Food is one of the most important items in fish culture economy. Juvenile fish prove the fastest growth rates and that is the reason why their appropriate nourishment is so important. Surface drift of terrestrial insects provides an excellent food for rheophilic fish species . Reophilic fishes are able to utilise also plants and particularly algae too. Terrestrial insects can be attracted to water surface by various ways. Is it a light trap during the night. The installation of colour traps is another possibility of insect enticement, for example when located several centimetres bellow the water. We can use various coloured traps {--} yellow, red, blue and other. Light is very attractive for night insects, killing them by electricity. Insects which fall down to water provide an excellent complementary food sources. The experiments were performed with young chub (Leuciscus cephalus). Coloured traps (yellow and red), raffia mats supproting algal growth and electric insect killer were tested. No-trap tanks served as a control. The experiment was run for two growing seasons.. As compared to control, the variants provided with coloured traps proved significantly better results regarding fish growth and condition. However, the best results were achieved using the light trap. Basing on the study results, it can be concluded, that the traps can contribute to successful breeding of juveniles of reophilic fish.

The Caucasus region is characterized by high rate of endemism and taxa richness of fishes. Azerbaijan is a country situated on the border between Europe and Asia with rivers flowing in the Caspian Sea. Natural environment of this country is represented by various habitats with diverse ichthyofauna. This region is very attractive for biogeographical studies because it lays on the border of two different ecoregions. Even on the modern stage of scientific cognition, there is still lack of data about freshwater fishes from that region. Spirlins or rifle-minnows (Alburnoides Jeitteles, 1861, Actinopterygii, Cyprinidae) is a genus of small freshwater fishes and it has been chosen as a focus of this thesis because of numerous reports of new species from surrounding countries. The presented thesis is one of the seldom molecular studies trying to reveal the taxonomical situation within the genus Alburnoides, describe the phylogenetic relationships between geographically isolated populations, and provide biogeographical implications for fishes in the Caspian Sea river basins. Both mitochondrial (cytochrome b, cytochrome oxidase subunit I) and nuclear (RAG1, rhodopsin) markers were used in the study and the Maximum Likelihood, Maximum Parsimony and Bayesian phylogenetic analyses were performed. Further, the...

Brown trout Salmo trutta L. is a fish species with high socio-economic value, which is favourable among anglers and a successful invader worldwide. The aim of this thesis is to explore environmental factors affecting body growth and survival of brown trout with emphasis on density dependent selection in juvenile life stages. This thesis is specifically focused on: (1) effect of population density on growth and survival with respect to a dynamic of a local group of individuals (papers I and II); (2) effect of inter-individual differences in behaviour on the relationship between individuals life-history traits and available resources (papers III and IV); (3) link between demo-genetic structure of population and growth and mortality rates of individuals (papers V, VI and VII). Datasets for this thesis were collected during a long-term mark-recapture study on wild brown trout population (2005-2011) in the catchment of the Otava River in Šumava National Park (Czech Republic) and a set of field and laboratory studies conducted on wild populations in streams on west coast of Sweden. In accordance with some previous studies, this thesis showed that growth of juvenile brown trout is negatively affected by population density. Nonetheless, this thesis reveals that the negative effect of density dependent...

1 ABSTRACT The thesis is conceived as detailed guide to create a dermoplastic models for teachers of natural history and biology. The first part focuses on the actual field of taxidermy and its methods. It includes some possible methods leading to the making of dermoplastic models of mammals, reptiles and fishes. The second part describes the created models of mammals, reptiles and fishes. This section also contains the characteristics of individual species and recent research from specialized foreign literature.

Mercury and its compounds are one of the most toxic global pollutants in the environment. It occurs in all segments of the environment, and it attains the food chain ang human body by people consuming fish. The theoretical part of this thesis examines the characteristics of mercury, its occurrence, the roots of its pollution, and the toxicity of various forms of mercury. Consequently, the thesis delineates analytical methodologies applied to determine the overall level of mercury and chemical forms of mercury. The practical part focuses on monitoring the level of mercury and methylmercury in 12 extracts of fish meat. The analyzer AMA 254 has been used to determine the level of mercury and methylmercury in these extracts. Based on the level that resulted from the measurements, the thesis concludes a risk that correlates with consuming this type of meat.

