https://canalrivertrust.org.uk/things-to-do/canal-and-river-wildlife/canal-and-river-invasive-species/signal-crayfish
American Signal Crayfish | Invasive Species | Canal & River Trust
Found throughout England, these 15cm-long beasts from North America are bigger, more aggressive, breed faster and eat more than our native species.
american signal crayfishinvasive speciescanal rivertrust