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Acceptance of Fish Predators by Students of Chosen High Schools
Sůva, David ; Andreska, Jan (advisor) ; Hanel, Lubomír (referee)
The thesis describes the attitude students of professionally oriented high schools have toward chosen species of fish-hunting predators, namely the eurasian otter, the american mink, the great cormorant and the sea eagle. The first part of the thesis focuses on both historical and present recognition of these species in our country, description of each species including their population and protection measures. The second part of the text analyzes the curriculum framework of chosen high schools. The third part is a field study. The field study found which textbooks are used by students to learn about the fish-hunting predators listed above as well as the student's perception of them. A sample of 191 students were questioned, out of which 98 are students of schools of forestry and 93 are students of schools of fisheries. The worst acceptance was found with the great cormorant. The best acceptance was of the sea eagle. Key words: predation, eurasian otter, american mink, great cormorant, sea eagle
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The role of fish-eating predators and socio-economic trends in recreational fishing
Lyach, Roman ; Čech, Martin (advisor) ; Adámek, Zdeněk (referee) ; Jurajda, Pavel (referee)
Recreational fishing is a very important leisure activity and one of the most important ways how humans influence freshwater habitats and wild fish populations. Both fish-eating predators and socio-economic trends play a major role in recreational fishing. This thesis found that the Eurasian otter feeds mainly of small (5-10 g) and very abundant fish species of low angling value. In this case, gudgeon Gobio gobio dominated in the otter diet. The overlap between catches of otters and anglers was very low, and commercially important salmonids made up only 10 % of the otter diet by biomass. Cormorants also prey mostly on smaller (10-100 g) a very abundant fish species. In this case, roach Rutilus rutilus dominated in the cormorant diet. The overlap between catches of cormorants and anglers was also quite low. Commercially important fish species made up less than 10 % of the cormorant diet. Even though cormorants consume mostly smaller fish, they are potentially removing fish that serve as prey for piscivores, and they are also removing smaller fish that would grow into angling size. The Atlantic salmon Salmo salar reintroduction programme has not yet been successful. However, cormorant predation is not the main reason for its low success. The main problem is somewhere on the lower River Elbe in...
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Importance and species composition of non-fish prey in the diet of fish-eating predators
Mach, Jakub ; Čech, Martin (advisor) ; Vejřík, Lukáš (referee)
Piscivorous birds are usually considered to be exclusive fish eaters which are responsible for signifiant numerical and economical losses to fish populations. With a method of literary research the importace and species composition of non-fish prey is determine in the diet of selected fifteen species of piscivorous birds. The aim of this work is to determine the extent of non-fish part of the diet of particular piscivorous predators and categorize them on the grounds of differences between size of this part in their diet. Another goal is to determine any effects which can influence amount and species composition of non-fish part of nourishment, and also factors, which can influence obtained results based on the chosen method of analysis. According to the data found, diet of five bird species was composed almost exclusively with fish. Eight other bird species also showed preference for fish prey, but in most of these cases was present also important part of non-fish prey. Two bird species seems to be very oportunistic in case of composition their diet. As factors that can affect the extent of non-fish part in the diet was established especially the prey availability in environment, used method for diet composition analysis, insufficient attention for parts of prey other than fish, or also less...
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VARIOBN IN WINTERING NUMBERS OF GREAT CORMORANT ON SELECTED ROOST SIZES IN CENTRAL BOHEMIA
Dušek, Ondřej ; Musil, Petr (advisor) ; Zasadil, Petr (referee)
The study is based on summarization of current knowledge on population development of Great Cormorant (Phalacrocorax carbo) in Europe and in Czech Republic. Moreoverr, it is focused on assessment of methodical approach to monitoring of wintering population. The Great Cormorant is regularly wintering species in the Czech Republic, since 1985. Nevertheless, it exceeds 1000 individuals since 1993 up to now. The surveys aimed at Cormorant numbers are compared according, results and interpretation of outputs methodology. The compared surveys include both International Waterbird Census carried out by ornithologists and survey organized by Czech Anglers Association.
Moreover, the results of the own field survey are analysed in the paper. The field survey was carried out in Veltrubský luh (village Pňov Předhradí, district Kolín, Central Bohemia) during winter months (December to March) 2015/2016. The numbers varied between 0 and 79. The fluctuations were affected by tree cutting, walking of people as well as by direct cormorant disturbance by local anglers. Nevertheless, the numbers reached between 59 and 78 in days without disturbance. Moreover, regular occurrence of great Cormorants was confirmed also in another neighbouring sites, such as in Poděbrady lake, sand pit lake Samberk, lake Sadská and Žehuňský fishpond.
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The Assessment of compemsation damages caused by the Great Cormorants (Phalacrocorax carbo) in fish farms in South Bohemia.
KÖSSLOVÁ, Hana
The thesis analyses compensations of damages caused by great cormorant (Phalacrocorax carbo) in fish farms in South Bohemian Region pursuant to Act. No 115/2000 Sb. till 2011. In the introductory section is described a development of population of nesting and migrating Great cormorants in Europe, particularly in the Czech Republic from the 80th of last century, and reasons for conflict between this species conservation and fish farming including legal conditions for compensation to pond owners and a development of compensation issues in the Czech Republic. This thesis assesses an overall status of the compensation of damages already paid in South Bohemia, analyses claimants according subject type and compares the amount of compensation of damages in relation to the number and the pond area including the frequency of submitted apllications by different types of claimants and the relationship to individual districts of South Bohemian Region. The survey in five chosen ponds in Třeboňsko region evaluates a current secondary damages caused by Great cormorants in the form of injured fishes obtained during fishing out.
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