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Large-scale rehabilitation in the alluvial area along the lower reaches of the Dyje River
Lusk, Stanislav ; Pražák, O. ; Lusková, Věra ; Halačka, Karel ; Vetešník, Lukáš
The Dyje River between Lednice and Bulhary was straightened, canalised, and provided with levees. Most of the alluvial area near Podivin was transformed to arable land. Due to elimination of floods, save for exceptions, areas denoted as wetlands and reed beds were qute dry for most of the year. As a result, the native fish communities typical of alluvial habitats gradually vanished from their habitats. In recent years, some 470 hectares on the left bank of the Dyje River, owned by a single private person, were transformed into a deer sanctuary. In the past two years, the arable land in that area has been gradually turned into meadows and a floodplain forest, together with restoring and enlarging the area of permanently waterlogged parts denoted as wetlands. As a result, the conditions permitting permanent occurrence of fish have been significantly improved and for a purposeful restoration of their fish communities in which native species predominate (the Carassius-Misgurnus type).
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Floodplains: special measures needed for the development and stabilisation of fish biota
Lusk, Stanislav ; Hartvich, P. ; Lojkásek, B. ; Lusková, Věra ; Pražák, O. ; Halačka, Karel ; Sovíková, L.
The preserved extent of the initial floodplains along major rivers is limited and has been distinctly altered by hydrological dynamics. The results exert a negative impact on aquatic biota, above all, fishes (the floodplains of Odra, Dyje, Lužnice rivers). The most marked changes include construction of ponds, canalization of streams with levees, absence of meadow management. The consequences: absent landscape formation activity of streams, expansion of wetland vegetation, gradual silting and downfall of alluvial habitats, their total drying, destruction of elements such as channels, ditches, river arms and other habitats, a limitation or disappearance of populations of Misgurnus fossilis, Rhodeus amarus, Cobitis spp., Carassius carassius, Leucaspius delineatus. Retrieval: maintenance of optimum condition of aquatic habitats, creation of artificial wetlands, restoration populations of protected fish species. Passive protection of habitat and species is no solution any longer.
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The mercury load in fishes inhabiting the upper section of the Divoká Orlice and Tichá Orlice rivers
Korunová, Vlasta ; Lusková, Věra ; Lusk, Stanislav
In the boundary section of Divoká Orlice R. the mercury content in the tissues of brown trout did not exceed 0.2 mg.kg-1. WHO risk limit, 1.6 µ mercury per 1 kg human body weight per week, is attained by a person weighing 75 kg and consuming 0.63 kg trout muscular tissue a week. In Divoká Orlice drainage area, the mercury content was determined in roach (Rutilus rutilus) in 1987-1995. In a majority of specimens analysed, the values of mercury contents in their muscular tissue exceeded 0.2 mg.kg-1 (max. 0.683 mg.kg-1). In the upper part of Tichá Orlice R., increased mercury contents were found in brown trout. Below the Králíky profile, the mercury contents varied around 0.50 mg.kg-1 in the muscular tissue, and up to 0.85 mg.kg-1. The mercury loads in the fishes decreased gradually in the downstream direction down to the value around 0.20 mg.kg-1. In the uppermost part of Tichá Orlice R. below the town of Králíky, the risk limit is only 0.24 kg trout meat consumed per week.
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The fish community in the Divoká Orlice River near Kostelec nad Orlicí, and the genetic diversity of the local common gudgeon population
Mendel, Jan ; Lusková, Věra ; Lusk, Stanislav ; Halačka, Karel
The fish community was investigated in two localities (r. km 46.7 and 49.1) on the Divoká Orlice River near Kostelec nad Orlicí . Besides the species characteristic of salmonid waters (Salmo trutta, Thymalus thymallus, Phoxinus phoxinus, Cottus gobio ) there are species typical of a barbel community (Barbus barbus, Leuciscus cephalus, L. leuciscus, Gobio gobio). The occurrence of Lampetra planeri has also been recorded. The abundance attained 4,294 and 6,612 exx..; the weight, 363.8 and 509.7 kg respectively, converted to 1 hectare of water surface. The allozyme analysis of G.gobio has shown that the diversity of the population under study is average, compared to other populations examined in other streams Using the RAPD method, two identification markers have been found for the fish in the population examined. The genetic analysis of mtDNA provided a unique haplotype serving to differentiate the gudgeon population.
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Molecular biological analyses of Sand gudgeon (Romanogobio kesslerii) in the waters of the Czech Republic and Slovakia
Mendel, Jan ; Lusk, Stanislav ; Lusková, Věra ; Koščo, J. ; Papoušek, Ivo ; Halačka, Karel ; Vetešník, Lukáš
Kessler's gudgeon belongs to critically endangered species protected by both national and European legislation. We present the first findings concerning the genetic diversity of 5 R. kesslerii populations from the Czech and Slovak rivers. On the basis of sequencing of the control region, as well as of the first intron of the S7 r-protein, 30 specimens were analysed. Altogether nine haplotypes were identified. Analyses of mtDNA showed the existence of two groups differing by 6.2%. The first group included the specimens from the rivers Bečva and Ipel and the second group included the specimens from the rivers Topl’á, Laborec and Morava. The inter-population diversity was 0.4% within the first group and it ranged from 0.5% to 1.0% within the second group. The combination of the methods of sequencing of parts of mtDNA and nDNA and allozyme analysis revealed the presence of hybrids of G. gobio and R. kesslerii in the Morava and Ipel’ rivers.
