Conservationists are stepping up their efforts to save a native species that is under threat from its aggressive American cousins.
The white-clawed crayfish is one of the largest freshwater invertebrates in the UK, but is under threat of extinction in the wild because of the introduced American signal crayfish, which out-competes its British counterpart for food and carries a killer plague.
The native species is found in just two Devon rivers, from which conservationists at the Whitley Wildlife Conservation Trust, the Environment Agency and Buglife hope to boost the breeding population.
Tracey Hamston, from the Whitley Wildlife Conservation Trust, based at Paignton Zoo, said: "We have a chance to save this species for Devon. The situation is urgent."
It follows a similar campaign in and around Bristol.