Department of Agriculture and Fisheries
Release Date:
Tuesday, 6 October 2015 - 10:30am

Monday, October 5, 2015
Conference Room #3 Central Administration Complex 
2:00 p.m.

Pelagic sargassum is a brown alga, or seaweed that floats free in the ocean and never attaches to the ocean floor. These free-floating forms are only found in the Atlantic Ocean. Sargassum provides refuge for migratory species and essential habitat for some 120 species of fish and more than 120 species of invertebrates.  It’s an important nursery habitat that provides shelter and food for endangered species such as sea turtles and for commercially important species of fish such as tunas. There are two species of sargassum involved in the sargassum influx: Sargassum natans and Sargassum fluitans.

Sargassum travels on ocean currents. Scientists are able to determine where the sargassum comes from by back-tracking from its stranding location using ocean models and data on movements of satellite trackers that are deployed at sea. It is believed that the recent influxes are related to massive sargassum blooms occurring in particular areas of the Atlantic above the North Equatorial Current, not directly associated with the Sargasso Sea, where nutrients are available and temperatures are high. It is in that region that the sargassum consolidates into large mats and wind-rows and is transported by ocean currents towards and throughout the Caribbean. This is why countries like Trinidad, Belize and even West Africa for the first time have received massive amount of sargassum washing up on their shore.

Sargassum occurs naturally on beaches, albeit in smaller quantities. It plays a role in beach nourishment and is an important element of shoreline stability. Sand dune plants need nutrients from the sargassum and sea birds, for example, depend on the sea life carried in the sargassum for food. During decomposition there will inevitably be a smell and insects around. The experience in locations that have left the sargassum on the beach is that it will eventually get washed away or buried in the next storm, with rain easing the smell. Leaving sargassum on the beach has proven to be the simplest and lowest cost approach, also helping to nourish the beach and stabilise the shoreline. When large mats of sargassum lands on beach and mounds of 3 feet and greater are present it is the recommend to remove the excess sargassum as it is not allowed to dry properly and begins to decompose at a slower rate causing prolonged odor and in some conditions marine life to die due to oxygen being depleted in the water by decomposing bacteria.

In the water, the seaweed is harmless, but once it lands on the beach and starts decomposing, that is when it starts releasing hydrogen sulfide. The gas is a colorless, poisonous and highly flammable gas. It spreads an unpleasant odor.  But there is no need to be significantly alarmed as the gas can only be detrimental to one’s health in concentrated amounts in enclosed spaces like sewers. While hydrogen sulphide is classified as toxic and the higher temperatures of the summer months increase the rate of bacterial decay, in open, ventilated spaces like the beach and bays, the concentration of it in the air is not harmful. Although some doctors indicate that inhaling the gas in small doses could trigger irritation of the eyes and the respiratory system.

The species of pelagic sargassum involved in the influx are different from those grown as sea moss in the Caribbean and sometimes used in food and drinks. New uses for sargassum collected from beach strandings are being developed – as biofuel, fertiliser and livestock feed or fish food, for example.

The Conservation and Fisheries Department will host an Education Campaign in collaboration with the Department of Agriculture and Environmental Health.  Clean Up Campaign - to include all Service Clubs and other community minded individuals; this will take place during the month of October. Agricultural Usage - seaweed is being "processed" to be used as fertiliser and mulch on the farm at Paraquita Bay and farms throughout the Territory. We are also looking at the viability of collecting the sargassum to be used in areas affected by beach erosion.  But care is needed in how this is done so as to avoid damaging sand dunes and to avoid impacting sea turtle nesting and bird nesting habitat.  Research – we are continuously investigating what our colleagues in the region are doing as well as all available scientific information which will inform our localised efforts.  We have recently discovered that the purpose built machine may not be a viable option to deal with this problem as the floating mats of seaweed are spawning grounds for many of the fish species.

Thank you.