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Fyzikálně chemické vlastnosti vody stabilizačních nádrží z hlediska welfare ryb
OKROUHLÝ, Vít
This bachelor thesis deals with influence of physicochemical indicators of water on the assigned fish stock, including the balance (TN, TP, N-NH4 +, BSK5, CHSKCr and NL105) and the retention of TP and TN in biomass of fish. The work also evaluates the growth ratio and mortality of the deployed fish and it also monitors the balance between primary and secondary production. In the introductory part of the thesis are theoretically described parameters, which were measured in SN2. The main part of the presented work describes the experiment and its conditions, methodology of measurement of individual parameters and summary of data in the form of tables and graphs to achieve a clear presentation of physico-chemical properties of water, balance of nutrients in the reservoir, fish production and abundance of zooplankton organisms. The data in this section was also summarized briefly under tables and charts. In spite of the frequent unfavorable values of the measured parameters, the fish stock aquired an excellent gain of 932.72 kg and 907 kg.ha-1 but the mortality of the carp was slightly higher due to the possible predation of water predators or different demands on the environment by different age groups of carp (Cyprinus carpio). The survival of other deployed fish was within normative losses, except for the fetus of Sander lucioperca, which was not able to survive under these conditions. The cause of fish survival in often extreme conditions can be due to the fact that it migrates to places where the conditions are more favorable or because the fish is in a good condition due to natural food supply. The nutrient balance in SN2 was positive for TP, TN and N-NH4 +. The measured values at the inlet were therefore higher than the SN2 effluent values. The content of organic matter (BSK5, CHSKCr, NL105) was higher at the SN2 outlet than its inlet. The weight on organic solvents and suspended solids has increased on drainage due to the development of production processes.
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