White-Clawed Crayfish

Austropotamobius pallipes

About

The White-clawed crayfish is small, typically 6-8cm. The carapace (hard upper shell) is generally brown to olive in colour, with a pitted appearance. They have large pincers (claws) that are pale cream or rose on the underside, which gave them their name.

They are omnivorous, so eat everything from other invertebrates to carrion and water plants. When they are small, they can be eaten by dragonfly larvae. When bigger, they can be eaten by trout, herons, mink and otters.

Crayfish are mostly nocturnal and are more active and visible during the spring and summer. They mature after 3-4 years and can live up to 12 years.

They live in ponds, lakes, rivers and canals. They require water bodies to be alkaline, calcium-rich, clean and well oxygenated. They favour shallow waters which have stones and over-hanging vegetation where they can hide from predators and keep cool. They are an indicator of high water quality as they are intolerant of pollution.

The literature on White-clawed Crayfish disagrees on whether this species is native to the UK, or was introduced in the Middle Ages by French monks for whom it was a delicacy. Whatever its origins, it is now found in the southern part of Western Europe, UK and Ireland and it is thought that the UK has about a quarter of the world’s population.

Conservation status

Under threat, mainly from the Signal crayfish which was introduced from the USA which outcompetes them for food and also carry diseases including crayfish plague, which is lethal to White-clawed crayfish. Also under threat from habitat degradation and pollution. About 70% of the UK population has been lost since the 1970s.

‘Endangered’on the IUCN Red List.