Barbados is smothering under a blanket of seaweed. That’s the word from Hakai Magazine, which is studying a sudden, lethal growth in sargassum that seems to be choking off the islands (and the sea life) of the Eastern Caribbean:
In Dominica, a sargassum mat came ashore in the town of Marigot a few days before Barbados was inundated.
“It’s the worst we’ve seen it. [The seaweed] took up the entire bay,” says Andrew Magloire, who has worked in Dominica’s fisheries sector for more than 20 years. “The fishermen could not go to sea for two or three days. They couldn’t get the boats out because it was so thick.”
In Montserrat, conservationist Veta Wade says “huge walls of sargassum” have come ashore on the island’s eastern coast.
The seaweed’s arrival in Barbados started as a trickle around January, Monnereau says. But the amount arriving has ramped up dramatically since early June. “It’s really come back in full force,” Monnereau says. “It’s just been disastrous.”
Historically, small quantities of the floating macroalgae naturally drifted into the Caribbean from the Sargasso Sea to the north. Since at least 2011, however, sargassum from a new source—the north equatorial recirculation region (NERR)—has begun inundating the region with thick mats of seaweed.
Under normal climatic conditions, sargassum can double its mass in just 11 days, [Hazel] Oxenford[, a biologist at the University of the West Indies in Barbados,] says. A warmer sea will dramatically boost its growth potential, she says.
“As bad as [sargassum] is, [it] has a lot of life in it,” says Barbadian fisherman Allan Bradshaw.
Since the sargassum rafts began appearing in the eastern Caribbean in 2011, fishers have been landing more mahi-mahi than ever before, Bradshaw says. Juvenile mahi-mahi congregate near sargassum rafts. “Never before would you have seen those in such vast quantities,” Bradshaw says.
But Barbados’s crucial flying fish fishery has taken a hit. While the mechanism remains unclear, the arrival of such massive amounts of sargassum have coincided with a dramatic decrease in flying fish landings. Compared to the first six months of 2014, when Barbadian fishers landed 981 tonnes of flying fish, the catch plummeted to just 278 tonnes a year later, during 2015’s major influx of seaweed—a 72 percent decrease in one of the island’s most important fisheries.
This includes risks to human health. While the hydrogen sulphide gas released when the seaweed decays occurs naturally in the human body, it is dangerous in large amounts, causing headaches, dizziness, nausea, and even asthma. It can also cause “rapid and extensive damage to concrete and metals,” writes the US Environmental Protection Agency.
Dramatic photos at the link.