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Fish assemblage of the polluted middle part of Elbe River
Švanyga, J. ; Valová, Zdenka ; Janáč, Michal ; Bialek, M. ; Machala, M. ; Jurajda, Pavel
In July 2005, four stretches of the River Elbe were surveyed. In each river stretch, 3 sections were sampled: under the weir, middle zone and above the weir. Adult fish were sampled by boat electrofishing, juvenile fish by seine netting and electrofishing . Totally, 22 species of adult fish were caught. Bleak, chub and roach were the most abundant adult species. Species richness was similar in all river stretches. Fish abundance decreased slightly downstream, both between and within river stretches. 14 species of juvenile fish were caught, most of them represented by a few individuals. Bleak and bitterling were the most common juvenile species. Chub and common bream were co-dominant species in some sections. Fish assemblage of the surveyed sections was relatively poor with a negligible natural reproduction . Despite of the strong pollution source, geomorphological and hydrological stream character seems to be the most important for fish assemblage.
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