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Calcium volume and ratio effect in food of freshwater pearl mussel (Margaritifera margaritifera) on its survival and growth rate
Macháček, Vojtěch ; Horáčková, Jitka (advisor) ; Tichá, Kamila (referee)
The freshwater pearl mussel (Margaritifera margaritifera) is a protected critically endangered species in the Czech Republic, whose juvenile stages are currently unable to survive and grow on many streams, partly due to the absence of quality food with sufficient calcium supply. Pearl mussels only live in oligotrophic rivers and streams, which are generally poor in calcium. However, they need enough calcium in their food, as they use it, among other things, to build a hard shell. It is not yet clear in what form pearl mussels take calcium in their diet, but it is clear that some of its forms are a key factor for the growth and survival of juveniles. We therefore focused on the study of various forms of organic calcium in their diet (fine particulate organic matter, further shortened as "detritus") and further feeding experiments to evaluate their suitability. Within this work, detritus was collected in thirty-five localities in the upper Vltava and Blanice river basins in three seasons in two years. Samples originated both from main river channels, their tributaries and springs. Afterwards, two organic forms of calcium in the samples - citrate and oxalate - were quantified. Then, twenty localities with different contents of both forms of calcium were selected from the tested samples, from which...
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Limit factors for survival of Unionoidea in the freshwater hyporeal with a focus on Margaritifera margaritifera
Macháček, Vojtěch ; Horáčková, Jitka (advisor) ; Barák, Vojtěch (referee)
This bachelor thesis deals with physical, mechanical, chemical and biological factors that limit the occurrence, survival and reproduction of large bivalve molluscs of the Unionoidea superfamily. Accent is placed on freshwater pearl mussel (Margaritifera margaritifera) for which a rescue action plan is being implemented in the Czech Republic, as it is one of the most endangered bivalve mollusc in our country and in Europe. In addition to the already thoroughly explored factors as - water temperature, conductivity, river dynamics, river bed structure, pH, concentration of various forms of nitrogen, phosphorus and oxygen, and the interaction of large bivalve molluscs with other animals, I deal with relatively new issues of pesticides and pharmaceuticals. These are appearing in the streams due to human (in)activity, and we know almost nothing about their impact on large freshwater bivalve molluscs. I also deal in more detail with the issue of calcium, which is essential for bivalve molluscs, because they make their shells out of it, although it is not yet clear which form they accept.
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Limit factors for survival of Unionoidea in the freshwater hyporeal with a focus on Margaritifera margaritifera
Macháček, Vojtěch ; Horáčková, Jitka (advisor) ; Barák, Vojtěch (referee)
This bachelor thesis deals with physical, mechanical, chemical and biological factors that limit the occurrence, survival and reproduction of large bivalve molluscs of the Unionoidea superfamily. Accent is placed on freshwater pearl mussel (Margaritifera margaritifera) for which a rescue action plan is being implemented in the Czech Republic, as it is one of the most endangered bivalve mollusc in our country and in Europe. In addition to the already thoroughly explored factors as - water temperature, conductivity, river dynamics, river bed structure, pH, concentration of various forms of nitrogen, phosphorus and oxygen, and the interaction of large bivalve molluscs with other animals, I deal with relatively new issues of pesticides and pharmaceuticals. These are appearing in the streams due to human (in)activity, and we know almost nothing about their impact on large freshwater bivalve molluscs. I also deal in more detail with the issue of calcium, which is essential for bivalve molluscs, because they make their shells out of it, although it is not yet clear which form they accept.
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Abundance of pearl mussel (Margaritifera margaritifera) in the selected locality in South Bohemia
TULACHOVÁ, Marie
The freshwater pearl musel (Margaritifera margaritifera) is critically endangered species. Its survival depends on the abundance of host fish (Salmo trutta m. fario), on which early mussel stages parasitize. More important is to preserve suitable environment of unpolluted cold rivers with corresponding extensive management of surrounded landscape. To preserve population of pearl mussel in Czech Republic it is essential to describe environmental conditions necessary for its survival. In this study, we observed the influence of water temperature on the abundance of populations of pearl mussel and the individual quantity change after introduction of a new nutriet source. This source is represented by the nutrient stream, flowing through the adjacent grassland with the wide outfall into the river. For the monitoring, the pearl mussels were distinguished into two groups: juvenile and adults forms. The results were evaluated for the both groups separately. We found significant difference between each year, for both, juvenile and adult stage. The year 2009 was an exception, because the difference in the number of adults was not observed. We noticed substantial increase of the number of observed juvenile individuals during summer. The quantity was in direct proportion with the water temperature, but the influence of tempeature was not statistically proved.
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