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Hodnocení efektivity reintrodukce lipana podhorního (Thymallus thymallus L.) do vybraných lokalit jihočeských toků
KOLAŘÍK, Tomáš
The aim of this bachelor thesis is to evaluate the stocking efficiency and fishing records of European grayling in selected angling districts of South Bohemian Rivers based on the angling union data. Furthermore, additional aim is to evaluate the recent results of restoration/ enhancement of European grayling populations by stocking effort in sections of the Blanice Vodňanská River under the Husinec Reservoir and the Vltava River under the Lipno Reservoir. The European grayling was in the past abundant in both sections under study and natural reproduction was also recorded. However, this species almost disappeared in the recent years and its presence in these sites is rare these days.
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Age and growth of the European grayling Thymallus thymallus (L.) originally from different localities - assessment based on the scale analysis
CHYTRÝ, Martin
The main aim of this thesis is to evaluate and to compare the age and length growth of European grayling in selected watercourse in the South Bohemia (Blanice vodňanská, Volyňka, Teplá Vltava a Otava) and in Austria (the Traun River and the Salzach River), focusing on the watersources of the Teplá Vltava River and the Traun River. Possible rules adjustment of sport fishing can give reasons eventually to be done on the basis of results in order to protect and to strenghten natural populatin of grayling. 53 individuals (fish) were studied in total which were in observed localities fished from 2011 to 2015 using power generator or fishing rods. The determination of age and growth were based on analysis of scales of the biggest individuals. The method of Rosa Lee (1920) was used for back-calculation of length growth. The oldest fish, 8 years old, was found among graylings in the Teplá Vltava River. The oldest fish from studied group of fish in Austrian Traun River where graylings trophy are occured belonged to the age group 5+. Graylings from the Traun River came up to faster growth distinctly which is related to more optimal living conditions (water temperature, the amount of food) in the pariticular watersource. Furthermore graylings from observed watersources in the South Bohemian region already grow up to minimum fishing length (30 cm) at the age of 3 4 years old. They can participate in natural reproduction only once or twice a life. Increase of miminal fishing length is absolutely eligible and it is the reason for increasing number of natural spawning and strenghtening of indigenous population of grayling.
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Semi-intensive rearing of young breeding European grayling (Thymallus thymallus L.) using self-seeded insect.
SADLOŇ, Patrik
The aim of the experiment was to test the semi-intensive rearing of grayling (Thymallus thymallus) using technical equipment to lure flying insects. The experimental fish came from two sources and were reared in these localities: The Trout Farm ČRS Kaplice and The Experimental Fish Culture and Experimental Facility (ERPP) of the Faculty of Fisheries and Protection of Waters SBU in Vodňany. The rearing was carried out between the beginning of May and the end of October or half November 2014. Three concrete troughs were used in Kaplice. One for the control group and the other ones with technical elements installed to lure insects: one with a light source pointed to a plastic board placed under the water surface and the second with electric insect traps. In Vodňany, the fish were reared in two nurseries. One was used for the control group and the second was fitted with the combination of underwater light and insect traps. All groups were fed with commercially manufactured pellet feed. The fish were regularly measured (total length, body length, weight) and examined by a veterinarian. During the experiment, better growth in the trough with the lighted board was noticed in the first period of rearing in Kaplice. It was visually confirmed that the fish took the insects in the vicinity of the technical elements in both localities. The course of the experiment was later strongly influenced by the deteriorating health condition of the fish with the subsequent bad intake of feed in both localities especially between June and the end of September. In Kaplice, the inflow water quality became unstable and some predatory fish invaded the rearing trough. This led to high losses of the reared fish in both localities. In spite of some positive findings, the effect of the applied elements on grayling rearing in the selected objects has not been successfully proved.
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Genetic diversity of European greyling (Thymallus thymallus) in the Czech Republic based on mitochondrial DNA variation
HAVELKA, Miloš
Goal of this Thesis is the comparison of the Grayling˘s genetic diversity. The complete mitochondrial DNA (mtDNA) control region (1083 base pairs) and gene for cytochrom B (1076 base pairs) were sequenced in 147 European grayling (Thymallus thymallus), from 21 populations in Czech Republic, Slovakia and Bosnia. In samples, 17 haplotypes were detected with average haplotype diversity Hd = 0,5480 and genic differentiation (FST) from 0,001 to the 0.9341. The most common haplotype TH1 was detected in 92 samples. An inferred intraspecific phylogenetic tree revealed three well-separated clades. One clade was represented by Danubian haplotypes from Slovakia. Second highly divergent clade contained individuals from river Vrbas in Bosnia, and the last biggest clade included haplotypes of all three sea basins from Czech Republic. We suppose that the gained results will be later utilized to the choice of suitable conservation measures that will lead to stabilization of the state of ancestral population of this ever more rare species in our region.
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Sensitivity to anesthetic clove oil different species of adult fish
ŠKEŘÍK, Jindřich
Nomenclature: Sensitivity to anesthetic clove oil different species of adult fish Sensitivity of breeding fishes of various species (Siberian sturgeon, Brook trout, Black carp- young breeding fishes) for anesthetic clove oil was probed by the tests performed at temperature in the period of stripping (apart from Brook trout and Black carp). The tests were carried out with 17 fish species- with cyprinids (Ide- golden form, Common dace, European Chub, Sneep, Barbel, Grass carp, Black carp, bighead carp), salmonids (Brown trout, Rainbow trout, Brook trout), thymallinae (Grayling), pikes (Northern pike), perches (Pike-perch), sturgeons (Siberian sturgeon, Beluga) and airbreathing catfishes (North African catfish). Using concentration of 0,03ml.l-1 (Brown trout, Rainbow trout, Brook trout, Grayling, Pike, Pike perch, Ide, Dace, Chub, Barbel and Sneep), 0,04ml.l-1 (Grass carp, Black carp, Bighead carp), 0,05ml.l-1 (North African catfish) and 0,07ml.l-1 (Siberian sturgeon, Beluga) the IIb. Phase has been achieved, which is sufficient for manipulation with fishes during stripping. The anesthesia subsided after time period of 10-17 minutes (12 species) at the majority of fishes and at others after interval of 20-26 minutes (5 species). The results confirmed concentrations recommended for salmodis and Grayling (0,025-0,03ml.l-1), sturgeons (0,07ml.l-1), and North African catfish (0,05ml.l-1). At the majority of cyprinids (apart from Grass carp, Black carp and Bighead carp), the concentration used was lower than recommended (0,04-0,05ml.l-1)
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Possibilities of increasing of European grayling (Thymallus thymallus L.) quality stock production for running waters
NEBESKÝ, Václav
European grayling (Thymallus thymallus L.) is important and ancestral kind of fish in Czech Republic. Today number of grayling in open waters is decreasing. It caused many reasons. Mainly increasing fishing pressure, unfavourable regulation of streams, water pollutinon, raising occurrence of predators etc. That is why is necessarily devote care to this problem. Main goals of this work were optimalization of technologies to decrease post-spawning mortality of grayling spawners. Optimalization of technologies for breedig offspring of European grayling (Thymallus thymallus L.). Use artificially propagated stock of European grayling (Thymallus thymallus L.) in conditions of open waters. Experiments were done in Blanice River in South Bohemia (Czech Republic) and a hatchery of the Czech Anglers´ Union in Husinec. Part works were done in 2005, but majority in 2006. Results of this work indicate that is possible decrease post-spawning mortality of grayling spawners with using antibiotics. Also using stockfish from controlled conditions for restocking the open waters is conditionally possible. Problem is however with high losses after release.
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