UK Wildlife

Invasive Signal Crayfish and Native Species Welfare

Signal crayfish introduced from North America have devastated native white-clawed crayfish populations through disease and competition, exemplifying invasive species welfare and conservation impacts.

Key Facts

Signal crayfish was introduced for aquaculture in 1970s and escaped widely into UK waterways
Carries crayfish plague disease to which native species have no immunity
Burrows into river banks causing erosion and habitat damage
White-clawed crayfish has declined by around 95% with many local extinctions
Control through trapping is used but cannot eradicate established populations

Welfare Considerations

Signal crayfish impacts illustrate the welfare and conservation consequences of introductions without adequate biosecurity planning. Control through trapping causes suffering to individual signal crayfish while protecting the native species. Never transfer signal crayfish between water bodies.

What You Can Do

Never move signal crayfish between water bodies - this is illegal and harmful
Support wildlife trust ark site programmes for white-clawed crayfish conservation
Report any apparent crayfish plague die-offs to the Environment Agency