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Transmission and detection of the crayfish plague pathogen under experimental conditions
Svoboda, Jiří ; Petrusek, Adam (advisor) ; Fiala, Ivan (referee)
The crayfish plague pathogen, Aphanomyces astaci, is one of the most serious threats to European indigenous crayfish species, e.g., the noble crayfish (Astacus astacus). The only way to protect susceptible crayfish species from the disease is to prevent the dispersion of the pathogen to their populations. One of the most important sources of the crayfish plague pathogen in Central Europe is the spiny-cheek crayfish (Orconectes limosus), a species of North American origin, which can carry the parasite in its cuticle for years. Some literature sources claimed that the pathogen dispersion from the American vectors is restricted to periods of moulting or to the time before and after the crayfish death. However, experimental evidence for such hypotheses was lacking. The main aim of my thesis was to test these predictions, and the alternative scenario that the crayfish plague pathogen can be transmitted from the infected spiny-cheek crayfish also in other periods. For this purpose, experiments were set up to investigate A. astaci transmission from infected spiny-cheek crayfish to non-infected spiny-cheek or noble crayfish. As expected, the pathogen was transmitted to noble crayfish much more easily than to the uninfected American host. Nevertheless, we succeeded in the pathogen transmission also among spiny-cheek...
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Seasonal variation of activity and pathogen prevalence in populations of the spiny-cheek crayfish
Matasová, Klára ; Petrusek, Adam (advisor) ; Slavík, Ondřej (referee)
The most widespread of invasive crayfish in the Czech Republic is the spiny-cheek crayfish (Orconectes limosus). It is a major disease carrier of crayfish plague, caused by the pathogen Aphanomyces astaci. The infection is lethal to European native species of crayfish. Transmission of this disease is usually associated with the spread of crayfish, which is dependent on their movement. The main aim of this work was to evaluate the differences in crayfish migratory activity in the Pšovka brook among seasons, and assess the factors that may affect it, by the use of radiotelemetry and trapping. We tested the hypothesis that crayfish use brook in the period from spring to autumn and then return back into a pond to overwinter. Furthermore, we evaluated how far from the pond crayfish migrate, and whether there is any relationship between migration and the season or water temperature. The results demonstrate that the activity varies among seasons (being strongly affected by breeding season) but in most studied periods did not significantly depend on water temperature. According to our monitoring, the spiny-cheek crayfish does not spread substantially to upstream parts of the Pšovka. Seasonal migration between the pond and the brook was monitored using two-way flow-through traps installed at the mouth of...
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Seasonal variation of activity and pathogen prevalence in populations of the spiny-cheek crayfish
Matasová, Klára ; Petrusek, Adam (advisor) ; Slavík, Ondřej (referee)
The most widespread of invasive crayfish in the Czech Republic is the spiny-cheek crayfish (Orconectes limosus). It is a major disease carrier of crayfish plague, caused by the pathogen Aphanomyces astaci. The infection is lethal to European native species of crayfish. Transmission of this disease is usually associated with the spread of crayfish, which is dependent on their movement. The main aim of this work was to evaluate the differences in crayfish migratory activity in the Pšovka brook among seasons, and assess the factors that may affect it, by the use of radiotelemetry and trapping. We tested the hypothesis that crayfish use brook in the period from spring to autumn and then return back into a pond to overwinter. Furthermore, we evaluated how far from the pond crayfish migrate, and whether there is any relationship between migration and the season or water temperature. The results demonstrate that the activity varies among seasons (being strongly affected by breeding season) but in most studied periods did not significantly depend on water temperature. According to our monitoring, the spiny-cheek crayfish does not spread substantially to upstream parts of the Pšovka. Seasonal migration between the pond and the brook was monitored using two-way flow-through traps installed at the mouth of...
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Transmission and detection of the crayfish plague pathogen under experimental conditions
Svoboda, Jiří ; Petrusek, Adam (advisor) ; Fiala, Ivan (referee)
The crayfish plague pathogen, Aphanomyces astaci, is one of the most serious threats to European indigenous crayfish species, e.g., the noble crayfish (Astacus astacus). The only way to protect susceptible crayfish species from the disease is to prevent the dispersion of the pathogen to their populations. One of the most important sources of the crayfish plague pathogen in Central Europe is the spiny-cheek crayfish (Orconectes limosus), a species of North American origin, which can carry the parasite in its cuticle for years. Some literature sources claimed that the pathogen dispersion from the American vectors is restricted to periods of moulting or to the time before and after the crayfish death. However, experimental evidence for such hypotheses was lacking. The main aim of my thesis was to test these predictions, and the alternative scenario that the crayfish plague pathogen can be transmitted from the infected spiny-cheek crayfish also in other periods. For this purpose, experiments were set up to investigate A. astaci transmission from infected spiny-cheek crayfish to non-infected spiny-cheek or noble crayfish. As expected, the pathogen was transmitted to noble crayfish much more easily than to the uninfected American host. Nevertheless, we succeeded in the pathogen transmission also among spiny-cheek...
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Epizoa of crayfish
PŮBALOVÁ, Lenka
The aim of my work was to evaluate quantitatively animals, which colonizes the surface of the noble crayfish (Astacus astacus). Epizoa was sampled using baths in magnesium chloride. This work was concentrate especially on the genus Branchiobdella. Data were collected from three sites. Two sites were in the Czech Republic and the third was sampling site in Austria. Two species of species occurred Branchiobdella (B. parasita and B. pentodonta) were found of the seven in Europe. Only B. parasita was found in the Czech Republic. B. parasita (88%) dominanted over B. pentodonta (12%) in Austria. Furthermore were Ciliata particularly Epistylis and Vorticella; Rotifera in the genus Keratella, Lecane and Branchionus; Acanthocyclops and Ostracoda and genus Plumatella were determined on the crayfish originated from Vodňany.
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Activity of noble crayfish (Astacus astacus) and spiny-cheek crayfish (Orconectes limosus) under the laboratory coditions
MUSIL, Martin
Activity of noble crayfish (Astacus astacus) and spiny-cheek crayfish (Orconectes limosus) under the laboratory coditions University of South Bohemia České Budějovice - Faculty of Agriculture, Department of Fisheries Author: Martin Musil Contact: mue.@seznam.cz Abstract: Some authors point out, that the American species are more activated than European during the day. Noble crayfish (Astacus astacus L.) is the night animal. Spiny-cheek crayfish (Orconectes limosus Raf.) is the most agresive species with more activity during the day, whose is of itself ecologic and reproductions characteristic typical r{--}strategist. And over than above it is a vector of crayfish plague. Objective of this study was the observe the daily and noctural of both species, the influence of fish predators and murmurs of agresivity. The bulk of this work was in ethologic laboratory with using videotechnic in control conditions and directed lightregimen. The findings see the big diference between species, that the spiny-cheek crayfish is more activated that the noble crayfish (51,4%{$\pm$}4,33 of the 24 hour activity) with slight diference between the day and night. Someones of the subjects don´t look for the cover during the experiment, it were mainly the females, whose activity were better than the male. Noble crayfish embodied low aktivity (15,1%{$\pm$}8,22 of the 24 hour activity) with more highly diference between the day and night and with slight diference between the sex. The inherence of the fish predator have had slight influence on the both species, rather sometimes take on the crayfish attention. The agresivity of the both is at least comparable, so it isn´t clear, that the spiny-cheek crayfish would be more successful in proximate competetion without the infection of crayfish plague.
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