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On the occurrence of rare and protected lamprey and fish species in the Morava River drainage area
Lusk, Stanislav ; Lusková, Věra ; Lojkásek, B. ; Halačka, Karel ; Vetešník, Lukáš ; Merta, L.
The occurrence of a considerable number of rare and protected lamprey and fish species in the Czech Republic is exclusive for the drainage area of the Morava River. Eudontomyzon mariae occurs only in the Račí potok Brook. Lampetra planeri occurs in a section ca 20 km long in the upper part of the Morava R. Romanogobio kessleri initially occurred only in the Bečva R. After 2000 was newly recorded in the Morava R. Romanogobio albipinnatus occurs in the lower reaches of the rivers Morava and Dyje; locally, we have observed in the upper parts of these rivers. After 1990 species Pelecus cultratus, Gymnocephalus schraetser, G. baloni, Zingel streber, and Z. zingel re-occurred in the confluence of Morava and Dyje rivers. The only actual range of Sabanejewia balcanica in the Czech Republic is in a short section of the Vlára R. (the Váh R. drainage area) near the boundary of Slovakia. Cobitis elongatoides occurs, in its pure form, only in the upper part of the Dyje R. drainage area.
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The present distribution of species of the family Cobitidae over the Slovakian drainage area of the Tisza River
Koščo, J. ; Košuth, P. ; Lusková, Věra ; Lusk, Stanislav ; Košuthová, L. ; Halačka, Karel
Cobitis elongatoides is common to frequent in the eastern Slovakian part of the Tisza drainage area (d.a.) where it populates all habitat types. The occurrence of this species is less frequent in the western part of the Tisza d.a. No marked differences have been observed in the past and present distribution of this species. The occurrence of Misgurnus fossilis is concentrated in the lowland areas of the Tisza d.a., particularly in its eastern part. Ichthyocoenoses in which M. fossilis occurs are poorer in species, and they overlap considerably with those containing C. elongatoides but differ markedly from those containing Sabanejewia balcanica. M. fossilis was rather successful in adapting to artificial wetlands. The species is rather rare in western part of the Tisza d.a. The range of S. balcanica is shifted more upwards to the submontane region, exclusively in running waters. No marked differences have been observed in the past and present distribution of this species.
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The Red List of lampreys and fishes in the Czech Republic - Version 2005
Lusk, Stanislav ; Hanel, L. ; Lusková, Věra ; Lojkásek, B. ; Hartvich, P.
The new Red List was compiled on the basis of data obtained in the course of five past years. Besides the overall evaluation for the Czech Republic, the data were separately evaluated for the North Sea, Baltic Sea, and Black Sea basins. The status and degree of danger imminent to the populations of the particular species were evaluated also separately for each of the 16 water regions. Compared to the 2000 evaluation, classification was changed for following species: Salmo salar (previously EW, now CE), Acipenser ruthenus (NE / CE), Sabanejewia balcanica (EX / CE), Zingel streber (EX / CE), Chondrostoma nasus (EN / VU), Lota lota (VU / NT), Rhodeus amarus (NT / EN), Leucaspius delineatus (NT / EN), Alburnoides bipunctatus (VU / EN), and Carassius carassius (VU / EN). The degree of jeopardy for Alburnoides bipunctatus, Vimba vimba, Rhodeus amarus, Carassius carassius, Misgurnus fossilis is basically different in different water regions, varying between Extinct and Near Threatened.
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Problems posed by the protection of lamprey and fish localities of European importance in the drainage areas of the Dyje, Morava, and Odra rivers
Lusk, Stanislav ; Lusková, Věra ; Lojkásek, B. ; Halačka, Karel
In consequence of the accepted legislation concerning the protection of lamprey and fish species of European importance, potential sites of community interest (pSCI) have been selected for such species. At present, the national list of the proposed pSCI is being examined by the European Commission. If approved upon, the pSCI will be proclaimed "special areas of conservation" within the NATURA 2000 system. Although such pSCI and their populations are protected by legislation, there occur risks that endanger, both directly and indirectly, the quality of the pSCI and the population of the particular species. The examples mentioned in the paper indicate that such risks include local emergency pollution, construction of weirs and small hydraulic power plants, extraction of sediments from streambeds, cruising vessels, and stream modification. Such risks are due to the inconsequence and reluctance in observing the legal protection measures by concrete authorities of nature conservation.
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Invasive fish species in the Czech Republic
Lusk, Stanislav ; Lusková, Věra
In the Czech Republic, the following fish species are evaluated as invasive: Carassius auratus, a species showing a significantly negative influence on the occurrence of native species Carassius carassius and Tinca tinca in natural habitats. Certain manifestations and properties (such as the invasive way of dispersal, numerous populations, great ecological tolerance etc.) typical of invasive species can also be seen in Pseudorasbora parva, Ameiurus nebulosus, and Proterorhinus marmoratus. In some of its manifestations, even Cteropharyngodon idella can affect biodiversity in a negative way. One cannot exclude the future invasion or introduction of any alien species evaluated as invasive, particularly those of the genus Neogobius that occur in the Slovakian part of the Danube, and Perccottus glenii that has already invaded the Tisza River drainage area and the lower part of the Danube.
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