6 Oct 2016

Do fish have accents?

11:05 am on 6 October 2016

There might be plenty of fish in the sea, but their foreign accents could mean the chances of them finding love are dwindling.

Scientists in Britain are looking at the sound cod make to attract a mate, and whether regional populations could have different accents.

Atlantic cod

Atlantic cod Photo: Wikicommons

University of Exeter marine biologist Steve Simpson said it was important to understand whether there are these regional dialects for different populations.

"When cod make noise it's generally the males that make noise and they're usually producing sound to convince the female that she wants to mate with him. And so, much of this is really a love song."

"In that sound there's actually a lot of information about the size of the fish, the quality of the fish and what condition he's in, and he's just got 15 seconds or so to get that song just right to convince her as they swim towards the surface that she'll release her eggs for him."

There was also evidence from studies in Canada that when cod swim towards the surface the females only released eggs about a third of the time.

"So she's clearly picky, and that sound is one of the most important pieces of information she has to go on - and remember it's the middle of the night - to whether the male she's swimming with is any quality or not."

He said cod were being forced closer to the poles by warming and there were several populations which could mingle because of it. Because cod tended to have traditional spawning grounds, subpopulations could become genetically quite different.

"And they have the opportunity then for the sounds that they produce to diverge in different ways. Cod have quite a repertoire of sounds that they can make," Prof Simpson said.

"And if they have a specific sound that they produce during reproduction and that sound is presented to the wrong female then it might start to disentangle reproduction.

There was also the threat of human noise in the marine world on the fish populations.

"The funding that we have is actually from the British government and the research council NERC (Natural Environment Research Council) to look at the effect of human noise in the marine world.

"So when you dip your hydrophone in the water - underwater microphone - in the UK what you tend to hear is human noise.

"Shipping, pile driving, construction or drilling and things like that. So we're actually quite seriously looking at the effect of human noise drowning out these important natural sound that fish depend on."

"We've actually been doing this in coral reefs for a long time, listening to coral reefs and we know that the sounds we hear tell us who lives there but also tell us about the quality of the habitat. And we've never really done the same thing in the UK, to characterise the soundscapes of the marine environment."

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