Research is also being undertaken into ways to eradicate non-native crayfish species, as well as the crayfish plague
, but a solution has yet to be found.
The protected species is highly susceptible to pollutants and has suffered a serious population decline due to competition from introduced American crayfish species, crayfish plague
and the destruction of suitable habitat.
"It's big and aggressive and eats smaller crayfish and has brought crayfish plague
, which kills the native species."
It is now being checked to see if it was carrying the crayfish plague
. The find also prompted an area survey, starting yesterday, to find if there are more invaders.
The use of insecticides, crayfish plague
and competition from other crayfish means that they could be extinct within 30 years.
It is very likely that crayfish plague
is responsible for the disappearance of the native crayfish - which can grow up to five inches - in the Huddersfield Narrow Canal.
Agency staff say the American species is an aggressive variety that carries a disease called crayfish plague
, which kills the smaller native white-claw crayfish.
leniusculus not carrying the crayfish plague
, suggesting that long term displacement can occur, aided by higher fecundity, faster growth rate, and earlier hatching (Vorburger and Ribi, 1999).
Coun Lloyd added: "Unfortunately, the publicly accessible nature of Ensor's Pool has meant it has always been relatively vulnerable to crayfish plague
, which can be transmitted on damp or wet items including fishing equipment, boats and inflatables, dogs and on wellington boots.
The signal also carries a fungal toxin known as Crayfish Plague
, which has killed large numbers of native crayfish.
The native species are trapped using the sex hormones and checked for signs of crayfish plague
Spherical baculovirosis (Penaeus monodon-type baculovirus); Infectious hypodermal and haematopoietic necrosis; and Crayfish plague