White-clawed crayfish: advice for making planning decisions
Source: gov.uk (2025-04-07)

How to assess a planning application when there are white-clawed crayfish on or near a proposed development site.

This is Natural England’s ‘standing advice’ for white-clawed (or Atlantic stream) crayfish (Austropotamobius pallipes). It is a material planning consideration for local planning authorities. You should take this advice into account when making planning decisions. It forms part of a collection of standing advice for protected species (https://www.gov.uk/guidance/protected-species-how-to-review-planning-applications#standing-advice-for-protected-species).

You should read this guidance alongside Protected species and development: advice for local planning authorities (https://www.gov.uk/guidance/protected-species-how-to-review-planning-applications).

Following this advice:
- avoids the need to consult on the negative effects of planning applications on white-clawed crayfish (WCC) in most cases
- can help you make decisions on development proposals
You may need a qualified ecologist to advise you on the planning application and supporting evidence. You can find one using either the:
- Chartered Institute of Ecology and Environment Management (CIEEM) directory (https://cieem.net/i-need/finding-a-consultant/)
- Environmental Data Services directory (https://www.endsdirectory.com/)
How white-clawed crayfish are protected

WCC are protected under the Wildlife and Countryside Act 1981.

It is an offence to intentionally take them.

It is also an offence to intentionally or recklessly:
- possess or transport them (or any part, alive or dead)
- sell, offer, or publish an advert to sell them
Some WCC populations are qualifying features of Special Areas of Conservation (SACs), so are also protected under the Conservation of Habitats and Species Regulations 2017. You can read on the Joint Nature Conservation Committee’s website which SACs have WCC as a qualifying feature (https://sac.jncc.gov.uk/species/S1092/).

WCC are included on the list of species of principal importance in England (https://www.gov.uk/government/publications/habitats-and-species-of-principal-importance-in-england) under section 41 of the Natural Environment and Rural Communities Act (2006). You must consider the conservation of WCC as part of your planning decision. Find out more about your biodiversity duty (https://www.gov.uk/guidance/complying-with-the-biodiversity-duty).

The developer must comply with the legal protection of WCC.

The developer may need a licence for activities that affect WCC (https://www.gov.uk/government/collections/white-clawed-crayfish-licences).

The developer may need permission from the Environment Agency to trap WCC (https://www.gov.uk/guidance/permission-to-trap-crayfish-eels-elvers-salmon-and-sea-trout) as part of their development proposal.

When to ask for a survey

You should ask for a survey if distribution and historical records suggest WCC may be present. You can search the National Biodiversity Network Atlas (https://nbnatlas.org/) by species and location.

Absence of a record does not mean there are no WCC. It could mean there is no survey data available for that location.

You should check that surveys are carried out from July to September.

WCC are vulnerable and endangered. The distribution of WCC (https://sac.jncc.gov.uk/species/S1092/) might show the species is lost in an area, but there could be isolated populations still present. Translocations have taken place over recent years to restore WCC to sites where they had been lost.

WCC can be found in:
- rivers
- streams
- canals
- pools and lakes
WCC need refuges to help them avoid being attacked or washed away in high waters. They use natural and artificial refuges, like rocks or rock baskets, tree roots and crevices that are:
- fully submerged
- big enough to cover the crayfish, but not too big for the size of animal
- stable and resistant to high waters
- aerated
- not being used by other wildlife
You must check if the ecologist is qualified and experienced to carry out surveys for WCC. CIEEM publishes:
- competencies required for species surveys (https://cieem.net/resource/competencies-for-species-survey-css/)
- advice on the valid age of ecological reports and surveys (https://cieem.net/wp-content/uploads/2019/04/Advice-Note.pdf)
What to survey for

Survey work can include:
- manual hand searching (when the water is clear, the flow is low and it is safe)
- hand-netting
- night searching by torch if it is safe
- trapping using an artificial refuge trap approved and licenced by the Environment Agency (when water is too deep or cloudy for manual searches)
- eDNA surveys
Baited traps are unsuitable in most areas because of the presence of other wildlife that may be impacted such as water voles, otters and water shrews.

