Florida's Coral Reef Disease Outbreak

NOAA and partners combat devastating coral disease and plan for restoration

This photo shows rapid progression of tissue-loss disease across a colony of symmetrical brain coral (Pseudodiploria strigosa). Photo: Brian Reckenbiel/Florida Fish and Wildlife Conservation Commission

As scientists and resource managers wage war on a highly lethal coral disease, rescued coral colonies in zoos and aquariums across the country are carefully being maintained, waiting for the time when they and their offspring can help restore Florida’s fragile coral reefs.

In an unprecedented response, more than 60 government agencies, academic institutions, and other organizations are methodically working to identify the pathogen responsible for the disease, create innovative treatments, conduct aggressive interventions, search for resilient corals, and undertake strategic restoration. The collaborative effort focused on Florida stands to benefit coral reefs in the Caribbean and worldwide.

Surveys find disease continuing to progress beyond Key West

In September 2020, surveyors reported stony coral tissue loss disease continuing its progress west of Key West, Florida. The new disease boundary is approximately 17-20 miles southeast of Pulaski Light in Dry Tortugas National Park on the western edge of the Marquesas Islands. No lesions were found inside park waters. In other areas of the Florida Keys, active disease appeared to slow on inshore and mid-channel patch reefs as colonies paled or bleached during the warm summer months. Intervention work continues to show promise with the mortality rate after 18 months at less than 3%. Additionally, trials of a probiotic cocktail are underway on reefs off Broward County and in laboratories.

Additional Caribbean outbreaks confirmed

During Summer 2020, scientists confirmed stony coral tissue loss disease on the reefs of Guadeloupe and St. Lucia, bringing the total affected jurisdictions to 15, including Florida. The disease also continued to spread on the reefs of St. Croix in the US Virgin Islands, New Providence in The Bahamas, and farther south along the Mesoamerican Reef Tract.

Story map tells of efforts to save large corals

Nova Southeastern University’s GIS & Spatial Ecology lab released a story map in October 2020 chronically how disease intervention saves large corals. These reef-scape scale interventions, although costly and time consuming, are the only effective stopgap tool while the larger causative agents of stony coral tissue loss disease are identified and remediated. A no-action alternative would lose large amounts of live tissue, promoting bioerosion, and let some of the oldest reef residents die.

For diseased corals, new probiotic treatments come in bags and pastes

Researchers at the Smithsonian Marine Station have developed two new methods for applying probiotic treatments to wild corals infected with stony coral tissue loss disease on Florida’s Coral Reef. In early September, Smithsonian Marine Station scientists partnered with Dr. Brian Walker's GIS & Spatial Ecology laboratory at Nova Southeastern University to test the two new treatment approaches on the reef: a bag for covering whole colonies and a paste for individual disease lesions.

For the whole colony treatment, divers cover an entire great star coral colony with a weighted bag and inject probiotics. The divers remove the bag after two hours, allowing the probiotic bacteria to colonize the coral. For the lesion treatment, Smithsonian Marine Station developed a probiotic-loaded paste to apply directly to individual disease lesions. The paste hardens on contact with seawater to prevent it from floating away and adheres to the coral tissue, which allows the probiotic bacteria to colonize the coral.

The research team will revisit treated colonies regularly to assess the probiotic treatment success and retreat corals if necessary. These two innovative strategies mark the first coral probiotic treatments of stony coral tissue loss disease on the reef. Researchers will continue to look at other potential treatment methods and advanced knowledge of coral probiotics in relation to stony coral tissue loss disease.

Great star coral spawn in captivity for the first time

Scientists capture great star coral eggs as they spawn. Photo: Rachel Ionata/Nova Southeastern University

In August 2020, scientists at the Nova Southeastern University Marine Larval Ecology and Recruitment Laboratory in Florida have successfully induced colonies of great star coral, a major reef-building species, to reproduce in captivity for the first time ever. Great star corals are susceptible to stony coral tissue loss disease and the ability to complete this coral's reproductive cycle in land-based aquaria represents a breakthrough in coral science and restoration.

Historic spawning of restored massive corals

A restored colony of mountainous star coral releases gametes into the water column. Photo: Joe Berg

For the first time in Florida or Caribbean waters, restored massive corals were observed spawning - part of sexual reproduction that could result in the next generation of coral offspring - thanks to Mote Marine Laboratory & Aquarium's innovative efforts to restore Florida's Coral Reef. In August 2020, Mote coral scientists observed colonies of mountainous star coral (Orbicella faveolata) on a reef near Cook Island release their gametes in an extraordinary display. This is the first time that restored massive corals have been documented to spawn on Florida’s Coral Reef.

Aquarium succeeds in second lab-induced spawning of threatened species

Rare pillar coral spawns under artificial conditions at The Florida Aquarium Coral Conservation Complex in Apollo Beach. Photo: The Florida Aquarium

The Atlantic pillar coral (Dendrogyra cylindrus) successfully spawned for the second consecutive year at The Florida Aquarium Center for Conservation’s Induced Coral Spawning Lab. A total of 14 corals spawned over three days, and larvae were created through assisted fertilization of 11 separate genotypes. The original collection locations of the corals range from Northern Miami to Sand Key Sanctuary Preservation Area, 7 miles west of Key West. All but one tiny piece of the parent colonies are now dead in the wild. Larvae were settled at The Florida Aquarium and additional larvae were transferred to Nova Southeastern University and the Smithsonian Marine Station at Fort Pierce. The Pillar Coral Genetic Rescue Project is conducted under Florida Keys National Marine Sanctuary permit to Dr. Cynthia Lewis at Keys Marine Laboratory and Dr. Karen Neely at Nova Southeastern University.

Mote expands coral restoration work

Mote plans to build a land-based coral nursery in Islamorada, Florida, at Bud N' Mary's Marina. (Photo: Conor Gould/Mote)

On June 8, 2020, Mote Marine Laboratory & Aquarium announced plans to build an additional land-based coral nursery in Islamorada, Florida, and an expanded coral gene bank in Sarasota County, Florida. Corals raised in the Islamorada nursery will support Mission: Iconic Reefs and Islamorada Conservation and Restoration Education. I.CARE engages citizen-divers to help outplant and monitor Mote-supplied coral fragments onto Islamorada's reefs. The gene bank, purposefully chosen to be built at an inland location, will be housed in a Category 5 hurricane resistant building, with state-of-the-art environmental systems and controls.