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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...
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European catfish (Silurus glanis, Linneus 1758): Is the global warming the main reason of increasing of catches of the largest freshwater predator in Europe?
Bakeš, Michal ; Čech, Martin (advisor) ; Černý, Martin (referee)
European catfish (Silurus glanis, Linneus 1758) is our only fish which amount of catch is growing in our country in the last thirty years. The main goal of my work is to find out if global warming is essential for increasing catch of catfish, or whether rising temperatures are marginal, and the main reason is growing focus of fishermen on catfish. This thesis summarized knowledge about effect of global warming on ecosystems mainly on freshwater bodies that seem to be the most influenceable among terrestric ones. The enlarging populations of catfish in countries of south Europe (e.g. Spain, Italy) where catfish was recently introduced can be explained by the fact that warm water is suitable for catfish. However, some socioeconomic studies carried out in the Czech Republic as well as abroad clearly demonstrate that popularity of catching of catfish increases in time. I verified this idea by the results of my questionnaire survey, where 82 % of respondents approved that the popularity of catfish among fishermen is highest in the last decade. Based on the evidence we can say that increasing temperatures has a positive effect on the metapopulation of catfish in the Czech Republic, but this influence seems to be marginal. The main reason for still increasing catch is very likely the change of preferences...
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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...
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The distribution of rainbow trout catches during the year with respect to stocking events
ČTRNÁCT, Petr
This bachelor thesis deals with the differences between the distribution of rainbow trout catches during the year on a different fishing grounds with respect to stocking events. Angler's records from the Svitava 1 and Blanice Vodňanská 4B fishing grounds were used and elaborated for these purposes. This thesis evaluates the rate of rainbow trout return and the ratio between stocking weight and catch weight in angler's records.
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