National Repository of Grey Literature 70 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
Non-fish prey in the diet of fish-eating mammals, Eurasian otter (Lutra lutra) and mink (Neovison vison)
Tuzarová, Veronika ; Čech, Martin (advisor) ; Poledníková, Kateřina (referee)
The Eurasian otter (Lutra lutra) is considered, along with the American mink (Neovison vison), a significant fish predator not only in the Czech Republic but also in other regions across Europe. One of the goals of this study is to determine, based on available literature, the types of prey that form the diet of the Eurasian otter and the American mink, specifically focusing on the non-fish component of their food and how the percentage representation of these items changes in the diet of both species depending on habitat and season. Another objective is to verify whether the American mink has a higher proportion of non-fish prey in its diet compared to the Eurasian otter. The processed data describing the diet through spraint analysis in biomass units were divided according to climatic regions, i.e., temperate, Mediterranean, and also based on the type of aquatic environment, i.e., stagnant or flowing water. The results of the study indicate that the American mink consumed, on average, three times more non-fish prey (74 % biomass) throughout the year than the Eurasian otter (24 % biomass). The seasonal variation had the most notable impact on the consumption rate of frogs and birds in the non-fish diet of both predators. According to the analyzed data, both predators especially focused on frogs,...
Round goby (Neogobius melanostomus) in the diet of great cormorant (Phalacrocorax carbo): the role of the season and temperature
Starý, Vojtěch ; Čech, Martin (advisor) ; Adámek, Zdeněk (referee)
Round goby (Neogobius melanostomus) is invasive species, present in the Elbe river since 2015. This study The purpose of this study was to find out how piscivorous predators have adapted to its presence, using the example of the great cormorant (Phalacrocorax carbo). The research was carried out on the basis of the analysis of cormorant's pellets, collected at a locality near Velké Březno (50ř40ʹ34.2ʹʹ N, 14ř07ʹ28.5ʹʹ E) under roosting trees in the period from 1 October 2020 to 15 April 2021, during a total of 7 visits. A total of 1,775 pieces of fish, 15 species belonging to 5 families, were determined from the diagnostic bones. Of this number, 1,115 were round gobies, i.e. a total of 62.8 % of the cormorant's food consisted of these fish. However, the weight share of the total reconstructed weight of all fish caught (113.6 kg) was only very small - 6.6 %. The mean daily food intake (DFI ± S.D.) of cormorants was determined to be 423.7 ± 113.6 g. It was found that cormorants hunting only round gobies overwhelmingly do not consume the necessary prey weight to cover their energy expenditure. Furthermore, the dependence of the size of the hunted prey on the average daily temperature was tested. Linear regression did not show any significant dependence in this case. The hypothesis that at lower...
Ellimination of unwanted fish species from dam reservoirs - Possibilities, efficiency and economic evaluation.
Jůza, Tomáš ; Blabolil, Petr ; Čech, Martin ; Draštík, Vladislav ; Holubová, Michaela ; Hůda, J. ; Kočvara, Luboš ; Kolařík, Tomáš ; Muška, Milan ; Peterka, Jiří ; Prchalová, Marie ; Říha, Milan ; Sajdlová, Zuzana ; Tušer, Michal ; Vašek, Mojmír ; Vejřík, Lukáš ; Kubečka, Jan
spontaneous development of populations and the influence of human interventions. For situations where a certain part of the fish population needs to be caught, within the project 'Biomanipulation as a tool for improving the water quality of reservoirs', we tested the available approaches in terms of their effectiveness and difficulty. The target species of catches were mainly cyprinid fish (bream, bleak, roach, rudd, white bream), which feed mainly\non zooplankton and tend to form very large populations. Among the most effective methods of catch during spawning are catches using electrofishing boats and fyke nets. In the non-spawning period, it is possible to carry out mass catches using trawl nets. Catches are effective both before spawning (in April) and during the summer. However, with repeated catches in the same places, their effectiveness decreases as a result of the fish being spooked. The efficiency of the catches partially improves again if the catches are repeated with a break of approximately 1–2 weeks. Catches also vary according to the stocking density of a given water body. With effective catches, the cost of catching 1 kg of fish is in the range of CZK 15–50.
Fourier transform on polytopes and tiling with rectangles
Couf, František ; Kala, Vítězslav (advisor) ; Čech, Martin (referee)
The aim of this thesis is a detailed exposition of the proof of a theorem on nice intervals in d dimensions and a theorem on the properties of harmonic intervals. We introduce first the notions of a nice rectangle and a tiling of a set. Then we extend the notion of a nice rectangle to that of a nice d-dimensional interval. We subsequently prove the main theorem (a closed interval tiled by nice closed intervals is also nice) in d dimensions. Then we define harmonic intervals and prove in detail several important theorems on tiling by harmonic intervals. We illustrate their assumptions with examples which demonstrate their importance. We show the connection between the notions of a harmonic interval and a multiple of an interval for intervals with integral edges at the end of the last chapter. 1
Information system for a company making parts of transportation devices
Čech, Martin ; Kofroň, Jan (advisor) ; Šerý, Ondřej (referee)
In this work we propose a specific implementation of an information system for small and middle-sized companies. Its purpose is to manage data about employees, partner institutions (both providers and customers), purchase orders and products themselves. The application consists of three parts: a database layer, application server, and client program. In addition, it focuses on the products management, division into elementary components and production processes. Another significant part is documentation of workers' production, which enables supervising the process evolution and also generation of salaries. In this work we focus especially on solution of each program part and communication among them.
