Young fish can be attracted to degraded coral reefs by speakers playing healthy reef sounds, new research shows released today [29 November] in Nature Communication.
An international team of scientists from the UK universities of Exeter and Bristol, and James Cook University in Australia and the Australian Institute of Marine Sciences, said this “acoustic enrichment” could be a valuable tool to help restore damaged coral reefs.
Working on Australia’s recently devastated Great Barrier Reef, scientists placed underwater speakers playing recordings of healthy reefs in patches of dead coral and found that twice as many fish were arriving – and staying – Compared to equivalent plates where no sound was played.
“Fish are essential for coral reefs to function as healthy ecosystems,” said lead author Tim Gordon, University of Exeter.
“Strengthening fish populations in this way could help jump-start natural recovery processes, countering the damage we are seeing on many coral reefs around the world.”
This new technique works by regenerating sounds that are lost when reefs are soothed by degradation.
“Healthy coral reefs are remarkably noisy places – the crackle of crunchy shrimp and the screeches and growls of fish combine to form a dazzling biological soundscape. Juvenile fish pick up on these sounds as they search for a place to settle down. “said senior author Professor Steve Simpson, also of the University of Exeter.
âReefs ghostly become silent when they degrade, as shrimp and fish disappear, but by using speakers to restore this lost soundscape, we can attract young fish again. “
Dr Mark Meekan, a fish biologist at the Australian Institute of Marine Sciences, added: “Of course attracting fish to a dead reef will not automatically bring it back to life, but recovery relies on fish that clean up the reef and create space for coral regrowth. “
The study found that spreading healthy sounds to reefs doubled the total number of fish arriving at experimental reef habitat plots, and increased the number of species present by 50%.
This diversity included species from all sections of the food web – predatory herbivores, scavengers, plankctivores and piscivores.
Different groups of fish perform different functions on coral reefs, which means that an abundant and diverse fish population is an important factor in maintaining a healthy ecosystem.
Professor Andy Radford, co-author of the University of Bristol, said: âAcoustic enrichment is a promising technique for management at the local level.
âIf combined with habitat restoration and other conservation measures, rebuilding fish communities in this way could 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.”
Gordon added, âWhile attracting more fish will not on its own save coral reefs, new techniques like this give us more tools in the fight to save these precious and vulnerable ecosystems.
“From innovations in local management to international political action, we need significant progress at all levels to paint a better future for reefs around the world.”
“Acoustic enrichment can enhance fish community development on degraded coral reef habitat” by Timothy AC Gordon, Andrew N. Radford, Mark G. Meekan, Stephen D. Simpson et al in Nature Communication