Under water grunts, chirps and pops recorded by an Auckland scientist have revealed a mysterious language used by New Zealand fish.
Audio recordings analysed for the first time in New Zealand to find out whether fish talk, will be played to an audience in Wellington today, presented by Auckland University researcher Shahriman Ghazali.
His study began two years ago, when he started listening to recordings taken by colleagues studying ambient noise in the Leigh marine reserve north of Auckland. They made an underwater microphone, with which Mr Ghazali decided to try to establish which sounds were being made by which fish.
"Bigeyes are producing something like a popping sound but they organise them temporarily so it's like morse code."
To discover which fish was making each noise, Mr Ghazali brought groups of individual species from the sea to a tank at the laboratory.
Using an easily obtainable hydrophone, or underwater microphone, he continually recorded crayfish to test if there was any basis to the commonly held belief they made sounds when divers approached.
"Funnily enough, I didn't get any sound from any of them."
Instead, he repeated the test with bigeye, an endemic nocturnal fish which lives in similar environments, and found they were making the noises. It was possible they made sounds in response to divers approaching, and that other fish used sound for functions including communicating and orienting themselves around reefs.
Getting any fish to start making the sounds had not been easy while they were held in the tanks. They only made sounds in groups, and also took some time to adapt to their new environment.
Gurnard were found to be making distinctive grunts which followed a particular pattern throughout the day.
"Goldfish have excellent hearing, but excellent hearing doesn't associate with vocalisation – they don't make any sound whatsoever."
Mr Ghazali's research is being presented at the three-day NZ Marine Sciences Society conference, which begins today.
- © Fairfax NZ News
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