''Astacus astacus'', the European crayfish, noble crayfish, or broad-fingered crayfish, is the most common
species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...
of
crayfish
Crayfish are freshwater crustaceans belonging to the clade Astacidea, which also contains lobsters. In some locations, they are also known as crawfish, craydids, crawdaddies, crawdads, freshwater lobsters, mountain lobsters, rock lobsters, mu ...
in
Europe
Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...
, and a
traditional food source. Like other true crayfish, ''A. astacus'' is restricted to
fresh water
Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. Although the term specifically excludes seawater and brackish water, it does include ...
, living only in
unpolluted streams, rivers, and lakes. It is found from
France
France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of Overseas France, overseas regions and territories in the Americas and the Atlantic Ocean, Atlantic, Pacific Ocean, Pac ...
throughout
Central Europe
Central Europe is an area of Europe between Western Europe and Eastern Europe, based on a common historical, social and cultural identity. The Thirty Years' War (1618–1648) between Catholicism and Protestantism significantly shaped the area' ...
, to the
Balkan Peninsula
The Balkans ( ), also known as the Balkan Peninsula, is a geographical area in southeastern Europe with various geographical and historical definitions. The region takes its name from the Balkan Mountains that stretch throughout the who ...
, and north as far as
Scandinavia
Scandinavia; Sámi languages: /. ( ) is a subregion#Europe, subregion in Northern Europe, with strong historical, cultural, and linguistic ties between its constituent peoples. In English usage, ''Scandinavia'' most commonly refers to Denmark, ...
and
Finland
Finland ( fi, Suomi ; sv, Finland ), officially the Republic of Finland (; ), is a Nordic country in Northern Europe. It shares land borders with Sweden to the northwest, Norway to the north, and Russia to the east, with the Gulf of B ...
, and Eastern Europe. Males may grow up to 16 cm long, and females up to 12 cm.
Ecology
![Potamobius astacus](https://upload.wikimedia.org/wikipedia/commons/d/da/Potamobius_astacus.jpg)
European crayfish feed on
worm
Worms are many different distantly related bilateral animals that typically have a long cylindrical tube-like body, no limbs, and no eyes (though not always).
Worms vary in size from microscopic to over in length for marine polychaete wor ...
s,
aquatic insects,
mollusc
Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is esti ...
s, and plants.
They are
nocturnal
Nocturnality is an animal behavior characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnal meaning the opposite.
Nocturnal creatures generally have highly developed sens ...
, spending the day resting in a
burrow
An Eastern chipmunk at the entrance of its burrow
A burrow is a hole or tunnel excavated into the ground by an animal to construct a space suitable for habitation or temporary refuge, or as a byproduct of locomotion. Burrows provide a form of sh ...
. 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.
''A. astacus'' become
sexually mature after three to four years and a series of
moults, and breed in October and November.
Fertilised
Fertilisation or fertilization (see spelling differences), also known as generative fertilisation, syngamy and impregnation, is the fusion of gametes to give rise to a new individual organism or offspring and initiate its development. Proce ...
eggs are carried by the female, attached to her
pleopod
The decapod ( crustaceans such as a crab, lobster, shrimp or prawn) is made up of 20 body segments grouped into two main body parts: the cephalothorax and the pleon (abdomen). Each segment may possess one pair of appendages, although in various ...
s, until the following May, when they hatch and disperse.
The main
predator
Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill th ...
s of ''A. astacus'', both as juveniles and adults, are
European mink,
eel
Eels are ray-finned fish belonging to the order Anguilliformes (), which consists of eight suborders, 19 families, 111 genera, and about 800 species. Eels undergo considerable development from the early larval stage to the eventual adult stage ...
s,
perch
Perch is a common name for fish of the genus ''Perca'', freshwater gamefish belonging to the family Percidae. The perch, of which three species occur in different geographical areas, lend their name to a large order of vertebrates: the Percif ...
,
pike
Pike, Pikes or The Pike may refer to:
Fish
* Blue pike or blue walleye, an extinct color morph of the yellow walleye ''Sander vitreus''
* Ctenoluciidae, the "pike characins", some species of which are commonly known as pikes
* ''Esox'', genus of ...
,
Eurasian otters, and
muskrat
The muskrat (''Ondatra zibethicus'') is a medium-sized semiaquatic rodent native to North America and an introduced species in parts of Europe, Asia, and South America. The muskrat is found in wetlands over a wide range of climates and habitat ...
s.