Theoretical part of the master thesis deals with the occurrence of different mercury species in the environment and describes analytical methods used for determination of mercury in biological samples. In practical part of the master thesis mercury concentration in 14 samples of selected fish and fish product was determined using single purpose absorption spectrometer AMA 254. Measured results were statistically processed and consulted with EU legislative norm.

The thesis deals with potentialities of a company, whose activities are focused in the intrnet environment. Together with maintaining a fisherman portal, the company is involved in producing instructional and narrative movies with fishing themes. In the thesis, different ways to approach special interest groups are discussed, as well as different means of advertising services to these groups. The thesis concludes in several proposals, that may result in the company growth.

The genus Pelasgus (Cyprinidae) is endemic to the southern part of the Balkan Peninsula and includes seven species. In this work, a multilocus approach has been applied to study phylogenetic relationships between the species and their populations and to revise their distribution areas. 180 specimens from 47 localities from 30 river drainages were analyzed, comprehensively covering the distribution range of the genus. Moreover, samples from type localities of all species were included in the analyses. Mitochondrial (cytochrome b) and nuclear markers (the first intron of ribosomal protein S7, recombination activating gene RAG1 and rhodopsin) were used. Existence of seven well supported lineages was revealed based on cytochrome b, which is the most variable marker. These lineages correspond to P. laconicus, P. marathonicus, P. minutus, P. stymphalicus, P. thesproticus, P. prespensis and Pelasgus sp. The most variable nuclear marker was first intron of S7, which provides almost the same results as cytochrome b, revealing six well supported lineages, whereas RAG1 and rhodopsin appear to be less informative, revealing only four well supported clades. These markers did not separate several species (P. marathonicus, P. stymphalicus, P. thesproticus, and Pelasgus sp.) due to low variability of the markers...

Gobies (Gobiidae, Actinopterygii) are small, predominantly cryptic, marine, brackish and freshwater fishes. They abundantly inhabit coastal waters, although their occurrence is far from being mapped due to their inconspicity, often hidden lifestyle and a lack of commercial use. Information about distribution of many species is therefore still rather poor. Many species are known only from a few locations scattered throughout the Mediterranean Sea and the Atlantic. This suggests that most species could actually have a relatively continuous distribution area. Comparing the genetic variability of geographically distant populations of the same species can help to detect whether there is some population subdivision and whether populations are genetically isolated from each other. The aim of my thesis was to compare genetic variability of the populations of eight goby species: Corcyrogobius liechtensteini, Gobius cruentatus, Gobius geniporus, Gobius incognitus, Chromogobius quadrivittatus, Chromogobius zebratus, Millerigobius macrocephalus and Zebrus zebrus within Mediterranean Sea and north-eastern Atlantic Ocean. Samples used in this work were collected from two Atlantic (Spain and Portugal) and seven Mediterranean localities (France, Sicily, Croatia, Montenegro, Greece, and Cyprus - northern and...

This diploma thesis deals with recirculating aquaculture systems (RAS) in terms of their effects on quality of surface water. In the theoretical part, recirculating aquaculture systems, physicochemical parameters of water, eutrophication and fish species that were part of the experiment were described. The methodological part was focused on the detailed description of sampling, parts of the recirculating system, used feed, the origin of reared fish and methods for determination of the individual physicochemical parameters of water and sediment. Samples of water and sediment were collected and analyzed at the Department of Fisheries and Hydrobiology at Mendel University in Brno. In the practical part, the physicochemical parameters were evaluated depending on the number of fish in the system, the daily ration and the type of feed used. It was found that the ammoniacal nitrogen content of the recirculating systems is mainly dependent on the number of fish, the nitrite nitrogen content per daily feed rate, the higher the nitrate content coincides with the minimum water change and the nitrification, the amount of extractable phosphorus in the sediment depends on the type of feed used as well as the total nitrogen content. The smallest impact of phosphorus and nitrogen emissions was demonstrated in the BIOMAR Efico Enviro 920 Advance 4.5 mm feed, which also contained the highest organic content.