National Repository of Grey Literature 79 records found  beginprevious62 - 71next  jump to record: Search took 0.00 seconds. 
Sampling of the offshore fry fish communities of reservoirs by trawls
Jůza, Tomáš ; Kubečka, Jan ; Čech, Martin ; Draštík, Vladislav ; Jarolím, Oldřich ; Peterka, Jiří ; Vašek, Mojmír
The offshore area of six Czech reservoirs was sampled by pelagic fry trawl in late summer in 2003-2005. In Římov, Želivka, Vrané and Slapy reservoirs cyprinids dominated in offshore area. The main species here were roach, bream and bleak. In Lipno and Nýrsko reservoirs percids dominated in offshore area (Lipno-pikeperch, Nýrsko-perch). Trawling in offshore areas revealed that almost all 0+ fish were caught in the surface stratum (0-3m depth). In reservoirs where percids and cyprinids occured together, cyprinids dominated in 0-3m depth while percids usually prevailed in catches of 0+ fish from 3-6m depth. In ordinary canyon-shaped reservoir like Římov and Želivka the 0+ fish abundance decreased from the upstream end toward the dam, so the biggest abundance was in tributary area. In cascade reservoirs like Slapy and Vrané, the offshore area in tributary is almost without fish. The peak of abundance is more downstream and from this place, the trend is similiar to non-cascade reservoirs.
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.
Species composition along the vertical gradietn in canyon-shaped reservoirs
Prchalová, Marie ; Kubečka, Jan
During years 2004 and 2005, vertical gradients of fish distribution within two canyon-shaped Czech water supply reservoirs (Římov, Švihov) were examined by Nordic multimesh gillnets in both pelagic and benthic habitats. In the open water, most fish were found in the upper 5 m of depth. Below this depth nearly no fish occurred. The community was represented mainly by bleak. Towards deeper parts the portion of perch increased. In benthic areas, most fish were in the upper 3 m of depth. Abundance declined to 10 m and below this depth nearly no fish were present. Perch and roach dominated the littoral community. Ruffe preferred the deeper habitats. With respect to biomanipulative removal catches, it is sufficient to fish in the upper 5 m of the open water and in the upper 3 m in the littoral of the reservoir. For getting a rough but adequate assessment of fish community, it is satisfactory to sample the upper 5 m of the open water and the upper 10 m in the benthic part of the reservoir.
Complex assessment of the fish assemblage of the Želivka reservoir, the biggest water supply reservoir in the ČR, in years 2004 and 2005
Prchalová, Marie ; Kubečka, Jan ; Jůza, Tomáš ; Říha, Milan ; Jarolím, Oldřich ; Tušer, Michal ; Peterka, Jiří ; Vašek, Mojmír
In the summer 2004 and 2005, the complex assessment of the fish assemblage of the Želivka reservoir (1432 ha) was carried out by gillnetting, adult and fry seining, adult and fry pelagic trawls and hydroacoustic sampling. Detailed picture of the fish assemblage was composed from every fishing gear from every depth strata of the open water as well as from the littoral zone. During two-years survey, 40.168 fish of 19 species and one hybrid were captured. The fish assemblage was dominated by cyprinid species in both years – bleak prevailed in the open water together with roach and bream; perch was abundant in the littoral zone. The assemblage of the Želivka reservoir was found to be in the stable cyprinid phase. The average abundance was 1.700 ind/ha and average biomass was 110 kg/ha. In the fish spatial distribution, the general gradients could be found – higher abundance and number of species in the tributary area and in the epilimnion and littoral.
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.

National Repository of Grey Literature : 79 records found   beginprevious62 - 71next  jump to record:
See also: similar author names
2 Kubečka, Jakub
2 Kubečka, Jaroslav
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