Brain coral photo via Canva Pro.

From hotter temperatures that contribute to ocean acidification and coral degradation to instances of coral bleaching caused by a combination of warmer oceans, overfishing and pollution, Caribbean reefs have been facing some serious challenges. Now, Trinidad and Tobago's Institute of Marine Affairs (IMA) has warned of another threat — Stony Coral Tissue Loss Disease (SCTLD), which it says is “wreaking havoc on coral reefs in the Caribbean.”

Since it was first noticed in Florida in 2014, SCTLD has spread to several other regional territories, including The Bahamas, The Cayman Islands, Jamaica, the Dutch Caribbean, and even islands in the Lesser and Greater Antilles. This is because the SCTLD pathogen is both highly transmissible and easily spread through direct contact with infected coral, water currents, and ballast water, making ports a common “early site of infection.”

Infected corals have lesions in spots where there is dead tissue. These areas get bigger as the disease advances — and it's a fast mover, killing coral within weeks to months. The cause of the disease may be wholly bacterial, or perhaps a combination of bacteria and a virus. In an effort to save regional reefs, infected corals are being treated with antibiotics, with some even being moved to land-based facilities in the short term for a better chance of survival.

Of the 45 stony coral species found in the Caribbean, the IMA reports that SCTLD has infected over 20 of them, including the maze, mountainous and brain corals that are abundant in tourism-focused Tobago, long known as a dive location. According to the IMA, “even the world-renowned, giant brain coral found in Speyside is a species that is highly susceptible to the disease.”

Should there be an outbreak of the disease in Tobago's coral populations, it could be devastating for the island. In a June 2008 research paper titled “Coastal Capital – Economic Valuation of Coral Reefs in Tobago and St. Lucia by Lauretta Burke, Suzie Greenhalgh, Daniel Prager and Emily Cooper, the annual value of Tobago’s coral reefs was cited as anywhere between USD 120–160 million.

While SCTLD does not appear to have yet reached Tobago, affected reefs in other areas have been dying quickly, which has been raising local concerns. Citing a study conducted by William Precht on coral reef sites in southeast Florida, the IMA blog post noted that some heavily impacted species were reduced to less than three percent of their initial population; others, like the brain coral so dominant in Tobago, to less than 25 percent. SCTLD has already been confirmed in neighbouring Grenada and some Dutch Caribbean islands, however, leading the IMA to predict that it will be “only a matter of time until it arrives.”

How, then, to be prepared? “Survival is most probable when there is action from authorities, education of the public, and built capacity to strengthen defences against the threat,” the post continued. From the IMA perspective, a grant it received in 2024 from the Specially Protected Areas and Wildlife Regional Activity Centre (SPAW RAC) for a one-year project focused on building preparedness and resilience against coral disease, will prove valuable.

In January of this year, IMA coral reef ecologists received training in January 2025 from the Perry Institute of Marine Science (PIMS) in San Andres, Colombia, to assess coral disease, identify SCTLD, and prepare and apply the antibiotic treatment to infected corals. By strengthening their capacity, the IMA is now better equipped to raise SCTLD awareness, as well as implement strategies to monitor coral reefs and spare them from the vagaries of the disease.

The organisation is educating local sea-goers as to what to look for to spot SCTLD in coral, which they can report by using the IMA's seaiTT app. It has also urged snorkellers and divers not to touch corals — good advice even with healthy reefs — but if there is an infection, touching corals hastens the potential spread. In the same vein, divers should make sure to sanitise their gear, just in case they have come into contact with infected coral; bilge water in boats should also be routinely disinfected — small steps that can make a big difference when it comes to controlling spread.

“We must […] work together to be guardians for our coral reefs,” said the IMA. Charged with “the duty to preserve the ecological and economic services of our reefs,” it sees only one way to minimise the potential devastation SCTLD can bring: to be proactive in responding to the threat.