An appeal for help to stop the spread of invasive American signal crayfish in Northumberland was announced today by the Environment Agency, Natural England, Northumberland Rivers Trust and Northumberland Wildlife Trust.
A large population of American signal crayfish have been confirmed in the River Blyth – a blow for our internationally important population of native white-clawed crayfish on the neighbouring River Wansbeck.
To safeguard our native crayfish, anglers and other river users are being urged to stop the spread of the signal crayfish, and the plague it carries, by following three simple steps: Check, Clean and Dry.
The American species of crayfish is bigger, more aggressive and out-competes our native crayfish. More importantly it also carries a fungal disease known as crayfish plague that has wiped out our native crayfish from most rivers in the south of England.
Because they are larger than our native species, signal crayfish can have a significant impact on fisheries by eating fish eggs and also increasing the erosion of river banks through their burrowing.
Fiona Morris, fisheries and biodiversity team leader at the Environment Agency, said:
"We don't yet know how far the signal crayfish have spread, but the numbers we have found recently are not good news. It is impossible to totally eradicate populations of signal crayfish. All we can do now is try our best to contain them and stop them from spreading, to help protect our native crayfish.
"We're calling on all river users and anglers who fish the River Blyth to help us by Checking, Cleaning and Drying all their fishing tackle and footwear thoroughly, so that we can halt the spread of the disease that the signal crayfish carry.
"In the North East we still have native populations which are holding out against the invasion, and we want to keep it that way."
Peter Kerr from the Northumberland Rivers Trust said:
"We must do all we can to stop signal crayfish getting into the Wansbeck, where their effect will be devastating on the native population. We would ask all anglers and river users to follow the Check, Clean Dry Campaign."
Although it is legal to catch crayfish with a licence in other parts of the country, requests for a licence in the North East are rejected to protect vulnerable native crayfish populations.
Scientific evidence has shown that small scale trapping can make the situation worse for our native crayfish. Large male signal crayfish tend to be caught in the traps and, because they also cannibalise young crayfish, larger males can help to control the population size. In some areas where trapping has occurred there has been an increase in the numbers of signal crayfish over subsequent years. Trapping can also increase the risk of spreading signal crayfish and the plague they carry.
A byelaw for trapping crayfish in England and Wales came into force in 2005, which restricted the accidental or deliberate movement of alien crayfish and 'crayfish plague', whilst still allowing the legitimate trapping of the crustaceans in some postcode areas. None of these are in the north of England.
Check your equipment and clothing for living organisms
Clean and wash all equipment, footwear and clothes thoroughly
If you do come across any organisms, leave them at the water body where you found them
Dry all equipment and clothing - some species can live for many days in moist conditions
Make sure you don't transfer water elsewhere.
Important information on crayfish trapping
Native white clawed crayfish are a protected species. Anyone handling or trapping native crayfish must have a license from Natural England or Countryside Council for Wales.
In some parts of England and Wales crayfish trapping is not permitted due to the potential for catching native crayfish. Requests for a licence in the North East are rejected to protect vulnerable native crayfish populations. In other areas trapping is only allowed with written consent from the Environment Agency, permission from the landowner and only with certain types of trap to minimise the potential for harming water voles and other wildlife. Therefore, anyone wishing to make an application to trap crayfish is advised to contact the Environment Agency before spending money on traps.
About Natural England
Natural England is the government's independent adviser on the natural environment. Established in 2006 our work is focused on enhancing England’s wildlife and landscapes and maximising the benefits they bring to the public.