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Potrava násady kapra (Cyprinus carpio L.) v rybnících - analýza obsahu zažívadel.
SÝKORA, Ondřej
The aim of this bachelor thesis was to comprehensively evaluate the diet of two-year old common carp in semi-intensive pond culture from the stage of two-year carp (K2) to the stage of market carp (Kt). The extent to which the carp use natural and presented food and whether its composition changes during the season was monitored. The experiment itself was part of a large-scale GAČR project (Nutrients from Fish or Nutrition for Fish: Revealing Hidden Risk of Pollution and Nutrient Retention in Ponds through Nutritional Bioenergetics of Fish), which was conducted at the experimental facility of the VÚRH Vodňany. The experiment of food study was conducted in three ponds (0.16 ha), which were slowly filled from mid-April onwards, for the development of natural food after being left dry. Subsequently, 150 individuals of carp (337 ? 57 g) and 35 individuals of pikeperch (S. lucioperca L.; W=14.5 ? 38.8 g), were stocked on 26th April 2022 to prevent the development of undesirable fish species. Carp rearing lasted 162 days, during which time carp diet was monitored approximately once a month using the flushing method of Faina (1975). The contents of intestines of four carps were collected from each pond, at each date. At the beginning of the season, the diversity of the diet was high. Zooplankton was the most abundant food component throughout the entire experiment. However, if we consider the size of the feeding organisms, zoobenthos, consisting mainly of chironomid larvae, played a significant role in the diet of the carp at the beginning of the season. As the season progressed, the number of zoobenthos individuals decreased, while the number of zooplanktonic organisms in the diet increased, mostly represented by planktonic cladocerans and copepods. These two groups of organisms also had the highest frequency of occurrence and abundance in the digestive tract throughout the experiment. Along the season, in addition to the increasing abundance of zooplanktonic organisms, the proportion of grains in the carp diet also increased.
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Potravní zdroje plůdku reofilních ryb v rybnících s instalovanými světelnými a barevnými atraktanty hmyzu
KAJGROVÁ, Lenka
The aim of this work was to evaluate the food base (zooplankton, zoobenthos and aerial insects) and production results in culture of two-year-old golden ide (Leuciscus idus aber. orfus) and chub (Squalius cephalus). The specifics of the study were to use the attractants (yellow plates) and submersed lights as a supplement to the nutrition of farmed fish. Experimental rearing took place in the earth ponds in the area of Experimental Fish Culture Facility in Vodňany (Czechia) and in the storage ponds in Schlossfischerei Schönau bei Litschau (Austria). Zooplankton composition and physico-chemical parameters were monitored during regular two-week sampling periods. Monitoring of zoobenthos and terrestrial insects captured by attractants was performed at monthly intervals. Macrozoobenthos was sampled by Ekman Grab. After processing the samples in the laboratory, the benthic invertebrates were divided into three groups - Chironomidae, Oligochaeta and Varia. Zooplankton was collected by planktonic mesh in the 3 m long hauling and divided into the fraction of small zooplankton (Daphnidae < 499 micrometre, Copepoda < 999 and > 1000 micrometre and Others - small Cladocera), and into the fraction of coarse zooplankton (Daphnidae 500 - 999, Daphnidae 1000 - 1499 and > 1500 micrometre). Terrestrial insects were captured by installed attractants for a specified time period of day (colour attractants) or night (light attractants). The results show that the environmental conditions of the monitored ponds did not differ significantly. Abundance of coarse zooplankton in both experimental cultures was influenced by fish. The density of zoobenthos did not differ significantly. However, the values in the ponds with the lights were higher than in the control. According to the analysis of growth and production data, the installation of insect attractants as a supplementary measure to fish nutrition in aquaculture seems to be beneficial for production results. The average weight of golden ide increased during the growing season from the initial 4,3 g to 26,9 +- 4,9; 32,3 +- 6,5 and 41,2 +- 9,2 g in control ponds, ponds using lights and yellow plates, respectively. The differences between both control and experimental treatments as well as between lights and yellow plates were highly significant (p < 0,001). In the culture of chub using light attractants, the average fish weight increased from the initial 12,7 g to 41,9 +- 2,2 g, respectively to 26,7 +- 5,5 g in control. In both treatments, the production was analogously higher.
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Evaluation of the environmental quality of the Novomlýnský rybník reservoir (cadastral zone Nová Bystřice)
NOVOTNÁ, Barbora
Seasonal variations of zooplankton, zoobenthos, fish assemblage and hydro-chemical and limnological indicators were studied in the Novomlýnský rybník reservoir (PP Homolka Vojířov) near Nová Bystřice in 2014. The results were used for the evaluation of factors influencing the quality of the environment of a small water reservoir. The measurements and samples were taken monthly from April to October (with the exception for June) in the pelagial at the point of the pond maximum depth. The sampling of fish to determine the species present took place once, in April of 2014. At the same time, two measurements and sample taking took place at the reservoir inflow and outflow. The results of this survey could be useful during planning and water management of the reservoir with the aim to restore the environment and increase the range of present large filtering zooplankton, particularly those from the Cladocera family, which are scarce in the reservoir.
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Sledování interakcí abiotických složek vodních ekosystémů a rostlin z hlediska jejich kontaminace těžkými kovy: Výzkum vodních ekosystémů v rámci povodí
GEOtest, Brno ; Hillermannová, Michaela
Zpráva obsahuje literární přehled doplněný o zahraniční materiály a rozdělený do částí 1. Sledování interakcí abiotických složek vodních ekosystémů a rostlin z hlediska jejich kontaminace těžkými kovy (sedimenty dna, povrchové vody, podzemní vody, autotrofní organismy - řasy, nárosty, makrofyta, zoobentos a ryby), 2. Kovy v jednotlivých složkách vodních ekosystémů, 3. Fytoremediace a 4. Technologie sanace zemin kontaminovaných těžkými kovy. V rámci řešení se uskutečnily také tři monitorovací cykly. Popis terénního šetření, odběru vzorků a výsledky chemických analýz.
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Sledování interakcí abiotických složek vodních ekosystémů a rostlin z hlediska jejich kontaminace těžkými kovy: Výzkum vodních ekosystémů v rámci povodí
GEOtest, Brno ; Hillermannová, Michaela
Zpráva zpracovává všechny získané a dosažené výsledky za celé období řešení projektu 2004-2006. Je zde uveden literární rozdělený do částí 1. Sledování interakcí abiotických složek vodních ekosystémů a rostlin z hlediska jejich kontaminace těžkými kovy (sedimenty dna, povrchové vody, podzemní vody, autotrofní organismy - řasy, nárosty, makrofyta, zoobentos a ryby), 2. Kovy v jednotlivých složkách vodních ekosystémů, 3. Fytoremediace a 4. Technologie sanace zemin kontaminovaných těžkými kovy. Zpráva obsahuje výsledky šesti monitorovacích cyklů realizovaných v letech 2005 a 2006. Jsou uvedeny a slovně zhodnoceny výsledky chemických analýz a závěry k cílům projektu. Jedním z cílů bylo získání poznatků o schopnosti vodních rostlin absorbovat těžké kovy obsažené v sedimentech dna a povrchových vodách a ukládat je ve svých tkáních. Dalším cílem bylo porovnání schopnosti akumulace těžkých kovů jednotlivými skupinami vodních rostlin a určení vhodnosti jejich případného využití ve fytoremediačních postupech.
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