National Trust creates Northumberland ‘ark’ to protect endangered crayfish

White-clawed crayfish are Britain's only native freshwater crayfish. Photograph: Annapurna Mellor/© National Trust Images/Annapurna Mellor

An “ark” refuge is being created by the National Trust to help save one of the UK’s most endangered native species from extinction.

The white-clawed crayfish is the UK’s only indigenous crayfish but the population has been almost wiped out because of the introduction of a bigger American species in the 1970s.