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Fish population on the river Dyje at NP Podyjí
Štrunc, David ; Kalous, Lukáš (advisor) ; Kuříková, Pavlína (referee)
This thesis is focused on changes of fish populations in the river Dyje located at the national park Podyjí. These changes are caused mostly due to presence of two large dams (Znojemská and Vranovská dam) between which w the study locality is situated. There are also other factors affecting ichtyofauna composition as piscivorous predators, non-native species or restocking of particular target species. First information about the fish populations appeared in year 1921. In that years, the locality contained species, that are not present at the river site at the moment. Examples given: sturgeon (Acipenser ruthenus) and danube salmon (Hucho hucho). These species extincions were associated with interupted fish migration between locality and Donau river basin. On the other hand, new fish pecies (that are not-native to Czech Republic and were not observed before 1921) started to appear during following years. From the former fish population of type Barbus-Chondrostoma the type changed to Salmo-Thymallus. Most of this change was caused by regular restocking of the salmonids. Since 1993 there is evidence on new presence of tolerant fish species that do not necesarilly need cold, flowing water. There is high probability, that this appearance is caused by slowing down the river stream and also the heating of the water, that takes place in the dam.
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Environmental risk assessment of ornamental aquaculture
Patoka, Jiří ; Kalous, Lukáš (advisor) ; Antonín, Antonín (referee)
The ornamental aquaculture comprises both outdoor and indoor keeping of aquatic animals and plants for ornamental purpose which is a very popular hobby with many followers worldwide. It is also commercially profitable for specialized producers and vendors. Associated environmental risks include particularly introduction of non-native species, biological invasions and intensive field capture of exploited and marketed species. Since subsequent regulation, mitigation and eradication of naturalised alien species is very difficult and ineffective in many cases, the most important above all is to prevent new introductions. This trend is accented with a short delay in European legislature. The European Union (EU) currently initiates formation of list of the most invasive alien species. Although invasive potential of certain ornamental species such as red-eared slider (Trachemys scripta elegans) is well known, the vast majority of traded species has never been tested and analysed from this point of view. Publications attached to this thesis are focused on monitoring and survey of market with ornamental animals, such as fishes and crayfishes, with special emphasis on list of advertised species, size classes, prices, origin and availability on market. With use of predictive models the probability of naturalisation and potential invasiveness of mentioned ornamental species were estimated. These information are supported by analysis of hobbyist behaviour. Results in present thesis highlight known environmental risks associated with ornamental aquaculture and also show detailed information about overlooked risks from the Czech Republic's as well as from EU perspective. Therefore this thesis should to help formation of aforementioned list of the undesirable species.
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Elephant fishes in pet trade
Habartová, Anna ; Kalous, Lukáš (advisor) ; Kuříková, Pavlína (referee)
This thesis discusses the family Mormyridae and the use of its representatives in the ordinary aquarium. It provides further informations about morphology, physiology and location of the general representatives of the family, and particularly focuses on Gnathonemus petersii, as one of the representatives of the ability electroreception, electrolocation and electrogenezis. Furthermore there are in the text informations about the use of electrical signals such as communication, orientation in space, or the perception of live and lifeless objects and their distribution in space. The work also includes a sociological research about breeding of African fish, which was realized among Czech aquarists.
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Application of bioscanners and videotechnique for studies of fish migration
Porš, Jaroslav ; Kalous, Lukáš (advisor) ; Lucie, Lucie (referee)
In recent years there has been a significant decrease in abundance and species diversity of migrating fish. A significant decrease was recorded especially in diadromous fish species such as Atlantic salmon (Salmo salar) and eel (Anquilla anquilla). A significant population decline was also observed in potamodromous abundant fish species. Transverse barrier which prevents fish migration in rivers and impaired water quality are considered as the main causes of this situation. At present there is being improved a surface water quality, habitat rehabilitation and restoration of the possibility of free migration of aquatic animals. Design and construction of fish ladders are the most important factors to improve conditions of the fish migration. Closely related to this is a migration permeability testing of these fish ladders while the biological function and the activity of a single technical solution is evaluated. A non-invasive automatic monitoring method using a bioscanner Riverwatcher was selected to assess the functionality of fish passage on the river Ohře in Kynšperk nad Ohří. Bio scanner was installed at the end of the track of fish passage. Riverwatcher camera system, a product of Vaki Aquaculture Systems Ltd., was used in the Czech Republic for the very first time. Direct catches of fish samples in the river using an electric unit (section under fishway) were also used for the data collection. Size and species selectivity was tested at the fish ladder. The influence of external factors affecting the course of migration, such as flow rate, water temperature and light, was monitored at the same time.
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Optimization of the rearing of the species Danio rerio (Hamilton, 1822)
Gottwald, Milan ; Kalous, Lukáš (advisor) ; Martin, Martin (referee)
The diploma thesis summarizes the experimental method for the rearing of zebrafish Danio rerio (Hamilton, 1822) screed. The work of figuring out which of the methods of rearing fry in the transitional period of the ontogenetic development is best for the survival rate and growth of the standard length of the surveyed individuals.
The test was carried out on two basic lines of zebrafish Wild Type and Casper. At the beginning of the test were created four groups divided by feeding mode. The control group was fed once a day with pellet feed GEMMA Micro 75 and one day from the 10th day after fertilization the fed with nauplii stages of brine shrimps Artemia salina (Linnaeus, 1758). The second group was fed only once a day with pellet feed GEMMA Micro 75. The last two groups were fed five times a day saltwater rotifer species Brachionus plicatilis (Müller, 1786), and only one of them and the other was still three times daily nourished with nauplii stages of brine shrimps. For each group of four representative have been created initially, thirty tanks of fish at the age of five days after fertilization.
The results of this method have shown that the methods they use to feed the rotifers, did not have a statistically significant impact on the survival rate of individuals. In the growth of this method has proven to be statistically significant result in the group where the fed in combination with brine shrimps, where to achieve the average standard size of juvenile fish 16.02 +/- 0.80 mm for the Wild type and 17.39 +/- 0.81 mm for Casper, compared to the control group, that has been the standard length 11.63 +/- 0.64 mm for the Wild Type and 9.54 +/- 0.56 mm for Casper.
This method has great potential and breeding is therefore necessary to further develop this method and to adapt it to individual zebrafish facilities.
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Fish production with usage of aquaponics
Tůmová, Veronika ; Kalous, Lukáš (advisor) ; Nechanská, Denisa (referee)
This bachelor thesis deals with fish and plant production in aquaponic systems. It describes the principle of aquaponics, the interaction between individual system elements, use of technical equipment and technology. Thesis links the connection in different requirements of each ecosystem component in water quality parameters and nutrient intake. In the second half, it deals with fish and plant production strategies, plant and fish species suitable for aquaponics and with economics of the production. Thesis is focused on aquaponic systems as such in general with greater focus on the smaller one, hobby aquaponics.
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