Austropotamobius torrentium, also called the stone crayfish, is a Europe

Europe

Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

an species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 of freshwater

Fresh Water

Fresh Water is the debut album by Australian rock and blues singer Alison McCallum, released in 1972. Rare for an Australian artist at the time, it came in a gatefold sleeve...

 crayfish

Crayfish

Crayfish, crawfish, or crawdads – members of the superfamilies Astacoidea and Parastacoidea – are freshwater crustaceans resembling small lobsters, to which they are related...

 in the family Astacidae

Astacidae

The family Astacidae comprises the freshwater crayfish native to Europe and western North America. It is made up of three genera. Pacifastacus is found on the Pacific coast of the United States and British Columbia and includes the signal crayfish and the Shasta crayfish...

. It is mostly found in tributaries of the Danube

Danube

The Danube is a river in the Central Europe and the Europe's second longest river after the Volga. It is classified as an international waterway....

, having originated in the northern part of the Balkan Peninsula.

Description

A. torrentium grows to a length of around 10 centimetres (4 in), and has a smooth brown carapace

Carapace

A carapace is a dorsal section of the exoskeleton or shell in a number of animal groups, including arthropods such as crustaceans and arachnids, as well as vertebrates such as turtles and tortoises. In turtles and tortoises, the underside is called the plastron.-Crustaceans:In crustaceans, the...

, with an untoothed triangular rostrum

Rostrum (anatomy)

The term rostrum is used for a number of unrelated structures in different groups of animals:*In crustaceans, the rostrum is the forward extension of the carapace in front of the eyes....

; the underside is creamy white. Males have larger claw

Claw

A claw is a curved, pointed appendage, found at the end of a toe or finger in most mammals, birds, and some reptiles. However, the word "claw" is also often used in reference to an invertebrate. Somewhat similar fine hooked structures are found in arthropods such as beetles and spiders, at the end...

s than females, but females have a noticeably larger abdomen

Abdomen

In vertebrates such as mammals the abdomen constitutes the part of the body between the thorax and pelvis. The region enclosed by the abdomen is termed the abdominal cavity...

. As in other crayfish, the first two pairs of pleopods are specialised for sperm

Sperm

The term sperm is derived from the Greek word sperma and refers to the male reproductive cells. In the types of sexual reproduction known as anisogamy and oogamy, there is a marked difference in the size of the gametes with the smaller one being termed the "male" or sperm cell...

 transfer in males, while the female's pleopods are uniform, and used for brooding eggs

Egg (biology)

An egg is an organic vessel in which an embryo first begins to develop. In most birds, reptiles, insects, molluscs, fish, and monotremes, an egg is the zygote, resulting from fertilization of the ovum, which is expelled from the body and permitted to develop outside the body until the developing...

.

Distribution

The distribution of A. torrentium is centred on the Danube

Danube

The Danube is a river in the Central Europe and the Europe's second longest river after the Volga. It is classified as an international waterway....

 system, extending from the Olt River

Olt River

The Olt River is a river in Romania. It is the longest river flowing exclusively through Romania. Its source is in the Hăşmaş Mountains of the eastern Carpathian Mountains, near the village Bălan. It flows through the Romanian counties Harghita, Covasna, Braşov, Sibiu, Vâlcea and Olt...

 in Romania

Romania

Romania is a country located at the crossroads of Central and Southeastern Europe, on the Lower Danube, within and outside the Carpathian arch, bordering on the Black Sea...

 upstream to Germany

Germany

Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...

 and Switzerland

Switzerland

Switzerland name of one of the Swiss cantons. ; ; ; or ), in its full name the Swiss Confederation , is a federal republic consisting of 26 cantons, with Bern as the seat of the federal authorities. The country is situated in Western Europe,Or Central Europe depending on the definition....

 and into parts of the Rhine and Elbe

Elbe

The Elbe is one of the major rivers of Central Europe. It rises in the Krkonoše Mountains of the northwestern Czech Republic before traversing much of Bohemia , then Germany and flowing into the North Sea at Cuxhaven, 110 km northwest of Hamburg...

 basins. It is widespread in southern Germany

Southern Germany

The term Southern Germany is used to describe a region in the south of Germany. There is no specific boundary to the region, but it usually includes all of Bavaria and Baden-Württemberg, and the southern part of Hesse...

