Non-indigenous invasive freshwater crustaceans (Crustacea: Malacostraca) in Slovakia - page 3

Decapoda

The non-indigenous freshwater crayfish species (Crustacea, Decapoda) were introduced to Europe mainly from the North American continent. These species were introduced to Europe due to their resistance to the crayfish plague and to re-establish crayfish populations in European rivers which had significantly declined after being infected by Aphanomyces astaci (Edgerton et al., 2004; Kozubíková et al., 2006; Kozubíková and Petrusek, 2009).

According to Holdich and Black (2007), Orconectes limosus (Rafinesque, 1817) is the first non-indigenous crayfish species intentionally introduced to Europe from the United States. In reference to the Danube River, in the late 1980s two populations (dispersal centres) of O. limosus could be distinguished. A population of low density was found in the Bavarian upper Danube and the more frequent and abundant population in the Hungarian middle Danube, which is a source of progressive spreading (Nesemann et al., 1995). O. limosus was recorded for the first time in Slovakia in 2007 in the river Váh and Ipeľ (Janský and Kautman, 2007). Further research reported this species in the Slovak stretch of the Danube River as well (Puky, 2009). This species colonizes the Slovak stretch of the Danube from Štúrovo to Komárno (as assumed by Janský and Kautman, 2007) and colonizes tributaries of the Danube River, like the Ipeľ and Váh River.

The species is present in March River in Slovakia as well (Nesemann et al., 1995). It was recently recorded in the vicinity of Bratislava (Figure 1) in the Danube River at two sites (Vitázková, 2013).

Pacifastacus leniusculus (Dana, 1852) is another American freshwater crayfish species known to occur in Slovak inland waters (Figure 1). So far P. leniusculus has been known from the March River only (Petrusek and Petrusková, 2007). Recent research also discovered the species in the Danube River in the vicinity of Bratislava (Vitázková, 2013).

Eriocheir sinensis H. Milne Edwards, 1853 is a commercially important catadromous species native to Eastern Asia (Puky et al., 2005). The specimen was recorded several times in the Hungarian part of the Danube and is to be found in the Austrian and Serbian stretch of the river as well (Paunović et al., 2004; Puky et al., 2005; Puky et al., 2008; Škraba et al., 2013). This species was also confirmed in Slovakia (Figure 1) occurring in the Váh River in the past (Janský, 2013). Procambarus sp. Ortmann, 1905 was recorded by Janský and Mutkovič (2010) in a gravel pit in the vicinity of the Váh River in 2010 (Figure 1). Introduction of the species is most likely a consequence of illegal release of the specimen obtained from the aquarium trade. The species present a serious threat to the native decapod species if it becomes established and extends its range. So far, the population seems well isolated (Janský and Mutkovič, 2010).

 

Fig01

Figure 1: Distribution of non-indigenous invasive decapods. Triangles indicate the occurrence of the spinycheek crayfish (O. limosus), the circles indicate the occurrence of the signal crayfish (P. leniusculus), the diamond indicates the occurrence of the marbled crayfish (Procambarus sp.), and the square indicates the finding of the Chinese mitten crab (E. sinensis).

 

Amphipoda

Nine species of non-indigenous amphipods occur in Slovak waters and all of them originate from the Ponto-Caspian region (Table 2). All of the species occur in the Slovak stretch of the Danube and some of the species invaded its tributaries as well. The invasive non-indigenous species, mainly of the genus Dikerogammarus, colonize the lower sections of the March and Váh River. Corophium curvispinum Sars, 1895 reaches the Dyje River, a tributary to the March near to the border of the Czech Republic, but was not found as far as Hodonin (March River) in the Czech Republic.

C. curvispinum as like C. sowinskyi Martynov, 1924 is among the first invaders that extended its range of occurrence (Bij de Vaate et al., 2002ô Borza, 2011). C. curvispinum is known from the Slovakian part of the river since 1950s (Brtek, 1953) and is now the most widespread corophiid species in the Middle Danube (Figure 2) (Nesemann et al., 1995; Borza, 2011). The species has also colonized the Tisa River, reaching up to Eastern Slovakia (Borza, 2011).

The range extension route of this species was the central corridor and is the first Ponto-Caspian crustacean to have invaded Polish inland waters (Bij de Vaate et al., 2002).The earliest record of C. curvispinum outside its native range was in the spree-havel system near Berlin (Germany) and was described as a new species to science by Wundsch (1912). The species was later synonymized with C. curvispinum (Jażdżewski and Konopacka, 1996). The species has extended its range of occurrence on the continental level. At several sites it has become a dominant macroinvertebrate, e.g. in the Rhine River (Bij de Vaate et al., 2002).

C. sowinskyi is a first Ponto-Caspian species that extended its range towards Western Europe through the Southern corridor (Borza, 2011). The species was recorded in the Hungarian stretch of the Danube as early as 1917, and then later in the 1930s it was recorded in the Slovak-Hungarian section of the Danube as well (Borza, 2011). Brtek (2001) and Štraskraba (1962) reported this species in the lower parts of the Danube in Slovakia (Figure 3). The species is very similar to C. curvispinum and its taxonomic status was uncertain for a long time (Jażdżewski and Konopacka, 1996).

 

Fig02
Figure 2: Distribution of C. curvispinum. The squares indicate the occurrence confirmed by Brtek (2001), circles indicate the occurrence of the species confirmed by Elexová et al. (2010). Diamonds present the occurrence by Borza (2009) and triangles indicate the occurrence confirmed in the research in 2011.

 

Fig03
Figure 3: Distribution of C. sowinskyi. The squares indicate the occurrence confirmed by Brtek (2001), triangles indicate the occurrence confirmed in the research in 2011.