Crayfish of Romania

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Austropotamobius torrentium (Schrank 1803)
stone crayfish Steinkrebs écrevisse des torreents racul-de-ponoare

General description. Distribution

identification guide

Crayfish that rarely measures over 10 cm long. The crust is smooth and the colour of the dorsal part varies from dark brown to light orange or even white, depending on several factors (factors like the last moulting, the age or the habitat). The ventral part is lighter in colour almost white cream coloured on the abdominal part and the lower part of the legs, more intense on the ventral part of the claws. The rostrum has the shape of an isosceles triangle, smooth and having thin margins. The apex is short compared to that of the noble crayfish. It has only one post - orbital ridge without any thorns. The cervical section is smooth. The claws are quite strong, almost like those of the noble crayfish but having shorter fingers. The propodit has a median cavity that has on both sides tubercles and the dactilopodit has a single tubercle in the proximal third.

Aboriginal, it lives in Central and South Europe, its genetic center being in the South of the Balcanic peninsula. The north limit of its habitat is Germany and Czech Republic, the west limit is Luxemburg and the East of France, at East in Romania and Bulgaria and in South Greece and even Turkey (Souty-Grosset et al. 2006). Its distribution in Romania is in mountains and the South West sub mountain area to the Olt Valley as well as the Apuseni mountains. Its distribution overlaps a little the distribution of the noble crayfish (Astacus astacus) - for details visit the Distribution page.

Sexual dimorphism

The males have often longer and stronger claws than the females and the abdomen is visibly larger at the females. In order to precisely distinguish the males from the females, especially when we are talking about young crayfish/juveniles, one may verify the sternal disk and the pleopodes to be sure. Male crayfish have the first two pairs of pleopodes strong and oriented towards the back (for the transfer of the spermatophores) while the female has all the pleopodes equal. The shape of the first two males pleopodes also constitute an important criteria to distinguish it from similar species, so that the first pleopod (Pl. I) has the distal lobe almost 1/2 of the total length while the second pleopod (Pl. II) has the exopodit no longer that 2/3 from the endopodit length, the distal lobe of the endopodite being almost 1/2 of its length.

Habitat and Ecology

Its favorite habitat is the cold and fast running waters (springs, brooks) but it can also be found in rivers or even lakes in the mountain area. Unlike its common name it is not a species that lives in the underground waters but it can arrive here once with high food. Usually it prefers galleries that it digs in the ground banks but it lives very often hidden under submerse roots, stones or rocks. It is more active during the night eating almost everything, that’s why it represents a truly sanitary of the waters. The juveniles eat mostly animal food like aquatic macroinvertebrates while the adults eat vegetal food or even foliated leaves that fall into water. It is sensitive to low concentration of oxygen and chemical pollution. In villages where traditional washing is practiced in the trough for washing, the population number of crayfish can suffer massive loss due to the use of detergents. The torrents regularization or the antropisation of the sub mountain regions represent a real problem for this species. The natural enemies are the fox, the wolf, the bear and the badger - for the adults, the fishes being a real threat for the juveniles. The increase in number of the North American species that are introduced in Europe represents a real threat, Pacifastacus leniusculus being capable to kill an entire population in 4 or 5 years. The parasitical diseases of viral nature, bacterial or the fungus represent very often a major problem for this species. The oomycet introduced once with the North-American species Aphanomyces astaci represents a major cause of its elimination because of the non aboriginal species. The aboriginal species do not have antibodies for this one. Ectoparasitism, without producing any damage, is frequently found at the branhiobdelides.

Life cycle

This crayfish mate during autumn, at the end of October, before the water is freezing. During this period white spermatophores can be observed on the sternal disk of the female. The laying contains a number of 40 to 70 eggs and it is carried by the female between the the pleopodes until the juveniles become independent. For a good embryonic development the water shouldn't be colder than 5°C. The success rate has large limits, from 10 to 70% from the total lay. The moulting is more frequent at young ages (up to 4 or 5 moulting per year) while at the adults the moult happens once or twice a year, usually between Mai and July. The next couple of days after this period of losing its skin are very critical for the crayfish because it loses the protection of the crust and can be easily attacked by fishes or even by other crayfish that have stronger crust. After this period the lost or hurt appendix can regenerate but usually a broken claw grows up smaller. The sexual maturity happens in 3 or 5 years at a dimension of 35 and 50 mm. The males can fecundate each year while the females remain sexual inactive one or more years after one laying.