, Switzerland

Switzerland

Switzerland name of one of the Swiss cantons. ; ; ; or ), in its full name the Swiss Confederation , is a federal republic consisting of 26 cantons, with Bern as the seat of the federal authorities. The country is situated in Western Europe,Or Central Europe depending on the definition....

, Austria

Austria

Austria , officially the Republic of Austria , is a landlocked country of roughly 8.4 million people in Central Europe. It is bordered by the Czech Republic and Germany to the north, Slovakia and Hungary to the east, Slovenia and Italy to the south, and Switzerland and Liechtenstein to the...

, Hungary

Hungary

Hungary , officially the Republic of Hungary , is a landlocked country in Central Europe. It is situated in the Carpathian Basin and is bordered by Slovakia to the north, Ukraine and Romania to the east, Serbia and Croatia to the south, Slovenia to the southwest and Austria to the west. The...

, Slovenia

Slovenia

Slovenia , officially the Republic of Slovenia , is a country in Central and Southeastern Europe touching the Alps and bordering the Mediterranean. Slovenia borders Italy to the west, Croatia to the south and east, Hungary to the northeast, and Austria to the north, and also has a small portion of...

 and Croatia

Croatia

Croatia , officially the Republic of Croatia , is a unitary democratic parliamentary republic in Europe at the crossroads of the Mitteleuropa, the Balkans, and the Mediterranean. Its capital and largest city is Zagreb. The country is divided into 20 counties and the city of Zagreb. Croatia covers ...

. Contrary to some previous records, A. torrentium does not appear to occur in Luxembourg

Luxembourg

Luxembourg , officially the Grand Duchy of Luxembourg , is a landlocked country in western Europe, bordered by Belgium, France, and Germany. It has two principal regions: the Oesling in the North as part of the Ardennes massif, and the Gutland in the south...

, Poland

Poland

Poland , officially the Republic of Poland , is a country in Central Europe bordered by Germany to the west; the Czech Republic and Slovakia to the south; Ukraine, Belarus and Lithuania to the east; and the Baltic Sea and Kaliningrad Oblast, a Russian exclave, to the north...

 or Ukraine

Ukraine

Ukraine is a country in Eastern Europe. It has an area of 603,628 km², making it the second largest contiguous country on the European continent, after Russia...

.

In France

France

The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...

, at the western edge of the species' range, two populations remain, one in Alsace

Alsace

Alsace is the fifth-smallest of the 27 regions of France in land area , and the smallest in metropolitan France. It is also the seventh-most densely populated region in France and third most densely populated region in metropolitan France, with ca. 220 inhabitants per km²...

 and one in Lorraine

Lorraine (région)

Lorraine is one of the 27 régions of France. The administrative region has two cities of equal importance, Metz and Nancy. Metz is considered to be the official capital since that is where the regional parliament is situated...

. The Czech Republic

Czech Republic

The Czech Republic is a landlocked country in Central Europe. The country is bordered by Poland to the northeast, Slovakia to the east, Austria to the south, and Germany to the west and northwest....

 and Slovakia

Slovakia

The Slovak Republic is a landlocked state in Central Europe. It has a population of over five million and an area of about . Slovakia is bordered by the Czech Republic and Austria to the west, Poland to the north, Ukraine to the east and Hungary to the south...

 are at the north-eastern periphery of the natural range of A. torrentium, with only four and six known populations, respectively, all those in Slovakia being in the hills (Lesser Carpathians). The northernmost point inhabited by A. torrentium is near the city of Dresden

Dresden

Dresden is the capital city of the Free State of Saxony in Germany. It is situated in a valley on the River Elbe, near the Czech border. The Dresden conurbation is part of the Saxon Triangle metropolitan area....

 in the German federal state

States of Germany

Germany is made up of sixteen which are partly sovereign constituent states of the Federal Republic of Germany. Land literally translates as "country", and constitutionally speaking, they are constituent countries...

 of Saxony

Saxony

The Free State of Saxony is a landlocked state of Germany, contingent with Brandenburg, Saxony Anhalt, Thuringia, Bavaria, the Czech Republic and Poland. It is the tenth-largest German state in area, with of Germany's sixteen states....

.

