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Age and growth of the European grayling Thymallus thymallus (L.) originally from different localities - assessment based on the scale analysis
CHYTRÝ, Martin
The main aim of this thesis is to evaluate and to compare the age and length growth of European grayling in selected watercourse in the South Bohemia (Blanice vodňanská, Volyňka, Teplá Vltava a Otava) and in Austria (the Traun River and the Salzach River), focusing on the watersources of the Teplá Vltava River and the Traun River. Possible rules adjustment of sport fishing can give reasons eventually to be done on the basis of results in order to protect and to strenghten natural populatin of grayling. 53 individuals (fish) were studied in total which were in observed localities fished from 2011 to 2015 using power generator or fishing rods. The determination of age and growth were based on analysis of scales of the biggest individuals. The method of Rosa Lee (1920) was used for back-calculation of length growth. The oldest fish, 8 years old, was found among graylings in the Teplá Vltava River. The oldest fish from studied group of fish in Austrian Traun River where graylings trophy are occured belonged to the age group 5+. Graylings from the Traun River came up to faster growth distinctly which is related to more optimal living conditions (water temperature, the amount of food) in the pariticular watersource. Furthermore graylings from observed watersources in the South Bohemian region already grow up to minimum fishing length (30 cm) at the age of 3 4 years old. They can participate in natural reproduction only once or twice a life. Increase of miminal fishing length is absolutely eligible and it is the reason for increasing number of natural spawning and strenghtening of indigenous population of grayling.
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Ichthyofauna of selected sections of the Jizera basin
CHYTRÝ, Martin
Rivers fragmentation by migration barriers has a significant negative effect on native fish communities and other river organisms. That is the reason why there has been put a lot of emphasis on creating fish pass in rivers in recent years. Between the years 2012 and 2013 there were carried out investigations on the new slit fish pass on the Jizera River in Turnov. The aim was to assess the technical realization of the construction of fish pass and functionality for local ichthyofauna. Primarily we have focused on hydraulic conditions in the fish pass (water flow, velocity, level differences in all chambers). During the fish pass technical inspection the fish was being caught by electric aggregate. The species composition of fish was also measured in the weir. Catching weir was used to catch the counter-migrating fish through the fish pass. The caught fish was taken its body length in mm and weight in grams and subsequently was calculated numerical dominance, diversity and evenness. There were 519 pieces of fish caught weighing 6.395 kg in total. There was confirmed presence of 10 species of fish in the fish pass, while in the weir were found 3 more species of fish and 1 species of lamprey. Reproductive migration was confirmed for brown trout and minnow. Roach, dace, perch and chub have settled down in the resting chambers permanently. There have been found several defects in the fish pass. There have been found large differences between the levels of chambers, high flow rates, reduced light penetration of the water in the fish pass, lack of entry attractiveness of the fish pass and non-minimum residual flows. Fish passage is considerably clogged by suspended dirt and the cleaning possibility is limited. Functionality and selectivity of the fish passage has not been demonstrated. There will be further investigations carried out in 2013.
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Fundamental indexing
Chytrý, Martin ; Musílek, Petr (advisor) ; Stádník, Bohumil (referee)
The paper deals with stock market indices. It reveals the flaws inherent in traditional market capitalization weighted indices, that causes a return drag. At the same time it shows how you can get rid of these flaws by using fundamental indices, and gives proofs about their superiority. The practical part focuses on building fundamental indices of czech stocks traded on the Prague Stock Exchange, dealing with historical data. It empirically demonstrates their outperformance of a benchmark market capitalization weighted index.
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