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The regulation of brown bullhead - \kur{Ameiurus nebulosus} (Lesueur, 1819)
BLÁHA, Jan
The presence of non-native fish species is one of the causes of loss of biodiversity or even degradation of entire ecosystems. The spread of non-native species is often of invasive nature, which is accompanied by a number of direct and indirect effects on the original organisms. These species are often characterized by greater aggressiveness, resistance, growth rate, early sexual maturity period or the presence of anti predatory mechanisms. The expansion of non-native species is mostly and significantly the result of human behaviour. This bachelor thesis is focused on the possibility of regulation of Brown Bullhead or its similar relative Black Bullhead. Brown Bullhead has been present in our country since 1890. The regulation was done by the means of traps. Different kinds of baits were also used in order to maximize the efficiency and selectivity. The data on the actual occurrence of these species in the Czech Republic has been obtained based on the mapping. Historical data need to be confirmed or disproved of and an assessment of its occurrence had to be made as accurately as possible. The thesis also describes other non-native fish species currently present in the waters of the Czech Republic that can affect water ecosystems. The conclusion also contains suggestions of some preventive measures that could be taken to eliminate the possibility of further spread of non-native species of fish in the Czech Republic.
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Morphometric analysis of two species Ameiurus melas and Ameiurus nebulosus, (Teleostei: Ictaluridae) occurred on territory of Czech republic
PÍCHA, Roman
North American freshwater catfishes (Ictaluridae) is family of freshwater catfishes and includes 7 genera and 48 species. Original habitat of those family is Northern and Central America, but some species were to be introduced to the other regions inclusive Europe. In Czech Republic was recorded occurrence of two species of genus Ameiurus. Brown bullhead (Ameiurus nebulosus) imported by J. Šusta in 1890, and black bullhead (Ameiurus melas), which was imported in 2003 as an admixture to load of Common carp stocking material from Croatia. Distribution of these species is restricted on a small areas in the Elbe river basin and Třeboň pond system in Southern Bohemia. These species are very similar and their resolution is possible only on the basis morphometrics and anatomical diversity (number of fin rays, serration of spine on pectoral fin). Therefore was necessary carry out detailed measuring of both species with the aim of find out appropriate next differences. We measured 63 measurements by digital slide gauge and next we quantified number of fin rays. Totaly was processed 90 black bullheads and 52 brown bullheads.
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Biological characteristics and meaning of bullhead catfishes in waters of Czech republic
PÍCHA, Roman
Bullhead catfishes (Ictaluridae) is family of freshwater catfishes and includes 7 genera and 48 species. Original habitat of those family is Northern and Central America, but some species were to be introduce to the other regions inclusive Europe. In Czech republic was recorded occurrence of two species of genus Ameiurus. Brown bullhead (Ameiurus nebulosus) imported by J. Šusta in 1890, and black bullhead (Ameiurus melas), which was imported in 2003 as an admixture to load of Common carp stocking material from Croatia. Their distribution is restricted on a small areas in Elbe valley and Třeboň pond system in Southern Bohemia These sorts are very similar and their resolution is possible only on the basis morphometrics and anatomical diversity (number of fin rays, serration of spine on pectoral fin). Therefore was necessary proceed closer investigation individuals hunted on territory of Czech republic with the aim of evidence occurrence of black bullhead and valorize influence of these species on our original fish species.
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The first record of the black bullhead (Ameiurus melas) in the Třeboň district, Czech Republic
Hartvich, P. ; Lusk, Stanislav
In the Czech Republic, the occurrence of the Black bullhead, Ameiurus melas (Rafinesque, 1820) was recorded for the first time. The species occurs in some of the fishponds in the environs of Lomnice nad Lužnicí, southern Bohemia. The species was introduced unintentionally as an admixture to carp stocking material from Croatia in 2003. In the autumn of 2005, the occurrence was observed of adults as well as yearling fry, indicating that natural reproduction had taken place in some of the ponds. The water from the fishpond system is released into the Lužnice River so that there is a possibility of the species spreading over natural habitats of the river mentioned. The occurrence of this species in the fishponds in southern Bohemia tends to confirm the fact that transports of stocking fish, above all, carp but other species as well, present a real risk of unintentional introductions of non-native species and an important way of their subsequent dispersal.
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