Tissue Samples Show Coral Disease at Flower Garden Banks is Not Stony Coral Tissue Loss Disease

June 24, 2024

During a monitoring cruise from August 30-September 2, 2022, Flower Garden Banks National Marine Sanctuary and National Coral Reef Monitoring Program divers observed a coral disease outbreak at East and West Flower Garden Banks. Initial analysis showed that symptoms were similar to the dreaded Stony Coral Tissue Loss Disease (SCTLD) affecting reefs in Florida Keys National Marine Sanctuary, including lesions and tissue loss.

Over the following months, divers enacted an emergency action plan to treat corals with antibiotics, photograph impacted corals, document their locations, and collect samples and other data. Coral disease experts then began reviewing this information to either confirm or rule out the presence of SCTLD and guide the next steps.

Two scuba divers apply a toothpaste-like paste to the edges of a white patch on a brain coral.
Sanctuary staff treated diseased corals with an antibiotic paste, which was placed around the edges of disease areas to try and prevent the disease from spreading. Photo: Kelly O'Connell/NOAA

Many coral diseases can be similar in appearance, which makes diagnosis difficult. So, scientists have been hard at work trying to develop a case definition for SCTLD, which would clearly identify specific characteristics of the disease and how it can be diagnosed. This means looking beyond the outward characteristics of diseased corals and examining the histology, a microscopic study of the coral tissues.

Thanks to all of this hard work, we can now say that the disease outbreak at East and West Flower Garden Banks was not SCTLD. The tissue samples from the diseased Flower Garden Banks National Marine Sanctuary corals did not match the case definition. The assumption now is that the 2022 disease outbreak was a form of white plague disease. As yet, there is no case definition for white plague disease, but there is hope that this can be developed using previously preserved samples from past outbreaks of the disease.

A brain coral that is mostly white from disease. Only a small brown (live) section remains on the right edge.
A diseased brain coral observed in Flower Garden Banks National Marine Sanctuary during the initial disease outbreak in September 2022. Photo: NOAA/NCRMP

The Good News: White plague disease is not as lethal or as quick-spreading as SCTLD.

The Bad News: Any disease outbreak is a sign that things aren't what they should be on the reef.

More About Coral Diseases

With names like white plague, white pox, black band, dark spot, and yellow band, it's clear that coral diseases are named for their appearances—but, what else do we know about them? NOAA's Coral Disease Health Consortium website goes into the details.