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DEVELOPMENT OF ICHTIOFAUNA IN THE NEW FILED POND CHABAŘOVICE
ŤUK, Josef
The Chabarovice coal mining pit arose by flooding the former strip mine area for brown coal. After filling, the pit area should reach about 225 hectare, total volume of water 34.4 mil. m3, average depth 15,6 meters with maximum of 23,3meters. It is assumed that the pond and adjacent areas will be used for recreation usage after completion of recultivation and ground shaping. I have performed the investigations in June and in August 2004 - 2005, using basic ichthyological methods. The data about recruitment were collected by the littoral seine net and adult fish (older than one year) were investigated by gillnets nets. Fish was determinated to genus, individually measured by slide caliper (fry) and by measuring plate (adult fish). The lenght of fish body (SL-standart lenght) was measured in millimeters and fish were weighted separately (W v g). In the year 2005, also scales were taken from individual fish for the age assesment. Obtained data were processed with regard to performed biomanipulation measures in individual sectores. Nine fish species and one hybrid were recorded by the monitoring with gillnets nets. The most numerous fish were juveniles and adults of rudd with SL 74 {--} 300 mm and the weight up to 618 g. The fish species with the strongest impact upon the pit ecosystem function is conitnuously the perch with the dominance of individuals with SL 46 to 337 mm and weight zup to 850 g.
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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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