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Toxic effect of fluorescence pigment on zebra fish (Danio rerio)
Poštulková, E. ; Mareš, J. ; Halačka, Karel ; Kopp, R.
The aim of the study was to determine the toxic effects of organic pigments Alizarin Red S and Alizarin Complexone on zebra fish (Danio rerio). For short-term acute toxicity tests on zebra fish concentration of 150; 300 and 600 mg/L were chosen for both dyes. Toxic effect of dyes was observed even in the variant with 10 g/L of sodium chloride. Addition of sodium chloride increases the deposition of dyes in the bone structures of the fish. LC50 values were analyzed graphically by using probit analysis. There was no mortality during the acute toxicity test with Alizarin Red S even at the highest concentration. Toxicity value (72hLC50) for zebra fish with a combination of Alizarin Red S + 10 g/L of sodium chloride is 546.42 mg/L. Mortality for Alizarin Complexone was 100% in 24 hours at\nconcentrations of 300 and 600 mg/L, with concentrations of 150 mg/L there was no mortality. In Alizarin Complexone supplemented with 10 g/L of sodium chloride was 100% mortality at all\nconcentrations up to 72 hours.
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Seasonal dynamics of ergasilosis in reservoir fish
Jelínková, E. ; Krechler, I. ; Jurajda, Pavel ; Papežíková, I. ; Navrátil, S. ; Marková, Z. ; Kosour, D. ; Palíková, M.
We evaluated ergasilosis seasonal dynamics at two reservoirs (Hubenov, Korycany) in the Morava River Basin (Czech Republic). Samples of fish were obtained at monthly intervals between April and October 2014. In total, 189 fish of 11 species were caught using electrofishing and seine nets. Highest overall values for E. sieboldi infection intensity and abundance were recorded at Hubenov in June and September. Prevalence ranged between 80 and 100%. Two highest peaks of infection intensity and abundance were recorded at Korycany in May and the second around September and October, prevalence ranging between 33 and 100%. As the nauplius and copepod stages of arthropods form part of the zooplankton assemblage, they will be found at highest numbers in reservoirs with low predatory pressure, i.e. where predatory fish suppress zooplanktonophagic fish species.
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