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Fish community as an indicator of river degradation
Jurajda, Pavel ; Janáč, Michal ; Ondračková, Markéta ; Adámek, Zdeněk ; Valová, Zdenka ; Streck, G. ; Machala, M. ; Wenger, M. ; Segner, H.
V příkladové studii na Bílině se ryby na úrovni společenstva projevily jako dobrý a rychlý indikátor ekologického stavu toku, avšak pro indikaci chemických látek v řece je nutné hodnotit specifické parametry na úrovni jedince.
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Nová metoda vzorkování fytofilních bezobratlých ve vynořené litorální vegetaci
Sychra, Jan ; Adámek, Zdeněk
The aim of the study was to design the sampling method for collection of phytophilous macroinvertebrates associated with submersed parts of hard emergent littoral vegetation in still waters, which will join technical sampler unpretentiousness, sampling simplicity and maximal quantitative accuracy. For these purposes, we developed a modified Gerking´s frame box sampler with movable cutter for sampling of animals in the littoral macrophyte beds and a new type of core sampler for collection of animals inhabiting the root zone of emergent plant beds. Both sampling devices are suitable for studies targeted on macroinvertebrates monitoring. The comparative sampling using frame box sampler and benthos handnet was performed in the littoral of three carp ponds. The sampling procedure utilizing the frame sampler was more labour demanding however it enabled significantly (P < 0.05) more efficient collection of slowly moving or sedentary animals.
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Potrava okouna říčního (Perca fluviatilis) v průběhu napouštění důlní propadliny Chabařovice (SZ Čechy, ČR)
Adámek, Zdeněk ; Jurajda, Pavel ; Musil, J. ; Janáč, Michal ; Kabilka, P. ; Polačik, Matej ; Ťuk, J. ; Valová, Zdenka ; Zeman, J.
The Chabařovice coal mining pit (Chabařovice lake) is currently still under the process of continuous flooding and its area increased up to 174 ha since 2001. The inflow water originates from surface waterbodies and hence the penetration of fish species, undesirable with respect to biomanipulation efforts, makes a serious problem in fisheries management of the lake. Adult perch have been the most numerous fish of the lake until 2004. Current perch population consists of one cohort (7+ - 8+) originating from the recruitment of two subsequent year classes. The food bulk of adult perch consisted of benthic animals and zooplankton in both years under study, however their proportion differed significantly. In 2004, dragon fly nymphs were the dominant food items with 58.80% proportion, followed by cladocerans Daphnia sp., which made up 23.82% of food ingested. In 2005, chironomid larvae prevailed in the food bulk with 41.95% and the diversity of ingested food items was obviously wider.
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