A less-than-postcard-perfect vacation to the Caribbean in 2013 resulted in one of the region’s most utilised tools for monitoring seaweed conditions on popular tourist beaches.

Mado Martin, a founder of sargassummonitoring.com, had envisioned crystal-clear, blue waters and white sand beaches when he vacationed in Belize and Mexico’s Riviera Maya. Instead, he encountered a stark – and smelly – contrast to the images promoted by tour providers.

Like many Caribbean tourists in recent years, he discovered white sand obscured by mounds of rotting seaweed and turquoise water browned by the decomposing masses.

“We experienced the inconvenience caused by the nauseating odour. We saw the sea becoming brown, and the fish and sea turtles dead, imprisoned in these thick, sometimes impassable carpets,” Martin said.

While most tourists would settle with leaving a disgruntled review online, he took his disappointment one step further. He turned it into a tool to help other tourists.

With sargassum-forecasting tools still in development, the maps offer one of the most comprehensive and up-to-date snapshots of the seaweed situation in the region.

Sargassum Monitoring compiles and maps images that show the sargassum impact across the region. One map shows beaches with sargassum and a separate map shows beaches without sargassum.

With sargassum-forecasting tools still in development, the maps offer one of the most comprehensive and up-to-date snapshots of the seaweed situation in the region.

The work requires extensive research and hours of time by a team of volunteers who check regional webcams, search the internet and cross-check information submitted by users.

Some areas, such as Cuba and Haiti, are more difficult to monitor than others. The team also runs into difficulty when monitoring webcams are shut off, at times to hide influxes of seaweed.

“We update multiple times a day, every day, seven days a week,” Martin said.

“Like journalists, we do a real job of investigation, because to be credible, we must provide true information and real images of the day, not those misleading ones that people or organisations that have essentially a financial interest are circulating, because the invasion of … sargassum induces economic losses in the millions of dollars.”

Sargassum influxes have spread across the region. This photo shows piles of seaweed in Islamorada, Florida, in March. – Photo: Robin Goldsmith

With 1.6 million visitors a year reported by Sargassum Monitoring, the information provided has generated substantial interest.

The team is considering launching an app to facilitate information sharing. But the task is not easy. Apps require investment and the Sargassum Monitoring team is unpaid.

Monitoring photos is also an imperfect approach, but more sophisticated forecasting is not yet possible.

“We receive lots of messages from people that are planning their trip, but unfortunately to this day, no one can predict the arrivals,” Martin said.

“A beach can be clean in the morning, and totally flooded by algae by the afternoon.”

Monitoring beaches across the Caribbean has also allowed the team to observe the environmental impact of sargassum arrivals and response efforts.

“All year long, with Sargassum Monitoring, we observe thousands of photos and we notice the erosion of beaches provoked by the back and forth of heavy machinery, but also wheelbarrows or pitchforks,” Martin said.

“These beaches that have taken years to form, and that have been appreciated by millions of tourists, are disappearing quickly because of the bad management of the sargassum.”

Exacerbated by lack of communication and information sharing, many countries in the region have repeated the same management mistakes, Martin said.

Sargassum Monitoring takes one small step toward bridging that information divide.

“We’ve learned a lot about sargassum and their impact on the tourism, sanitary and ecological sides. And we still learn more every day,” Martin said.

“It’s important because we don’t want to participate in disinformation.”