Fish Guidance Systems

Cod communicate with regional accents

A research team from the University of Exeter are attempting to discover if Cod moving north with climate change will be able to understand the accents of their more northerly counterparts. The team believe the fish, which make sounds with their swim bladders to attract mates, may have regional accents – so if the cod from the southwest communicate with a different dialect to those in the north it could threaten their ability to breed.

Leading the research, Professor Steve Simpson has been listening to fish for 15 years and said the cod had a series of vocalisations, with the ability to change the patterns of their sounds, producing thumps, growls and different frequencies. The research aims to find out what they sound like when they are hunting, when they are breeding, and what happens when fish with different ‘dialects’ collide, as warming seas drive species north.

Professor Simpson went on to explain: “Recordings of American cod are very different to those from their European cousins, so there is a precedent”.

“This species is highly vocal with traditional breeding grounds established over hundreds or thousands of years, so the potential for regionalism is there.”

With climate change, sea temperatures are rising and cold water species are migrating north. The research team initially wanted to understand how fish can use sound to navigate at night and select habitat to live in. But the group have now been identifying animals that make the sounds and decoding the meaning of different kinds of sounds. For example, says Professor Simpson: “We find the sounds of a reef indicate the quality of the habitat and the composition of the local community”. The study has also identified that fish are susceptible to noise pollution, and new research aims to see what is going on in the UK’s seas among fish such as cod and haddock, which also use vocalisations.

The team believe listening to fish is a really good way of surveying what is there, and what their behaviour is. Simpson concludes: “Given that cod produce a variety of sounds for establishing territories, raising the alarm and attracting mates, we may find that the ‘gossip’ essential for their society is being drowned out”.