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Fish diversity and spatial distribution of YOY fish in Vlatava cascade reservoirs
Draštík, Vladislav ; Kubečka, Jan ; Jůza, Tomáš ; Jarolím, Oldřich ; Hladík, Milan ; Kratochvíl, Michal ; Prchalová, Marie ; Říha, Milan ; Tušer, Michal
Fish communities of YOY were studied in four cascade reservoir by beach fry-seining and fry trawling. Highest fish fry density was found in Slapy and Vrané reservoir. Lowest density was found in Kamýk and Štěchovice reservoir, two small reservoirs with shortest retention time, lowest oxygen concentration and temperature. Pelagic fish fry assemblages had much lower density than littoral assemblages and follow general fish longitudinal gradient. Littoral assemblages were more difficult to interpret due to more factors which can play important role in fish fry spatial distribution (such as bottom substrate and slope, complexity of shoreline, availability of water vegetation). Cyprinid species (bleak (.i.Alburnus alburnus./i.), roach (.i.Rutilus rutilus./i.), bream (.i.Abramis brama./i.)) prevailed in most reservoirs, only in Kamýk reservoir percid species (perch (.i.Perca fluvitilis./i.), ruffe (.i.Gymnocephalus cernua./i.)) prevailed.
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