Scleractinian Tissue Loss Disease Outbreak along the Northern Florida Reef Tract

Since 2014, Florida’s coral reefs have experienced an unprecedented disease event resulting in coral mortality of up to 83 % in some locations. This newly described “stony coral tissue loss disease” was first observed in Miami-Dade County and is now affecting coral reefs throughout southeast Florida and the Florida Keys. The aggressive nature of this epidemic and its rapid spread across the Florida Reef Tract (FRT) have made this outbreak of particular and urgent concern among the scientific and management community. The Voss Lab is part of a multi-agency, interdisciplinary coordination effort to advance scientific understanding of the outbreak and to develop strategies to mitigate and/or prevent impacts to coral reefs.

Scleractinian tissue loss disease spread, 2020. Map credit: FDEP

The first observation of this disease by our lab was at our long-term monitoring site at St. Lucie Reef in the summer of 2017. The extent of the disease was realized during post-Hurricane Irma damage surveys in 2017, which were conducted for several months following the hurricane at over 20 sites between St. Lucie and Broward Counties. Since then, monitoring efforts have become focused at four locations on the Northern Florida Reef Tract, including: St. Lucie Reef, Jupiter, West Palm Beach, and Pompano Beach. Scleractinian coral cover, diversity, and disease prevalence is quantified quarterly via roving diver surveys at three dive sites within each location.

3D Modelling of Disease Progression

Top: 3D model of fate-tracked Montastraea cavernosa. Bottom: Rapid tissue mortality of Pseudodiploria clivosa after 3 months

We have optimized a low-cost 3D modeling protocol developed by Grace Young to quantify the progression of scleractinian tissue loss disease on fate-tracked coral colonies in SE Florida. The protocol can generate 3D models rapidly with free or low-cost software, and is designed to be adopted by collaborators to assist in disease monitoring efforts. This technique captures coral colony and disease surface area in three-dimensional space, improving upon current techniques that estimate percent affected from diver surveys or overhead photos. More information about data collection, model generation, and data generation and analysis can be found on our Github repository. Additionally, we are evaluating this 3D modeling method for estimation of error in small surface area measurements for other analysis applications beyond coral disease tracking. Using a standardized PVC frame across multiple reef habitats, we can ensure our surface area measurements are accurate.

Implementation and Comparison of Intervention Techniques

As a part of a larger collaborative effort, we have compared chlorinated epoxy and antibiotic methods to treat SCTLD lesions to determine how efficacy for halting lesions and overall disease progression as compared to untreated, SCTLD-affected controls. We found that while the antibiotic treatment (which is comprised of amoxicillin combined with an ointment “Base 2B” made by Ocean Alchemists LLC) was 95% effective at healing individual lesions over 11 months.  However, the treatment unfortunately did not necessarily prevent the colonies from developing new SCTLD lesions over time. These findings are still extremely promising in the face of the SCTLD outbreak, which continues to spread throughout the Caribbean and for which the cause remains unknown.​

Selected Publications

Shilling EN, Combs IR, Voss JD. 2021. Assessing the effectiveness of two intervention methods for stony coral tissue loss disease on Montastraea cavernosa. Scientific Reports 11, 856 doi.org/10.1038/s41598-021-86926-4

Combs IC, Studivan MS, Ecker RJ, Voss JD.2021. Quantifying impacts of  stony coral tissue loss disease on corals in Southeast Florida through surveys and 3D photogrammetry. PLOS One. In press.

Florida DEP SCTLD reports: https://floridadep.gov/rcp/coral/content/coral-disease-response-completed-projects

HBOI Team: Joshua Voss, Erin Shilling, Ashley Carreiro, Allison Klein, Gabrielle Pantoni, Michael Studivan*, Ian Combs*​

Partners: Florida Fish and Wildlife Conservation Commission (Jeff Beal), St. Lucie Inlet State Park (Charles Jabaly), Nova Southeastern University (Brian Walker and Karen Neely), South Florida Water Management District, Southeast Florida Coral Reef Initiative, Florida Fish and Wildlife Research Institute

Funding: FWC, Robertson Coral Reef Program, NOAA Coral Reef Conservation Program, Florida Department of Environmental Protection

* Denotes lab alumnus