New research from the universities of Essex and Exeter indicates that scientists can determine the health of a coral reef by its sound.
Healthy coral reefs can be heard using underwater microphones from kilometres away. But coral reefs impacted by human activity, such as overfishing, are quieter than protected reefs, scientists discovered.
The study involved taking acoustic recordings of coral reefs with different levels of protection around islands in the Philippines. The research found that the noise produced by the few remaining resident fish and crustaceans on unprotected reefs was only one third of the sound produced at healthy reef communities.
This is important to the larval stages of reef fish and invertebrates, which spend the first few days of their life away from reefs and use sound as an orientation cue to find their way back. With less sound being produced at impacted reefs, the distance over which larvae can detect habitat is 10 times less, the study found.