Recent Distribution of the Freshwater Crustacean Asellus Aquaticus (Linnaeus, 1758) (Isopoda; Crustacea) in Serbia (2007-2013 Period) - page 01

Asellus aquaticus is detritovore, feeding primarily on coarse particulate organic matter, fungi (Rossi and Fano, 1979) and algae (Moore, 1975). An autumn-shed leaves constitute a large part of the diet (Graça et al, 1994). Thus, although it is present in a wide array of freshwater habitats including rivers, lakes, springs and subterranean waters, even brackish waters (Gruner 1965), it avoids oligotrophic freshwater habitats like fast-flowing mountain streams and mires (Verovnik et al , 2005). The species commonly occurs in lower stretches of water courses with plenty of vegetation and trees (Williams, 1962; Graca et al, 1994). Asellus aquaticus is relatively tolerant to a range of pollutants and therefore has been used as a bioindicator (Maltby 1991). According to the AQEM database (AQEM, 2002), A. aquaticus is an alfa-mesosaprobic taxon, and a good indicator of organic pollution, with saprobic value of 2.80 and weighting factor 3 (Moog 2002).

For Serbia, excluding BAES database (Simić et al, 2006) there is no concise data regarding this taxon findings and overall distribution. Karaman (1952) analyzed races of A. aquaticus, while Paunović (2007) in his investigation of large part of Serbian freshwater macroinvertebrate communities, found A. aquaticus as one of the frequent taxa in larger rivers (catchements over 4000 km2).

This paper based on intensive field research covering almost entire territory of Serbia in 2007-2013 period aims to shed more light on the recent presence of this freshwater crustacean in this region.

 

Material and Methods

Macroinvertebrate samples were collected using a hand net (25x25 cm, 500 μm mesh size) twice per year, in the period summer/autumn within the Annual Water Quality Monitoring Program by Hydrometeorogical Service of Serbia and Serbian Environmental Protection Agency and investigations performed by the Institute for Biological Research "Siniša Stanković" in the 2007-2013 period. The multi-habitat sampling procedure (Hering et al, 2004) and the AQEM protocol (AQEM, 2002) were applied. All samples were preserved using 70% ethanol or 4% formaldehyde solution, further processed in the laboratory and specimens of A.aquaticus were separated. Identification was done by using appropriate taxonomic keys.

 

Fig01
Figure 1: Localities where Asellus aquaticus was found during 2007-2013 period in Serbia.