At the end of March, the Mote Marine Laboratory in Sarasota released the first Caribbean king crabs (Maguimithrax spinosissimus) raised in captivity onto a coral reef in the Lower Florida Keys.
This is a historic step in the restoration of Florida’s reef system, the third largest in the world. This area has lost more than 90% of its live coral in the last 75 years due to overfishing, diseases, algae proliferation, and climate stress.
The Role of the Caribbean King Crab
This crustacean is considered one of the most effective herbivores in the western Atlantic, capable of consuming macroalgae that block sunlight and compete with young corals for space.
Previous studies show that their presence can reduce algal cover by 50% to 85%. This significantly increases coral recruitment and the abundance of reef fish.
The Florida Coral Reef Restoration Crab Hatchery Research Center, a pioneering 6,000-square-foot facility, houses more than 300 adult crabs. It also has the capacity to produce up to 250,000 juveniles per year. The released specimens spend between three and five months in captivity before reaching the appropriate size and passing veterinary checks.
Project Objectives
The plan involves the release of 35,000 crabs throughout the Florida Keys National Marine Sanctuary, from Key Largo to the west of Key West. The urgency is evident: the marine heatwave of 2023 was the worst recorded in Florida’s history. There were temperatures up to 38°C that caused total bleaching in sites like Horseshoe Reef, Cheeca Rocks, Sombrero Reef, and Looe Key.
After that catastrophe, two critical species —the staghorn coral and the elkhorn coral— were declared functionally extinct in the region. Added to this is the stony coral tissue loss disease, detected in 2014, which has affected more than 90% of susceptible corals.
Mote’s program is not limited to crabs. Since 2008, coral transplants have been carried out, with a 75% survival rate even after the 2023 heatwave. Additionally, rescues of sea turtles and manatees affected by extreme weather conditions, such as cold and heat waves, are conducted.
Philosophy of Effort
Dr. Jason Spadaro, manager of Mote’s reef restoration program, summarized the mission with a strong phrase: “Now is not the time to give up, now is the time to step up the work”.
The release of Caribbean king crabs represents an innovative strategy that goes beyond coral transplantation. By reducing algae pressure and promoting reef recovery, this project offers hope for one of the planet’s most threatened ecosystems.
