Scientists say the sounds cod make to communicate differ from region to region – and may be vulnerable to noise pollution.
Cod often use sounds to attract mates and warn of nearby predators.
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But if the sounds are disrupted by human marine activity it may affect cod's breeding by inhibiting integration and reproduction, scientists say.
But can you hear the difference between a north-eastern Atlantic cod and a north-western Atlantic cod?
Apparently researchers can.They say there are different regional dialects used by cod.
The sounds are emitted from the fish's swim bladder.
Scientists are concerned that human-made noise pollution in the sea is disrupting their communication and mating patterns as a result.
To maintain global fish stocks, this must be understood and reduced, say the researchers.