Florida Reef Resilience Program Monitoring Shows Less Coral Bleaching than Previous Years, but More Prevalence of Disease

Big Pine Key, FL | December 12, 2016

The Florida Reef Resilience Program (FRRP) announces the results of its Disturbance Response Monitoring (DRM) for summer 2016. In contrast to the past two years, analysis of data collected on Florida’s shallow coral reefs from Dry Tortugas to Martin County from August through October of 2016 revealed mild to moderate coral bleaching. Despite a relatively mild bleaching season areas of widespread coral disease were prevalent among the surveyed sites.  

For the 2016 DRM season, FRRP reports that 162 sample sites throughout the Florida Reef Tract were closely monitored for instances of paling (the precursor to bleaching), bleaching, disease, and recent mortality.  This DRM “Quick Look Report” provides an initial analysis of the collected data. The list of surveyors in 2016 included: The Nature Conservancy, Broward County, Florida Department of Environmental Protection, Florida Fish and Wildlife Conservation Commission, Miami-Dade County, Mote Marine Laboratory, National Park Service, National Oceanic and Atmospheric Administration (NOAA), Nova Southeastern University and University of Miami. 

Coral Bleaching Results: During the months of peak annual temperatures, the Florida Reef Tract received a much needed break from severe thermal stress caused by elevated water temperatures that occurred in previous years. Due to gusty winds and frequent storms through the months of September and October, sea surface temperatures reported by the NOAA Coral Reef Watch (CRW), remained below the threshold for severe coral bleaching. Severe bleaching, defined by areas where greater than 50 percent of hard coral colonies experience paling or bleaching, was recorded in a few areas of the Upper Keys and moderate bleaching occurred in some areas of the South Palm Beach, Broward-Miami, Upper Keys, Lower Keys and Dry Tortugas sub-regions. Overall however, the prevalence of bleaching and paling was substantially lower than what was recorded in 2014 and 2015. Nevertheless, after back to back episodes of mass coral bleaching in 2014 and 2015, corals have remained in a considerable state of stress.  

Recent Mortality Results: The prevalence of recent mortality observed among the survey sites this summer was relatively lower than what was recorded during the past two summer surveys. The summer of 2014 was the worst bleaching year since the FRRP DRM surveys began in 2005. In 2014, corals also showed a relatively high prevalence of recent mortality although the ultimate cause of recent coral mortality is difficult to determine. Declines in bleaching prevalence in 2015 and 2016 also coincided with declines in recent mortality. While recent mortality has been observed across the entire reef tract, its highest concentration has remained in the Broward-Miami sub-region for the past three survey years. 

Diseased Corals Results: The prevalence of diseased corals among the sites in 2016 was greater than what was documented in both 2014 and 2015. The highest concentration of severely diseased sites in 2016 (severely diseased is defined as prevalence in >10% of all corals at the sites), was located within the Upper Keys sub-region where severe bleaching and paling had also occurred in some areas. Observations of unusually high occurrences of coral disease were first reported in 2014, and have continued through 2015 and 2016. While reports were initially concentrated offshore of mainland southeast Florida in Miami-Dade and Broward counties, disease has since been confirmed to the north in Palm Beach County, and to the south, including the Upper Keys and the Dry Tortugas in Monroe County.    

“The monitoring results we’ve seen this year did provide some reassurance however they still left us with cause for concern. Since waters did not reach the extreme temperatures seen in previous years, mass bleaching was less prevalent this year, but with multiple diseases impacting so many species of coral, the reefs are still imperiled. FRRP partners remain on watch and continue to move forward in disease research and response recommendations,” said Jennifer Stein, South Florida Marine Science Technician, The Nature Conservancy. 

The ongoing disease outbreak has been a continuing concern among reef managers and local scientists. While disease outbreaks are not unprecedented along the Florida Reef Tract, the current outbreak is particularly troubling in that it has persisted and continued to spread since 2014, includes multiple diseases, and has affected at least 18 species of coral. Reef managers, local scientists, and concerned stakeholders have been meeting regularly to keep updated on the current status of coral disease observations and coordinate response activities. Current response efforts include a combination of in-water surveys, coral tissue sample collection, and laboratory analysis to better understand the extent, severity, and potential causes of the disease outbreak so that additional impacts can be mitigated.   

The Florida Reef Resilience Program will continue to collect coral bleaching and mortality data as well as coral disease data during the annual Disturbance Response Monitoring that takes place through the summer months. The next DRM survey period will begin in August of 2017 lasting six to eight weeks. 

We encourage you to view and download the Summer 2016 DRM Quick Look Report. Additional data can be found directly on the FRRP website along with reef related publications and previous annual DRM Quick Look Reports from 2011 to 2016. Learn more and see how you can get involved with the Florida Reef Resilience Program.

The Nature Conservancy is a global conservation organization dedicated to conserving the lands and waters on which all life depends. Guided by science, we create innovative, on-the-ground solutions to our world's toughest challenges so that nature and people can thrive together. We are tackling climate change, conserving lands, waters and oceans at an unprecedented scale, providing food and water sustainably and helping make cities more sustainable. Working in 72 countries, we use a collaborative approach that engages local communities, governments, the private sector, and other partners. To learn more, visit www.nature.org or follow @nature_press on Twitter.

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