The White-clawed Crayfish may grow to 12 centimetres (5 inches) long, although sizes below 10 centimetres are more common. The White-clawed Crayfish typically lives in rivers and streams about 1 metre deep, where it hides among rocks, submerged logs and lakes, emerging to forage for food.
The population of White-clawed Crayfish is rapidly declining and once found across most of England and Wales in Great Britain, it is now more or less restricted to central and northern England and eastern Wales.
The White-clawed Crayfish is the only species of crayfish found in Ireland, occurring over limestone areas inhabiting rivers, streams, canals and lakes.
White-clawed Crayfish are absent from the more acidic waters of the west. They occur in streams with a moderate flow alongside other freshwater invertebrates such as caddis fly, mayfly and mollusc species.
Trout and 3 Spined Stickleback also occur in the same habitat. Tree roots, rocks in the banks provide shelter. Juvenile White-clawed Crayfish species shelter in vegetation such as watercress and grass mats growing out of the bank.
