A Coral Rescue Mission: Dry Tortugas National Park
Corals are the building blocks of reefs and create homes for 25% of all marine life. Yet, they are quickly disappearing around the globe due to rising ocean temperatures from climate change. Shedd’s conservation scientists are studying coral heat tolerance to better understand and protect these crucial animals as waters warm.
In summer 2023, our coral research team led an expedition to the Dry Tortugas in Florida that revealed severe coral bleaching and die-off due to record-hot water temperatures. A year later, and expecting bleaching events to continue, the team embarked on a critical mission: rescue and save the remaining live staghorn corals before it was too late.
Read this account of the trip from Shedd’s Coral Biologist Ross Cunning, Ph.D.
A staghorn coral colony found near Dry Tortugas National Park.
After witnessing the near complete bleaching and mortality of staghorn corals in the Dry Tortugas in 2023, it came as quite a surprise when I learned in June 2024 that a colleague observed a live staghorn coral on the Tortugas Bank, a deeper area of reefs to the west of Dry Tortugas National Park.
If some staghorn corals survived in that area, it could mean that the deeper waters of the Tortugas Bank buffered them from the worst effects of the heatwave, or that these corals have naturally higher heat tolerance that allowed them to survive. While we can’t know for sure (yet …,) even a chance that these corals are more heat-tolerant means they may be critically important not only for study, but for the future of the species. Thus, our mission was clear: find these staghorn survivors and get them into gene banks.
Gene banks are land-based facilities that store, propagate and study the genes of living things like corals to ensure their long-term preservation. Just a few hundred genetically unique individual staghorn corals remain in these gene banks. Thus, any new individuals we can add will help expand their genetic diversity, and more heat-tolerant corals can serve as broodstock for future reefs that are more resilient.
With another summer heatwave looming, we needed to act fast to find and safely transport any surviving staghorn corals from the Tortugas Bank to these gene bank facilities. Fortunately, the R/V Coral Reef II was literally made for the job, and Shedd’s coral team and collaborators were ready to go.
Shedd's research vessel, the R/V Coral Reef II.
We quickly planned the rescue operation in close partnership with the gene banks and the Florida Keys National Marine Sanctuary, which manages the Tortugas Bank. While we did not know how many staghorn coral colonies we might find – if any at all – our plan was to collect four finger-sized branches from any colony we found and distribute them to four different gene banks in the Florida region. This ensured that each genetic individual would be represented at multiple facilities, and the small fragments collected would not impact the coral’s ability to continue growing, spawning and contributing to natural recovery in the wild.
In August 2024, we spent three days diving on the Tortugas Bank to search for staghorn survivors. The team found 43 staghorn coral colonies across the bank! These living colonies spanned over 10 kilometers, and a depth range of 40 to 70 feet, giving us confidence that they represent many different genetic individuals. Other staghorn skeletons in the area indicated they didn’t all survive, and that these living colonies may indeed be more heat-tolerant individuals. They are also the only confirmed surviving staghorn corals beyond the Upper Keys, nearly 300 kilometers away. And now, they are being propagated in up to four different gene banks.
Divers measure, tag and collect staghorn coral fragments for gene banking.
The livewells (marine animal holding areas) of the R/V Coral Reef II provided safe transport for these corals over the long journey back to Miami – a great example of the unique capacities and contributions we can make with Shedd’s research vessel. When we arrived, we were met by representatives of the Florida Keys National Marine Sanctuary and teams from the gene banks, who carefully transferred the corals for their shorter journeys to their final destinations at the University of Miami Rosenstiel School of Marine, Atmospheric, and Earth Science (Key Biscayne, FL), The Reef Institute (West Palm Beach, FL), Mote Marine Laboratory (Sarasota, FL) and Reef Renewal (Ruskin, FL).
The team of Shedd staff, scientists and collaborators that made this rescue mission possible on the research vessel..
Under these facilities’ expert care, the rescued corals will grow quickly and allow us to conduct additional research (e.g., genetic sequencing and direct testing of their heat tolerance) and restoration (e.g., spawning and selective breeding.) We are thrilled to have had the opportunity to make this important contribution to the conservation of staghorn corals in Florida and look forward to continued work with these corals in the future.
Special thanks to our incredible crew of the R/V Coral Reef II, our team of scientists from Shedd, the University of Miami Rosenstiel School of Marine, Atmospheric, and Earth Science, the University of South Florida, the Florida Wildlife Commission, and the Sanctuary and gene bank facilities that made this mission possible.
Permit Number FKNMS-2023-092-A2