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: 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. 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: 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. Read next: Scientists at an aquarium just figured out how to save Florida’s ‘Great Barrier Reef’
