Loudspeakers Helping Restore Coral Reefs

University of Exeter marine biology doctoral student Tim Gordon sets up a loudspeaker on a coral reef. Image: Harry Harding/University of Bristol

In recent decades coral reefs have come under severe threat from pollution, unsustainable fishing practices, disease, global climate change and ship groundings. As a result scientists have scrambled to find solutions to help reverse damage and a new study suggests that loudspeakers may serve as an important remedy. 

As CBS News reported, researchers set up underwater loudspeakers in Australia’s northern Great Barrier Reef in late 2017, blasting recorded sounds of healthy reefs to encourage young fish to return to, and settle in, damaged ones. In a study published Friday in the journal Nature, the researchers said this “acoustic enrichment” can help revive coral reefs globally.

How This Works: As study author Dr. Steve Simpson of the University of Exeter explained, healthy coral reefs are remarkably noisy places – the crackle of snapping shrimp and the whoops and grunts of fish combine to form a dazzling biological soundscape. Juvenile fish home in on these sounds when they’re looking for a place to settle and when reefs die this noise fades. Using speakers to project the natural sounds of reefs can help attract these young fish back.

• Researchers found that twice as many fish flocked to the “acoustically enriched reefs” compared to areas where no sound was played — a crucial factor in kick-starting natural recovery processes.

Why This Matters: Severe bleaching events caused by marine heat waves over the past four decades have now affected almost every coral reef ecosystem in the world. While bringing back fish to damaged reefs won’t be all that’s necessary to restore reefs, fish can help with important aspects of recovery like cleaning reefs and creating space for coral regrowth.

Go Deeper: Satellites are being used as an important tool to track ocean acidification.