Italy

Italy

Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...

 is at the south-western margin of the distribution of A. torrentium, with at least two populations in the drainge (a tributary

Tributary

A tributary or affluent is a stream or river that flows into a main stem river or a lake. A tributary does not flow directly into a sea or ocean...

 of the Danube) near Tarvisio

Tarvisio

Tarvisio is a town in the Province of Udine, in the northeastern part of the autonomous Friuli–Venezia Giulia region in Italy...

. To the south-east, the species has entered the Drin River in Albania

Albania

Albania , officially known as the Republic of Albania , is a country in Southeastern Europe, in the Balkans region. It is bordered by Montenegro to the northwest, Kosovo to the northeast, the Republic of Macedonia to the east and Greece to the south and southeast. It has a coast on the Adriatic Sea...

, and was discovered in 2005 in the European part

East Thrace

East Thrace or Eastern Thrace , also known as Turkish Thrace, is the part of the modern republic of Turkey that is geographically part of Europe, all in the eastern part of the historical region of Thrace; most of Turkey is in Anatolia, also known as Asia Minor. Turkish Thrace is also called...

 of Turkey

Turkey

Turkey , known officially as the Republic of Turkey , is a Eurasian country located in Western Asia and in East Thrace in Southeastern Europe...

. In Romania

Romania

Romania is a country located at the crossroads of Central and Southeastern Europe, on the Lower Danube, within and outside the Carpathian arch, bordering on the Black Sea...

, it is present in the Apuseni Mountains

Apuseni Mountains

The Apuseni Mountains is a mountain range in Transylvania, Romania, which belongs to the Western Carpathians, also called Occidentali in Romanian. Their name translates from Romanian as Mountains "of the sunset" i.e. "western". The highest peak is "Cucurbăta Mare" - 1849 metres, also called Bihor...

 and in the Carpathian

Carpathian Mountains

The Carpathian Mountains or Carpathians are a range of mountains forming an arc roughly long across Central and Eastern Europe, making them the second-longest mountain range in Europe...

 foothills to the southwest, overlapping slightly with the distribution of the noble crayfish Astacus astacus

Astacus astacus

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, Astacus astacus is restricted to fresh water, living only in unpolluted streams, rivers and lakes...

.

The populations in the west of the species' range are genetically depauperate, while populations from the upper Kupa

Kupa River (Croatia)

The Kupa or Kolpa river forms a natural border between north-west Croatia and southeast Slovenia.The Kupa originates in Croatia in the mountainous region of Gorski kotar, northeast of Rijeka, in the area of Risnjak National Park...

 basin are as genetically distinct from the rest of A. torrentium as some species in related genera are from each other, suggesting A. torrentium originated in the Western Balkans.

Ecology

The preferred habitat

Habitat

* Habitat , a place where a species lives and grows*Human habitat, a place where humans live, work or play** Space habitat, a space station intended as a permanent settlement...

 of A. torrentium is cold, fast-flowing streams, although some live in larger rivers and lakes. It digs burrow

Burrow

A burrow is a hole or tunnel dug into the ground by an animal to create a space suitable for habitation, temporary refuge, or as a byproduct of locomotion. Burrows provide a form of shelter against predation and exposure to the elements, so the burrowing way of life is quite popular among the...

s in the banks and hides under submerged root

Root

In vascular plants, the root is the organ of a plant that typically lies below the surface of the soil. This is not always the case, however, since a root can also be aerial or aerating . Furthermore, a stem normally occurring below ground is not exceptional either...

s or rock

Rock (geology)

In geology, rock or stone is a naturally occurring solid aggregate of minerals and/or mineraloids.The Earth's outer solid layer, the lithosphere, is made of rock. In general rocks are of three types, namely, igneous, sedimentary, and metamorphic...

s, emerging at night to feed.

Adult A. torrentium consume a variety of plant materials, including fallen leaves, while the juveniles chiefly feed on aquatic invertebrate

Invertebrate

An invertebrate is an animal without a backbone. The group includes 97% of all animal species – all animals except those in the chordate subphylum Vertebrata .Invertebrates form a paraphyletic group...

s. Natural predators of fully grown A. torrentium include foxes

Red Fox

The red fox is the largest of the true foxes, as well as being the most geographically spread member of the Carnivora, being distributed across the entire northern hemisphere from the Arctic Circle to North Africa, Central America, and the steppes of Asia...

