The noble crayfish (Astacus astacus) is a freshwater crustacean native to Europe but it is present in the British Isles and is often the result of introductions. Known for its large size and ecological importance in its native range, the noble crayfish is highly vulnerable to the invasive signal crayfish (Pacifastacus leniusculus). In the British Isles, noble crayfish populations are of conservation interest due to their rarity and ecological significance, with efforts focused on protecting their habitats and mitigating threats.
