This is an audio from the BBC called the Life Scientific where Physicist Jim Al-Khalili interviews other scientists about their life

> Tim Lamont is a young scientist making waves. Arriving on the Great Barrier Reef after a mass bleaching event, Tim saw his research plans disappear and was personally devastated by the destruction. But from that event he discovered a novel way to restore coral reefs. Playing the sounds of a healthy coral reef entices fish in to recolonise the wrecked reefs. Tim's emotional journey forced him to realise that environmental scientists can no longer just observe. They need to find new prisms with which to view the world and to intervene to save or protect the natural environment.

https://www.bbc.co.uk/programmes/m001cp9f (podcast, mp3, stream or app from the BBC)

You can listen to the recorded fish sounds here

> From whoops to purrs, snaps to grunts, and foghorns to laughs, a cacophony of bizarre fish songs have shown that a coral reef in Indonesia has returned rapidly to health.

> Many of the noises had never been recorded before and the fish making these calls remain mysterious, despite the use of underwater speakers to try to “talk” to some.

https://www.theguardian.com/environment/2021/dec/08/whoops-and-grunts-bizarre-fish-songs-raise-hopes-for-coral-reef-recovery

This is the scientific paper on using the recorded fish sounds to improve reef restoration success (open)

> ...Here, using a six-week field experiment, we demonstrate that playback of healthy reef sound can increase fish settlement and retention to degraded habitat. We compare fish community development on acoustically enriched coral-rubble patch reefs with acoustically unmanipulated controls. Acoustic enrichment enhances fish community development across all major trophic guilds, with a doubling in overall abundance and 50% greater species richness. ...

https://www.nature.com/articles/s41467-019-13186-2