“Glimmer of hope” - Shedd Aquarium researchers rescue coral survivors of Florida bleaching event

Chicago (Dec. 16, 2024) – On a recent research trip to the Dry Tortugas, Shedd Aquarium scientists rescued the only known staghorn coral survivors in the area after last year’s devastating bleaching event in the Florida Keys. The remarkable discovery of live staghorn coral colonies is crucial for the future of this critically endangered species, enabling additional research on coral heat tolerance and restoration. 

Shedd’s research team found 43 living colonies of staghorn coral and utilized the aquarium’s research vessel, the R/V Coral Reef II, to safely transport small, living fragments back to land-based facilities to further safeguard the species. The fragments were distributed to four different gene banks in Florida: The Reef Institute, Mote Marine Laboratory, Reef Renewal and University of Miami Rosenstiel School of Marine, Atmospheric, and Earth Science. Under these facilities’ expert care, the rescued corals will grow, enable additional research and create opportunities for restoration of reefs. Additionally, researchers at Shedd hope that these surviving corals could represent more heat-tolerant individuals that have a better chance at resilience and recovery from future bleaching events in the wild. 

“It was devastating to witness the loss of most of Florida’s staghorn and elkhorn corals due to record-hot water temperatures in 2023, but these survivors offer a glimmer of hope for the future of corals in the region,” said Dr. Ross Cunning, research biologist at Shedd Aquarium. 

After near complete mortality on most of Florida’s reefs from last year’s heatwave, Shedd researchers received a report that a few living staghorn corals had been spotted on the Tortugas Bank, at the far western end of the reef tract and over 180 miles from the nearest documented survivors. In a few short weeks, Shedd partnered with the Florida Keys National Marine Sanctuary (FKNMS) and Florida gene banks to plan the rescue operation for these critical individuals. 

Over several days, researchers donned scuba gear and dove to search for any remaining staghorn corals. The team found 43 surviving colonies and collected four finger-sized fragments from each one, ensuring that the rescue operation did not impact the colonies’ abilities to continue growing and spawning in the wild. The saltwater livewell habitats on Shedd’s R/V Coral Reef II provided the unique opportunity and safe transport for these coral fragments on the 22-hour trip back to Miami. 

“The collection and successful transfer of these threatened corals by Shedd Aquarium researchers is a key step forward in the conservation and management of staghorn coral,” said Andrew Bruckner, sanctuary research coordinator at FKNMS. 

Now settled at the gene banks, these coral fragments add to the just few hundred genetic individuals living and being propagated at these facilities. Since most of the genetic diversity in the wild was lost in last year’s bleaching event, the addition of these rescued survivors is a major win for scientists and for the critically endangered species – especially if these survivors are more heat-tolerant.  

“If these corals that survived the 2023 heatwave prove to be especially heat-tolerant, they will be essential for research and restoration of Florida’s coral reefs,” said Cunning. “We’re incredibly thankful for the resources, support and partnerships that allowed Shedd to conduct this urgent rescue mission.” 

In the summer of 2023, record-high ocean temperatures in the Florida Keys caused widespread coral bleaching, an event when corals expel the algae living in their tissues and turn completely white. Bleached corals are under more stress and subject to mortality, and the event in Florida resulted in 90-95% of all corals showing signs of extreme bleaching. Some coral species, such as endangered staghorn and elkhorn coral, were nearly all dead. Staghorn coral is currently listed as critically endangered on the IUCN Red List. 

Shedd Aquarium and Cunning were recently awarded the Top Honors Research Award by the Association of Zoos and Aquariums for the ongoing field research and continued efforts in identifying heat-tolerant corals to develop conservation interventions for future climate-resilient reefs. More information on this research can be found on Shedd’s website. 

Those interested in taking action to protect coral reefs can make a donation to organizations like Shedd Aquarium and directly fuel ongoing coral research and intervention efforts. Guests can also support Shedd’s mission by visiting the aquarium and discovering the beauty of live corals in the new Wonder of Water exhibit. 

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About Shedd Aquarium  

Shedd Aquarium is a recognized leader in animal care, education, conservation and science that sparks compassion, curiosity and conservation for the aquatic animal world. Every year, Shedd serves as a portal for millions of guests, bringing them eye-to-eye with belugas and bluegills, stingrays and sturgeons, coral reefs, kelp forests and countless other species from around the world.  An accredited member of the Association of Zoos & Aquariums (AZA), the organization is an affiliate of the Smithsonian Institution and supported by the people of Chicago, the State of Illinois and the Chicago Park District. www.sheddaquarium.org