Astacus astacus

Astacus leptodactylus
Conservation status
Vulnerable (IUCN 2.3)[1]
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Subphylum:	Crustacea
Class:	Malacostraca
Order:	Decapoda
Family:	Astacidae
Genus:	Astacus
Species:	A. astacus
Binomial name
Astacus astacus Linnaeus, 1758
Synonyms
Astacus fluviatilis Fabricius, 1775

Astacus astacus, the European crayfish, noble crayfish or broad-fingered crayfish, is the most common species of crayfish in Europe, and a traditional foodstuff. Like other crayfish, the European crayfish 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 parts of the British Isles, Scandinavia, and the western parts of the former Soviet Union. Males may grow up to 16 cm long, and females up to 12 cm.^[2]

Ecology

A. astacus is nocturnal and feeds on worms, aquatic insects, molluscs and plants, spending the day resting in a burrow. They become sexually mature after 3–4 years and a series of moults, and breed in October and November. Fertilised eggs are carried by the female, attached to her pleopods, until the following May, when they hatch and disperse. The main predators of A. astacus, both as juveniles and adults, are mink, eels, perch, pike, otters, and muskrats.^[2]

Consumption

Noble crayfish vary greatly in colour^[3].

Astacus astacus was once abundant in Europe, although it was expensive to buy, and is considered to be the finest edible crayfish ^[2]. It is, however, susceptible to the crayfish plague carried by the invasive American species signal crayfish (Pacifastacus leniusculus), and is therefore listed as "vulnerable" by the IUCN Red List of Threatened Species.^[1]

Documentation of the consumption of A. astacus dates back to the Middle Ages, when it was popular among the Swedish nobility, spreading to all social classes by the 17th and 18th centuries due to its ready availability. The crayfish are collected from the wild in traps, a practice which is being replaced by more intensive aquaculture of the signal crayfish in man-made ponds.^[4] The consumption of crayfish is an important part of traditional Scandinavian culture, including the kräftskiva, a feast to mark the end of summer.^[4]

Astacin

Astacins are a family of digestive enzymes, discovered in the 1990s, which were first isolated from Astacus astacus. More than 20 enzymes of this group have since been discovered in animals from Hydra to humans.^[5]

References