Crayfish Consultants

We are crayfish consultants with experience in surveying all sizes of watercourse for the presence of crayfish. All our staff hold Natural England Crayfish Survey Licences to allow us to carry out crayfish surveys throughout the UK.

We have held Natural England site specific crayfish licences and have carried out exclusion work in cooperation with the Environment Agency.

All our staff have been trained in the handling and identification of white clawed crayfish. Details of any crayfish captured are provided to the Environment Agency where possible.

The information below is some general information on crayfish that will aid you in understanding the species and working out when you may need a crayfish consultant to help you.

General Crayfish Information.

Crayfish are the largest and most mobile freshwater invertebrate. The white-clawed crayfish (Austropotamobius pallipes) is the only native crayfish and this is protected under European and UK legislation.

White clawed crayfish are generally found in areas with relatively hard, mineral rich waters on calcareous and rapidly weathering rocks. They can be found in a wide variety of environments including canals, streams, rivers, lakes, reservoirs and water filled quarries.

White clawed crayfish are typically found in water between 0.75 and 1.25m deep but can occur in very shallow streams with as little as 50mm and in deeper, slow flowing rivers. They are typically found under rocks and submerged logs or among tree roots and in river-banks. White clawed crayfish are omnivorous but primarily carnivorous, eating macro invertebrates and carrion when available. They will also eat worms, insect larvae, snails, small fish, macrophytes, algae and calcified plants.

Crayfish can live for up to ten years and generally reach sexual maturity after three to four years. Breeding takes place between September and November when the water temperature drops consistently to below ten degrees centigrade. Females over winter with a clutch of eggs held beneath their tail. These eggs may number from 20 to 120 and hatch on the female. The juveniles are released from the mother from June in the south to August in the north.

The main threat to the indigenous white-clawed crayfish is the spread of introduced non indigenous species, particularly the larger, faster growing and more aggressive North American signal crayfish (pacifastacus leniusculus). They are also vulnerable to disease, particularly porcelain disease and crayfish plague, the latter is carried by the signal crayfish.

Crayfish are also extremely vulnerable to pollution incidents, particularly those involving biocides, silage and sheep dip.

As a result white-clawed crayfish are endangered across most of their range and have been given protection under both European and UK legislation.

The white-clawed crayfish is listed on Annex V of the Habitats Directive (EEC 1992), which means that Member States should take measures to ensure that the taking of white-clawed crayfish in the wild is compatible with their being maintained at a favourable status.

In 1998, the white-clawed crayfish was added to Schedule 5 of the Wildlife and Countryside Act giving partial protection in relation to Section 9(1) as far as it relates to taking and in respect of Schedule 9(5). It is therefore an offence to intentionally take any white-clawed crayfish from the wild and an offence to sell native crayfish.

Licences are available from Natural England to allow the taking of white-clawed crayfish for certain specified purposes, including scientific or educational purposes and for conservation purposes. A Natural England survey licence is required where any survey is aimed at finding white-clawed crayfish and involves handling them for counting or identification purposes.

A Natural England Crayfish Conservation Licence is required for the purpose of conserving white-clawed crayfish or introducing them to particular areas.

Non indigenous crayfish species are also covered under the Wildlife and Countryside Act 1981. Section 14 makes it an offence for any person to (a) release or allow to escape, any wild animal which is of a kind not ordinarily resident in or a regular visitor to Great Britain in a wild state or; (b) is included in Schedule 9 of the Wildlife and Countryside Act.

Three species of non-indigenous crayfish are listed on Schedule 9. These are the signal crayfish (Pacifastacus leniusculus), the narrow clawed crayfish (Astacus leptodacylus) and the noble crayfish (Astacus astacus). Any of these three species found during a survey cannot be returned to the wild.