White-Clawed Crayfish Survey Devon

Glade Ecology undertake white-clawed crayfish surveys throughout Devon and the surrounding area.

Our team of expert ecologists can help guide your project through the planning process. By working closely with our clients, we ensure that their developments progress smoothly and in full compliance with the law, orchestrating the best possible outcome for them and the natural world.

Considering ecological issues early on in the planning process can help ensure that potentially costly and time-consuming delays are avoided.

What is a white-clawed crayfish survey?

White-clawed crayfish are found within rivers, streams, canals, lakes and other standing water bodies throughout portions of England and Wales, though their populations are scattered and typically at low density. The British population has endured a long term decline, falling by approximately 70% since the 1970s, primarily due to a combination of habitat loss and degradation, and the introduction of the disease-carrying and predatory American signal crayfish. They are protected under UK law, making it an offence of kill, capture, or disturb them, though their habitat is not specifically protected. Works affecting white-clawed crayfish are subject to licensing procedures. 

Where water courses, lakes, reservoirs and water-filled quarries are deemed likely to be affected by project proposals, a white-clawed crayfish survey may be required, which aims to establish the presence/ likely absence of white-clawed crayfish on site, and identify potential for constraints and opportunities. The appraisal is used to inform the emerging scheme design, enabling significant ecological effects within the zone of influence to be avoided, mitigated, or compensated for, where necessary. This ensures the continued favourable conservation status of white-clawed crayfish, post development, and ultimately compliance with nature conservation legislation and planning policy. 

Presence/ likely absence surveys involve the systematic manual searching of five distinct patches of habitat throughout the survey area. A minimum of ten potential refuges are inspected within each patch, searching for evidence of white-clawed crayfish. The manual searches may be supplemented by torching surveys, whereby the banks of the water feature are traversed at dusk for a minimum of sixty minutes. The surveys encompass ecologically linked suitable habitat beyond the site. If white-clawed crayfish are identified, two additional manual searches with be required, to establish population density. The field survey is typically supplemented by a desk study, utilising maps and aerial photographs of the surrounding area to identify ecological connectivity, and published records of white-clawed crayfish, purchased from the local records centre.

Alternatively, if the survey area comprises an enclosed water body, eDNA sampling may be undertaken. This involves a rapid assessment of presence/ absence within water bodies, based on traces of white-clawed crayfish DNA within the water column, which typically persists for several weeks. If a negative result is returned, instant confirmation of absence can be established and the feature can be scoped out of the study, thereby expediting the survey process. However, if presence if confirmed, further survey will be required to establish the population size, which eDNA sampling alone cannot determine.

Requirements for any necessary avoidance, mitigation, or compensation measures will be identified, and opportunities for ecological enhancement will be outlined, to integrate on-site biodiversity net gain into the scheme at an early stage, where possible.​ If the proposals are deemed likely to adversely affect white-clawed crayfish, a mitigation licence may be required, prior to the commencement of works.

White-clawed crayfish surveys are seasonally constrained and protracted, making it prudent to plan ahead and consider ecological issues early on in the planning process. A robust white-clawed crayfish survey at an early stage in project planning and design can therefore deliver significant benefits, avoiding potentially costly and time-consuming delays.​

Though the presence of ecological constraints very rarely prevents a development from proceeding, avoidance, mitigation, or compensation measures may need to be implemented, to adequately negate adverse impacts to the site's ecological value. For more information about ecology surveys, click below.

White-Clawed Crayfish Survey

How Glade Ecology can help you

With over fifteen years' experience in undertaking ecological surveys, mitigation design, licensing, site supervision, and monitoring, our friendly team of expert ecologists can help guide your project through the planning process. By working closely with our clients and considering ecological issues early on, we can help ensure that potentially costly and time-consuming delays are avoided.

We pride ourselves on providing pragmatic, practical solutions for our clients, that not only ensure full compliance with wildlife legislation, but that achieve the best possible outcome, for both them and the natural world.

We undertake white-clawed crayfish surveys throughout Devon and the surrounding areas of Dorset, Somerset and Gloucestershire. For more information about the services that we provide, or to request a free quotation, please contact us below.

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