Assess the effect of development on white-clawed crayfish

Developers should submit information with their planning application on how their development proposal avoids or mitigates harm to WCC.

Activities that pose a potential threat to WCC include:
- introducing non-native crayfish by connecting previously unconnected watercourses
- spreading disease from poor biosecurity practice – developers should follow the check-clean-dry protocol, outlined on the GB Non-native Species Secretariat website (http://www.nonnativespecies.org/checkcleandry/) – may not be accessible to assistive technology
- loss or modification of habitat
- breaking up habitat by obstructing WCC movement, for example from new culverts
- a reduction in water quality and quantity from changes to water flow, increased siltation, decreased oxygenation or pollution incidents
Avoidance, mitigation and compensation measures

Where possible development proposals should avoid negative effects on WCC. Where this is not possible, the developer will need to include adequate mitigation or, as a last resort, compensation measures in their development proposal to allow you to make a planning decision.

To avoid possible effects on WCC, developers could redesign the development proposal to avoid carrying out work in or near the waterbody.

Where this is not possible, mitigation measures could include:
- carrying out work in summer
- changing the methods of working
- reducing disturbance to the river bank and bed
- reducing the amount of sediment released into the water
- reducing the area affected
- doing work in small sections
- improving water quality
- reducing water pollution including silt
- adding appropriate cobbles and large woody material as refuges
- excluding crayfish from construction areas
- designing and installing structures that stop the spread of non-native crayfish
Compensation measures could include:
- providing habitat to replace any that will be lost
- as a last resort, moving WCC to suitable locations within the catchment to reduce the chances of spreading disease
For more information on mitigation plans and compensation measures, read Protected species and development: advice for local planning authorities (https://www.gov.uk/guidance/protected-species-how-to-review-planning-applications#agree-avoidance-mitigation-or-compensation-measures).

Planning and licence conditions

The developer may need to apply for a WCC licence if their activities are likely to affect WCC.

They must apply for a WCC mitigation licence for development activities (https://www.gov.uk/government/publications/protected-species-apply-for-a-mitigation-licence-a05-and-a05a).

They must also:
- register for licence CL23 to move WCC for maintenance (https://www.gov.uk/government/publications/white-clawed-crayfish-licence-to-catch-them-to-carry-out-maintenance) if activity is to be undertaken between 1 July and 30 September
- consult Natural England by email at xxx@xxx.xx (mailto:xxx@xxx.xx) if maintenance is required at other times
A mitigation plan is a condition of holding a WCC licence.

You may also need to add mitigation or compensation strategies as a condition of planning permission. Before you can grant planning permission, you must:
- work with the relevant ecologist to make sure these conditions do not conflict with the requirements of a WCC licence
- be confident that Natural England will grant a wildlife licence – read section 4 of Protected species and development: advice for local planning authorities (https://www.gov.uk/guidance/protected-species-how-to-review-planning-applications)
You do not need to consult Natural England on the wording or discharge (approval) of any conditions you impose on a development proposal. Natural England is unable to provide advice on this.

Natural England will not generally issue a licence until planning conditions relating to protected species have been discharged. This applies to conditions that are intended to be and capable of being discharged before development begins.

Natural England will only confirm if you need a licence when the development proposal is a Nationally Significant Infrastructure Project (NSIP).

Enhance biodiversity

To meet your biodiversity duty (https://www.gov.uk/guidance/biodiversity-duty-public-authority-duty-to-have-regard-to-conserving-biodiversity), you should suggest ways for the developer to:
- create new or enhanced habitats on the development site
- achieve improvements in biodiversity through good design
- follow other relevant plans and strategies for nature
Site management and monitoring

You should consider the need for site monitoring and management. These measures are likely to be needed by protected species licences. A site management and monitoring plan should make sure:
- WCC refuges remain in place
- water quality is good
- water flow is maintained
- populations remain healthy
- water bodies are kept free from non-native species
- there’s no interference to the habitat after development
- numbers of WCC remain stable or increase
This can include carrying out management works to habitats and additional survey work to check that mitigation measures are working as intended, followed by remedial work if needed.