There is also some risk of predation via cannibalism.
''A. astacus'' is sensitive to dips in oxygen levels in the water it inhabits, which makes it particularly vulnerable to
eutrophication
Eutrophication is the process by which an entire body of water, or parts of it, becomes progressively enriched with minerals and nutrients, particularly nitrogen and phosphorus. It has also been defined as "nutrient-induced increase in phytopla ...
. However, they are capable of tolerating lower calcium levels than most other species of crayfish.
''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.
Consumption
This species was once abundant in Europe, although it was expensive to buy, and is considered to be the finest edible crayfish.
It is, however, susceptible to the
crayfish plague
Crayfish plague (''Aphanomyces astaci'') is a water mold that infects crayfish, most notably the European ''Astacus'' which dies within a few weeks of being infected. When experimentally tested, species from Australia, New Guinea and Japan were a ...
carried by the invasive North American species
signal crayfish
The signal crayfish (''Pacifastacus leniusculus'') is a North American species of crayfish. It was introduced to Europe in the 1960s to supplement the North European ''Astacus astacus'' fisheries, which were being damaged by crayfish plague, but ...
(''Pacifastacus leniusculus''), so is listed as a
vulnerable species
A vulnerable species is a species which has been Conservation status, categorized by the International Union for Conservation of Nature as being threatened species, threatened with extinction unless the circumstances that are threatened species, ...
on the
IUCN Red List
The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is the world's most comprehensive inventory of the global conservation status of biol ...
.
Since the introduction of the plague, ''A. astacus'' has dropped to about 5% of its preexisting population.
![Oulainen](https://upload.wikimedia.org/wikipedia/commons/0/05/Oulainen.vaakuna.svg)
Documentation of the consumption of ''A. astacus'' dates back to the
Middle Ages
In the history of Europe, the Middle Ages or medieval period lasted approximately from the late 5th to the late 15th centuries, similar to the post-classical period of global history. It began with the fall of the Western Roman Empire a ...
, when it was popular among the
Swedish nobility, spreading to all
social class
A social class is a grouping of people into a set of Dominance hierarchy, hierarchical social categories, the most common being the Upper class, upper, Middle class, middle and Working class, lower classes. Membership in a social class can for ...
es 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
Aquaculture (less commonly spelled aquiculture), also known as aquafarming, is the controlled cultivation ("farming") of aquatic organisms such as fish, crustaceans, mollusks, algae and other organisms of value such as aquatic plants (e.g. lot ...
of the signal crayfish in man-made ponds.
The consumption of crayfish is an important part of traditional Nordic culture, including the
crayfish party ( sv, kräftskiva; fi, rapujuhlat), a feast to mark the end of summer.
Hundreds of smaller or larger lakes were once found in the northern
Moldavia
Moldavia ( ro, Moldova, or , literally "The Country of Moldavia"; in Romanian Cyrillic: or ; chu, Землѧ Молдавскаѧ; el, Ἡγεμονία τῆς Μολδαβίας) is a historical region and former principality in Centr ...
, used for growing ''A. astacus'' meant for consumption during the extended fasting periods of the
Orthodox Christian
Orthodoxy (from Greek: ) is adherence to correct or accepted creeds, especially in religion.
Orthodoxy within Christianity refers to acceptance of the doctrines defined by various creeds and ecumenical councils in Antiquity, but different Churche ...
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'' ( ro, rac).
Astacin
Astacin
Astacins are a family of multidomain metalloendopeptidases which are either secreted or membrane-anchored. These metallopeptidases belong to the MEROPS peptidase family M12, subfamily M12A (astacin family, clan MA(M)). The protein fold of the pep ...
s 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
Hydra generally refers to:
* Lernaean Hydra, a many-headed serpent in Greek mythology
* ''Hydra'' (genus), a genus of simple freshwater animals belonging to the phylum Cnidaria
Hydra or The Hydra may also refer to:
Astronomy
* Hydra (constel ...
'' to
human
Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, culture, ...
s.
References
{{Taxonbar, from=Q210959
Astacidae
Freshwater crustaceans of Europe
Commercial crustaceans
Edible crustaceans
Crustaceans described in 1758
Taxa named by Carl Linnaeus