Reef Goats to the Rescue in Florida

Caribbean crabs can help balance Florida’s coral reef ecosystem.


The Florida Keys hosts crabs who are cleaning the coral reef ecosystem.

(Stephan Langhans /

Florida is a beautiful place characterized by brilliant sun, blue waters, and exotic wildlife. All year long, its beaches are packed with sunbathers and watersports enthusiasts.

Beachcombers may notice an overgrowth of seaweed washing ashore. This algae is negatively impacting the coral reefs, however researchers have found a creative solution. They are introducing native crabs who hungrily graze on the overgrowth, cleaning up the beaches and reefs!

The Caribbean king crab is found in both Florida and the Caribbean, according to FL Keys News. Known as  “reef goats,” they love to eat algae, making them ideal candidates to address the proliferation of seaweed in Florida. 

This explosion of algae has become problematic as it covers up coral, effectively blocking the light which facilitates the growth of baby corals. Without coral, the ecosystem of the ocean can be affected. According to the Natural History Museum, there can be thousands of species living on one coral reef. 

Additionally, the ridges found in coral reefs can reduce wave energy by 97 percent, helping protect the shore from tsunamis. Another incredible advantage of coral reefs is that the extract from plants and animals residing on the reef can be used to produce medicine for arthritis, cancer, heart disease, and asthma. 

Recognizing the dire need to save the coral, the focus has turned to Caribbean king crabs. A study published in Current Biology found that Caribbean crabs will eat many types of algae, and lots of it. These crabs even munch on the green algae called Halimeda, which most animals won’t consume. 

Mark Butler, co-author of the study, explains that seaweed can be extremely harmful as it produces chemicals that can impact the reproductive cycle of coral, making them more vulnerable to diseases. In addition, the chemicals that seaweed lets off repel larval reef fish, which primarily live within the coral reef. This disrupts the ecosystem of the reef and the ocean overall. 

Within the two experiments performed, Caribbean crabs were placed on reefs in the Florida Keys, while nine miles away the reefs were left alone. Divers calculated that the seaweed was reduced by 50 to 80 percent where the reef goats grazed. This is an incredible discovery which can positively affect the coral, communities of fish, and plant life. 

Butler told FL Keys News that he hopes to continue introducing Caribbean crabs onto Florida’s coral reefs, but they still need to research the exact density of crabs needed. Although the crabs are not abundant, they tend to stick to the reefs, so they would most likely not spread to other areas.

With such a positive outcome from this study, there is now great hope for saving Florida’s reef ecosystem, home to thousands of marine life species. It is amazing that one type of grazing crab could contribute to restoring coral reefs, and all they have to do is eat!

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