- Pontastacus leptodactylus (Eschscholtz, 1823)
- Astacus angulosus Rathke, 1837
- Astacus leptodactylus kessleri Karaman, 1963
- Astacus leptodactylus eichwaldi Karaman, 1963
Danube Crayfish, Galican Crayfish, Long-clawed Crayfish, Narrow-clawed Crayfish, Pond Crayfish, Slender-clawed Crayfish
Value of species
Astacus leptodactylus is referred to as a species complex. In the 1950s this species was believed to belong to the subgenus Astacus (Potastacus) along with A. (P.) pachypus, A. (P.) pylzowi and A. (P.) kessleri.The following four subspecies were attributed to A. (P.) leptodactylus: eichwaldi, cubanicus, salinus, and leptodactylus. Karaman (1962, 1963) however does not acknowledge A. (P.) cubanicus as a subspecies. In the 1970s, Pontastacus was raised to generic level. In the 1980s, Brodskij made a number of revisions within Pontastacus but the number of taxa varied within papers. In the mid 1990s Starobogatov (1995) split Pontastacus into two genera: Pontastacus - P. angulosus (Rathke, 1837); P. cubanicus (Birstein & Winogradow, 1934); P. danubialis (Brodskij, 1967); P. eichwaldi (Bott, 1950); P. intermedius (Bott, 1950); P. kessleri (Schimkewitsch, 1886); P. pyzlowi (Skorikov, 1911); P. salinus (Nordmann, 1942), and Caspiastacus with two species. However, there is great deal of criticism over the recent revision in taxonomy made by Ukranian and Russian taxonomists as it appears to be based on little evidence.
This is a widespread species and can be found throughout Europe, eastern Russia, and the middle east. However it is absent from some of the northern European countries such as Norway and Sweden, and the southern European countries Spain and Portugal (Souty-Grosset et al. 2006). It is considered indigenous in the eastern part of its range, but has been introduced into many of the western European countries (Machino and Holdich 2006, Souty-Grosset et al. 2006).
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.
This species is found in both fresh and brackish waters, e.g. lagoons, estuaries, as well as running freshwater rivers in the Ponto-Caspian Basin. Across Europe it is found in lakes, canals and rivers. It is tolerant to changes in temperature, low oxygen content, and low water transparency, and is known to occur in saline conditions such as estuaries. Tolerance experiments indicated that O+ juveniles and adults are well adapted for surviving salinities of at least 21ppt in the long term, and will tolerate being transferred directly back into freshwater. However, their ability to colonize the estuarine environment may be restricted to areas of low salinity (i.e. 7ppt) due to the adverse effects of seawater on egg development and hatching (Holdich, Harlioğlu and Firkins 1997).
In addition, this species is active during the day and during winter. These features and the high fecundity and fast growth suggest that it can outcompete Astacus astacus. Furthermore, it is an omnivorous species, but demonstrates a preference for zoobenthos, which makes up to 97.2% of the weight of its food in the first year of life in the Caspian Sea.