A deathly hush descending on coral reefs damaged by global warming is impairing the ability of young fish to find a home, research suggests.
Coral reefs are noisy places filled with the clicks, pops, chirps and chattering of numerous fish and crustaceans.
But a study conducted on Australia's Great Barrier Reef shows the "coral orchestra" has been quietened in areas damaged by cyclones and bleaching.
Scientists found that without the din, fish born outside the reef had a hard time locating a suitable place to live and breed.
Experiments showed that the soundscapes of damaged reefs attracted 40 per cent fewer juvenile fish than those of healthy reefs.
The loss of reef fish could have "devastating" consequences, warn the researchers.
Lead scientist Tim Gordon, a marine biologist at the University of Exeter in the UK, said: "It's heart-breaking to hear. The usual pops, chirps, snaps and chatters of countless fish and invertebrates have disappeared. The symphony of the sea is being silenced."
Bleaching occurs when sea water becomes too warm, causing corals to expel the algae living in their tissues and turning them white.
Under normal conditions the algae provide the coral with nutrients generated by photosynthesis. Without them, the coral can starve.
In some parts of the Great Barrier Reef 80 per cent of corals have been killed by bleaching. Scientists say there is a direct link between more frequent coral bleaching events and global warming.
Working on the northern Great Barrier Reef, the British-led international team of scientists built experimental reefs from coral rubble on sand flats.
Underwater speakers were then used to broadcast the sounds of healthy or degraded reefs to see how they attracted juvenile fish.
The noises of coral reef animals combine to form a soundscape that helps young fish find suitable reef habitats after a period of early development in the open ocean.
Co-author Harry Harding, from the University of Bristol, said: "If fish aren't hearing their way home anymore, that could be bad news for the recovery prospects of reefs.
"Fish play critical roles on coral reefs, grazing away harmful algae and allowing coral to grow. A reef without fish is a reef that's in trouble."
Gordon said the damage done to reefs worldwide was extensive but if nations fulfilled their international commitments to slash carbon emissions it was still possible to protect the reefs that were left.
