Coral larvae can be encouraged to settle and grow by exposing them to the sounds of a healthy coral reef.
That’s according to a new study undertaken by Woods Hole Oceanographic Institution (WHOI) researchers, who say the findings could have wide practical implications for reef conservation and restoration.
Coral lavae can float around for days or weeks before dropping to the ocean floor and using sensory cues to find a suitable place to attach and start growing.
Previous research has shown these cues include chemical and light signals, but this study demonstrates that sounds can help, too. Fish feeding and shrimps snapping help make up the rich soundscape produced by a healthy coral reef.
The WHOI team divided samples of golfball coral larvae (Favia fragum) into two cups placed in quiet, sandy bays in the US Virgin Islands, with a solar-powered speaker playing recordings from a healthy reef placed near one of the cups.
After 24 hours, 30% of the coral exposed to healthy reef sounds had settled, compared to zero in the control cup. After 48 hours, the settlement rates were similar, suggesting that this ‘acoustic enrichment’ is most effective in the first few days.
“Maybe we can really scale this up,” said the study’s senior author, Aran Mooney. “But we can’t just throw a speaker over the side of a boat and think it’s going to work. We have to know the system and it has to be integrated with other conservation and restoration efforts.”
A recent review of coral restoration studies found that while numerous practitioners have demonstrated effective small-scale, short-term methods of restoration, it is critical not to view these as a replacement for meaningful action on climate change.
