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Invasive American Crayfish Disrupt UK's Native Waterways
9 Oct
Summary
- Volunteers discover large American signal crayfish in River Beal
- Invasive species outcompetes and spreads disease to native white-clawed crayfish
- Causes extensive damage to waterway banks and habitats
On October 10, 2025, volunteers in the UK discovered the presence of the invasive American signal crayfish while cleaning up the River Beal. The "big" creature caused excitement among the kids helping out, as this non-native species was brought from the United States in the 1960s for restaurant delicacies but eventually escaped its farm confines and migrated across England's waterways.
Since the escape, the American signal crayfish has not been a happy family reunion with its British cousin, the native white-clawed crayfish. The white-clawed crayfish is the UK's only native species, but it has been endangered, losing over half its population since the 1970s. The larger size, aggression, and behavior patterns of the American counterpart have accelerated the decline of the native crayfish.
The invasive species' omnivore diet, which feeds on its English cousin's young, algae, fish, and aquatic plants, is affecting the local food chain. Additionally, the American crayfish carries and spreads the crayfish plague, a fungal disease that is deadly to the native white-clawed crayfish. The invader is also causing massive physical destruction of native habitats, burrowing deep into waterway banks and leaving canals vulnerable to collapse.
