National Repository of Grey Literature 13 records found  previous11 - 13  jump to record: Search took 0.02 seconds. 
Changes of some attributes of the barbel, Barbus barbus population from the Jihlava River during past 25 years and their causes
Peňáz, Milan ; Baruš, Vlastimil ; Prokeš, Miroslav ; Svobodová, Z.
A few cases of protandric sex reversals were found during a tagging experiment. Histological procedures confirmed the incidence of intersex individuals and the biochemical screening revealed a high vitellogenin concentration in blood serum of several males. All this supports the hypothese on putative feminisation processes and sex reversal in barbel that are obviously strongly affected, however not fully conditioned, by environmental pollution and xenoestrogene occurrence.
Giant traps for fishing in the inflow-zone of the Římov reservoir
Hladík, Milan ; Kubečka, Jan ; Pokorný, P. ; Čech, Martin ; Draštík, Vladislav ; Kratochvíl, Michal ; Peterka, Jiří ; Prchalová, Marie ; Vašek, Mojmír
The fish stock of the inflow-zone of the Římov Reservoir was studied by using two special constructed big traps. One trap was sampling the fish migrating from the reservoir to the Malse River, the other was sampling downstream migrants. The most intensive fish movement was recorded during spring spawning season. Proportionally to the fish stock of the reservoir, the tributary zone was used mainly by the bleak, .i.Alburnus alburnus./i., Asp, .i.Aspius aspius./i. and roach .i.Rutilus rutilus./i.. Smaller affinity to tributary spawning was found for the bream .i.Abramis brama./i. and perch, .i.Perca fluviatilis./i. (5 to 10 % of reservoir fish spawning in the tributary). Over 6000 kg of migrating fish were captured in the tributary area during spring periods of three years. Consequences of the application of tributary traps for fish exploitation and management are being discussed.

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