Signal crayfish

Found throughout England, these 15cm-long beasts are aggressive, breed faster than the native species, and damage banks with their burrowing.

American Signal Crayfish coming out of water onto grass American Signal Crayfish, copyright GBNNS

In high densities, signal crayfish burrow into banks, causing extensive damage, while eating most of the plants and small animals within the watercourse.

Their population has been thriving since they were brought to England as a fashionable seafood. This was unfortunate for our more docile white-clawed crayfish native to Britain.

Our native crayfish have been depleting in numbers over the last 30 years as a result, and are now a protected species.

The American signal also carries a fungal disease called ‘crayfish plague’, which is harmful to our native species, and can be spread by wet footwear and equipment.

Last date edited: 17 November 2020