Austropotamobius pallipes | Freshwater White-clawed Crayfish



Conservation status

Future ProspectsInadequate
Overall  Assessment of Conservation StatusInadequate
Overall Trend in Conservation Status Stable
Source: NPWS 2013.

IUCN Conservation Status
IrelandNot evaluated
Not evaluated*
GlobalEndangered [A2ce]
Source: Füreder, L. et al 2010.

*The species is European. The global evaluation could therefore be read as the European evaluation.

Legal status

Protected by the following legal instruments:

  • Habitats Directive (92/43/EEC), Annex II, Annex V.
  • Convention on the Conservation of European Wildlife and Natural Habitats (Bern Convention) Appendix III
  • Wildlife Act (1976), as amended
  • Wildlife (Amendment) Act, 2000
  • Wildlife (N.I.) Order 1985, as amended


Native status

Inconclusive native status. Possibly introduced.

Research into the genetics of Irish (as well as English and French) populations indicate the likelihood that Irish populations of A. potamobius are the result of intentional introduction as a food source.

Sources: Gouin et al 2010; Reynolds, 1998. 

Species Biology


As the White Clawed Crayfish is the only crayfish currently known to occur in Irish freshwater it should be readily identifiable as that species. Source: (Reynolds, 1998)

  • Viewed from above (dorsal surface) the body of the crayfish appears divided into three main sections the head, thorax and abdomen. Between the head and the thorax is the cervical groove. On the carapace of the thorax, behind the cervical groove is a row of few, prominent sharp spines.
  • The rostrum, a projection of the carapace extending forwards, above and between the eyes,has smooth edges and tapers gradually to a tip giving it an overall triangular shape.
  • On the carapace, just behind the eye is a single narrow ridge, a post-orbital ridge, with a point, or spine, on it at the end of the ridge nearest the eye.
  • The upper side of the claws are slightly granular to the touch.
  • The underside of the claws are lighter in colour than the upper side.
  • White-clawed crayfish coloration may vary from brown or olive, through grey to beige.
  • The underside of the claws although usually white, may be green or a very light pink but never red.
  • The claws do not appear out-sized relative to the body and are not narrowed and elongated.
  • Adults are generally less than 12cms in length.
  • Mainly active nocturnally.

Sources: Reynolds, 1998 ; ; Freshwater Invertebrate Survey of Suffolk.


The Freshwater Crayfish is found in rivers, streams and lakes in Ireland particularly in those with a calcareous influence.The species prefers pH above 7 and calcium levels of minimum 5mg/l and generally good quality, cool water but can tolerate some variation.

U.K studies in streams indicate the necessity for refuges whether this be vegetation, boulders or man made features. Hard substrates were found to be preferable to muddy substrates.

Adults can burrow in earthen banks. Females carrying eggs require undisturbed shelter over a prolonged winter-spring period.

Sources:  Reynolds J.D. 1998; Holdich D 2003; NPWS 2013.

Habitats include but are not necessarily limited to;

  • Eroding / upland rivers (FW1)
  • Depositing / lowland rivers (FW2)
  • Mesotrophic Lakes (FL4)
  • Drains (FW4)
  • Limestone / Marl Lakes (FL3)

Sources:  Reynolds J.D. 1998; Holdich D 2003; NPWS 2013;Fossitt, J.A., 2001.


Mating occurs October-November and males mate with more than one female. Eggs are incubated by the female for 8-10 months. Hatchlings remain attached to the female until after their second moult. Juveniles moult several times a year, mature males twice a year, mature females once.

Sexually mature at 3-4 years. Mature males have larger claws than mature females. Mature females have broader abdomen than mature males. Individuals can live to over 10 years.

Sources: Reynolds J.D. 1998;  Holdich D 2003.

Threats faced

Invasive non-native species
Introduction of disease (microbial pathogens) 
Pollution to surface waters (limnic & terrestrial, marine & brackish)
H01 Low
Dredging / removal of limnic sediments 
Management of aquatic and bank vegetation for drainage purposes 
Leisure fishing 


Source: NPWS 2013

Threats identified through the 2010 IUCN Red List assessment process accord well with those identified for Ireland in Article 17 reporting for the Habitats Directive.

The main threat identified is potential competition for resources with introduced crayfish species.

Although this is an issue in the rest of Europe it is not currently an issue in Ireland, because there are as yet no records of introduced crayfish species here. Introduced crayfish species in Europe harbour the pathogens Aphanomyces astaci and Thelohania contejeani which have resulted in significant declines there. Aphanomyces astaci has caused issues for particular Irish populations in the 1980s.

The threat of introduction to Ireland however is always present.

Sources: NPWS 2013; Füreder, L. et al 2010.

Conservation actions

In the Article 17 Habitats Directive reporting for the period 2007-2012 Conservation Measures listed as in place or in the process of being implemented for this species in Ireland were;

  • Continued legal protection of the species and its habitats inside and outside of Natura 2000 sites
  • Legal measures for the restoration and / or improvement of water quality inside and outside of Natura 2000 sites.

Source: NPWS 2013.


World distribution(GBIF)

Distribution is limited to the British Isles, France, along with pockets in central Europe and the Mediterranean.

Irish distribution

Clustered generally towards the centre of Ireland, records decline towards coasts.

Temporal change

Records submitted to Data Centre in 2022

The following map is interactive. If you would prefer to view it full screen then click here.

How can you help

The National Biodiversity Data Centre is trying to improve our knowledge on the distribution of the White-clawed Crayfish in Ireland. Should you observe the species, please submit sightings to add to the database. Detailed observations will assist us gaining a better insight into where the species is most abundant in Ireland and we might also be able to detect regional variations. Please submit any sightings and photographs at:

All records submitted on line can be viewed on Google Maps – once checked and validated these will be added to the database and made available for conservation and research.

Further information

For further information contact Dr. Liam Lysaght



Fossitt, J.A. (2001) A Guide to Habitats in Ireland. The Heritage Council.

Füreder, L., Gherardi, F., Holdich, D., Reynolds, J., Sibley, P. & Souty-Grosset, C. 2010. Austropotamobius pallipes. The IUCN Red List of Threatened Species. Version 2014.2. <>. Downloaded on 23 September 2014.

Gouin N, Grandjean F, Pain S, Souty-Grosset C And Reynolds J (2003). Origin and colonization history of the whiteclawed crayfish Austropotamobius pallipes, in Ireland. Heredity 91(1):70–77

Holdich D (2003). Ecology of the White-clawed Crayfish. Conserving Natura 2000 Rivers Ecology Series No. 1. English Nature, Peterborough.

NPWS (2013) The Status of EU Protected Habitats and Species in Ireland.  Species Assessments Volume 3. Version 1.0. Unpublished Report, National Parks & Wildlife Services. Department of Arts, Heritage and the Gaeltacht, Dublin, Ireland

Reynolds, J.D. (1998) Conservation management of the white-clawed crayfish, Austropotamobius pallipes. Part 1. Irish Wildlife Manuals, No. 1.