https://canalrivertrust.org.uk/things-to-do/fishing/caring-for-our-fish/freshwater-fish-species/rare-and-protected-fish/white-clawed-crayfish
White-clawed crayfish | Rare and protected fish
The white-clawed crayfish is not technically a fish but a crustacean.
white clawed crayfishrareprotected
https://www.gov.uk/guidance/white-clawed-crayfish-advice-for-making-planning-decisions
White-clawed crayfish: advice for making planning decisions - GOV.UK
How to assess a planning application when there are white-clawed crayfish on or near a proposed development site.
white clawed crayfishadvicemakingplanningdecisions