Virile crayfish (Orconectes virilis
Virile crayfish have been recorded in some lengths of river in the London area, these are the only known populations in the UK. They are not a European species and originate from the USA and Canada. Virile crayfish are likely to be carriers of crayfish plague and can increase in numbers quickly. Their burrowing activity causes damage to river banks.
Virile crayfish (Orconectes virilis) © D.M. Holdich
FACTFILE: The Virile crayfish has a body length less than 10cm and it is smooth, chestnut or chocolate in colour with a bowl-shaped or wine glass-shaped light brown pattern. Their claws are the same colour as the body on the upper surface and dirty-white on the underside; they have prominent yellow warty spots on them. They can easily be confused with spiny-cheek crayfish and other species, especially when young.
Virile and Signal crayfish © Adam Ellis