By Gemma Handy
Stinking sargassum seaweed is once again carpeting some of Antigua’s most cherished beaches, repelling bathers and putting critically endangered wildlife at risk.
Much of prized Rendezvous Bay was yesterday covered with a thick mat of the brown algae, to the dismay of swimmers celebrating this week’s reopening of beaches which had been a no-go zone for more than a month.
Environmentalists say satellite images reveal almost six million tonnes of sargassum are currently afloat in the region – and “favourable conditions” for growth mean they are bracing themselves for a deluge this summer.
Blooms are particularly prevalent in the south of the island, including around Nelson’s Dockyard National Park.
In addition to being unsightly and emitting a stench as it decomposes, the seaweed poses a threat to marine life such as sea turtles.
That’s frustrating for members of the Environmental Awareness Group (EAG) who have dedicated many years to protecting the country’s critically endangered hawksbills.
“It’s a concern,” says the EAG’s executive director Arica Hill, “but one that we can’t do very much about. It’s a natural hazard.”
Hawksbills’ prime nesting season is now underway, with Rendezvous Bay a key site for females to lay their eggs. Hatchlings already face horrendous odds with just one in 1,000 making it to adulthood thanks to omnipresent marine predators.
Hill says sargassum further exacerbates their challenges.
“Seagulls use the sargassum mat as a great place to perch and wait for food,” she explains. “It just makes things even more difficult for an already endangered species.”
Sargassum first appeared in the Eastern Caribbean in 2011, confounding beachgoers, governments and scientists alike. It returned three years later and by 2015 quantities had reached epic proportions.
In 2018, piles of stinking sargassum lining Antigua’s Mamora Bay forced the St James Club resort to close its doors for three months.
“It’s one of those things we have to think about like a hurricane, because there is very little we can do to stop it,” says Ruleo Camacho, a marine ecologist with the National Parks Authority.
Camacho says the volume of the algae across the region increased from 4.3 million tonnes in March to 5.8 million tonnes last month.
“Based on satellite images, this year looks like it will be on a par with what we saw in 2015,” he tells Observer.
April 2019 saw a colossal seven million tonnes of sargassum in the Caribbean, and 2018 as a whole broke records in regards to magnitude and length of exposure.
“Sargassum blooms have progressively gotten worse each year since the initial observations in 2011,” Camacho continues.
While the seaweed can spell disaster for tourism, it’s not all bad news for the environment.
Out at sea it forms rafts as thick as seven metres deep and which serve as vital feeding and breeding grounds for some species, and hiding places from predators for others.
“Once it hits land is when the problems really start,” Camacho explains. “Small creatures get trapped in it and die. It also absorbs substances from water and carries toxins. And it can cause beach erosion too.”
When the sargassum dies and decomposes, the decaying organic matter removes oxygen from the water, which can kill fish. Too much sargassum can also block much-needed sunlight from coral reefs.
Camacho says much remains unknown about what has become an almost annual phenomenon but its prevalence in the Caribbean is thought to be climate change-related. Sargassum originates close to the coast of South America and is carried by currents around the Florida peninsula on its way to the Sargasso Sea.