Although stunningly vibrant, it may seem silent when you snorkel over a flourishing coral reef, but researchers have discovered they're in fact full of sound. They've identified in their recordings the crackle of the claws of crustaceans, snapping shrimps (like popcorn) and "the chatter, chirp, whoop or growl of fish".
Documenting these marine melodies and replaying the recordings over degraded ones, they managed to lure in twice as many fish, which is a new development for reef-restoration. Whilst the major problems of reef health, such as climate change, over-fishing and water pollution, drastically need addressing, fish are vital for the survival of coral, with different groups providing different functions, from cleaning to recycling and depositing nutrients.
Working on the Great Barrier reef, the scientific team, from Australia and the Universities of Bristol and Exeter, analysed the ways in which fish use sounds to navigate and select the ones where they wanted to stay. They re-played the healthy 'reef music' over some of the 33 test sites they'd created from particularly degraded patches of the Great Barrier Reef and the results showed that twice as many fish arrived, and stayed, on the noisy patches compared to the silent ones.
Whilst these appealing symphonies aren't going to bringing whole reefs back to life, it's hoped that, when combined with other conservation measures, they could potentially speed their recovery.