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Round goby (Neogobius melanostomus) in the diet of great cormorant (Phalacrocorax carbo): the role of the season and temperature
Starý, Vojtěch ; Čech, Martin (advisor) ; Adámek, Zdeněk (referee)
Round goby (Neogobius melanostomus) is invasive species, present in the Elbe river since 2015. This study The purpose of this study was to find out how piscivorous predators have adapted to its presence, using the example of the great cormorant (Phalacrocorax carbo). The research was carried out on the basis of the analysis of cormorant's pellets, collected at a locality near Velké Březno (50ř40ʹ34.2ʹʹ N, 14ř07ʹ28.5ʹʹ E) under roosting trees in the period from 1 October 2020 to 15 April 2021, during a total of 7 visits. A total of 1,775 pieces of fish, 15 species belonging to 5 families, were determined from the diagnostic bones. Of this number, 1,115 were round gobies, i.e. a total of 62.8 % of the cormorant's food consisted of these fish. However, the weight share of the total reconstructed weight of all fish caught (113.6 kg) was only very small - 6.6 %. The mean daily food intake (DFI ± S.D.) of cormorants was determined to be 423.7 ± 113.6 g. It was found that cormorants hunting only round gobies overwhelmingly do not consume the necessary prey weight to cover their energy expenditure. Furthermore, the dependence of the size of the hunted prey on the average daily temperature was tested. Linear regression did not show any significant dependence in this case. The hypothesis that at lower...
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Sampling of young-of-the-year fishes in rivers. New version
Jurajda, Pavel ; Slavík, O. ; Adámek, Zdeněk ; Janáč, Michal
Metodika je sestavena tak, aby bylo možné s jejím použitím provést odlov, základní zpracování a vyhodnocení vzorku plůdku ryb pro potřeby monitoringu ryb v tocích. Zvolená strategie odběru vzorků musí poskytovat informace o současném stavu rybího společenstva v dané lokalitě. V metodickém návrhu jsou obsaženy základní informace o cílové skupině ichtyofauny, výběru lokalit pro získávání vzorků, vlastním odběru vzorků, jejich zpracování a hodnocení.
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Sustainability principles of fish stock of cultural monuments and historical settlements water elements
Adámek, Zdeněk ; Rozkošný, Miloš ; Hudcová, Hana ; Kratina, Josef ; Sedláček, Pavel
The object of the monuments procedure is to put into practice suitable and verified principles of composition of fish stocks of cultural monuments water elements, for production ponds and reservoirs, and for ornamental reservoirs, basins and pools. At the same time, it brings information about methods of fish stock management, principles of introduction of predatory fish, use of fish for biomelioration of aquatic environment. It also provides recommendations for the maintenance and care of farmed fish. To achieve this, it also includes a section aimed at identifying and describing an appropriate approach to solutions to improve water status, including water quality, and ensure the sustainability of fish stocks. Part of the monuments procedure is also a brief analysis of the issue of degradation of the reservoirs and ponds environment from the perspective of fish survival, due to pollution and water eutrophication. It also describes the individual causes of the unsuitable state of the aquatic environment.
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Management plan of small water supply reservoirs of Landštejn type
Halačka, Karel ; Adámek, Zdeněk ; Jurajda, Pavel ; Mareš, J. ; Kopp, R. ; Grmela, J.
The aim of the methodology is to provide managers and users of small water reservoirs Landštejn type with methodological tools for optimization of the water quality monitoring based on the current level of knowledge and research. Furthermore, provides a design of a methodology for fish community monitoring and optimization of treatments to reduce unwanted fish species and strengthen the status of suitable fish species with the aim of achieving the topdown effect and maintaining or improving water quality in these water reservoirs. The presented methodology summarizes the findings obtained during the monitoring and evaluation of selected parameters of water quality, planktonic and fish communities in water supply reservoirs Landštejn in recent years. It also contains an evaluation of applied treatments, focused mainly on fish stock. Unwanted fish species were caught and the predatory fish were stocked with the aim of optimizing the fish community composition and positively influencing the quality of the water in the reservoirs. The methodology contains recommendations for monitoring of the water quality in the reservoir, including monitoring of planktonic communities, monitoring of fish and recommended manipulation with fish stock. The methodology provides guidance and information for optimization of monitoring and treatments for small water supply reservoirs of the Landštejn type.
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Management plan of small water supply reservoirs of Bojkovice and Ludkovice type
Halačka, Karel ; Adámek, Zdeněk ; Jurajda, Pavel ; Mareš, J. ; Kopp, R. ; Grmela, J.
The aim of the methodology is to provide managers and users of small water reservoirs Bojkovice and Ludkovice type with methodological tools for optimization of the water quality monitoring based on the current level of knowledge and research. Furthermore, provides a design of a methodology for fish community monitoring and optimization of treatments to reduce unwanted fish species and strengthen the status of suitable fish species with the aim of achieving the topdown effect and maintaining or improving water quality in these water reservoirs. The presented methodology summarizes the findings obtained during the monitoring and evaluation of selected parameters of water quality, planktonic and fish communities in water supply reservoirs Bojkovice and Ludkovice in recent years. It also contains an evaluation of applied treatments, focused mainly on fish stock. Unwanted fish species were caught and the predatory fish were stocked with the aim of optimizing the fish community composition and positively influencing the quality of the water in the reservoirs. The methodology contains recommendations for monitoring of the water quality in the reservoir, including monitoring of planktonic communities, monitoring of fish and recommended manipulation with fish stock. The methodology provides guidance and information for optimization of monitoring and treatments for small water supply reservoirs of the Bojkovice and Ludkovice type.
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Management plan of small water supply reservoirs of Hamry type
Halačka, Karel ; Adámek, Zdeněk ; Jurajda, Pavel ; Mareš, J. ; Kopp, R. ; Grmela, J.
The aim of the methodology is to provide managers and users of small water reservoirs Hamry type with methodological tools for optimization of the water quality monitoring based on the current level of knowledge and research. Furthermore, provides a design of a methodology for fish community monitoring and optimization of treatments to reduce unwanted fish species and strengthen the status of suitable fish species with the aim of achieving the topdown effect and maintaining or improving water quality in these water reservoirs. The presented methodology summarizes the findings obtained during the monitoring and evaluation of selected parameters of water quality, planktonic and fish communities in water supply reservoirs Hamry in recent years. It also contains an evaluation of applied treatments, focused mainly on fish stock. Unwanted fish species were caught and the predatory fish were stocked with the aim of optimizing the fish community composition and positively influencing the quality of the water in the reservoirs. The methodology contains recommendations for monitoring of the water quality in the reservoir, including monitoring of planktonic communities, monitoring of fish and recommended manipulation with fish stock. The methodology provides guidance and information for optimization of monitoring and treatments for small water supply reservoirs of the Hamry type.
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