White-clawed crayfish surveys
Once widespread throughout Europe, the white-clawed crayfish is in serious decline due to habitat modification, pollution and more recently, the introduction of North American signal crayfish. With northern and central England now recognised as the European stronghold, white–clawed crayfish are afforded protection through national legislation and planning policy. Surveys for white-clawed crayfish are likely to be required where development may affect rivers, streams, lakes and other clean mineral-rich water bodies that provide suitable habitat for this species.
The first stage in undertaking a white-clawed crayfish survey is normally a river corridor survey to evaluate the suitability of watercourses within and surrounding the development to support this species. If necessary, more detailed surveys can then be undertaken to determine the presence or likely absence of white-clawed crayfish. These should follow Natural England’s guidelines (Peay, 2003) and could include searching for crayfish under boulders, using baited traps and/or night viewing.
If white-clawed crayfish are found to be present within the site then appropriate measures may need to be put in place to enable the development to progress. See our white-clawed crayfish mitigation page for more information.