Green staghorn coral may be more likely to survive ocean warming if crabs are around

A team of environmental scientists at Duke University, working with colleagues from the University of New South Wales, the University of Queensland and the University of California, has found that green staghorn coral around Heron Island (part of the Great Barrier Reef) are more likely to survive warming water temperatures if hoof-clawed crabs live in the near vicinity.

In their study published in the journal Proceedings of the Royal Society B, the group collected coral samples and tested them in their lab.

Prior research has shown that climate change is endangering coral reefs, which in turn endangers the creatures that live on and around them. Coral reefs are in trouble for two reasons: The first is that the water in which they live is rising, and the second is that the high amounts of atmospheric carbon dioxide are making sea water more acidic.

The research team noted that coral reefs have a symbiotic relationship with many oceanic species. They wondered if any of those relationships might help the corals survive changing conditions.

Prior research has shown that climate change has been heavily impacting green staghorn coral, which create shallow reefs—they are suffering from bleaching, which makes them more susceptible to disease and predation by starfish. More specifically, when star fish feed on coral, they cause open wounds that lead to infections, and oftentimes death.

The researchers knew that hoof-clawed crabs lived in the vicinity of green staghorn coral, and that the relationship between them has been viewed as beneficial to both. To find out if the crabs might be helping the coral survive changes to their environment, the researchers collected several samples and brought them back to their lab for testing.

In the lab, the research team put the coral in conditions identical to their natural sea home, even pumping in seawater from the collection site. They then noted that predation by starfish led to wounds that "bled" a type of mucus, which in turn attracted other species, one of which was the hoof-clawed crab. The researchers observed that the crabs fed on the mucus but did not harm the coral.

But they also found that they fed on nearby seaweed, typically the vectors for infectious bacteria, which led to infection prevention in the corals. The researchers determined that compared to a control group, coral that were protected by the crabs were 60% less likely to suffer tissue loss, greatly increasing their chance of survival, even as the water grew warmer.

© 2025 Science X Network