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A new tool for improvement the quality of water ecosystems
Blabolil, Petr ; Říha, Milan ; Peterka, Jiří ; Prchalová, Marie ; Vašek, Mojmír ; Frouzová, Jaroslava ; Jůza, Tomáš ; Muška, Milan ; Tušer, Michal ; Draštík, Vladislav ; Ricard, Daniel ; Sajdlová, Zuzana ; Šmejkal, Marek ; Vejřík, Lukáš ; Matěna, Josef ; Borovec, Jakub ; Kubečka, Jan
The Czech multimetric fish based index (CZ-FBI) was developed recently. The aim of CZ-FBI is to assess the ecological potential of heavily modified and artificial water bodies and to detect ecosystems, particularly their specific components, in unsatisfactory conditions. This article describes steps of CZ-FBI development. Since the philosophy used, particular events presenting the results, to recent stage. CZ-FBI is a part of certified methodology of the Ministry of the Environment of the Czech Republic and the comparison with other assessment methodologies within a geographical intercalibration group is in process.
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Past, present and future of lake trauts
Blabolil, Petr ; Peterka, Jiří ; Čech, Martin ; Draštík, Vladislav ; Frouzová, Jaroslava ; Jůza, Tomáš ; Kratochvíl, Michal ; Matěna, Josef ; Muška, Milan ; Prchalová, Marie ; Říha, Milan ; Sajdlová, Zuzana ; Šmejkal, Marek ; Tušer, Michal ; Vašek, Mojmír ; Vejřík, Lukáš ; Kubečka, Jan
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What do the fish say about the quality of aquatic ecosystems
Blabolil, Petr ; Říha, Milan ; Peterka, Jiří ; Prchalová, Marie ; Vašek, Mojmír ; Jůza, Tomáš ; Čech, Martin ; Draštík, Vladislav ; Kratochvíl, Michal ; Muška, Milan ; Tušer, Michal ; Frouzová, Jaroslava ; Ricard, Daniel ; Mrkvička, Tomáš ; Sajdlová, Zuzana ; Vejřík, Lukáš ; Šmejkal, Marek ; Borovec, Jakub ; Matěna, Josef ; Boukal, David S. ; Kubečka, Jan
The first Czech methodology for the assessment of ecological potential of heavily modified water bodies and artificial water bodies based on fish communities was developed. The first step of developing the methodology was preparing the typology of water bodies. The typology distinguishes between water bodies of different altitudes and with and without thermal stratification. Fish were sampled by multimesh gillnets following European standard procedures. The selection of fish metrics was based on statistical analyses in which metrics (fish community indicators) were correlated with the most common stressor – eutrophication. The analysis detected several sensitive metrics (metrics showing the best correlation with the stressor) in which ecological class boundaries were set. Afterwards, combination of sensitive metrics was used for calculation of the ecological quality ratio (EQR) for each of the reservoir sampled. The EQR expresses the deviation between a reservoir’s current ecological status and its maximum potential. The next step consisted of validating the EQR with an independent pressure index and verifying the time stability of ecological potential assessment. The metrics used in the methodology fulfill all the obligations set forth in the Water Framework Directive (2000/60/EC), which include assessment of the composition, abundance and age structure of fish fauna.
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Fish behaviour in response to a trawl gear
SAJDLOVÁ, Zuzana
Předkládaná práce by měla čtenáře blíže seznámit s chováním ryb, které tito živočichové vykazují vůči vlečným sítím během vzorkování pelagiálu vodních těles. Zaměřuje se na oblast v ústí tralu, kde je spektrum reakcí nejširší. Některé specifické rysy chování jsou uvedeny na příkladech z mezinárodních výzkumů v teoretické části. Jsou zde rovněž přiblíženy základní techniky, používané při studiu chování ryb ve vztahu k vlečným sítím. Praktickou částí je dvouletý výzkum (2009 a 2011) chování ryb na českých údolních nádržích Želivka a Římov ve vztahu k tralovým sítím. Chování ryb v ústí pelagického tralu bylo monitorováno prostřednictvím vertikálního sonaru SIMRAD EK 60 o frekvenci 38 kHz. Předmětem výzkumu bylo studium reakcí jednotlivých ryb se zaměřením na vertikální složku jejich pohybu. Zjišťovali jsme rozdíly mezi denní a noční aktivitou ryb, rychlost a sklon ve vodním sloupci, přímočarost trajektorie pohybu, souvislost mezi velikostí ryb a jejich rychlostí, a v neposlední řadě také vliv abiotických faktorů, které únikové chování podstatně ovlivňují. Znalost tohoto typu chování pomůže vypovědět o selektivitě zařízení, kterou je vhodné znát pro efektivní průzkum zdejších nádrží. Stejně tak užitečné jsou nové informace o vlastním chování ryb, které jsou přínosem nejen pro ekologii.
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ELECTROCHEMICAL DETECTOR WITH ELECTRODES ARRAY AND ROTATING DISK
SAJDLOVÁ, Zuzana
The thesis deals with the testing and optimization of hydrodynamic conditions of the electrochemical detector, which consists of a flow cell containing the electrochemical sensor with an array of electrodes. The flow cell includes a rotating disc-shaped component, which allows radial flow of analytes along the sensor electrodes. This principle imitates the rotating disk electrode, with the difference that here the electrodes are immobile. Hydrodynamic phenomena in this case are similar to RDE. Therefore, the theoretical part of my work deals with hydrodynamics and mass transfer for the well-described case of rotating disk electrode. It was found that in the current set-up under certain conditions, an analyte flowed back from the output cell channel to the sensor, even at the laminar flow. This causes a nonlinear response of the electrodes and their low reproducibility. The solution is to reduce the distance between the rotation component and the electrodes surface and reduce flow speed of analyzed liquid towards the sensor. A novel type of sensor with annular electrodes was designed and tested. It showed four times higher conversion rate of the analyte compared with the originally used AC9 electrochemical sensor having electrodes in the form of full circles lying on a circumference of a common circle. Based on calculations, conversion of the analyte on the plane electrode can be increased up to 100% when using this annular sensor, adjusting flow cell and reducing of the input flow rate. The detector was connected to the liquid chromatograph and its function was tested on two substances - ascorbic acid and dopamine. For the current detector these parameters were set: dynamic range, linearity, noise, detection limit, time constant and the temperature range at which the detector can be operated.
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Fish avoidance behaviour in response to a trawl gear
SAJDLOVÁ, Zuzana
The main objective of the thesis is an introduction to the problematics of fish avoidance behavior in response to a trawl gear towed by one or two trawlers (motor boats). Avoidance or escape reactions are dependent on many factors and ecological conditions influencing animals´ behaviour therefore it is necessary to refer about fish sensory organs and perception. The content also deals with methods useful for studying fish behaviour in the wild. These are invasive and noninvasive technics and methods like acoustics, video cameras and towed gears (mainly trawls). All of them have become an important tool in recent surveys of marine environment as well as freshwater lakes and reservoires.
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