Government officials have expressed concern over the effects of a massive buildup of seaweed along Saint Lucia’s eastern shore, and have called on communities and agencies to band together to help rid the coast of the decaying mass.
“It is quite a challenge to deal with,” said Biologist Thomas Nelson from the Department of Fisheries. “The volume of seaweed requires large machinery and other resources, so we would need a number of agencies to come together. It needs to be a collaborative effort.”
The seaweed, which washed up along the island’s shoreline Tuesday, is the free-floating algae, Sargassum. It is a type of large brown seaweed that floats in island-like masses, and is common in the Atlantic Ocean near Bermuda in an area called the Sargasso Sea.
“Around this time, large quantities tend to break off because of ocean currents, and so we have an influx,” Nelson said.
The phenomenon is not particular to Saint Lucia. Sargassum has washed up along the Florida Keys, the Gulf of Mexico coastline and other Caribbean islands. Its effects vary.
“There are some benefits,” Nelson said. “Sargassum habitats provide food and protection for large numbers of juvenile fish species, and can be used as compost by farmers. Traditionally, residents have been known to collect seaweed for use on their farms.”
Former Police Commissioner Aubert Regis, who owns an agricultural farm in the Dennery village, said he has used the algae for the last three years with outstanding results.
“I usually collect it, create a stockpile, allow it to decompose and use that compost as a substitute to commercial fertilizer,” he said. “I have used it successfully over the years.”
In addition, due to its high saline content, Regis also uses it as a deterrent for slugs and African snails.
On the downside, the rapid growth of Sargassum is harmful to marine life. Dennery residents said that as the seaweed washed up on the shore, dead fish, and other marine life washed up with it. The stench of the decomposing seaweed is also an inconvenience.
“Excess Sargassum, as it decomposes, will lessen the amount of oxygen available for marine life. It also impedes circulation which interrupts the flow of water, so it creates conditions that are not conducive to marine life,” Nelson explained, “but it is important to note that it does not flourish in our waters so it doesn’t pose a permanent threat.”
According to the US Department of Environmental Conservation (DEC), the rapid growth of seaweed, also called an algae bloom, is caused when a body of water gets too much nitrogen and phosphorus due to intensive agricultural practices, industrial activities and sewage runoff. These pollutants enter the water, causing the excessive growth of algae.
Saint Lucia can expect to experience the largest deposits of Sargassum during the months of July and August. As such, officials are appealing for collaboration to rid the coast of the seaweed.
“With a community effort, the situation can be alleviated,” Nelson said.