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The main aim of the diploma thesis is to evaluate the fish management of a trout reserve Svitava 2 and to suggest a correction on the basis of results from the performed surveys and information from the Moravian Fisherman's associotion evidence. Field surveys were realized on 3rd and 4th September 2013. During these surveys 12 fish species out of 5 families were demonstrated by electrofishing. Caught fis were released back to the river measuring weight and lenght. The ichthyologic research was evaulated using indi-cators for fish populations. On account of acquired knowledge and data, I recommend following correction: advance quantity biennial brown trout on 200 fish per hectare, reduce rainbow trout 40 fish per hectare and advence quantity biennial qrayling on 200 fish per hectare.

Presented master thesis deals with the issue of assessment of management in salmonid fishing ground Svitava 4. The main aim was to compare the state of fish community with the state after the last survey from 2003-2004 and to evaluate the economic evidence (level of fishermen's pressure, level of reached catch and the stocking of economically important species) for ten years in a row. The ichthyological survey was carried out in summer season in 2014 at four localities within the fishing ground Svitava 4. The topographic data of particular localities were measured by the modern devices. Also basic physicochemical parameters of water were measured. The catching was realized by electric-fishing gear. After measuring of morphometric characteristics all the fish were returned back to the fishing ground. The survey established the presence of 8 fish species in 5 families. The abundance of fish community varied on particular localities in the range from 338 to 1633 pcs.ha-1, the biomass from 53,6 to 199,2 kg.ha-1. The fish community of concerned stream has gone through significant changes since the last survey. Considerable decrease in abundance was recorded mainly in the grayling population.

The main aim of this thesis is to evaluate the biological status of species populations of agriculturally important fish species in the district Svitava 5 and the evaluation of the evidence in the district's ten-year series. Ichthyological surveys were carried out in autumn 2015, on 20th and 21st November. At various locations were determined basic physicochemical parameters of the water and found topographical data. Catches were made by using electrical units. All fish were returned gently back to the territory after finding plastic signs. In all localities have been detected 3 fish species from two families. The total abundance ranged from 899 to 3634 ks.ha-1 and the biomass from 58.7 to 250.6 kg per ha -1. Big drop in the number of caught individuals was recorded at grayling, when it reduce the number of catches from 21 ks.ha -1 to 1 ks.ha -1 in the ten-year series.

The aim of the work will be based on the diet composition monitoring of the introduced rainbow trout and wild brown trout and grayling in defined time intervals, and assessing the degree of the food competition among the monitored species. The experiment was held in the second half of September 2010 in the river Blanice in the protected fish areas close to the village Těšovice, where several dozens of rainbow trout were stocked. In a predefined several - day interval of were caught 30 pieces of the rainbow trout (SL = 266 ? 14 mm, m = 347 ? 54 g), 33 brown trout (SL = 244 ? 19 mm, m = 219 ? 51 g), 14 graylings (SL = 256 ? 27 mm, m = 240 ? 91 g) and 12 resident rainbow trout (SL = 255 ? 13 mm, m = 280 ? 47 g) originated from the last plant. Within these groups a fish stomach content and consequently food selectivity was examined by using of the Ivlev's selectivity index (1961), a food competition was examined by using of the Schoener's index food overlap (1970) and the importance of various food components was examined by using of the index of preponderance according to Natarajan (1961). Rainbow trout began to ingest food immediately after the stocking into the stream and its occurrence was seen in all fish crop caught during the period. The insect (Insecta) was given as a preferential food of the rainbow trout and according to the index of preponderance (IP), it formed 54%, Trichoptera (IP) 24% and Ephemeroptera (IP) 19% orders belonged to the most preferable kinds of the food. According to the index of preponderance, gastropod (Gastropoda) formed (IP) 25% of a secondary food. The rainbow trout was accepting the same dietary components as well as the original sorts of salmonoid fish within the river. According to the index of a food overlap (S), the food competition between rainbow trout and brown trout was equal to the value of (S = 0.566) during the whole monitored period and the grayling was equal to (S = 0.520). Even though both of these values are slightly below the significant food overlap (S = 0.6), we can still say that the food competition is relatively high among these kinds.