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.

Steve Simpson, a professor at the University of Exeter and senior author on the team’s paper, said:

Reefs become ghostly quiet when they are degraded, as the shrimps and fish disappear, but by using loudspeakers to restore this lost soundscape, we can attract young fish back again.

Approximately 89 percent of The Great Barrier Reef is dead or dying. Countless species of “reef fish” have fled the decaying ecosystem, and others like it, taking with them the essential nutrients needed for coral’s survival. While luring fish won’t solve the problem entirely or save the reefs from increasing climate change, it can help kick start regeneration and, essentially, aid in bringing them back from the brink. This is because coral needs fish pee.

Our gilled friends are like vitamin filters for coral reefs. They pee and poo and shed scales and die and do all sorts of things that allow giant reefs to soak up nutrients. In return, we all get to live.

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As things stand right now, without those fish and their pee, the world’s coral reefs are doomed to go extinct. This is a very bad thing. As marine scientist Michael Crosby told Business Insider last year, the reefs’ health is directly related to ours:

You like to breathe? Estimates are that up to 80 percent of the oxygen you are breathing in right now comes from the ocean. It doesn’t come from the land. In order for you to continue to breathe, you have to have a healthy ocean.

And a healthy ocean means having plenty of freaky fish around to make babies and pee everywhere.

For more information on the underwater loudspeaker experiments, check out the team’s research paper “Acoustic enrichment can enhance fish community development on degraded coral reef habitat” here on Nature.

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