Coral reefs are experiencing heat stress due to rising ocean temperatures, but researchers are using crabs to help the coral thrive.
The warmer waters encourage algae to grow on the coral and produce toxins, turning the once-brightly colored reefs into craggy white tombstones underwater.
To combat the impacts of this heat stress, researchers at the Mote Marine Laboratory and Aquarium in Sarasota, Florida, have created a crab nursery program to raise crustaceans that help preserve the delicate coral ecosystems.
Crabs are a natural part of the coral ecosystem, and they help preserve it by eating algae growing on and competing with the corals, according to Mote's Coral Reef Restoration Research Program manager Jason Spadaro. This allows the coral to grow faster and reproduce sooner, and then baby corals can be recruited to the reef more frequently and successfully.
However, Spadaro noted that the crabs are few and far between in the coral ecosystem, largely because they are often hunted by wildlife and humans. Because of this, the positive impact the crustaceans can have on coral reefs is diluted.
"With this enhancement program, we're able to kind of circumvent that bottleneck, produce more crabs, and then get that functional response that we're looking for out on the reef," Spadaro said.
Introducing nursery crabs into the wild does present some challenges, particularly regarding how the crabs have not learned how to protect themselves from predators. To teach them this skill, Spadaro’s team is testing a method involving puppets made by the Florida Keys Elementary School to irritate the crabs and induce a predation response.
"We've yet to see if this actually works, but it's been a blast using it as an outreach tool and as a research objective," Spadaro said.