protect sensitive areas
- 4
Valorization
Research on composting and transforming collected algae
Tips for travelers to St. Barth
Plan your stay taking into account potential sargassum risks
If you plan to visit St. Barth between May and September, here are some tips for managing sargassum:
Regularly check sargassum alerts issued by the Collectivity of Saint Barthelemy.
Avoid the most exposed areas like Grand Cul-de-Sac and Lorient during peak periods.
Plan alternative sea activities to avoid beaches affected by sargassum.
What are the alternative beaches in case of sargassum?
Find safe spots for your sea activities
During periods of heavy sargassum presence, here are some alternative beaches where you can go:
Toiny: exposed coast, little accumulation.
Gouverneur: rarely impacted.
Colombier: protected by its configuration.
Frequently asked questions about sargassum in St. Barth
Answers to the most common questions about this natural phenomenon
What is sargassum?
Sargassum are brown pelagic algae that develop in the open sea, primarily in the Sargasso Sea located in the North Atlantic.
How does the Collectivity manage sargassum?
The Collectivity of Saint Barthelemy uses a combination of satellite monitoring, preventive collection, floating barriers, and valorization to manage sargassum.
Which areas are most affected?
The areas most exposed to sargassum are Grand Cul-de-Sac and Lorient, while Toiny, Gouverneur, and Colombier are generally less affected.
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