Signal Crayfish - Pacifastacus leniusculus

Alt Name
American Signal Crayfish
Description

Introduced from the USA, these crayfish are up to 15 cm, encased in a tough shell and armed with two large smooth claws. They are bluish-brown to reddish-brown in colour. They have a white to pale blue-green patch near the claw hinge. The claws are orange/red on the underside.

Similar Species

For a comparison of Crayfish species follow this link: http://www.boxvalley.co.uk/nature/fiss/General/crayfish.asp

Photo ID?
Habitat

Rivers, lakes and ponds.

When to see it

All year round.

Life History

A voracious predator it will eat almost anything it finds including plants, invertebrates, snails, small fish and fish eggs. It is also a cannibal that makes a meal of its own young. The Signal Crayfish digs burrows up to three feet long in river banks where each year it lays more than 250 eggs at a time. The spread of this species is threatening the future of our native White-clawed Crayfish.

UK Status

This invasive crayfish has now reached plague proportions in many parts of Britain and marine biologists have been desperately seeking a way of halting its relentless spread. It is also well established in Leicestershire and Rutland.

VC55 Status

Common in Leicestershire and Rutland.

Leicestershire & Rutland Map

UK Map