Astacidae

Astacidae is a family of freshwater crayfish found in the Northern Hemisphere. These crustaceans are characterized by their ten legs, with the first pair being large pincers or chelipeds. They inhabit a variety of freshwater environments, including rivers, lakes, and streams, often preferring areas with rocky or sandy substrates where they can find shelter. Astacidae members are omnivores, feeding on a diet of plants, insects, snails, and dead animals.

The family Astacidae is divided into several genera, including Astacus, Pacifastacus, and Cambarus. Species within this family exhibit a range of sizes and appearances. For instance, the European crayfish, Astacus astacus, is a well-known species native to Europe. The Signal crayfish, Pacifastacus leniusculus, originally from western North America, has been introduced to many parts of the world and is considered an invasive species in some regions due to its ability to outcompete native crayfish.

Reproduction in Astacidae typically involves the female carrying fertilized eggs attached to her pleopods until they hatch. The young crayfish, called fry, remain with the mother for a period before becoming independent. Astacidae play an important role in their ecosystems as both predators and prey. They are also of commercial and recreational importance, with many species being harvested for food. However, populations of some astacid species have declined due to habitat loss, pollution, and the spread of crayfish plague, a fungal disease caused by Aphanomyces astaci, which has significantly impacted European astacid populations. Conservation efforts are underway for several endangered astacid species.