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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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The shell shape plasticity of Thick Shelled River Mussel (Unio crassus, Unionidae) depending on locality and size variables
Jandáková, Miriam ; Douda, Karel (advisor) ; Petrtýl, Miloslav (referee)
This thesis focuses on shell shape plasticity of Unio crassus at 12 localities. 1129 shape outlines were used for the purposes of this work. The outlines were gained from 260 individuals in the way of analysing the winter growth lines. The Elliptic Fourier Analysis appeared to be reasonable tool for the bivalves' shells shapes assessment. The winter growth lines' consideration showed great potential for morphometric analyses. The results shows that PC1 and PC2 axes (from principal component analysis of shape coeficients) are growth- dependent. The allometry influence was removed by residual values assessment obtained from generalized linear model (GLM). The age, length and width parameters appears to be favourable combination for general allometry influence removal (by using these parameters as describing variables in GLM model). The results point to significant differences among localities in all assessed parameters. Furthermore, the significant difference in growth speed was approved. Speed growth indicator correlates with shape variables. The localities can be divided into two groups with different growth speed each (Bertalanffy growth constant, length in the third year and age relative length). These groups differs in about 10 mm in average lengths. The most similar localities were "Blanice...
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