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Concentrations of heavy metals and changes in concentrations of the mercury in muscle tissues of the barbel (Barbus barbus) from the river Jihlava
Peňáz, Milan ; Baruš, Vlastimil ; Prokeš, Miroslav
Heavy metsl concentrations were studied in muscles of barbel, Barbus barbus from three sites of the Jihlava River. Only low concentrations of eight elements (As, Cd, Hg, Pb, Cr, Ni, Cu, Zn), not exceeding the maximum permissible values, were found in four mixed samples collected on the site near Hrubšice (RK 46.0-49.1), with a relatively high water quality. Samples differed by the sex, size and age of the fish. Solely the mercury content was analysed on other two sites in the river Jihlava located upstream and downstream the effluents from the sewage plant of the Třebíč city (RK 89.5-91.0 and 85.0, resp.). The obtained values exceeded the maximum permissible value of 0.1 mg.kg-1 in all of 27 individually analysed specimens and averaged 0.208 and 0.187 mg.kg-1, resp., of fresh matter. A high capability of barbel to indicate the burden of aquatic ecosystems by heavy metals was emphasized.
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Phases of the ontogenesis of the Mušov Reservoir of the waterwork Nové Mlýny - fish yield and condition parameters of silver bream (Blicca bjoerkna)
Baruš, Vlastimil ; Peňáz, Milan ; Prokeš, Miroslav
Overall yields of the carp and of the non-preferred group of coarse "other fish" exhibited in the Mušovská nádrž Reservoir (Fishing ground MRS Dyje 7) significant changes during 1981-2001. The decrease of yield during 1996-1999 is significantly correlated with a decreased fishing pressure (number of fishing visits per year and hectare of fishing ground) while it insignificantly correlates with the quantity of annually stocked carps. The length/weight relationship of the silver bream, if comparing the values from 1980 with those from 1996, exhibit a significant drop. It was concluded, that the reservoir is actually in a phase of stabilised production and characteristic by a feeding competition between the carp as a preffered game fish and the coarse fishes. Also an increased predation by wells exhibited on the non-predatory fishes including the stocked carp can not be excluded.
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Methodical notes to morphometric studies in ichthyology
Mazurová, E. ; Zukal, Jan ; Jurajda, Pavel
Comparison of 30 morphometric characters is made between measurements made by two persons and between re-measurements made by one person. There are considered statistically significant differences in both measurements, e.g. in characters on head (eye diameter) and on tail (tail height, minimum body height). Also the effect of increase of different characters amount is considered. That is induced by index expression of characters (in % of body length, head length, total body length).
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Comparison of point abundance and sampling methods for 0+ fish
Janáč, M. ; Jurajda, Pavel
We compared structure of 0+fish assemblages estimates given by two different sample strategies: point abundance sampling (PAS) and continual sample method (CS). No statistital significant difference was found betweem both strategies in number of species, dominance and indices of diversity. CS is more time consuming sampling strategy.
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Several biological characteristic of Carassius auratus
Vetešník, Lukáš ; Lusk, Stanislav ; Spurný, P.
Based on realized research it was found that the present population of Carassius auratus occurred in the lower reach of the river Dyje does not have any significant differences in plastic and meristic characters when compared to the individuals occupying this area 27 years ago. The growth depends on the living conditions of studied individuals. The growth of 2n males was significantly slower comparing to 3n females.
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Fish assemblage and stone loach (Barbatula barbatula) population in the river Haná
Prokeš, Miroslav ; Baruš, Vlastimil ; Peňáz, Milan ; Koubková, B. ; Gelnar, M.
Ecological parameters of the fish assemblage and stone loach population are presented. In total, 25 fish species from 7 families in the river Haná (23 species), including its sources Velká Haná (5 species) and Malá Haná (7 species), were found. Index of species diversity (H') ranged from 0.00 to 1.96, abundance was 89.0 - 22754.8 (mean = 3874.5) exx.ha-1 and biomass was 1.87 - 599.1 (mean = 115.07) kg.ha-1. In five localities in middle and lower parts of the Haná of total 20 localities, no fish was found. Stone loach occured in the whole longitudinal profile within the trout and cyprinid assemblages in abundance of 12.7 - 18260.7 (mean = 2452.8) exx.ha-1 and in biomass of 0.04 - 58.8 (mean = 10.27) kg.ha-1. Species weight dominance (D) was 0.31 - 15.00% (mean = 4.96%). Population of stone loach is a suitable in the stream for investigations of the fish metazoan parasite biology and ecology.
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