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29 December 2008
Natural England and the Environment Agency announce results of five-year crayfish breeding programme.
The white-clawed crayfish, one of England’s most endangered species, is clawing its way back from the brink of extinction, thanks to a pincer movement by Natural England and the Environment Agency in the Yorkshire Dales.
The five year pioneering project bred 300 juveniles this year – making it the UK’s most successful breeding programme for the native white-clawed crayfish.
Once common in many upland rivers and streams, this rare crustacean is being driven out by the larger, more aggressive American signal crayfish which was brought to the UK to be farmed and carries a deadly “plague” fatal to native crayfish.
Dr Helen Phillips, Chief Executive of Natural England, said: “The news that white-clawed crayfish are breeding in increasing numbers in the Yorkshire Dales is extremely encouraging and shows that targeted conservation work can make a real impact. The species has been all but wiped out following the introduction of its American cousin, but the success of this project gives grounds for hoping that extinction is by no means inevitable”.
Since it began in 2003, the Yorkshire Dales project has moved from a project designed to ring-fence surviving pockets of white clawed crayfish to protect them from the “crayfish plague” and from predation by its bigger cousin, towards an active breeding programme. Natural England’s ecologist Paul Bradley, and Environment Agency fisheries officer Neil Handy, took the project one step further by developing techniques for captive breeding and rearing of white-clawed crayfish. A recent stock assessment showed that over 60% of the hatchlings had survived; in the wild only a small fraction would reach breeding age.
Neil Handy, Environment Agency Fisheries Officer who has been responsible for developing and managing the facility, said, “We are at a critical stage in protecting our remaining native crayfish populations and our work in the Yorkshire Dales is at the forefront of conserving this endangered species. Its required a lot of hard work but the results demonstrate just how successful we have been in rearing native white clawed crayfish. We now need to build on this success.”
Funding is being sought to expand the programme to produce at least 500 white-clawed crayfish per year. Once approaching sexual maturity, these individuals would be reintroduced into carefully selected sites. The expanded facility would also rear native trout and salmon to re-stock local rivers.
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Notes for editors:
For further information or for interviews please contact Natural England’s national press office on: 0845 603 9953, press@naturalengland.org.uk out of hours 07970 098005.
Adult white-clawed crayfish may grow to about 120 mm and can live for more than 10 years. They usually reach sexual maturity after three to four years. Breeding takes place in autumn and early winter (September to November) when the water temperature drops below 10°C for an extended period. Females over-winter with a clutch of eggs held beneath the tail and timing of release of juveniles varies from June in the south to August in the north. The white-clawed crayfish is largely nocturnal, although it can be seen foraging in the shallow margins of lakes as dusk approaches on warm summer evenings. Migration into deeper water may occur in the winter.
Non-native species that become invasive are one of the biggest threats to wildlife worldwide, and are estimated to cost the British economy at least £2 billion a year. In May this year, England, Scotland and Wales launched the first co-ordinated plan (the Invasive Non-Native Species Strategy) to tackle the threat to Britain’s native biodiversity from invasive non-native species. Further information on the strategy can be found in Defra's press release
