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The influence of fishery farming intensity on water quality in ponds
KREJČÍ, Filip
The introductory part deals with the history of czech fish farming and there is given further information on selected quality parameters of pond water, which are important and risky in terms of fishery production. The main part of the thesis summarises data from the literature, final reports and RIFCH (The research institute of fish culture and hydrobiology) Vodňany database is processed in a form of tables and graphs for clear presenting of physiochemical properties of pond water, including brief details about the way of fish farming, eventually about other important factors, which could also affect the water quality. The main data source of my thesis were four projects, which dealt with this issue during a relatively long period of time, from the seventies of the last century until the year 2012. The greatest attention was paid to data gained under NAZV QH-82113 project "Careful and effective fish farming with maximal utilization of current trophic potential and keeping of sufficient water quality and fish production" in the years 2008-2012 at experipentals ponds of RIFCH Vodňany. There was a comprehensive set of data gained from semi-intensive conditions, where working multiple times and in a very well comparable and under well documented conditions (size of ponds, water supply, fish farming methods) was possible. Based on some published data and data obtained from VÚRH Vodňany database, it was able to demonstrate a direct influence of the size of initial stocking density on the water quality of ponds (especially the concentration of suspended solids, volume of organic pollutions and the total concentration of a phosphor). Generally, parameters, which often do not comply with legislative requirements, could be described as suspended solids, concentration of oxygen, ammonium, total phosphor and Biochemical oxygen demant (BOD5) and Chemical oxygen demant (CODMn or CODCr) values, whose values are sometimes influenced by factors such as for instance the history of a pond, other than production usage of the pond in the previous period (deponie of waste from livestock production, recreational activities etc.)
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