Coral reefs are among the most diverse and threatened ecosystems on the planet, facing multiple stressors from climate change, pollution, and overfishing. But a new global project aims to use the power of sound to help them recover.
The project, called Coral Soundscapes, is led by researchers from the Woods Hole Oceanographic Institution (WHOI) and involves collaborators from around the world. The idea is to record the natural sounds of healthy coral reefs and play them back through underwater loudspeakers near degraded reefs.
“Sound is really important for many marine animals, especially fish,” says Aran Mooney, a marine biologist at WHOI and the principal investigator of the project. “They use sound to find their way around, to find food, to avoid predators, and to find mates.”
Mooney says that healthy coral reefs are noisy places, full of clicks, pops, grunts, and chirps from various fish and invertebrates. These sounds act as cues for larval fish that are looking for a suitable habitat to settle and grow. But when coral reefs are damaged by bleaching, disease, or storms, they become quieter and less attractive to fish.
“We’re trying to restore that acoustic environment and make it more appealing for fish to come back,” Mooney says. “We hope that by bringing back the fish, we can also bring back the health and resilience of the reef.”
The project is currently underway in four locations: Australia, Belize, Fiji, and the U.S. Virgin Islands. The researchers are using hydrophones to record the sounds of both healthy and degraded reefs, and then analyzing the acoustic data to identify the key features that attract fish. They are also testing different types of loudspeakers and sound playback systems to find the most effective and durable ones.
Mooney says that the project is still in its early stages, but he is optimistic about its potential. He says that soundscapes could be a low-cost and scalable tool to complement other reef restoration efforts, such as coral gardening or transplantation.
“We’re not saying that sound is the magic bullet that will save all the coral reefs,” he says. “But we think it could be a useful tool in the toolbox of reef managers and conservationists.”
