Nadège Aoki, a doctoral candidate at WHOI and lead author of a study on the topic, stated that her research indicates that coral larvae may use sound cues when selecting a location to settle.

A reef that has deteriorated due to factors like coral bleaching, disease, or human activities loses its ability to sustain a diverse range of species and emits a significantly quieter and less vibrant soundscape. According to the recent WHOI study, sound could be an important tool in the efforts to restore coral reefs.

Last summer, the team conducted their research in the US Virgin Islands. They set up speakers to broadcast the soundscape of a healthy coral reef in an area where the reef had deteriorated. Their findings revealed that this acoustic environment prompted coral larvae to recolonise the damaged site.

An increase in settlement

The WHOI researchers told CAI the coral “settled at rates 1.7 times (and up to 7 times) higher in a degraded environment enriched by recorded sounds than at reefs where no sounds were added, underscoring the power and potential of this enrichment technique.”

Aoki expressed optimism that this method could contribute to coral reef restoration efforts, admitting that sound alone would not solve all the problems on a reef, but to give corals a fighting chance, there needs to be an array of tools available to use and sound could be one of them. She noted that her team also observed fish congregating near the speakers, which she hopes could initiate a beneficial cycle.

“If you are able to attract some of these animals to an area that maybe they aren’t going to for some reason, and if they’re able to survive and thrive there, then they are going to start producing those sounds and those cues that will attract more animals back,” said Aoki.

A passive approach

Aoki mentioned that certain reef restoration techniques can be quite labour-intensive, whereas using sound offers a more passive approach. The research involved collaborating with WHOI Engineer Ben Weiss to ensure that the recordings were played from the speakers at the appropriate times of day, aligning with when fish and other marine creatures would naturally produce the sounds being broadcast. WHOI intends to conduct similar studies on Pacific corals in Hawaii later this year.