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The influence of the water quality on managed ichthyocenosis in the Berounka River, 1975-2003
Pivnička, K. ; Humpl, Martin
In 1962-2004 the stepwise increase of the concentration of NO3-, NH4+, Cl-, and SO42- was found up to the end of 1980´s with their subsequent decrease; only for BOD the gradual decrease in all sites and years was observed. These environmental factors (EF) together with the fishery statistics from two fishing wards (B7 and B8) in the Berounka River near Radnice were used in RDA models for the evaluation of the variability in fish assemblage structure in relation to the given EF. The best results in both wards were obtained using model with three EF (BOD, NO3-, SO42-), next models with four (five) factors explained more variability, some EF were, however, not significant. The partial effect of carp as EF on the yield of other species was non significant in B7 and closely above the significance (p=0.036) in B8. The changes in the frequency of fish species in fishery statistics are influenced by EF; the fishery statistics can be used for the evaluation of changes in fish assemblages in the past.
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Abundance of the barbel, Barbus barbus in the river Jihlava
Peňáz, Milan ; Pivnička, K. ; Prokeš, Miroslav ; Baruš, Vlastimil
A four-year experiment with a total of 993 individually tagged barbel, Barbus barbus, resulted in the assessment of survival and abundance. The Jolly-Seber method was used to estimate abundance from autumn 1999 to spring 2001 (minimum 233, maximum 563 ind./ha). The mean annual survival rate was 0.862, but the partial values assessed separately for seasons (spring - autumn and autumn - spring) differed considerably and the possible reasons for this phenomenon are discussed. On the basis of known survival rate, the abundance was subsequently estimated (for the entire studied stretch and per hectare) using the Petersen capture-recapture method for the period spring 1999 to autumn 2001. Its mean values reached 303 +- 110 ind./ha (minimum 195, maximum 498 ind./ha). These results were in autumn 2001 supported by another simultaneously conducted census following the removal method by Zippin (316 ind./ha).
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The fish stock diversity of the lower Kyjovka river stream
Horák, Václav ; Mendel, Jan
The ichthyological research of the Kyjovka River showed that it is inhabited by highly diversificated communities. The Kyjovka community is the source, which can support by migration local fish populations in the adjacent hydrological system within the floodplain forest. It is shown that active stream is essential for maintenance of stable and diversificated fish communities in the passive alluvium.
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Fishes in streams of the Beskydy Protected landscape region
Lusk, Stanislav ; Lusková, Věra ; Halačka, Karel ; Lojkásek, B.
The river network of the Beskydy PLR (1,620 km2 ) belongs to the hydrological systems of Baltic and Black seas. It mainly consists of minor streams of the orders I and II. The basic components of their fish stock include Salmo trutta m. fario and Cottus poecilopus.In lower part of bigger streams are also additional species (Thymallus thymallus, Leuciscus cephalus, Alburnoides bipunctatus, Gobio gobio, Cottus gobio, etc.).
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