Essex Biodiversity Project
White Clawed Crayfish
Identification - the White Clawed Crayfish (Austropotamobius pallipes) is the only native freshwater crayfish in the British Isles. They are up to 12 cm from the tip of head to the tail. The head tip sides are smooth and converge towards the base of the small triangular apex. There is a fine mat of hair covering the top surface. The body is smooth and generally brown to olive coloured. The claws are rough on the top side and dirty-white to pink on the underside.
General ecology - it is fairly docile and is generally found in clean, calcareous streams, rivers and lakes and also water filled quarries. They were formerly present in the rivers Blackwater, Pant, Stour and Stebbing and Robins Brooks, but are very vulnerable to crayfish plague caught from non-native Signal and Turkish crayfish and through competition from them.
White-clawed Crayfish are Britain’s only native crayfish. They play an important role in the aquatic food web, providing a food source for a variety of animals such as fish, birds and mammals such as the otter. They like clean water and shelter in crevices under submerged stones, tree roots and plants.
White-clawed Crayfish have suffered a dramatic decline since the 1980s and have disappeared from many parts of the country. Should the current trend in the decline continue, the species faces extinction in Britain within 30 years. Part of the problem has been the release of non-native American Signal crayfish. These larger animals compete for food, feed on White-clawed Crayfish themselves and can carry a lethal fungal disease called ‘crayfish plague’. Essex Biodiversity Project has been working with other partners to estabish "Ark" sites away from rivers where it is hoped that translocated White Clawed Crayfish will survive, as its has no reasonable future in any of our rivers.
What can you do to help?
To help save our native White-clawed Crayfish, we need to know where they are located. The EBP has an information card which contains information on their ecology, identification and what individuals can do to help. We need help in distributing these cards, and help in telling people about the importance of these animals. If you are able to distribute copies, we would be very grateful.
Download the Crayfish Card (PDF 613KB)
Surveying tips - please contact Essex Biodiversity project or the Environment Agency if you know where this species occurs.
Work to Date
2015 Crayfish Strategy Document - a new summary document setting out the work which has been carried out so far and further work that needs to be developed and funded.