Healthy coral reef (c) Oona M. Lönnstedt
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Dying coral reefs 'dull fish senses'

Researchers in Australia and Sweden have found that coral bleaching and death can have a direct effect on how reef-dwelling fish learn about their environment - particularly how to avoid predators.

The team from James Cook University in Queensland and Uppsala University carried out tests in enclosed "mini reefs" that simulated the environment they were studying.

They put young damselfish in their reefs, half of which contained healthy coral, the other half containing the skeletons of dead coral.

The scientists then trained the fish to recognise the scent of a new predator - pairing that scent with another chemical that damselfish release when they're under attack. Only the fish in the healthy reefs learned the new predator's smell, and hid among the coral in response. On dead reefs, the fish just kept on exploring, leaving themselves vulnerable.

The researchers say their results show worrying signs of the direct impact of coral damage on marine animals' behaviour and survival.

The findings are published in the journal Proceedings of the Royal Society B.

Coral reef timelapse footage courtesy of Pim Bongaerts. Tropical fish pictures and footage courtesy of Alex Vail, Oona Lonnstedt and Mark McCormick

Video produced by Victoria Gill

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