White-clawed Crayfish


White-clawed crayfish survey mitigationPBA are leading white-clawed crayfish (WCC) specialists, providing surveys, rescues, mitigation works and translocations to new sites. Since 2001, we have also delivered national and regional crayfish training for CIEEM etc.


White-clawed crayfish are classified as Endangered in the IUCN Red List of Endangered Species and their populations are declining throughout much of their range. It is predicted that the species will face extinction in much of their former range within the next few decades. White-clawed crayfish populations are under threat from: (i) a fungal-like disease, ‘crayfish plague’; (ii) direct competition from introduced alien crayfish species; and, (iii) biochemical degradation of lotic/lentic habitats.


White-clawed crayfish are protected under Schedule 5 of the Wildlife & Countryside Act 1981 (as amended). As an Annex II species under the Habitats Directive, member states are required to maintain favourable conservation status through the selection of a series of European Sites. Only a decade or so since site selection, only two SAC now support white-clawed crayfish populations in favourable condition.


White-clawed crayfish conservationWhite-clawed crayfish may be surveyed by a range of methods, including diurnal refuge search, nocturnal activity survey, passive trapping, and otter spraint examination. Of these, the most widely applied method at relatively shallow clear-water lotic situations is diurnal refuge search, carried out in low flow conditions, and scheduled between July and September. A Natural England licence is required to survey white-clawed crayfish and guidance on competence for white-clawed crayfish survey should be followed (Bradley & Peay, 2013).


The SAC monitoring protocol is based upon diurnal inspection of 50 refuges per site, with the aim of detecting sites supporting a relatively high-density of white-clawed crayfish. The standard SAC protocol though has not been designed to survey species distribution. A 2004 reconnaissance survey, carried out for the Environment Agency (Pugh, Bradley & Lobo, 2005) applied a more intensive diurnal inspection survey method, which recorded species presence at 3x the number of locations.


PBA has unequalled capabilities in the survey and monitoring of white-clawed crayfish, and (importantly) the experience to interpret survey results, assess population status, risk assessments, and to assist with conservation initiatives. We can help you with:


Baseline surveys

Population status assessment

Risk assessment

Development mitigation

Quarantine & ‘Ark Site’

Training and guidance (CIEEM training)


If you have any queries or think you may require these services please contact us.


White-clawed crayfish survey calendar