The spiny-cheek crayfish (Orconectes limosus)

The spiny-cheek crayfish has been introduced from Pennsylvania (USA) into the Oder river system at the end of 19th century and has become widespread in many areas (Germany, Northern France, Pannonian lowland).

Few thousands of specimens of O. limosus were imported in 1970 into Austria and stocked in a number of lakes and gravel pits. There were eleven localities out of 1,172 inhabited by the spiny-cheek crayfish recorded by Pöckl (1999). Living stocks were introduced also to ponds near Budapest, Hungary in 50-thies of last century, where later entered to the the Danube river system. Thuránszky & Forró (1987) reported the spiny-cheek crayfish for first time in a back-water of the Hungarian section of the Danube river at rkm 1,654 and in the Bavarian Danube near Ingolstadt (Nesemann 1987). Two disjunct populations of O. limosus in the Danube river existed above and below the Slovak section of the river, but the species in known by its fast migration (reaching up to 5 km er year according to Mann 1985). In Austria, the isolated population of O. limosus was discovered in the Olhafen in the eastern part of Vienna (rkm 1,918) in 1991 (Pöckl 1999). The map of the O. limosus distribution in Austria published by Pöckl (1999) shows an occurrence spot on the estuary of the Morava river into Danube (area approximate between Hainburg and village of Markthof), but there is no mention in the text of the article on this occurrence. If this record is reliable, it could be considered as a first reported occurence of the spiny-cheek crayfish in water bodies adjacent to Slovakia.

In the Czech republic, the occurrence of O. limosus is known from 60-ties of last century, but first published record appeared in 1988. All known sites are situated in the catchment of the Labe river (including its largest tributaries), but no occurrence is known from Moravia till now.

The Hungarian population of O. limosus was continually spreading along the Danube river in both directions and infested rivers of Serbia downstream. Upstream, O. limosus was reported in Slovakia for the first time by Janský & Kautman (2007) in estuaries of rivers Ipeľ and Váh to the Danube river. The population in the Ipeľ river is stable as it was confirmed by our recent research during last years. Further colonization of all rivers in the area (Ipeľ, Hron, Váh, Nitra, Malý Dunaj etc) as well as continual spreading of O. limosus upstream the Danube river can be expected during next years.

Records and distribution of O. limosus in Slovakia.

Fig 1. Distribution of Orconectes limosus in Slovakia and adjacent areas.

 

The signal crayfish (Pacifastacus leniusculus)

Some 2,000 specimens of P. leniusculus were imported directly from California into Austria during summer 1970 (Pöckl 1999) and released into water bodies in Salzburg, Styria, Upper Austria and Lower Austria (Spitzy 1971, 1973). More than 120 localities are known inhabited by the signal crayfish in Austria recently. There are several sites adjacent to Slovakia shown in the distribution maps by Pöckl (1999), situated above the Slovak section of Morava river (on the Dyje river) as well as below Vienna in Danube river.

In Czech republic, P. limosus is widely distributed in Moravia.

The Morava river is the only river inhabited by P. leniusculus. P. leniusculus in Slovakia was reported for the first time in Slovakia by R. Rovný in backwater of the Morava River in 2005, but his record remained unpublished till now. First published record was made by Adam Petrusek on 20.8.2006 (Petrusek 2007).

Records and distribution of P. leniusculus in Slovakia.

Fig 2. Distribution of Pacifastacus leniusculus in Slovakia and adjacent areas.

 

Procambarus clarkii

One of the most dangerous invasive crayfish species was not reported in open water bodies in Slovakia - mainly because of low witer temperatures.

 

Procambarus sp.

Permanent populations of parthenogenetic species of uncertain species were reported in Germany and the Netherlands.

Recently, these individuals were found as common pet animals sold in pet shops in Bratislava and some other cities in Slovakia. Due to some irresponsible owners, such individauls were released to garden ponds, where they formed breading populations.

Fig 3. Occurrence of the parthenogenetic species Procambarus sp. in Slovakia.