The European Crayfish (Astacus astacus) is the only native crayfish species in Lithuania and has inhabited our waters since the Ice Age. It is found in clean, cold, and well-oxygenated lakes and rivers, where it hides in burrows, under stones, or among aquatic vegetation.
It is a large crayfish species, growing up to 18 cm in length. Active mainly at night, it feeds invertebrates, plants, and detritus.
Females reach sexual maturity at approximately three years of age, while males mature at around four years. Mating takes place in October and November, when the water temperature falls below 10°C. A female produces up to 400 eggs, which, after fertilization, are attached to the swimmerets beneath her abdomen and carried until June or July of the following year. Their development requires well-oxygenated water, as eggs are highly sensitive to oxygen deficiency and elevated temperatures. After approximately 26 weeks, nearly fully developed, transparent larvae hatch. For some time, they remain attached to the mother’s abdomen and feed on the remains of their yolk sac. About ten days later, after their first molt, the larvae leave the protection of their mother and begin an independent life.
Due to crayfish plague, the spread of invasive species, and habitat loss, populations of the noble crayfish have declined dramatically. As a result, this species is now protected and is listed in both the Lithuanian and international Red Lists of threatened species.