, bears

Eurasian Brown Bear

The Eurasian brown bear is a subspecies of brown bear, found across northern Eurasia. The Eurasian brown bear is also known as the common brown bear, European brown bear and colloquially by many other names....

, wolves

Eurasian Wolf

The Eurasian Wolf , also known as the, European, Common or Forest Wolf is a subspecies of grey wolf which has the largest range among wolf subspecies and is the most common in Europe and Asia, ranging through Mongolia, China, Russia, Scandinavia, Western Europe and the Himalayan Mountains...

 and badgers, while the young animals are targeted by fish

Fish

Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...

. The species is sensitive to low levels of dissolved oxygen

Oxygen saturation

Oxygen saturation or dissolved oxygen is a relative measure of the amount of oxygen that is dissolved or carried in a given medium. It can be measured with a dissolved oxygen probe such as an oxygen sensor or an optode in liquid media, usually water.It has particular significance in medicine and...

, and to chemical pollution

Pollution

Pollution is the introduction of contaminants into a natural environment that causes instability, disorder, harm or discomfort to the ecosystem i.e. physical systems or living organisms. Pollution can take the form of chemical substances or energy, such as noise, heat or light...

.

Beside naturally-occurring threats, A. torrentium has also suffered from the introduction of the crayfish plague

Crayfish plague

Crayfish plague, Aphanomyces astaci, is a water mould that infects crayfish, most notably the European Astacus which dies within a few weeks of being infected...

, Asphanomyces astaci, carried by invasive

Invasive species

"Invasive species", or invasive exotics, is a nomenclature term and categorization phrase used for flora and fauna, and for specific restoration-preservation processes in native habitats, with several definitions....

 crayfish species from North America

North America

North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

, and from the release of detergent

Detergent

A detergent is a surfactant or a mixture of surfactants with "cleaning properties in dilute solutions." In common usage, "detergent" refers to alkylbenzenesulfonates, a family of compounds that are similar to soap but are less affected by hard water...

s into streams while washing laundry

Laundry

Laundry is a noun that refers to the act of washing clothing and linens, the place where that washing is done, and/or that which needs to be, is being, or has been laundered...

.

Life cycle

Mating

Mating

In biology, mating is the pairing of opposite-sex or hermaphroditic organisms for copulation. In social animals, it also includes the raising of their offspring. Copulation is the union of the sex organs of two sexually reproducing animals for insemination and subsequent internal fertilization...

 takes place at the end of October. The female then carries the 40–70 fertilised eggs on her pleopods until the eggs are ready to hatch. Juveniles moult

Ecdysis

Ecdysis is the moulting of the cuticula in many invertebrates. This process of moulting is the defining feature of the clade Ecdysozoa, comprising the arthropods, nematodes, velvet worms, horsehair worms, rotifers, tardigrades and Cephalorhyncha...

 up to 4 or 5 times per year, but as they mature, this slows to once or twice a year, usually in May, June or July. Sexual maturity

Sexual maturity

Sexual maturity is the age or stage when an organism can reproduce. It is sometimes considered synonymous with adulthood, though the two are distinct...

 is reached after 3 to 5 years, by which time the animal has grown to a length of 35–50 mm (1.4–2 ). Adult males can reproduce every year, but females do not reproduce for at least one year after producing eggs.

Conservation status

A. torrentium is one of the most threatened species in Europe: as well as protection under various national laws, it is designated Data Deficient

Data Deficient

Data Deficient is a category applied by the IUCN, other agencies, and individuals to a species when the available information is not sufficient for a proper assessment of conservation status to be made...

 on the IUCN Red List

IUCN Red List

The IUCN Red List of Threatened Species , founded in 1963, is the world's most comprehensive inventory of the global conservation status of biological species. The International Union for Conservation of Nature is the world's main authority on the conservation status of species...

, it is listed in Appendix III of the Bern Convention

Convention on the Conservation of European Wildlife and Natural Habitats

The Bern Convention on the Conservation of European Wildlife and Natural Habitats 1979, also known as the Bern Convention , came into force on June 1, 1982....

, and it is protected under the EU

European Union

The European Union is an economic and political union of 27 independent member states which are located primarily in Europe. The EU traces its origins from the European Coal and Steel Community and the European Economic Community , formed by six countries in 1958...

 Habitats Directive.