Fishing Lines: Reeling off a tuna with the bass

A VERY famous angler once claimed that Verdi arias were just the thing for encouraging roach to feed. At the time, we thought it was a load of nonsense. But one of the country's leading research institutes has now proved that fish not only hear what's going on, but are probably singing away themselves.

Fawley Aquatic Research Laboratories at Southampton has been listening to fish for the past couple of years. Far from being about as uncommunicative as Trappist monks, it seems that cod and salmon, roach and haddock chatter away like a Patrick Moore lookalike convention.

Andy Turnpenny, managing director at Fawley, describes the sounds as 'uninteresting to the human ear: a mixture of clucks, clicks, bumps and thumps'. But the lab's biologists have now managed to understand fishtalk enough to produce an electronic version of 'We Gotta Get Out Of This Plaice'. For Nuclear Electric, one of the sponsors of the research, dead fish are bad news, and not just for environmental reasons. Power stations such as Hinckley use sea-water for cooling. Shoals of mangled mackerel can block an inlet, causing overheating and forcing the station to shut down.

So Fawley has come up with an acoustic fish-deterrent system, which can be customised to scare off specific species. 'It has huge advantages because it can be installed quickly, it's unaffected by fast flows and the fish are not harmed,' Turnpenny says.

Getting the right words is very important. It's no good trying to scare off a cod in fluent turbot. But the sound barrier can be very selective. Fawley has been undertaking the research alongside an American power company in Sacramento, which is using sound waves to keep young salmon away from an intake, while allowing mature fish to ascend the river.

Turnpenny's team have also discovered that male and female fish talk at the same rate, though they're more garrulous at night and in warm water. And not every fish likes a good gossip. While salmon and members of the cod family like whiting and pollack have a very wide range of sounds, eels are a taciturn lot.

The range of 'words' can convey a whole range of fishy emotions. 'With haddock, we have recorded mating calls and played them back to get mating behaviour,' Turnpenny says.

Most of the work has centred on sea fish and salmon, but experiments are starting with freshwater fish. Turnpenny expects good results because carp, roach and others are very sensitive to sound.

The implications are enormous. With more fish being farmed, the system offers immense possibilities, particularly 'ranching', where fish are not kept in cages but encouraged to stay in a particular area. Turnpenny added: 'It is certainly possible that it could be used to pen fish in.' It could also be possible to attract fish by playing something romantic: perhaps 'Salmon Chanted Evening'?

The system is a bit expensive so far for anglers. But they can look forward to a time when a portable unit will attract just the fish they want. In the meantime, you'll probably have to stick to a burst of 'O Sole Mio', or perhaps something by Rod Stewart. A small, tasteless prize for the most suitable song.