The virile crayfish, Orconectes virilis (Hagen, 1870) (Crustacea: Decapoda: Cambaridae), identified in the UK

A population of the virile crayfish, Orconectes virilis (Hagen, 1870), has been recorded within the River Lee system of North London in the United Kingdom. First detected in 2004 and thought to be the spiny-cheek crayfish, Orconectes limosus (Rafinesque, 1817), a recent re-examination of the specimens has confirmed that this is the first recorded breeding population of O. virilis in the United Kingdom. A monitoring programme is being established to assess the rate at which the species colonises the catchment and its ecological impact.