The past century hasn't been kind to coral reefs. These delicate, complex, important ecosystems have been hit hard by environmental changes like pollution, ocean acidification and warming seas due to global climate change, resulting in damaged and diseased corals. And coral reef ecosystems need healthy corals to function, but corals also need the help of other organisms — mostly hundreds of fish species — to remain healthy. Biodiversity is key to keeping a reef system healthy, and different species have different jobs on the reef — eating algae, plankton, other fish and random crud off the reef. If a few of them abandon a reef due to sickly corals, a few more will decide it's intolerable, and eventually everybody will abandon ship, resulting in a dead reef.
But research published Nov. 29, 2019 in the journal Nature Communications finds there might be a solution to the large-scale desertion of coral reefs by fish species: playing them the sweet music of a healthy reef.
"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," said senior author Steve Simpson, professor of Marine Biology & Global Change in the Department of Biosciences at the University of Exeter, in a press release. "Juvenile fish home in on these sounds when they're looking for a place to settle."
The research team conducted their sound experiments on recently wrecked portions of Australia's Great Barrier Reef. They played recordings of a thriving reef through loudspeakers in the rubble of once-healthy reef habitat and found twice as many fish were attracted to these damaged reefs as were to similar habitats where speakers were set up but no sounds were played. And the fish stuck around for the entire 40 days of the study, even after they figured out the party wasn't as cool as advertised.
Never underestimate the power of a good DJ.
And though attracting fish to the reef won't automatically bring it back to life — and won't fix the problems that started this whole mess to begin with — improving the reef soundscape could be a useful tool in jump-starting degraded reefs.
"Acoustic enrichment is a promising technique for management on a local basis," said co-author Andy Radford, professor of behavioural ecology in the School of Biological Sciences at the University of Bristol, in the press release. "If combined with habitat restoration and other conservation measures, rebuilding fish communities in this manner might accelerate ecosystem recovery. However, we still need to tackle a host of other threats including climate change, overfishing and water pollution in order to protect these fragile ecosystems."