Some observations on surveying Native and Signal Crayfish

Our native Crayfish Austropotamobius pallipes is a priority species under the UK Biodiversity Action Plan. It has suffered a significant decline in recent decades, caused principally by a plague carried by the introduced American Signal Crayfish Pacifastacus leniusculus. This article describes the methodology and procedures adopted, including the mistakes and pitfalls, during a survey of crayfish on a small