Ecology of the White-clawed crayfish
White-clawed crayfish © C Jackson
The White-clawed crayfish is mainly nocturnal and generally inactive in the winter due to the low water temperature - this can make them difficult to observe in the wild. Like other crayfish species the White-clawed crayfish is an omnivore, feeding on freshwater invertebrates, carrion and aquatic vegetation.
The life cycle of the White-clawed crayfish starts in the autumn (October/November) when water temperatures fall. This drop in temperature stimulates the male crayfish to search for a female with which they can reproduce with. Once a male locates a female he will fertilise the female’s eggs which are attached to the underside of the female’s body. Each female carries between 20 and 150 eggs.
A female will carry the fertilised eggs for nine months until they hatch, she will keep the newly-hatched juvenile crayfish attached to her for a further two weeks. Once released from their mother the juveniles are at great risk from predation from fish, birds and larger aquatic invertebrates - including adult crayfish. Consequently the mortality rate for juveniles is high during the first two months after hatching.
The maximum life expectancy for White-clawed crayfish is 12 years and they reach sexual maturity in their third or fourth year. Crayfish undergo an average of two moults a year over the course of their lifespan. Click for a diagram of the crayfish life cycle. See links below for information about their habitat and other references.