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Using of biocide Diazinon 60 EC in fish farming and its toxicity for fish and another water organisms
Máchová, J. ; Prokeš, Miroslav ; Faina, R. ; Kroupová, H. ; Svobodová, Z. ; Peňáz, Milan ; Baruš, Vlastimil
Diazinon 60 EC (chemical insecticide, organophosphate, active substance diazinon at a concentration of 600 g/l) is used in fish-farming in well-founded cases as a biocide to supress excessive propagation of coarse daphnian zooplankton (used concentration of Diazinon 60 EC 0,010 mg/l). Diazinon 60 EC is highly toxic for daphnian zooplankton (48hEC50 = 0,00029 mg/l by the using of artificially prepared adulterating water according to the standard and 48hEC50 = 0,0029 mg/l by the using of pond water). Toxicity of Diazinon 60 EC is markedly lower for other water organisms (96hLC50 for Poecilia reticulata, Cyprinus carpio and Orcorhynchus mykiss are in the range 3-10 mg/l and 72hIC50 for Desmodesmus subspicatus = 10 mg/l). At the concentration of 0,01 mg/l (i.e. 100 g per 1 ha at 1 m mean depth of the pond), Diazinon 60 EC can highly selectively eliminate daphnian zooplankton, causes no harm to fish and is reltively quickly decomposed in the aquatic environment.
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Rearing of the zander (Sander lucioperca) stock material under controlled conditions (preliminary results)
Baránek, V. ; Mareš, J. ; Spurný, P. ; Prokeš, Miroslav ; Baruš, Vlastimil ; Němec, M.
The aim of this study was to check the possibilities of exploitation of summer zander (Sander lucioperca) fry for production of stock material under controlled conditions. Two groups of these fish were converted from natural diet to artificial diet using the semi-moist feeding mixtures (variant A) and trout feed (Dan-Ex 1352 - variant B). The average total length of imported fish was 44,3 mm and the average idividual weight was 0,606 g. There were 255 individuals in each tank. The initial stock density was 2,34 g.l-1 (3,86 ks.l-1). The water temperarute during this experiment fluctuated in intervals 21 ů 23 oC. Our simple experiment confirmed possibility of exploitation of summer zander fry to intensive rearing of stock material.
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