Underwater speakers can rejuvenate damaged corals by playing healthy coral sounds that make them more attractive to young fish, according to an experiment on the Great Barrier Reef in northern Australia. In recent years, the Great Barrier Reef has been affected by climate change and coral bleaching has become increasingly serious.
Healthy coral reefs are filled with diverse life, as reflected in the underwater sounds and other cues they emit into the surrounding waters. By contrast, albino coral reefs are a quiet place. Corals rely on attracting a wide variety of fish to maintain healthy ecosystems. These marine “residents” take care of their corals by performing a series of “housekeeper” duties, such as cleaning and cleaning dead coral reefs, which in turn providespace for new growth.
Many fish migrate to corals at an early age, and when deciding where to settle, they are thought to be caused by sensory cues. Young fish are less likely to be attracted to silent corals, which may indicate poor health. A new study by an international team of scientists suggests that playing the sound of healthy corals on underwater speakers may encourage young fish to settle on damaged coral reefs.
Study lead author Tim Gordon, of the University of Exeter in the UK, said: “Fish is vital to maintaining a healthy ecosystem on coral reefs. Increasing fish stocks in this way can help initiate the natural recovery process and offset the damage we see on many coral reefs around the world. “
The 40-day experiment took place between October 2017 and December 2017, during which young fish naturally migrated to new coral reefs. The scientists compared observations on damaged coral locations with function speakers compared to observations at controlled locations, some of which were bare and others operated with fake speakers. This is done to test whether changes in marine populations and diversity are caused by acoustic treatment itself or by increased environmental complexity brought about by the new speaker system.
According to the team, the speakers at the reef site made a healthy reef sound compared to the control group site, and the number of fish arrived was twice as high as at the control group site. Importantly, regions benefiting from acoustic enrichment also show 50 per cent diversity in the number of species attracted.
The authors of the new study warn that simply encouraging fish to return to damaged corals is not enough to fully rejuvenate them. However, the technology does show hope and, when combined with other restoration methods, may be an effective weapon against loss of marine habitat.
The paper on the study has been published in the journal Nature Communications.