New hope for coral reef restoration by playing healthy reef sounds on speakers

A clownfish in an anemone. Credit: Tim Gordon, University of Exeter

According to a new study published today (November 29, 2019) in Nature Communication.

An international team of scientists from the British University of Exeter and Bristol University, and the Australian James Cook University and the Australian Institute of Marine Sciences, say 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 arrived – and stayed – 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.

“Boosting fish populations in this way could help kick-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.

Tim Gordon explains “acoustic enrichment”. Credit: University of Exeter

“Healthy coral reefs are remarkably loud places – the crackle of snapping shrimp and the screeches and growls of fish combine to form a dazzling biological soundscape. Juvenile fish pick up on these sounds when they are looking for a place to settle, ”said lead author Professor Steve Simpson, also from the University of Exeter.

“Reefs ghostly quiet when they degrade, as shrimp and fish disappear, but by using speakers to restore this lost soundscape we can attract young fish again.

Australian Institute of Marine Science fish biologist Dr Mark Meekan added: “Of course attracting fish to a dead reef won’t automatically bring it back to life, but recovery relies on fish that clean the reef and create space for coral regrowth. . “

The study found that delivering healthy sound to reefs doubled the total number of fish arriving at experimental reef habitat plots, while increasing the number of species present by 50%.

Coral Rubblefield in Sulawesi, Indonesia

A field of coral rubble in Sulawesi, Indonesia. Credit: Tim Gordon, University of Exeter

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: “Acoustic enrichment is a promising technique for management at the local level.

“If 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, “While 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 meaningful progress at all levels to paint a better future for reefs around the world. “


Reference: “Acoustic enrichment can enhance fish community development on degraded coral reef habitat” by Timothy AC Gordon, Andrew N. Radford, Isla K. Davidson, Kasey Barnes, Kieran McCloskey, Sophie L. Nedelec , Mark G. Meekan, Mark I. McCormick and Stephen D. Simpson, November 29, 2019, Nature Communication.
DOI: 10.1038 / s41467-019-13186-2

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