How to control Sargassum seaweed

Sargassum seaweed has been fouling resort beaches for years. The exact reason for the proliferation of this aquatic weed is unclear, however, it is having major impacts on tourist locations in the Caribbean and Gulf of Mexico. Antigua, Dominican Republic, Belize, St. Vincent, Mexico, and Barbados are some of the more heavily affected areas.

This seaweed can pile up several feet high on the beach, it limits access to the sea and once it starts to decay generates an unpleasant odor. There have been many approaches that have been tried to address the issue, which led to Elastec developing the Beach Bouncer exclusion boom, to solve this increasing problem.

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WHAT OPTIONS ARE AVAILABLE FOR REMOVING SARGASSUM SEAWEED?

Manual Sargassum Seaweed removal on beach

Manual removal of seaweed from the beach

Small quantities of seaweed may be removed by hand but this is often a futile effort. It creates a heavy toll on workers and could introduce potential health side effects or injury.

Seaweed removal with heavy equipment

Pumps, macerators, conveyors, and earth moving equipment all require a lot of logistics and financial investment. They create noise and disturbance that is not conducive to a tourist environment.

Mechanical recovery of Sargassum at sea

The logistics of moving tons and tons of material with boats is impractical. The distance to offloading points will affect the performance; multiple boats would be required with a high degree of maintenance and running costs.

Exclusion booming

Elastec has taken this approach due to the minimal impact. Exclusion booms or barriers are moored in selected locations to keep the Sargassum seaweed off the beach where it will move with the wind and current either back to sea or down the coast.

EXCLUSION BOOM INSTALLATION CONSIDERATIONS

Wildlife concerns

Turtles need to access the beach to lay eggs. Concerns have been raised if an exclusion boom/barrier will limit their access (noting that the seaweed in itself is a huge barrier). Elastec developed Beach Bouncer under the guidance of a marine biologist to ensure the safety of marine wildlife. As the Beach Bouncer is skirt is shallow, sea turtles will have no issue swimming under the barrier. Beach Bouncer uses a finely woven material so there is no issue of being entangled in a net. Turtles can safely navigate around the product while seaweed is contained or deflected.

Appearance

Oil exclusion boom and sediment curtains are typically bright orange or yellow. Beach Bouncer Type 1 and Type 2 are produced in blue providing a better visual aesthetic to the beautiful landscape people want to enjoy.

If desired, Beach Bouncer can be built in other colors when requested.

Construction

Booms with solid skirts, such as those used for oil booming applications, are not suited for seaweed. The weight of the seaweed and water movement causes entrainment until the boom fails and everything flushes underneath the boom.

A woven skirt, like employed by Beach Bouncer, allows water to pass through, and reduces the drag. A net is dangerous as it will snag turtles and other wildlife as well as create entanglement in the seaweed which could eventually weigh down and sink the boom.

When the boom/barrier is moored in areas where there may be wave action, a proportional freeboard and high buoyancy-to-weight ratio is desirable. This will allow the barrier to follow the waves and reduce the amount of splash over.

Location, mooring, and installation

Appropriate location and mooring of the boom is key as it will need to withstand any loading and currents. The choice of location where there is low wave energy will enhance the performance, reduce the quantity and size of anchors and reduce maintenance time.

Note: Any structure moored in water will need some level of maintenance (periodic adjustments and cleaning, etc). Avoid contact with sharp objects such as coral, rocks and quay walls. Ideally, the skirt should be floating and not touching the seabed.

SUBSEQUENT PRODUCT IMPROVEMENTS

The original Beach Bouncer – TYPE I is manufactured in flexible 22 oz PVC fabric with a woven skirt, supported with a galvanized ballast chain in pocket. It has been upgraded with a tension cable both above the float and under the float for anchor point strength and lower center of gravity. It has 25 ft interval anchor points, flow-through skirt and a heavier ballast chain in double-layer pocket.

This type of boom is for seasonal use, it can be maintained and repaired using our hot air gun kit. The Beach Bouncer is available in 25, 50 and 100 ft sections.

A more durable version, the Beach Bouncer – TYPE II, was developed in 2019. It features a large diameter float design (18 inch / 0.4 m and 24 inch / 0.6 m) providing increased freeboard for optimal surface debris capture and visibility. The floats are coupled with rugged log connection hardware with a 4.75 ton working load limit (WLL) and a tensile breaking strength of 60,000 lb / 27,216 kg. It also features the same 3 ft (1 m) woven skirt below the surface of the water. The skirt attaches to the rigid float by sliding on a rod, making it easily replaceable independently of the float. The float is a rotational molded HDPE plastic, foam-filled and reinforced with a galvanized steel bar that runs the length of the float. Floats are linked together using chain / shackles, the gap is sealed with a replaceable flexible fabric section. Also available in Yellow or Black, 10 or 20 ft (3 or 6 m) sections.

A third model, Beach Bouncer – TYPE III, was added to the lineup in 2021 and has seen great success. Beach Bouncer – Type III is a seaweed control barrier that consists of a heavy-duty coated woven barrier supported by molded hard floats. It features a stainless steel load-carrying cable and ballast at the bottom of the skirt. This construction allows for ready servicing in the field with easy replacement of the floats or base fabric.