JUVENILE fish follow the crackle and fizz from a coral reef to help them find it. The 鈥渇rying bacon鈥� sound of snapping shrimps for example can be picked up 20 kilometres away.
Stephen Simpson at the University of Edinburgh, UK, and his colleagues set up 24 artificial reefs, each with a speaker system, near Australia鈥檚 Great Barrier Reef. On six consecutive nights they played recordings of natural reefs at half the sites. A reef that was noisy one night was silent the next and vice versa. Reefs with the audio cue attracted four times as many cardinal fish and nearly twice as many damselfish (Science, vol 308, p 221).
The discovery helps explain how fish that start life in the open ocean are able to find reef habitat in which to settle. But it also raises concerns that noise pollution from shipping and underwater drilling might affect their behaviour. 鈥淲e don鈥檛 know if these sounds repel fish or attract them,鈥� says Simpson.
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Artificial playback could have practical uses. For example, mimicking reef sounds could be used to lure fish for the aquarium trade or attract fish to replenish overfished areas. It could also prove to be a useful conservation tool, says Stephen Swearer, a zoologist at the University of Melbourne, Australia. 鈥淚t has potential to be a method for ameliorating the decline in reef fisheries,鈥� he says.
