Astacus Leptodactylus Classification Essay

Declines have been noted in some parts of this species range as a result of competition with the crayfish Orconectes rusticus, and the crayfish plague (Aphanomyces astaci). Declines are most notable in the western part of this species range where it has been introduced.

Austria: There is no information on the status of this species in this country.

Azerbaijan: There is no information on the status of this species in this country.

Belarus: There is no information on the status of this species in this country.

Bosnia and Herzegovina: There is no information on the status of this species in this country.

Bulgaria: This species is widespread and of commercial interest (Zaikov and Hubenova 2007).

Croatia: This species is dense in parts of its range and is expanding its range size (I. Maguire and G. Klobučar pers. comm. 2009).

Georgia: There is no information on the status of this species in this country.

Greece: This species is found in the Evros River (Perdicaris et al. 2007).

Hungary: It is usually present in lowland waters and fish ponds, and is most common in the southern and eastern part of the country (Puky et al. 2005). It has been wiped out from different habitats by several factors e.g. the introduction of the European eel (Anguilla anguilla) to Lake Balaton leading to its extinction in the 1960s there and in the lower stretch of the inflowing River Zala; the spread of Orconectes limosus along the southern part of the Hungarian Danube stretch at the turn of the 1990s and 2000s. However, previously unknown populations are also being described for the first time, as such at a national level its status is indeterminate;  it appears stable in some areas, with declines in others (P. Miklós pers. comm. 2009).

Iran: There are good stocks of this species in this country (Souty-Grosset et al. 2006).

Israel: There is no information on the status of this species in this country.

Kazakhstan: This species is described as abundant in countries such as Kazakhstan (Souty-Grosset et al. 2006).

Moldova: There is no information on the status of this species in this country.

Romania: There have been significant historical declines in the population numbers of this species, however attempts are being made to re-stock it into former parts of its range (M. Miron and L. Miron pers. comm. 2009).

Russia: This species is described as widespread and abundant in countries such as Russia (Souty-Grosset et al. 2006). Pollution has affected crayfish species in Russia (Fedotov, Bykadorova and Kholodkevich 1998) especially in the lower River Don where abundance is reported to have declined 4-17 fold since the 1980s (Souty-Grosset et al. 2006)

Serbia: Spreading in some regions, but declining in others as a result of Orconectes limosus (Holdich et al. 2009).

Slovakia: Though this species is listed as Critically Endangered in Slovakia, the population is thought to be currently stable (P. Manko pers. comm. 2009).

Turkey: There have been fluctuations in the harvest of this species over the years, though is said to have shown an increasing trend since 1995. However, since 2005 there has been a decline in the catch from 2,317 tonnes in 2004, to 809 tonnes in 2005, to 797 tonnes in 2006, and to 750-760 in 2007. The reason for this apparent decline is not clear and there is no indication that it is related to crayfish plague, though over-harvesting is thought to be contributing (Harlioğlu and Harlioğlu 2009).

Turkmenistan: There is no information on the status of this species in this country.

Ukraine: Widespread and abundant (Souty-Grosset et al. 2006).

Astacus leptodactylus, the Danube crayfish,[1]Galician crayfish,[1]Turkish crayfish[2] or narrow-clawed crayfish is a species of crayfish imported and introduced to Central Europe in 19th century from the Caspian Sea region.[2]

Description[edit]

Astacus leptodactylus can grow up to 30 centimetres (12 in) in length from the tip of the rostrum to the end of the telson (tail), but is more commonly found at around 15 cm (6 in) in length. The sides of the thorax are very rough, usually pale yellow to pale green in colour. A. leptodactylus has two pairs of post-orbital ridges, the second of which may have spines. It also has a prominent tubercle (small nodule) on shoulder of the carapace. The claws of Astacus leptodactylus are long and narrow (hence the common name 'narrow-clawed crayfish'). Their upper surface is rough and the underside is the same colour as the body. A tubercle can be found on the fixed side of the claw. A. leptodactylus can be distinguished most easily from the European or broad-fingered crayfish, Astacus astacus, by the relatively thinner "fingers" of the claws.

Ecology[edit]

Astacus leptodactylus is fairly docile, especially the male with large claws, and favours relatively still waters such as lakes and canals. It is listed as a species of Least Concern on the IUCN Red List.[3]

References[edit]

0 comments

Leave a Reply

Your email address will not be published. Required fields are marked *