PBA Applied Ecology
PBA Applied Ecology

White-clawed Crayfish

PBA Applied Ecology have unequalled capabilities in the survey and monitoring of white-clawed crayfish, with the experience to interpret survey results, assess population status, and to assist with conservation initiatives. Since 2001, we have delivered national and regional crayfish training for the Chartered Institute of Ecology and Environmental Management (CIEEM). We have a proven track record of working in high-risk sites such as SACs and SSSIs, and all our work is conducted to the highest standard of biosecurity. Company Director Paul Bradley is a lead author on the currrent JNCC guidance for the monitoring of white-clawed crayfish, and also CIEEM competency guidelines for the survey of white-clawed crayfish. 

What services do we offer?

PBA are leading white-clawed crayfish specialists, providing surveys, translocations, mitigation works and the scoping and delivery of ark sites. We can provide:

  • Baseline surveys using a range of techniques:

    • ‚ÄčManual handsearch

    • Artificial Refuge Traps (ARTs)

    • Baited funnel traps

    • Torch survey

  • Population status assessments

  • Risk assessment

  • Development mitigations

  • Quarantine & ‘Ark Site’ solutions

  • Training and guidance (CIEEM training)

Survey approaches tailored to your project

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).

White-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 stillwater situations is diurnal refuge search, carried out in low flow conditions, and scheduled within the survey season (July 1st and September 30th).

The current Common Standards Monitoring guidance for Freshwater Fauna (2015) is applied to protected sites such as SACs. This guidance, co-written by Paul Bradley, is based upon diurnal inspection of a minimum of 100 suitable refuges per site, with the aim of detecting sites supporting a relatively high-density of white-clawed crayfish. In relatively low density sites the search effort is increased to 250 suitable refuges per site.

Legislation protecting white-clawed crayfish

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 riverine/stillwater 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.

If you have any queries regarding the services your project may require, please contact our Aquatic team specialists.