Friday 17 May
Freshwater white-clawed crayfish (Austropotamobius pallipes)
Freshwater white-clawed crayfish fact file
- Find out more
- Print factsheet
Freshwater white-clawed crayfish description
The only freshwater crayfish native to the UK (3), this species is olive-green to brown in colour and can reach up to 12 centimetres in length. The common name refers to the fact that the undersides of the claws are off-white to pinkish in colour. Females tend to have wider abdomens than males, and males have larger claws. In males, the first two appendages are specialised; they are used to place a sperm mass (spermatophore) underneath the female during mating (2).
- Length: up to 12 cm (usually less than 10 cm) (2)
Freshwater white-clawed crayfish biology
This crayfish tends to be nocturnal, emerging at night to feed on a broad diet consisting of detritus, animal matter and plants. It also occasionally indulges in cannibalism, particularly on individuals with soft cuticles following their moult (2).
Mating takes place in autumn; the eggs develop whilst attached to the mother's abdomen, and the female overwinters with the eggs still attached to her. After the eggs hatch, the juveniles remain attached to the mother before becoming independent at the beginning of summer. During the first year of life, juveniles may moult more than seven times. After they reach maturity, however, there tends to be an annual moult (2).Top
Freshwater white-clawed crayfish range
This crayfish was once widely distributed across Europe, but has undergone a severe decline, and remaining populations are increasingly fragmented (2). Before 1980 this species was also widespread throughout Britain and Ireland (2), but a large number of populations have since been lost (3). It is currently still fairly abundant in central and northern areas of England (2).Top
Freshwater white-clawed crayfish habitatTop
Freshwater white-clawed crayfish status
The freshwater white-clawed crayfish is classified as Endangered (EN) on the IUCN Red List (1). Listed in Appendix III of the Bern Convention, Annexes II and V of the EC Habitats Directive and protected under Schedule 5 of the Wildlife and Countryside Act 1981 (3)Top
Freshwater white-clawed crayfish threats
Perhaps the most devastating factor affecting freshwater white-clawed crayfish at present is crayfish plague, a virulent fungal disease carried by the aggressive introduced species, the American signal crayfish (Pacifastacus leniusculus) (4). Spores of this disease can be spread in the water, on wet equipment and on fish (2). Competition with introduced crayfish species has also affected our native crayfish (3); signal crayfish were first introduced to the UK in the 1970s and are now naturalised and breeding (2). Two other introduced species have become established (3); the narrow-clawed (or Turkish) crayfish (Astacus leptodactylus) and the noble crayfish (Astacus astacus) (2). Pollution and river works are also likely to have affected the species (2).Top
Freshwater white-clawed crayfish conservation
The freshwater white-clawed crayfish has been targeted as a priority for conservation under the UK Biodiversity Action Plan (UK BAP). The Species Action Plan aims to maintain the current distribution of the species through a combination of restricting the spread of non-native crayfish and crayfish plague, as well as providing suitable habitat features (3). The Environment Agency has carried out research into potential methods of controlling the signal crayfish, and is currently investigating the use of pheromones to lure this introduced species into traps (5). It is an offence under Schedule 9 of the Wildlife and Countryside Act to release the three introduced species of crayfish into the wild (3).Top
Find out more
The UK BAP Species Action Plan is available at:
For more on the Environment Agency:
Information authenticated by the Environment Agency:
- Active at night.
IUCN Red List (Feburary, 2011)
- Environment Agency. (2001) Freshwater Crayfish in Britain and Ireland. The Environment Agency, Bristol.
UK BAP Species Action Plan (November, 2001)
- Environment Agency. (2001) Preventing the Spread of Crayfish Plague in the South West. Environment Agency, Bristol.
The Environment Agency (November, 2001)
More »Related species
Play the Team WILD game
MyARKive offers the scrapbook feature to signed-up members, allowing you to organize your favourite ARKive images and videos and share them with friends.
Terms and Conditions of Use of Materials
Copyright in this website and materials contained on this website (Material) belongs to Wildscreen or its licensors.
Visitors to this website (End Users) are entitled to:
- view the contents of, and Material on, the website;
- download and retain copies of the Material on their personal systems in digital form in low resolution for their own personal use;
- teachers, lecturers and students may incorporate the Material in their educational material (including, but not limited to, their lesson plans, presentations, worksheets and projects) in hard copy and digital format for use within a registered educational establishment, provided that the integrity of the Material is maintained and that copyright ownership and authorship is appropriately acknowledged by the End User.
End Users shall not copy or otherwise extract, alter or manipulate Material other than as permitted in these Terms and Conditions of Use of Materials.
Additional use of flagged material
Green flagged material
Certain Material on this website (Licence 4 Material) displays a green flag next to the Material and is available for not-for-profit conservation or educational use. This material may be used by End Users, who are individuals or organisations that are in our opinion not-for-profit, for their not-for-profit conservation or not-for-profit educational purposes. Low resolution, watermarked images may be copied from this website by such End Users for such purposes. If you require high resolution or non-watermarked versions of the Material, please contact Wildscreen with details of your proposed use.
Creative commons material
Certain Material on this website has been licensed to Wildscreen under a Creative Commons Licence. These images are clearly marked with the Creative Commons buttons and may be used by End Users only in the way allowed by the specific Creative Commons Licence under which they have been submitted. Please see http://creativecommons.org for details.
Any other use
Please contact the copyright owners directly (copyright and contact details are shown for each media item) to negotiate terms and conditions for any use of Material other than those expressly permitted above. Please note that many of the contributors to ARKive are commercial operators and may request a fee for such use.
Save as permitted above, no person or organisation is permitted to incorporate any copyright material from this website into any other work or publication in any format (this includes but is not limited to: websites, Apps, CDs, DVDs, intranets, extranets, signage, digital communications or on printed materials for external or other distribution). Use of the Material for promotional, administrative or for-profit purposes is not permitted.