Astacus astacus

Superregnum: Eukaryota
Cladus: Unikonta
Cladus: Opisthokonta
Cladus: Holozoa
Regnum: Animalia
Subregnum: Eumetazoa
Cladus: Bilateria
Cladus: Nephrozoa
Cladus: Protostomia
Cladus: Ecdysozoa
Cladus: Panarthropoda
Phylum: Arthropoda
Cladus: Pancrustacea
Superclassis: Multicrustacea
Classis: Malacostraca
Subclassis: Eumalacostraca
Superordo: Eucarida
Ordo: Decapoda
Subordo: Pleocyemata
Infraordo: Astacidea
Superfamilia: Astacoidea

Familia: Astacidae
Genus: Astacus
Species: Astacus astacus
Name

Astacus astacus Linnaeus, 1758
Synonymy

Astacus fluviatilis Fabricius, 1775
References

Fabricius, J.C. 1775. Systema entomologiae, sistens insectorum classes, ordines, genera, species, adiectis synonymis, locis, descriptionibus, observationibus. Libraria Kortii, Flensburgi et Lipsiae. xvi+ 832 pp. DOI: 10.5962/bhl.title.36510. BHL. Reference page.

Vernacular names
беларуская: Рак шыракапальцы
čeština: Rak říční
English: European crayfish
español: Cangrejo noble
français: Écrevisse à pattes rouges
magyar: Folyami rák
polski: Rak szlachetny
русский: Рак
svenska: Flodkräfta

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 16 cm long, and females up to 12 cm.[3]
Ecology
Noble crayfish can vary greatly in colour.[4]

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.[1] 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.[1]

A. astacus become sexually mature after three to four 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 European mink, eels, perch, pike, Eurasian otters, and muskrats.[3] There is also some risk of predation via cannibalism.[1]

A. astacus is sensitive to dips in oxygen levels in the water it inhabits, which makes it particularly vulnerable to eutrophication. However, they are capable of tolerating lower calcium levels than most other species of crayfish.[1]

A. astacus is regarded as a keystone species in the environments it inhabits. Crayfish are an important part of the freshwater food web as they provide a source of food to many aquatic species and boost primary productivity by foraging on freshwater plants. The loss of crayfish in a freshwater environment is known to cause macrophyte growth, which can be a cause for eutrophication and an overall degradation in water quality.[5]
Consumption

This species was once abundant in Europe, although it was expensive to buy, and is considered to be the finest edible crayfish.[3] It is, however, susceptible to the crayfish plague carried by the invasive North American species signal crayfish (Pacifastacus leniusculus), so is listed as a vulnerable species on the IUCN Red List.[1] Since the introduction of the plague, A. astacus has dropped to about 5% of its preexisting population.[5]
A golden crayfish pictured in the coat of arms of Oulainen

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.[6] The consumption of crayfish is an important part of traditional Nordic culture, including the crayfish party (Swedish: kräftskiva; Finnish: rapujuhlat), a feast to mark the end of summer.[6]

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 (Romanian: rac).
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.[7]
References

L. Edsman; L. Füreder; F. Gherardi & C. Souty-Grosset (2010). "Astacus astacus". The IUCN Red List of Threatened Species. 2010. IUCN: e.T2191A9338388. doi:10.2305/IUCN.UK.2010-3.RLTS.T2191A9338388.en.
Crandall, Keith A; De Grave, Sammy (2017). "An updated classification of the freshwater crayfishes (Decapoda: Astacidea) of the world, with a complete species list". Journal of Crustacean Biology. 37 (5): 615–653. doi:10.1093/jcbiol/rux070.
"Noble crayfish (Astacus astacus)". ARKive. Archived from the original on March 28, 2008. Retrieved May 6, 2007.
Peter Scheffel & Bernd Sceiba. Plants and Animals of Central Europe (Pflanzen und Tiere).
"Value of Biodiversity - Documenting EU examples where biodiversity loss has led to the loss of ecosystem services". ieep.eu. Retrieved 2022-10-14.
"Astacus astacus". Slow Food Foundation. Retrieved December 18, 2019.
J. S. Bond & R. J. Benyon (1995). "The astacin family of metalloendopeptidases". Protein Science. 4 (7): 1247–1261. doi:10.1002/pro.5560040701. PMC 2143163. PMID 7670368.