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Detection and variation of the crayfish plague pathogen in selected crayfish populations
Mojžišová, Michaela ; Petrusek, Adam (advisor) ; Buřič, Miloš (referee)
Crayfish plague is an emerging disease caused by the oomycete Aphanomyces astaci, a pathogen listed among the 100 World's Worst Invasive Alien Species. It was introduced into Europe in the second half of 19th century from North America and caused collapses of European native crayfish populations. Nowadays, A. astaci is widespread in Europe and has spread also to other parts of the world, threatening all susceptible crayfish of non-North American origin. The aims of this MSc thesis were 1) to provide information about crayfish plague outbreaks from recent years, and by using microsatellite and mtDNA markers reveal A. astaci genotypes involved; 2) to test healthy-looking indigenous crayfish for potential occurrence of chronic infections by A. astaci in Czechia. Six new crayfish plague outbreaks were confirmed from 2016 to 2018, involving at least five distinct pathogen strains. My results provide first evidence of the A. astaci genotype group D causing Astacus astacus and Austropotamobius torrentium mass mortalities in Czechia. MtDNA sequencing revealed two haplotypes of the D haplogroup, indicating two independent sources of infection presumably either from ornamental crayfish or spreading from neighbouring countries. The genotype group A was recorded in two A. astacus mortalities and genotype group...
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Factors influencing diurnal activity of crayfish and its seasonality
Plasová, Kateřina ; Petrusek, Adam (advisor) ; Buřič, Miloš (referee)
Crayfish is mainly but not exclusively a nocturnal animal. The crayfish aktivity is taxon specific and can be further affected by various factors. The aim of this thesis is to create an overview of factors affecting the activity and to summarize their impact. Factors can be divided into those influencing daily activity and those influencing seasonal behaviour. This thesis focuses on discussing different reactions to the factors and its intensity by individual species. Insufficient data covering activity during the winter season offers an opportunity for further research. Key words: crayfish; daily activity; abiotic factors; biotic factors; seasonality
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Detection and variation of the crayfish plague pathogen in selected crayfish populations
Mojžišová, Michaela ; Petrusek, Adam (advisor) ; Buřič, Miloš (referee)
Crayfish plague is an emerging disease caused by the oomycete Aphanomyces astaci, a pathogen listed among the 100 World's Worst Invasive Alien Species. It was introduced into Europe in the second half of 19th century from North America and caused collapses of European native crayfish populations. Nowadays, A. astaci is widespread in Europe and has spread also to other parts of the world, threatening all susceptible crayfish of non-North American origin. The aims of this MSc thesis were 1) to provide information about crayfish plague outbreaks from recent years, and by using microsatellite and mtDNA markers reveal A. astaci genotypes involved; 2) to test healthy-looking indigenous crayfish for potential occurrence of chronic infections by A. astaci in Czechia. Six new crayfish plague outbreaks were confirmed from 2016 to 2018, involving at least five distinct pathogen strains. My results provide first evidence of the A. astaci genotype group D causing Astacus astacus and Austropotamobius torrentium mass mortalities in Czechia. MtDNA sequencing revealed two haplotypes of the D haplogroup, indicating two independent sources of infection presumably either from ornamental crayfish or spreading from neighbouring countries. The genotype group A was recorded in two A. astacus mortalities and genotype group...
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