Scientists are relying on the signal crayfish’s powerful sex drive to help get them under control.
Boffins have been experimenting with traps laced with the pheromones the female signals use to attract a mate.
Paul Stebbing, from Newcastle University, has been testing the sex traps since August. “Results so far suggest that using pheromones with established trapping methods could be a viable option for controlling this species,” he said.
“Female crayfish pheromones only attract the males so we are now working with male pheromones in an attempt to capture the females as well.”
Experts fear the rampaging signals, which are spreading across much of the south and Midlands, could be the final nail in the native cray’s coffin. Its american rival is bigger, more aggressive and breeds at an earlier age.
The signal crayfish also carries a fungal disease which has wiped out large numbers of native crayfish. In large numbers they can wipe out spawning fish and fry, clear areas of aquatic plants and even damage the habitat of endangered species like water voles. British waters seem to suit them.
The biggest signal ever found – all 200 grammes of it – came from Nottinghamshire, in 2000.
The signal crayfish was introduced in Britain in the 1970’s as a commercial venture to supply the restaurant trade. But some were accidentally released or escaped into the wild and their colonies are spreading.
If successful, the project could be extended to other aliens in UK waters including the narrow-clawed, noble, red swamp and spiny-cheek crayfish.
More than 100 delegates are attending a conference at Nottingham University, to discuss ways of controlling signals.
