From the BBC:
Endangered crayfish colony found
Britain’s only native crayfish which was feared extinct in Essex has made a comeback.
Essex Biodiversity Action Plan environmentalists have discovered a colony of white-clawed crayfish thriving in the River Chelmer.
The survey found 18 of the crustaceans from mature crayfish to babies.
The species has been wiped out in many parts of the country by the non-native larger American signal crayfish with whom they have to compete for food.
Project officer Mark Iley said: “It’s the only site in Essex where we know that we have these white-clawed crayfish.”
Australian crayfish: here.
Slender crayfish here.