An international team of scientists from Australia’s James Cook University and the Australian Institute of Marine Science, as well as the UK’s University of Bristol and the University of Exeter, have been working on an exciting project to save coral reefs. Working together on Australia’s recently devastated Great Barrier Reef, they came up with an idea to place loudspeakers underwater playing the sounds of a lively coral reef environment.
What they discovered was that young fish were drawn to the noise of healthy coral reefs and began to populate the patches of dead coral. Their findings show that “acoustic enrichment” could be a valuable tool in helping to restore damaged reefs. The research has been published in Nature Communications.
Tim Gordon of the University of Exeter and lead author of the study said:
Fish are crucial for coral reefs to function as healthy ecosystems. Boosting fish populations in this way could help to kick-start natural recovery processes, counteracting the damage we’re seeing on many coral reefs around the world.
The experiment worked out so well that twice as many fish arrived (compared to equivalent patches where no sound was played) and stayed in the once desolate coral reef. There were also 50% more species present, which is essential because different groups of fish provide different functions on coral reefs. A diverse and abundant fish population is vital to maintaining a healthy ecosystem.
Gordon added:
Whilst attracting more fish won’t save coral reefs on its own, new techniques like this give us more tools in the fight to save these precious and vulnerable ecosystems. From local management innovations to international political action, we need meaningful progress at all levels to paint a better future for reefs worldwide.
The team noted that the diversity of the fish they attracted included herbivores, planktivores, detritivores, and predatory piscivores – that’s species from all sections of the food web. The innovative technique works because it’s regenerating the sounds that are lost when reefs are silenced by degradation.
Prof Steve Simpson at the University of Exeter and senior author of the study said:
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. Juvenile fish home in on these sounds when they’re looking for a place to settle. 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.
Dr. Mark Meekan, an Australian Institute of Marine Science fish biologist, added:
Of course, attracting fish to a dead reef won’t bring it back to life automatically, but recovery is underpinned by fish that clean the reef and create space for corals to regrow.
Like most regenerative processes, there is no one solution. Playing recordings of a healthy coral reef is but one of many things that could be employed simultaneously to save our dying marine ecosystems.
Prof Andy Radford at the University of Bristol and a co-author of the study said:
Acoustic enrichment is a promising technique for management on a local basis. 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.
Coral are dying worldwide, primarily due to global warming and rising CO2 emissions. The oceans absorb CO2 from the atmosphere, which causes ocean acidification. The acidity etches away the fragile coral carbonate skeleton and weakens the coral, ultimately destroying the reefs. If the world doesn’t start treating the climate emergency as the threat that it is, then loudspeakers underwater won’t help revive anything because everything will be dead.
