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Diversity and microcystins content of cyanobacteria in fish ponds (South Moravia, Czech Republic) related to fishery management intensity
Kopp, Radovan ; Ziková, Andrea ; Adamovský, Ondřej ; Brabec, T. ; Straková, L. ; Mareš, J.
During the vegetative period of the years 2005-2007 (June--October) we carried out hydrobiological and hydrochemical monitoring of selected ponds inhered in Southern Moravia in relation to different fishery management intensities. Water temperature, dissolved oxygen content, pH, conductivity and water transparency were monitored directly at taking place, N--NH4+, N--NO2-, N--NO3-, P--PO43- content and chlorophyll-a concentration were measured in hydrochemical laboratory.
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Young of the year fish assemblage structure of the Czech Elbe river
Švanyga, J. ; Janáč, Michal ; Jurajda, Pavel
During the late summer 2007 a juvenile fish assemblage of the Elbe river was surveyed. Using electrofishing, 36 localities were sampled along a 177 km long segment between Verdek and Brandýs nad Labem. These localities consisted of nine backwaters, 14 channelized localities and 13 beach like localities with natural riverbeds. Altogether 4521 individuals of 0+ juvenile fishes were caught, belonging to 26 species. Significant differences in species diversity and fish fry abundance were found among the three types of environment. The most species-rich fish populations with the highest abundance were confirmed at the natural and beach like localities. On the contrary, the least species-rich and abundance were channelized localities near Hradec Králové. Generally, both the abundance and the diversity changed markedly along the studied stretch. The other ecological parametres like dominance, frequency, reproduction and ecological groups and faunistic similarity were evaluated too.
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Common carp (Cyprinus carpio) growth and distribution in the Brno and Dalešice reservoirs
Prokeš, Miroslav ; Mareš, J. ; Baruš, Vlastimil ; Habán, V. ; Peňáz, Milan
The study of growth and distribution parameters in tagged carp (Cyprinus carpio) from the canyon-shaped dam reservoirs (Brno and Dalešice) was performed. Altogether, 59 (1.5%) and 274 (4.6%) individuals from the Brno and Dalešice reservoirs, respectively, were re-captured and documented (by anglers) from originally 4000 and 6000 tagged fish released. The growth performance of tagged fish (two-year-old carp K2) was only moderate during the first year after stocking in the Brno reservoir (for time span d0-d360 it corresponds to TL = 304-384 mm, w = 497-1170 g, and SGR = 0.2378 %.d-1), very similar to that in the Dalešice reservoir (d0-d360 TL= 301-386 mm, w = 510-1215 g and SGR = 0,2399 %.d-1). The condition parameters (TL:w and FWC) were very similar as well. Different distributional patterns of the catches were however recorded. The growth performance of carp in the Brno reservoir was lower than expected on the basis of its altitude and mean annual water temperature.
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The latest findings concerning the species diversity of gudgeon of the genera Gobio and Romanogobio in the territory of the Czech Republic and Slovakia
Mendel, Jan ; Lusk, Stanislav ; Lusková, Věra ; Koščo, J. ; Vetešník, Lukáš ; Halačka, Karel
During last 15 years the taxonomy of gudgeon have undergone extensive changes. The findings important for preservation of ichthyofauna of the Czech Republic and Slovakia include confirmation of generic differentiation of the original genus Gobio into two genera Gobio and Romanogobio. On the basis of genetic analyses, the originally accepted uniform structure of the species Gobio gobio was divided into the structures which can be assigned the level of species (G. gobio, G. obtusirostris, G. carpathicus, Gobio sp.). The original R. albipinnatus can be divided into the species R. vladykovi and R. belingi. The original species R. kesslerii can be divided into R. banaticus and apparently also Romanogobio sp. With regard to newly acquired knowledge it is necessary to revise the system of efficient preservation of the biodiversity found in the above mentioned taxa. The areas of sympatric occurrence of some species were localized and hybridization within both the genera was demonstrated.
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Ploidy and sexual status of the "Carassius auratus" complex in the waters of the Czech Republic
Lusková, Věra ; Lusk, Stanislav ; Halačka, Karel ; Vetešník, Lukáš ; Papoušek, Ivo
The "Carassius auratus" complex, non-indigenous in the Czech Republic, comprises several forms: C. a. auratus (decorative form), C. a. gibelio (predominant), and C. a. langsdorfii (Japanese form). C. a. gibelio is considered a "non-indigenous invasive species". Around 1975, the form invaded the waters of the Czech Republic from the Danube drainage area. The first invasive individuals were triploid females reproducing gynogenetically. The first males occurred in the Dyje River drainage area after 1990 and began transforming to a mixed type, both the sexual and ploidy status of C. a. gibelio populations changing. At present, the overall percentage representation of males in C. a. gibelio populations varies around 30 %, most of them being diploids, triploids occurring only occasionally. A larger part (60 %) of the females, which still predominate in the population, are triploids, the rest being diploids. Tetraploid individuals of both sexes occur quite singly.
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Renewal of migration permeability in the fragmented river network of the Morava River drainage area
Lusk, Stanislav ; Lusková, Věra ; Klíma, Ondřej
The migration permeability of weirs for fishes is considered one of the strategic revitalisation measures which can significantly contribute to the restoration and stabilisation of fish biodiversity. It is inevitable to define priorities for the preparation and realisation of successive steps in this respect. In principle, the migration permeability should be renewed systematically, starting from the lowest lying migration barriers and proceeding upstream. Highest priority should be given to measures and constructions that are vital in renewing the occurrence and dispersion of native and mostly protected and rare species (Zingel zingel, Z. streber, Pelecus cultratus, Gymnocephalus schraetser, G. baloni, among others). High priority should be given to fish ladders which permit reproduction migrations (Chondrostoma nasus, Leuciscus idus, Lota lota, Vimba vimba, etc.), in which this is an important part of biology, and the condition of restoring stability of their populations.
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Accuracy of successive removal method
Konečná, G. ; Janáč, Michal ; Jurajda, Pavel
Accuracy of successive removal method for two different localities (a trout brook and a smaller lowland river) was examined. Our aim was to define optimal sampling effort to get reasonable results of fish assemblage parameters (species richness, species relative abundance, abundance). Estimates of population and assemblage size were made using the Leslie and Davis graphic method. On the trout brook and the lowland river locality, time cost of the sampling was evaluated. Our suggestion is that one succesive removal pass is the optimal sampling effort for the trout brook, two passes are needed on the smaller lowland river for optimal description of assemblage parameters. More passes are necessary if population size estimates are made and in assemblages with less catchable species.
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Indicative value of fish community in a case of persistent chemical pollution in rivers
Jurajda, Pavel ; Janáč, Michal ; Valová, Zdenka ; Streck, G.
The aim of the study was to evaluate indicative capability of fish community in chronically polluted rivers. Fish were studied in the Elbe River in four inter-weir sections in July 2005 and 2006. Sixteen sites in Bílina stream were sampled in June 2006 and 2007. Twenty two species were registered in two seasons in selected sites of the Elbe River. However generalists form a majority of the fish community in all sections. There was no significant difference in fish species richness between polluted and unpolluted sections. Channelization of the Elbe River seems to be the most important determinant of fish community structure. Fish community in the Bílina stream is strongly influenced by anthropogenic impact. Presence of reservoir changed fish community and point source pollution affected water quality up to complete fish absence. Fish were not a good biological indicator of chemical pollution.
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