Signal Crayfish Pacifastacus leniusculus
Photo credit: Trevor Renals
- Appearance: Lobster-like crustacean, claws have red undersides and small turquoise/white blotch on the upper surface at the claw hinge. Much larger (adults 16-18 cm) than the protected native White-clawed crayfish (10-12 cm).
- Diet: Fish, amphibian eggs, young fish, invertebrates, detritus and vegetation.
- Impact: Carries Crayfish plague, a disease causing the decline of native White-clawed crayfish. Negative impact on the diversity and abundance of aquatic communities including commercial fisheries. Burrowing can cause erosion and destabilisation of riverbanks and increase flood risk.
- Pathway: May have escaped or been deliberately released into the wild.
- Legal status: Species of special concern listed under the retained EU Regulation 1143/2014 and the Invasive Alien Species (Enforcement & Permitting) Order 2019.
- Unless you have a licence or permit or an exemption applies you must not:
- keep them in your house, garden or business
- sell them to other people
- exchange them for goods
- release them into the environment
- let them breed or escape
- import them into the UK
- transport them within the UK
- export them to other countries
- What to do if you see Signal crayfish for sale or other offences being committed: Make a report by following the guidance here.
- What to do if you see this animal in the wild: Record it with a photograph (where possible).