https://thenextweb.com/insider/2019/12/03/scientists-lured-fish-back-to-the-great-barrier-reef-by-making-it-sound-alive/

The Earth’s coral reefs are dying and they need our help. We either have to come up with some magical way to trick fish into returning and spawning or convince the planet’s politicians and business leaders to take the climate crisis seriously. And since science can’t do the impossible, a team of international researchers has taken on the problem of convincing fish to make the beast with two dorsal fins in the hollowed out bones of a coral graveyard.

The team posited that dead coral reefs don’t sound or smell the same as lively ones. In order to test this hypothesis, they recorded the sounds from thriving areas of the Great Barrier Reef and played them over loudspeakers in areas that were dead and dying. They found, astoundingly, that 50 percent more fish returned to dying areas that sounded healthy versus similar areas without audio pumped in.