Reef fish eavesdrop to find home

Coral reef fish spend weeks scouting out a new neighborhood before they move in – just like human house buyers do, Edinburgh scientists have revealed.

The fish use their acute sense of hearing to eavesdrop on locations before deciding where to live.

Edinburgh University researchers studied shoals of fish near the Great Barrier Reef off Australia.

They found damselfish, cardinalfish, emperors and blennies chose communities by the “reef noise” they give off.

They then choose one based on their needs – in much the same way that a human would choose a new neighbourhood based on local schools or work commitments.

Very young fish – those who have just developed as larvae in the open sea – choose locations with invertebrates such as shrimp, which give off a high frequency sound, and hide in holes snatching passing food.

As they grow older, scientists say the fish become “more aware” of the social groups and communities they would like to live in.

They are then drawn towards reefs populated with fish – which produce a lower pitched sound – where they can find shoal mates, forage for food and expand their territories.

The research shows that these natural “cues” are important for determining how communities are established.

Shipping, drilling, mining and active sonar are all adding to levels of noise pollution, but the impacts on community structure are not known.

Dr Steve Simpson, of Edinburgh University’s school of biological sciences, said: “These findings show that hearing is crucial for the survival of fish.

“Reef noise includes the sounds of invertebrates and fish feeding, and so provides other fish with direct information about the residents on the reef.”

The research, funded by the Natural Environment Research Council (NERC) , the Fisheries Society of the British Isles (FSBI) and the British Ecological Society, has been published in the journals Coral Reefs, Animal Behaviour and Proceedings of the Royal Society.