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Kdo je boss teď? aneb dopad farmaka sertralinu na hierarchii raků
MAREŠ, Josef
Pharmaceuticals' pollution of open waters is a current threat to aquatic organisms. The development of pharmacies and increased consumption of drugs leads to a burden on the aquatic environment with dangerous pollutants. Due to the fast and stressful lifestyle, the consumption of antidepressants increases significantly in the majority of the human population. After consumption and excretion, antidepressants and other drugs enter groundwater and surface water through wastewater treatment plants, which can have a secondary effect on non-target organisms. This master thesis assesses the possible impact of the commonly used antidepressant sertraline on the mutual social behavior of marbled crayfish (Procambarus virginalis). The experiment was based on monitoring the behavior of different pairs of different crayfish. The created dyads assessed mutual interactions between control crayfish, crayfish exposed to sertraline, and reciprocally between both crayfish groups. Three weeks before monitoring, crayfish were exposed to an environmentally relevant sertraline concentration of 1 g?l-1. The results were evaluated by sensory assessment according to available methods, and subsequently, the statistics were assessed. No group of crayfish observed showed a significant difference in behavior. Thanks to the initial phase of experiments of this type, we cannot determine with certainty from the results that sertraline does not affect the social behavior of marbled crayfish. However, along with other antidepressants, sertraline, a selective serotonin reuptake inhibitor, is undoubtedly a potential threat to the environment.
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Vliv různých teplot na konkurenceschopnost raka mramorovaného v agresivních interakcích
KREJČÍ, Miloslav
Crayfish are an important aquatic ecosystems engeneers. Non-indigenous crayfish often decrease the abundance of native species and they affect ecosystem balance. Changes in freshwater ecosystems are usually caused by invasive species of crayfish, especially North American species. These species transmit crayfish plague (Aphanomyces astaci) too. One of these species is marbled crayfish (Procambarus virginalis).Aim of the thesis was an experimental comparison of the competitiveness of marbled crayfish in interspecies interactions with red swamp crayfish (Procambarus clarkii), signal crayfish (Pacifastacus leniusculus) and spiny-cheek crayfish (Faxonius limosus) depending on water temperature. The experiment included 20 runs of interspecific interactions at 16 °C, 18 runs of interspecific interactions at 20 °C and 19 runs of interspecific interactions at 24 °C. Interactions occurred in individual plastic tanks with tempered water. Interactions in tanks were recorded by camera. Subsequently, the agonistic interactions of crayfish were evaluated from 30 minutes of recordings. In conclusion, marbled crayfish is competitive opponent for psychrophilic and thermophilic crayfish species, especially at higher temperatures. The global warming could increase the success of spreading to new areas for marbled crayfish, as well as the survival of winter. In new areas, marbled crayfish could cause negative impacts for native organisms, especially native crayfish species.
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Vliv chloridazonu na raná vývojová stádia raka mramorovaného
ŘEHOŘEK, Martin
The main objective of this bachelor thesis is to evaluate the influence of chloridazon on the early growing stages of marbled crayfish (Procambarus virginalis). The influence of chloridazon is assessed using various factors such as biomarkers of oxidative stress, growth, mortality, ontogenetic development, and crayfish behaviour. The acquired results from this research will extend the current knowledge and data on the influence of chloridazon on crayfish and on water ecosystems.
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Zhodnocení přežívání a růstu dvou invazivních raků v teplotně suboptimálních podmínkách
MARKOVÁ, Kateřina
Biological invasions of non-native species are one of the most serious threats negatively impairing global biodiversity. The negative influence of these invasions is especially noticeable in freshwater ecosystems also exemplified by the populations of native crayfish species in Europe. Dominance of non-native species of crayfish over native ones is relatively well known and studied, but the interactions between individual non-native invasive species are significantly less explored. As the range expansion and numbers of non-native crayfish species constantly increases, it becomes apparent that the non-native species will dominate in European waters. However, it is not clear which of these invasive species, and under which conditions will perform better. The goal of this bachelor thesis was to create a literature review focusing on factors that negatively influence the population of the native species (mainly the issue of non-native species and crayfish plague which these species often transmit). Consideration was paid to the importance of the water temperature for the crayfish and to the focused species used in the experimental part the marbled crayfish Procambarus virginalis Lyko, 2017 and signal crayfish Pacifastacus leniusculus Dana, 1852. The experiment was focused on the evaluation of survival, growth, damage to the claws, and the maturation of these species at the water temperature of ~16 °C, which is in the optimal range for signal crayfish, but suboptimal for marbled crayfish (yet, within a range presumably allowing its successful reproduction). If these species should meet more frequently in the wild, it is important to understand their relationships.
