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 “scleractinian 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, 2019. Map credit: FDEP

This disease was first observed by our lab 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 monthly 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, the Voss Lab will implement novel coral disease intervention strategies on reefs at our Pompano Beach sites. Beginning spring 2019, fate-tracked coral colonies of Montastraea cavernosa  will be grouped into experimental treatments to compare the success rates of various intervention strategies on halting disease progression. All diseased corals will have a trench created around all disease lesions, with some colonies treated with an antibiotic epoxy, some with a chlorinated epoxy, and a small control group remaining trenched but untreated. Samples will be taken of the coral colonies' mucus to analyze any changes in bacterial communities following intervention, since symbiotic microbial assemblages have demonstrated an important role in immune responses to coral diseases. Results from this experiment will be compared across multiple coral species, and will hopefully identify successful intervention strategies for future disease outbreaks. 

Selected Publications

Walker BK, Brunelle A. 2018. Southeast Florida large (>2 m) diseased coral colony intervention summary report. Florida DEP & FWC, Miami, FL. 164 pp. PDF

Walker BK. 2018. Southeast Florida reef-wide Post-Irma coral disease surveys. Florida DEP, Miami, FL 37 pp. PDF

HBOI Team: Joshua Voss, Michael Studivan*, Ian Combs, Erin Shilling

Partners: Florida Fish and Wildlife Conservation Commission (Jeff Beal), St. Lucie Inlet State Park (Charles Jabaly), 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