To ask the Secretary of State for Environment, Food and Rural Affairs which rivers in the South West and southern areas host populations of (a) predominantly native and (b) predominantly American crayfish; and which rivers host significant populations of both species. (210702)

Populations of native crayfish can be found in river catchments such as the Alien, Culm, Great Stour and Thames, although the situation is continually changing. Across the region American signal crayfish are abundant in river catchments such as the Somerset Tone, Hampshire Avon, Windrush and Eden.

Many native crayfish catchments also contain signal crayfish, for example the Bristol Avon, but the two species rarely co-exist for long. American signal crayfish are now more widely distributed across South West and Southern rivers compared with native species.