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Porovnání raka mramorovaného a raka pruhovaného: přímá interakce a kompetice o zdroje
MAN, Milan
Biological invasions of non-native species are one of the most serious factors threatening global biodiversity. Their negative impacts are particularly evident in the case of freshwater ecosystems and native crayfish populations that live there. Generally, the higher dominance of non-native crayfish species over the native species is relatively well known, but the interactions between non-native crayfish species are significantly less investigated. Although their distribution is increasingly more important and it is obvious that non-native crayfish species will dominate in European waters. However, it is not yet clear which of these crayfish will be more successful. The aim of this diploma thesis was to create a literature review on the topic of interspecific interactions in crayfish with emphasis on native and non-native crayfish species occurring in Europe. The experimental part of the thesis was focused on the comparison of direct interactions and competition for shelter between the widespread spiny-cheek crayfish Faxonius limosus (Rafinesque, 1817) and the newly increasingly occurring marbled crayfish Procambarus virginalis Lyko, 2017. These species are becoming increasingly common in the European wild, but about their mutual direct interactions and competition is largely unknown. During agonistic interactions the marbled crayfish won in significantly more fights than the spiny-cheek crayfish in the absence as well as presence of the shelter. The marbled crayfish established a significantly greater dominance over the females of the spiny-cheek crayfish in the absence and in the presence of shelter, but not over the males. It is also important to say that the presence of the shelter reduces the number of fights and their total duration. There was no significant difference in dominance established by occupation of shelter between the marbled crayfish and the spiny-cheek crayfish. Still, thanks to its aggressiveness, marbled crayfish is able to compete with other non-native species or displace them from freshwater ecosystems.
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Chování vodních organismů a kontaminace vodních toků? nechtěná léčba deprese a nespavosti u raků
MAREŠ, Josef
This bachelor thesis evaluates the possible effects of pharmaceutically active compounds on non-target fresh water organisms and the risks connected with them. As model organism was used parthenogenetically reproducing non-native marbled crayfish, which were exposed to a mix of five commonly used drugs and one illicit drug - tramadol, citalopram, sertraline, venlafaxine, oxazepam and methamphetamine. The concentration was 1 microgram.l-1 for each of the tested compounds. The main part of the experiment was based on monitoring the behaviour of the exposed and control group of crayfish in arenas with or without shelter. Prior experiment crayfish were exposed for three-weeks to the mixture of compounds mentioned above. The results were analysed in the programme EthoVisionXT and later also statistically evaluated. In the system with available shelters the observed parameters (distance moved and activity) showed significant differences, where the exposed group walked significantly larger distances and was considerably more active than the control group. Exposed group also spent significantly more time outside the shelter. The results in the system without shelter were almost the opposite. The distance moved, velocity and activity were significantly different. The exposed crayfish showed considerably lower activity, velocity and moved shorter distances. The results of this experiment prove that the mixture of monitored compounds can have a significant impact on the behaviour of non-target fresh water organisms. The compounds had a softening effect and can affect sensory receptors of the exposed crayfish, which can have a significant impact on the populations in open waters.
