Guidance

White-clawed crayfish: advice for making planning decisions

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

• From: Natural England
• Published: 14 January 2022
• Last updated: 26 October 2023 — See all updates

Applies to England

This is Natural England’s ‘standing advice’ for white-clawed (or Atlantic stream) crayfish. 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.

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
• Environmental Data Services directory

How white-clawed crayfish are protected

WCC are protected under the Wildlife and Countryside Act 1981. It is an offence to intentionally take them.

WCC are also listed as rare and most threatened species under Section 41 of the Natural Environment and Rural Communities Act (2006). You must have regard for the conservation of Section 41 species as part of your planning decision. Find out more about your biodiversity duty.

The developer must comply with the legal protection of WCC.

You should consider if the developer has taken appropriate measures to avoid, mitigate or compensate (as a last resort) for any negative effects on WCC in their development proposal.

The developer may need a licence for activities that affect WCC.

The developer may need permission from the Environment Agency to trap crayfish as part of their 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 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 are becoming endangered. The distribution of WCC might show the species is lost in an area, but there could be isolated (or refuge) populations still present.

WCC can be found in:

• rivers
• streams
• canals
• quarry pools

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, 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
• advice on the valid age of data

The ecologist should also follow the Biodiversity code of practice for planning and development (BS 42020:2013) available on the British Standards Institute website. These documents may not be accessible to assistive technology.

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 (when water is deep and slow-moving, or in pools that are too deep to search by hand)
• trapping using a baited plastic mesh trap approved by the Environment Agency (when water is too deep or cloudy for manual searches)

Assess the effect of development on white-clawed crayfish

Developers should submit qualitative and quantitative information with their planning application on how their development 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
• loss of habitat
• breaking up habitat by obstructing WCC movement, for example from new culverts
• a reduction in habitat quality
• a reduction in water quality from changes to water flow, increased siltation, decreased oxygenation or pollution incidents

Avoidance, mitigation and compensation measures

To avoid possible effects on WCC, developers could redesign the proposal to:

• avoid carrying out work in or near the waterbody
• alter the timing of works, doing work at the right time of year
• change the methods of working

Where this is not possible, mitigation measures could include:

• reducing disturbance to the river bank
• reducing the amount of sediment released into the water
• reducing the area affected
• doing work in small sections
• reducing water pollution including silt
• adding appropriate vegetation and large woody material
• excluding crayfish from construction areas, but only when the water temperature is 4°C or higher
• 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, but only within the catchment to reduce the chances of spreading disease

For more information on mitigation plans and compensation measures, read the planners guide for protected species and development.

Planning and licence conditions

Developers must not move WCC without a wildlife licence. They must either:

• apply for a WCC mitigation licence for development activities
• register for licence CL23 to move WCC for maintenance between 1 July and 30 September
• consult Natural England by email at [email protected] if maintenance is required at other times

A mitigation plan is a condition of holding a WCC licence.

Before you can grant planning permission, you must:

• make sure any mitigation or compensation conditions you impose are not likely to conflict with the requirements of a wildlife licence
• be confident that Natural England will grant a wildlife licence

You can find more information in the guidance on protected species and development: advice for local planning authorities.

Enhance biodiversity

To meet your biodiversity duty, you should suggest ways for the developer to:

• create new or enhanced habitats on the development site
• achieve a net gain in biodiversity through good design, such as green roofs, street trees or sustainable drainage

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

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.

Published 14 January 2022
Last updated 26 October 2023 + show all updates

1. 26 October 2023

   Page updated because of new requirements for protected species mitigation licences for animals and plants in schedule 5 and schedule 8 of the Wildlife and Countryside Act 1981 (brought in by the Environment Act 2021).

2. 14 January 2022

   First published.