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Vývoj úlovků ryb v údolní nádrži Dalešice na řece Jihlavě
Gregr, Tomáš
The Bachelor thesis focuses on evaluation of caught trend in dam reservoir Dalešice (fishery Jihlava 7-8). The main object aim is to evaluate fish caught by angling in decade 2005 - 2014. Thesis focuses on predatory fish species and their ratio to other species. There is used research from 1991 - 2000 to compare results. This work discuses dam reservoirs and species structure of the fish community, compares each species of fish between them and its suitability for dam reservoirs. Amount of predatory fishes caught by anglers decreases during evaluated ten years, depending on quantity of each predatory fish species. The biggest influence had pike (Esox lucius), pikeperch (Sander luciopeca) and asp (Leuciscus aspius).The ratio between predatory fishes and other fish species depends also on proportion of each fish species to total richness of predatory fish species. In the second half of decade (since 2010) the ratio increases in fa-vour of not predatory (cyprinid) fish species.
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The dynamics of anglers' attendance and exploitation of carp in the Hostivař Reservoir directly after stocking and out of this period
Winterová, Michaela ; Jankovský, Martin (advisor) ; Čech, Martin (referee)
The main hypothesis supposes a different angler behavior directly after stocking and out of this period. The aim of this work was to evaluate carp preference according to time (within one day in one district) and place (choice of the locations) variability. As an explanatory parameter the number of environmental factors was tested such as weather, the type of a bait or the sensitivity of fishing technique. This information was surveyed by interviewing the anglers at the Hostivař reservoir. The survey took place in two periods - in autumn 2008 after stocking and comparing period in spring 2009. Data elaboration was taken with CANOCO statistic ver. 4.5 software, when the factors influencing frequency of fish species were searched for. Significantly tested were the factors of bread bait, increasing volume of fishing line and amount of anglers proving the concern of that group for orientation of carp catch. From the following results was obtained the average time spent by the anglers at Hostivar - approximately 5 hours. The average visit rate in autumn was 39.2 angler/day and in spring 34.1 angler/day. The analyses of fishing location show the popularity of places with easy entrance to the bank and the better carp catch in those places. The anglers' efforts were in autumn 2002.7 hours/ha/year and in...
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The contamintation level of sediments from water reservoir Orlík by organic and inorganic pollutants
Dvořák, Tomáš ; Száková, Jiřina (advisor) ; Vymazal, Jan (referee)
Due to sorption processes, sediments can retain a wide range of toxic substances, which are transported together with the sediment over long distances from the place of their origin. Dam reservoirs are significant sinks of such sediments and they can be indicative of the overall burden level in surface water of the basin. This thesis works with the assumption that sediments of a valley reservoir can help to estimate the sources and extent of water pollution in the area of interest.
The aim of this thesis was to assess i) the level of contamination of bottom sediments in the Orlík reservoir with organic and inorganic pollutants, and ii) the potential impact of individual tributaries on the overall level of contamination of the sediments. In the literature review, the current level of knowledge in the topic of the total contents and speciation of toxic elements and specificities of the behavior of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in water, sediments and aquatic organisms was evaluated. The biological activity and eutrophication potential of sediments were discussed, as well.
A total of 34 composite samples of bottom sediment collected in different parts of the Orlík reservoir and its major tributaries were evaluated. Bioavailability of major pollutants was also observed in individual tributaries based on their content in the tissues of mollusks.
Atomic spectrometry revealed increased concentrations of As, Cd and Zn in sediments of the Orlík reservoir. Arsenic concentration limits were significantly exceeded at the bottom part of the reservoir from the confluence of the Otava and Vltava rivers toward the body of the dam. Higher level of cadmium and zinc were detected in sediments of the Otava River. The analysis of tissues of bivalves in tributary areas confirmed significant bioaccumulation ability of cadmium. Among others, significant dependence of phosphorus level on the total content of iron and aluminum in sediments was detected.
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Redundant fingerling of perch (Perca fluviatilis L.) in Vír Reservoir and its impact on other trophic levels
VEJŘÍK, Lukáš
The composition and preferences of depth levels and habitats of pelagic fingerling was studied in the canyon-shaped Vír Reservoir during years 2009-2011. The perch (Perca fluviatilis) fingerling was dominant in all three years. The density of fingerling was above the mean in years 2009 and 2010. It was as many as 278 individuals in 100m3(mean is 52 individuals in 100m3). A marked fall on 1,9 individual in 100m3 was registered in 2011. Perch fingerling was mainly observed in metalimnion during the day and also at night, where concentration of oxygen was very low. The highest density of perch fingerling was observed in the middle part within longitudinal profile. A significant difference was found in food composition among the years with high density and low density of fingerling. A predation of carp (Cyprinus carpio) and bream (Abramis brama) was proved during the years with high density of fingerling.
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Analysis of the Lipno dam reservoir fisheries management
TOMS, Jan
The aim of the present bachelor thesis was to evaluate a development of the Lipno dam reservoir (the Vltava River, South Bohemia, Czech Republic) fisheries management during period from its filling in year 1958 to 1997 and during period 2004-2009. Fisheries statistics of number of stocked/caught fish (provided by the Czech Fishing Union; CFU) were used for the assessment of the state, as well as quantitative and qualitative changes of ichthyocenoses in time during monitored periods. These data were also compared with the results of the ichthyological screening at this dam reservoir in 2008 (undertaken by the employees of Biology Centre of the AS CR, v.v.i., Institute of Hydrobiology) in order to reveal a possible diference between a real fish assemblage compostion and structure of fishes caught by sport fishermen. Analyses of the catch sheets of the members of six choosen local organizations (belonging to CFU) from 2009 were used for evaluation of degree of fishing pressure during one choosen season (whole year) and for assessing of age structure of sport fishermen visiting Lipno dam reservoir.
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