Astacus astacus, the European crayfish, noble crayfish, or broad-fingered crayfish, is the most common species of crayfish in Europe, and a traditional food source. Like other true crayfish, A. astacus is restricted to fresh water, living only in unpolluted streams, rivers, and lakes. It is found from France throughout Central Europe, to the Balkan Peninsula, and north as far as Scandinavia and Finland, and Eastern Europe. Males may grow up to long, and females up to .
Ecology
thumb|left|Noble crayfish can vary greatly in colour.
European crayfish feed on worms, aquatic insects, molluscs, and plants.
They are nocturnal, spending the day resting in a burrow. They prefer habitats with high levels of shelter availability. The waters they are found in tend to be soft-bottomed with some sand, and they do not tend to be found in muddy water.
Consumption
This species was once abundant in Europe, although it was expensive to buy, and is considered to be the finest edible crayfish.
Hundreds of smaller or larger lakes were once found in the northern Moldavia, used for growing A. astacus meant for consumption during the extended fasting periods of the Orthodox Christian calendar. The area of the former Dorohoi County was one such area, and this legacy was visible in the county's historical coat of arms, featuring an A. astacus ().
Astacin
Astacins are a family of digestive enzymes, discovered in the 1990s, which were first isolated from A. astacus. More than 20 enzymes of this group have since been discovered in animals from Hydra to humans.