Selective bibliography

1. Băcescu, M.C. (1967): Fauna Republicii Socialiste România - Crustacea, Decapoda. Editura Academiei Republicii Socialiste România, Bucureşti, 4
2. Ingle, R. (1997): Crayfishes, lobsters and crabs of Europe - an illustrated guide to common and traded species. Chapman & Hall
3. Souty-Grosset, C., Holdich, D. M., Noël, P. Y., Reynolds, J. D., Haffner, P. (Eds). (2006): Atlas of Crayfish in Europe. Muséum national d’Histoire naturelle, Paris (Patrimoines naturels, 64)

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Austropotamobius torrentium (Schrank 1803)		stone crayfish Steinkrebs écrevisse des torreents racul-de-ponoare

General description. Distribution	identification guide
	Crayfish that rarely measures over 10 cm long. The crust is smooth and the colour of the dorsal part varies from dark brown to light orange or even white, depending on several factors (factors like the last moulting, the age or the habitat). The ventral part is lighter in colour almost white cream coloured on the abdominal part and the lower part of the legs, more intense on the ventral part of the claws. The rostrum has the shape of an isosceles triangle, smooth and having thin margins. The apex is short compared to that of the noble crayfish. It has only one post - orbital ridge without any thorns. The cervical section is smooth. The claws are quite strong, almost like those of the noble crayfish but having shorter fingers. The propodit has a median cavity that has on both sides tubercles and the dactilopodit has a single tubercle in the proximal third. Aboriginal, it lives in Central and South Europe, its genetic center being in the South of the Balcanic peninsula. The north limit of its habitat is Germany and Czech Republic, the west limit is Luxemburg and the East of France, at East in Romania and Bulgaria and in South Greece and even Turkey (Souty-Grosset et al. 2006). Its distribution in Romania is in mountains and the South West sub mountain area to the Olt Valley as well as the Apuseni mountains. Its distribution overlaps a little the distribution of the noble crayfish (Astacus astacus) - for details visit the Distribution page.


Sexual dimorphism
	The males have often longer and stronger claws than the females and the abdomen is visibly larger at the females. In order to precisely distinguish the males from the females, especially when we are talking about young crayfish/juveniles, one may verify the sternal disk and the pleopodes to be sure. Male crayfish have the first two pairs of pleopodes strong and oriented towards the back (for the transfer of the spermatophores) while the female has all the pleopodes equal. The shape of the first two males pleopodes also constitute an important criteria to distinguish it from similar species, so that the first pleopod (Pl. I) has the distal lobe almost 1/2 of the total length while the second pleopod (Pl. II) has the exopodit no longer that 2/3 from the endopodit length, the distal lobe of the endopodite being almost 1/2 of its length.


Habitat and Ecology
Its favorite habitat is the cold and fast running waters (springs, brooks) but it can also be found in rivers or even lakes in the mountain area. Unlike its common name it is not a species that lives in the underground waters but it can arrive here once with high food. Usually it prefers galleries that it digs in the ground banks but it lives very often hidden under submerse roots, stones or rocks. It is more active during the night eating almost everything, that’s why it represents a truly sanitary of the waters. The juveniles eat mostly animal food like aquatic macroinvertebrates while the adults eat vegetal food or even foliated leaves that fall into water. It is sensitive to low concentration of oxygen and chemical pollution. In villages where traditional washing is practiced in the trough for washing, the population number of crayfish can suffer massive loss due to the use of detergents. The torrents regularization or the antropisation of the sub mountain regions represent a real problem for this species. The natural enemies are the fox, the wolf, the bear and the badger - for the adults, the fishes being a real threat for the juveniles. The increase in number of the North American species that are introduced in Europe represents a real threat, Pacifastacus leniusculus being capable to kill an entire population in 4 or 5 years. The parasitical diseases of viral nature, bacterial or the fungus represent very often a major problem for this species. The oomycet introduced once with the North-American species Aphanomyces astaci represents a major cause of its elimination because of the non aboriginal species. The aboriginal species do not have antibodies for this one. Ectoparasitism, without producing any damage, is frequently found at the branhiobdelides.

Life cycle
This crayfish mate during autumn, at the end of October, before the water is freezing. During this period white spermatophores can be observed on the sternal disk of the female. The laying contains a number of 40 to 70 eggs and it is carried by the female between the the pleopodes until the juveniles become independent. For a good embryonic development the water shouldn't be colder than 5°C. The success rate has large limits, from 10 to 70% from the total lay. The moulting is more frequent at young ages (up to 4 or 5 moulting per year) while at the adults the moult happens once or twice a year, usually between Mai and July. The next couple of days after this period of losing its skin are very critical for the crayfish because it loses the protection of the crust and can be easily attacked by fishes or even by other crayfish that have stronger crust. After this period the lost or hurt appendix can regenerate but usually a broken claw grows up smaller. The sexual maturity happens in 3 or 5 years at a dimension of 35 and 50 mm. The males can fecundate each year while the females remain sexual inactive one or more years after one laying.

Selective bibliography
1. Băcescu, M.C. (1967): Fauna Republicii Socialiste România - Crustacea, Decapoda. Editura Academiei Republicii Socialiste România, Bucureşti, 4 2. Ingle, R. (1997): Crayfishes, lobsters and crabs of Europe - an illustrated guide to common and traded species. Chapman & Hall 3. Souty-Grosset, C., Holdich, D. M., Noël, P. Y., Reynolds, J. D., Haffner, P. (Eds). (2006): Atlas of Crayfish in Europe. Muséum national d’Histoire naturelle, Paris (Patrimoines naturels, 64)

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