Several countries from the Caribbean and Latin America have agreed to establish a plan of action to address the influx of sargassum seaweed after a meeting of experts in Cancun, Mexico.
The agreement highlights the need for cross-border information sharing on sargassum monitoring science, education and entrepreneurship.
Among countries that have signed on are Belize, Cuba, Dominican Republic, Guadeloupe, Guatemala, Guyana, Haiti, Honduras, Jamaica, Mexico, Nicaragua, Panama, and Trinidad and Tobago.
But Barbados, which has been heavily affected by the seaweed, is not a signatory, and it was not immediately clear why this was so.
As local environment officials continue to monitor the phenomenon since it first appeared in 2011, sargassum is now being blamed as the leading cause of beach erosion around the island.
Experts have told a forum hosted by the Barbados National Union of Fisherfolk Organisations (BARNUFO) of the impact of carpeting of beaches with the brown seaweed.
Director of the Coastal Zone Management Unit (CZMU) Dr Leo Brewster said: “When it comes in it will come in as a mat and it will settle in the area, you’ve seen it all the time. The waves can’t even break when it becomes very thick.
“But as the sargassum is being deposited either on the beach or within that near shore way in the area, what it is actually doing is compacting the water that is still moving on the bottom.
“And as it is moving on the bottom it is scouring out the sand that is part of the beach in the near shore, and this leading to a fall in the height of the overall beach, and leading to greater penetration inland. And the sand in its own right is not moving necessarily offshore but is being taken out.”
The marine expert recalled the sargassum invasion on Long Beach last year, resulted in erosion all the way back to the first line of vegetation.
Dr Brewster said: “Long Beach was probably one of the widest beaches for the island extending over 60 metres in front of vegetation line. I’m not talking about the dunes now, but where you have the grasses and the vines and those sort of things, it was over 60 metres wide.
‘”And by the time the sargassum had had its first round of impact on that beach, it had cut it back by half. And then you get the break, and then later on in the year when it came back, it took it right the way back to the vegetation line.”
This year, he said, the sargassum started coming to the island from January 1 and has since been appearing sporadically. He said there is cause for concern, and that CZMU is trying to manage the situation.
Dr Brewster said: “The issue that you’re really and truly dealing with is the fickleness of nature because sargassum will be in there today or stay for three days and then you wake up the next morning and the beach is clean. There’s almost no evidence that there was any sargassum there.”
Professor Hazel Oxenford of the Centre for Resource Management and Environmental Studies (CERMES) of the Cave Hill Campus of the University of the West Indies at Cave Hill, outlined the severity of the situation.
She said: “Last summer, on average we were getting 100 metric tonnes of wet weighted sargassum per kilometre beach per day. Dry, that’s 24 metric tonnes per kilometre beach per day. It gives you some idea of the extent of the problem.”
In addition to environmental effects she also detailed the impact on the island’s fisheries.
The UWI marine biologist said: “There’s a problem with access to the boats. There’s a problem with the moorings. There’s a problem in getting to the boats in the first place… and there’s problems with manoeuvrability.
“And then, of course, there’s the stench of rotting sargassum and smelling of rotten eggs and the ammonia gases also coming of it making fish markets unattractive places to buy fish, and it’s also very unsightly particularly when it comes in with a lot of plastic garbage.
“For folks on the water the visibility is really bad and the stuff that grows on the sargassum can really irritate your skin.”
Dr Oxenford also noted there are efforts to utilise early warning systems for sargassum, including the laboratory at the University of South Florida that processes satellite images in the Central Atlantic.
“At CERMES we got funding last year to put together our first Sargassum sub-regional outlook bulletin, and in that we try to work with just the Eastern Caribbean islands and some of the northern islands and actually come up with a much more detailed prediction over the next three months,” she said.
“We’re currently out of funding but we’re hoping very shortly to resume this and to make this a sustainable bulletin that we put out specifically targeting the fishing and the tourism industries so that at least you will know for three months ahead whether there’s gonna be a lot of sargassum, or whether it’s going to be sargassum free.”
But the researcher expressed optimism that while sargassum will likely keep coming, the flying fish population will bounce back.
Dr Oxford said: “There’s nothing in any of the data that shows that sargassum is actually damaging flying fish. In fact, flying fish is probably doing very well because of the sargassum.
“And we’ve seen in years when sargassum has disappeared the flying fish catches go straight back up again. It’s a species that only lives for a year so it can bounce back really quickly,” Dr Oxenford said.