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Inpact of fishery management on the structure and dynamics food sources and environmental conditions in selected fispond areas.
BAXA, Marek
The observation was carried out in twenty fishponds in the surrounding of Vodňany and seven fisponds in the surrounding of Třeboň. The aim of the work was to evaluete the quality and quantity of the zooplankton depending on fish production. The samples were obtained and the observations were realized during the 4 years in Vodňany fishponds area and during the 2 years in Třeboň fishponds area. At first the samples were collected and data about the observed localities were organized. These data should explain changes in the aquatic ecosystems of these fishponds areas during the last decades.
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INFLUENCE OF FEED PROCESSING TO PRODUCTION PARAMETERS IN MARKET CARP CULTURE AT TREBON FISCHERIES
HLAVÁČ, David
The aim of this study was to examine the production efficiency of processed triticale and compared to unmodified triticale during 135 day feeding experiment on ponds in the system Naděj. Dosing of feed, feeding technique and condition of the market carp in experimental ponds, the quality and quantity of natural food were observed. At the end of the experiment the main production indicators were evaluated and data were statistically evaluated. Higher production efficiency of mechanical and thermally processed cereals was not proved. The highest production efficiency was observed in variant with triticale supplementary feeding without processing (FCR ? 1.4; SGR ? 0.97 %.d-1; PER ? 6.74) and in variant with thermally processed triticale (FCR ? 1.63; SGR ? 0.88 %.d-1; PER ? 5.79). The lowest effective production was reached using grinded triticale (FCR ? 1.68; SGR ? 0.86 %.d-1; PER ? 5.62). Results were affected by different levels of quantity of zooplankton in the monitored ponds.
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Cladocerans and copepodans biodiversity in Naděje fishponds systém.
KOSÍK, Miroslav
Biodiversity of planktonic crustaceans, cladocerans and copepodans in southbohemian Naděje fishponds system were studied. Both fishpond and non-fishpond (pools, canals, sand-pits, river) localities were observed. Samples were taken from pelagic and littoral zones. Total of 21 species of copepodans and 44 species of cladocerans were recorded over whole area. Hypothesis {\clq}qA higher fish management intensity and higher fish stock cause a lower diversity of zooplankton in a pelagic zone`` was proven. Suppressed species are able to survive in a smaller space (littoral zones, pools, canals, fishponds with a lower fish stock and other non-fishpond localities), where predation pressure is not so strong. None or mild decline of a species diversity can be observed in large areas rich in different water ecosystems, with a reasonable management and production intensity. Different methods of sampling were also compared, those of {\clq}qprolovení litorálních partií`` proved good with the view of effectiveness.
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SEASONAL DEVELOPMENT OF ZOOPLANKTON - COMPARISON OF DIFFERENT WATER BODIES
KOSÍK, Miroslav
Structure and seasonal dynamic of zooplankton and hydrochemical and limnological parameters were studied in different type of small water bodies. Twelve localities of shallow standing waters were selected from four varied biotopes - pools, ponds, sink, surface depression, mining potholes and larger reservoirs like flooded excavated hollow. Zooplankton was primarily determinated by external factors influencing the overall character of water ecosystem and internal factors like fish stock and content of organic matter. Zooplankton species composition exhibits distinctive differences in the individual types of localities as well as in the season. Higher species diversity was recorded in pools, mesotrofic water bodies were considered as localities with lower species diversity. Results of this observation should be useful for water locality planning and management in restoration process in post-mining landscape.
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The morphological and genetic differentiation of \kur{Daphnia} in canyon-shaped reservoirs
HOROVÁ, Barbora
We analysed the pattern of spatial heterogeneity of Daphnia longispina species complex in 11 canyon-shaped reservoirs. We found for the first time that the spatial pattern is not random. Daphnia cucullata shows strong preference for upstream regions while Daphnia longispina and D. galeata x longispina are preferring the deep downstream parts of reservoirs. These not random pattern is probably driven by longitudinal and vertical ecological gradients (fish predation pressure, nutrient concentration, phytoplankton biomass etc.)
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Restoration of aquatic ecosystem and water quality in the drinking-water reservoir Římov after the flood in 2002
Hejzlar, Josef ; Kaštovská, Klára ; Seďa, Jaromír ; Znachor, Petr ; Jarošík, Jiří ; Haider, Z.
The extreme flood event in the catchment of the Malše River in August 2002 markedly changed hydrodynamics of Římov Reservoir (loss of thermal stratification; water residence time dropped from months to single days) and caused problems in water treatment due to a long-lasting increase in concentrations of dissolved organic matter. However, biota of the aquatic ecosystem was influences relatively little. Although large proportions of phytoplankton and zooplankton biomasses were flushed out of the reservoirs the originally dominant species re-established in their original size of biomass within less than one month. The fish community was influenced almost negligibly except for a temporal enrichment by species from streams and fishponds. These results evidence that the reservoir ecosystem is very stable towards fluctuations of hydrologic conditions.
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