Influence of age and rearing conditions of a fish on the chance to survive in the wild
Lyach, Roman ; Frouzová, Jaroslava (advisor) ; Čech, Martin (referee)
The task of this thesis is to summarize all the most important biotic and abiotic factors that can influence chances of reared fish to survive in the wild. It contains some of the most frequently reared and popular fishes, such as Sander lucioperca (pike perch), Samo trutta (trout), Micropterus salmoides (largemouth bass), Esox lucius (northern pike), Esox masquinongy (muskellunge) and the hybrid of northern pike and muskellunge, the tiger muskellunge. Mainly the factors such as success, survival, rate of growth and mortality have been studied. Survival increases with the size of the fish because of the fact that larger fish can easily avoid predation. Pellet-reared fish show higher mortality than minnow-reared fish because of the loss due to predation and also slightly worse ability to catch living prey and obtain food, even though their diet contains similar species. Temperature can also affect the mortality of the stocked fish, mainly when the temperature difference between the rearing pond or hatchery and the new environment exceeds 10 řC, which brings loss of majority of the stocked fish. It has been revealed that genetics is very important during the process of stocking, while fish from the local population show better abilities to adapt to the environment than those from other geographic...
Algebraic proofs of Dirichlet's theorem on arithmetic progressions
Čech, Martin ; Kala, Vítězslav (advisor) ; Příhoda, Pavel (referee)
Dirichlet's theorem on arithmetic progressions says that there are infinitely many primes in any arithmetic progression an = kn + with coprime k, . The original proof of this theorem was analytic using a lot of non-elementary methods. The goal of this thesis is to give sufficient and necessary conditions on k and under which a more elementary algebraic proof of the theorem can exist, and give the proof in these cases. 1
Diet of Eurasian otter (Lutra lutra) in relation to the stocking of brown trout (Salmo trutta m. fario) and grayling (Thymallus thymallus)
Lyach, Roman ; Čech, Martin (advisor) ; Poledník, Lukáš (referee)
This study aimed to evaluate otter predation on stocked trout and grayling. The diet composition of piscivorous Eurasian otters (Lutra lutra) was studied on the stream Chotýšanka in central Bohemia using spraint (otter faeces) analysis during one winter period (90 days). Stocking took place mostly in the second half of 2005. Around 5000 hatchery-reared brown trouts (Salmo trutta m. fario) of size about 10 cm, 600 graylings (Thymallus thymallus) of the same size and 480 rainbow trouts (Oncorhynchus mykiss) of size about 30 cm were stocked into the stream. Spraints were collected in December 2005 and January 2006. We found and identified 1531 fish in the spraints. The primary food source of otters was fish (almost 85 % of biomass). The main fish prey was small - sized, below 20 g in weight and 13 cm in length. The bulk of otter's diet consisted of less - valued species, especially the gudgeon (Gobio gobio). Other frequently consumed fish species were the European chub (Squalius cephalus), the common carp (Cyprinus carpio), the European perch (Perca fluviatilis), the brown trout and the rainbow trout. Consumption of stocked brown trout was 1,80 %, while cosumption of stocked rainbow trout was 10,90 % of biomass. Otters in this area consumed about 723 - 1446 brown trouts and 72 - 144 rainbow trouts...
Diet of great cormorant (Phalacrocorax carbo) in conflict localities
Ráslová, Pavlína ; Čech, Martin (advisor) ; Vrána, Pavel (referee)
vi Abstract Continental subspecies of the great cormorant (Phalacrocorax carbo sinensis) is the Czech Republic's most important fish-eating predator. It causes damage to production fish, as well as sport fishermen and even after its removal from the Czech list of endangered species in 2013, it did not disappear from the spotlight of both local fishermen and researchers. This thesis evaluates the qualitative and quantitative composition of the cormorant's diet during winter 2011/2012 at two selected locations: the Žehuň pond (Kolín district) and Berounka river in the natural reserve Zábělá near Pilsen. This work studies the main components of cormorant's diet in the selected locations and evaluates potential fluctuations and changes in its composition during winter. The study also conducted the analysis of the proportion of commercially harvested valuable fish in cormorant's diet and studied its diversity of the species spectrum. The resulting data for the two sites were compared with each other and with relevant literature. Regurgitated pellets analysis, as well as analysis of diagnostic bones and fish remains located at the sleeping roosts (night roosts) were used for the diet analysis. It was found that at both sites roach was the most caught fish, but from the point of view of total biomass, it was...

National Repository of Grey Literature : 70 records found   1 - 10nextend  jump to record:
See also: similar author names
33 ČECH, Martin
5 ČECH, Miroslav
7 Čech, Marek
4 Čech, Michal
1 Čech, Mikuláš
5 Čech, Miroslav
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