Stony coral tissue loss disease

Stony coral tissue loss disease (SCTLD) is a new lethal disease first reported in Florida in 2014. The cause of the disease is unknown but it is affecting >20 species of corals especially brain, pillar, star and starlet corals. The disease spreads quickly causing high coral mortality. Outbreaks of SCTLD have been noted in other parts of the Caribbean: Jamaica, Mexican Caribbean, St. Maarten and, most recently St. Thomas, USVI and the Dominican Republic.

Characteristic of this disease is that sick colonies display multiple lesions and quickly die. Highly susceptible species are the meandroid corals–i.e., pillar corals (Dendrogyra cylindrus), elliptical star corals (Dichocoenia stokesii), smooth flower corals (Eusmilia fastigiata) and maze corals (Meandrina spp.). Starlet corals that develop numerous “blotchy” lesions, as well as diverse brain and star (boulder) corals, are also dying fairly quickly, followed by star corals (Orbicella spp., Montastraea cavernosa) and other coral species.

Latest News

Florida Stony Coral Tissue Loss Disease Response Bulletin – Winter 2019/2020, March 24, 2020
These quarterly bulletins provide high-level updates on the Stony Coral Tissue Loss Disease (SCTLD) outbreak and response efforts with a focus on Florida. This information is compiled by the SCTLD Response Teams.

Between November 2019 and January 2020, new mid-channel and inshore sites near Key West have confirmed reports of SCTLD. Since the last bulletin, SCTLD has been confirmed in various locations around the island of Culebra in Puerto Rico, on Grand Turk in the Turks and Caicos Islands, and on Grand Bahama in the northern Bahamas. The disease has also been reported on St. John in the US Virgin Islands.

Tracking the Disease

Map of Stony Coral Tissue Loss Disease recorded throughout the Caribbean

If your browser fails to download this map, we suggest you try another browser. For Mac users: use Safari with OS 10.14.1; Firefox or Chrome with OS 10.14.2

See Country disease summaries below and on this Country page.

To cite or use this map in a report or publication: Kramer, P.R., Roth, L. and Lang, J. 2019. Map of Stony Coral Tissue Loss Disease Outbreak in the Caribbean. ArcGIS Online. Check back frequently for updates to the map.

Report Your Findings

Reef researchers, managers and sport divers should continue to be on the lookout for sites with an unusually high percentage of diseased and very recently dead corals. If you see see any instances of disease, please submit your findings via the survey form below. Thanks to everyone who has responded so far.

If you see any instances of Stony Coral Tissue Loss Disease or suspected disease, please submit your findings and photos via one of the 3 survey forms below. There are 3 types of survey forms to make it easy to submit your data BUT you only need to fill out ONE of the forms per reef site. You can enter data by Scientific Coral Name, by Common Coral Group Name or by Roving Diver Survey.

If you have any questions related to diseased coral outbreaks please contact

What does it look like?

This video gives a closer look at the SCTLD outbreak off the northern Caribbean region of the eastern Yucatan peninsula, Mexico. Researchers from UNAM’s Barcolab have been documenting its spatial extent and mortality since July 2018.

How is this disease different?

While disease outbreaks are not uncommon, the Stony Coral Tissue Loss Disease Outbreak event has never previously been recorded.

  • Key factors of the SCTLD outbreak are*:
  • • Many coral species affected -Unlike other coral diseases, SCTLD has affected >20 species of approximately 45 Caribbean reef-building coral species. Certain species are highly susceptible to SCTLD. Other species, like acroporids, have not been affected.
  • • High prevalence – SCTLD disease is seen in many to all colonies of highly susceptible species. In Florida, 66-100 out of every 100 colonies surveyed were infected.
  • • Rapid mortality – Once a coral is infected, it begins to rapidly lose living tissue and the colony dies within weeks to months.
  • • High rates of disease transmission –When SCTLD is present on a reef, it spreads rapidly. Recent studies have suggested the disease is caused by a bacterial pathogen which can be transmitted via direct contact or through the water column.
  • • Large geographic range – SCTLD outbreaks occur over large spatial scales. Over half of the Florida Reef Tract has been affected: > 96,000 acres since 2014. SCTLD is now found along the entire Mexican Caribbean coast and has affected >30% of all corals.
  • • Long duration of the outbreak. SCTLD has continued to spread for more than four years in Florida.
  • *Information adapted from the Florida Disease Advisory Committee and Florida Department of Environmental Protection

Which Corals Are Affected?

Highly Susceptible Species*: Early onset (the species first affected during an outbreak), with rapid progression, and total mortality ranging from one week for smaller colonies to complete mortality over 1-2 months for larger colonies. Typically, M. meandrites and D. stokesii are the first to become affected at a site, followed by C. natans, and then the others show disease signs shortly thereafter.

Intermediately and Low Susceptible Species: a comprehensive list of other species that are less susceptible are found on the Coral Disease Identification Page. *Information adapted from the Florida Disease Advisory Committee and Florida Department of Environmental Protection 

A Closer Look at Stony Coral Tissue Loss Disease

Coral Collapse: The Reef Plague, A Reuters Graphics Special, September 2019

How do I identify Stony Coral Tissue Loss Disease?

Move through this slideshow to see how to identify the appearance of Stony Coral Tissue Loss Disease (SCTLD) on susceptible corals in Florida. Slideshow provided by Karen Neely.

To view/download the complete slideshow in a PDF, click here.

Field Guide to Stony Coral Tissue Loss Disease

Learn more about which species are affected and view a field guide to SCTLD

Where is this Occuring

See where this has already been reported.

Stages of Coral Mortality

See how the stages of disease affect the reef

Monitoring and Interventions

Actions to monitor and prevent the spread of the disease

What You Can Do

Take these steps to help reduce the spread of the disease


See what resources are available