| Popis: |
The main aim of the study is the formation and the verification of methodology of Bryozoa cultivation in the laboratory conditions, then the establishing of the optimal method for detection of Myxozoa in the collected samples of Bryozoa, and finally the creation of effective and in practice usable method for eliminating Bryozoa in fish farming facilities. The creation and verification of the methodology of Bryozoa cultivation in the laboratory conditions was not successful. The optimal detection of Myxozoa in the collected samples of Bryozoa was verified by the technique of visual observation of given number of zooids in each sample using a microscope. Three chemicals (Savo Original, Persteril, formaldehyde), commonly used in fishery, were used in different concentrations for a testing elimination of Bryozoa in intensive fish breeding systems. Used preparations caused death of entire colonies of the species Plumatella emarginata at concentration: Savo Original 0,025 %, Persteril 0,00313 % and formaldehyde 0,00625 %; in case of species Cristatella mucedo: Savo Original 0,1 %, Persteril 0,00625 % and formaldehyde 0,0125 %. Obtained results show that formaldehyde is the only tested product that can be used in fish farming because the concentration needed for killing the colony of Bryozoa is lower than the lethal concentration for salmonid fish. Using formaldehyde in the concentration of 1.38 mg/l for the elimination of Bryozoa in a model system with a volume of 1000 m3 costs 37.5 thousand CZK. The cheapest variant is to use preparation Savo Original, but this product can be used only in a system which is temporarily without fish. |