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Vliv herbicidu s-metolachloru na raná vývojová stádia raka mramorovaného
MATERNA, Jan
S-metolachlor is a substance belonging to the group of herbicides, widely used in agriculture to protect crops. This substance with the chemical composition C15H22CINO2 and is used as the pre-emergent herbicides to control unwanted weeds. The aim of this work was to evaluate the influence of s-metolachlor on mortality, behavior, growth, ontogenetic development, oxidative stress level and activity of antioxidant enzymes of early developmental stages of marbled crayfish (Procambarus fallax f. virginalis). The effect of s-metolachlor was evaluated on the basis of embryo-larval toxicity test. Early developmental stages of crayfish were exposed to three concentrations of s-metolachlor, 1.1 micrograms/l, 11 micrograms/l and 110 micrograms/l for 45 days. All tested concentrations significant showed higher mortality, delay of ontogenetic development, lower growth and changes in behavior (total movement distance and movement speed). Moreover, significant decrease in catalase, glutathione-s-transferase, superoxide dismutase concentration, and reduced glutathione levels at the two higher test concentrations (11 micrograms/l and 110 micrograms/l) of s-metolachlor were observed. No significant changes in oxidative damage (TBARS levels) were observed in all the tested groups. Based on the results of this study, early developmental stages of marbled crayfish can be recommended as suitable organisms for toxicity test and their use for biomonitoring of the aquatic environment by herbicides.
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Interaction of non-native species of crustaceans in Czech waters: Predator or prey?
ŠVAGROVÁ, Kateřina
This diploma thesis deals with non-native species of crustaceans, which are already present not only in Europe but also successfully inhabit the territory of the Czech Republic. The species that this work deals with is the signal crayfish (Pacifastacus leniusculus), marbled crayfish (Procambarus fallax f. virginalis) and the killer shrimp (Dikerogammarus villosus). The main goal of this study was to demonstrate the ability of killer shrimp to attack and prey on the crayfish eggs and hatchlings of above mentioned species, which were used not only for theuir presencein Czech Republic but also as model representatives of families Astacidae and Cambaridae. It was therefore the confirmation of high aggressiveness of killer shrimp and point out, that this species is capable of negatively influencing even the bigger invertebrates by direct predation on their early developmental stages. Another aim was to assess whether the killer shrimp can be a suitable prey for a crayfish. As the experiments have shown, killer shrimp is able to predate on crayfish eggs and hatchlings even directly on females abdomens wehre they are incubated and protected. The results confirmed the theory of killer shrimp hazards to aquatic ecosystems and its potential to directly influence the populations of larger organisms. At the same time, it has been found that killer shrimp may be a suitable prey for adult and subadult individuals of signal crayfish and adults of marbled crayfish.
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Embryonic and postembryonic development of marbled crayfish in different temperatures
FOJT, Martin
The aim of this bachelor thesis was to characterise the life cycle by parthenogenetic reproduction of marbled crayfishProcambarus fallax f. virginalis and to focus on the effects of its life cycle at different temperatures. The theoretical part of this thesis is focused on the reproductive biology of crayfish, with emphasis on embryonic and postembryonic development of marbled crayfish. It also acquaints us with the reproduction of indigenous crayfish and introduced crayfish species occurring in the territory of the Czech Republic. The practical part acquaints us with the conditions that need to be adhered during the experiment, changes in embryo development and assessing embryo development at different temperatures. Our experiment confirmed that the postembryonic stages of marbled crayfish were able to survive at low temperature (10 °C). Individuals were able to undergo the first postembryonic stadium at the lower temperature, but they developed slowly. Individuals develop without problems at 15 °C. The duration of postembryonic development was a little bit longer than in warmer temperature. There were expectations that the highest survival rate would be at higher temperatures, but our experiment showed that our predictions were false. Temperature of 20 °C was shown as the lowest survival rate, but we suspect that this poor result wasn't caused by the effect of water temperature, but rather by other physical-chemical water parameters which were not controlled. The highest survival rate of embryos in our experiment was at 15 °C. This thesis deals with the prediction of survival rates of marbled crayfish in the Czech Republic as written in the scientific literature and the obtained results refer to the ability in hatched individuals of marbled crayfish to tolerate the natural conditions of low temperatures in the Czech Republic.
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