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Spatial distribution of the European catfish Silurus glanis influenced by familiarity
Fořt, Martin ; Slavík, Ondřej (advisor) ; Kozák, Pavel (referee)
One of the key elements of animal social behaviour is the recognition of individuals on the basis of previous experience. This relationship is called familiarity and affects individual's behaviour. We know many examples of familiarity-based behaviour among fish. Many results show that familiarity is advantageous. Familiar individuals are less aggressive, forage more, make more cohesive shoals and grow faster. We tested the influence of the familiarity on the spatial distribution of juvenile wels catfish Silurus glanis from two unfamiliar groups, which were held in separate tanks. In a laboratory experiment was the spatial distribution of individuals monitored in the artificial stream by using passive integrated transponders. Shelters, which were occupied by individuals, were placed in the stream. Two groups of fish were subsequently added into the experiment under conditions of limited or unlimited shelters. These groups came from the same tank (so they were familiar) or from different tanks (so they were unfamiliar). 1080 individuals were used in this experiment and over three million individual fish positions were recorded. We discovered changing levels of activity under different conditions. When we compared activity of original and additional individuals, we measured higher level of activity in...
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A behaviour of the European catfish Silurus glanis in the mating season and for rest of the year with focus on social interactions among individuals
Lüftner, Radek ; Slavík, Ondřej (advisor) ; Randák, Tomáš (referee)
Reproduction ability is the key factor for survival and dispersal of every species. There is, however, only limited information about reproduction of large-bodied fish. Males of European catfish, our biggest native fish, build nests in vegetation and mate there later with females. After succesful mating male guards the nest and takes care of eggs and fry. According to literature, the act of reproduction should take place at nights with water temperature from 18 to 24 řC. However, available records about reproductive behaviour are outdated, fragmentary or come from aquacultures. Thus, a study was designed to evaluate behaviour of European catfish in their natural environment in the Berounka river using radiotelemetry, the results of which I processed in this thesis. Spatial distribution of catfish was followed during the whole year, with special attention on separating mating season from the rest of the year. The goal was to determine conditions characteristic for the mating period and to verify that catfish in the field indeed reproduce in pairs. For this purpose, 10 adults were tracked for two-year period (2002-2004) in the Berounka river by radiotelemetry. Exact positions of all individuals were followed in fourteen-day cycles. In every tracking episode, the position of an individual fish was...
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European catfish (Silurus glanis, Linneus 1758): Is the global warming the main reason of increasing of catches of the largest freshwater predator in Europe?
Bakeš, Michal ; Čech, Martin (advisor) ; Černý, Martin (referee)
European catfish (Silurus glanis, Linneus 1758) is our only fish which amount of catch is growing in our country in the last thirty years. The main goal of my work is to find out if global warming is essential for increasing catch of catfish, or whether rising temperatures are marginal, and the main reason is growing focus of fishermen on catfish. This thesis summarized knowledge about effect of global warming on ecosystems mainly on freshwater bodies that seem to be the most influenceable among terrestric ones. The enlarging populations of catfish in countries of south Europe (e.g. Spain, Italy) where catfish was recently introduced can be explained by the fact that warm water is suitable for catfish. However, some socioeconomic studies carried out in the Czech Republic as well as abroad clearly demonstrate that popularity of catching of catfish increases in time. I verified this idea by the results of my questionnaire survey, where 82 % of respondents approved that the popularity of catfish among fishermen is highest in the last decade. Based on the evidence we can say that increasing temperatures has a positive effect on the metapopulation of catfish in the Czech Republic, but this influence seems to be marginal. The main reason for still increasing catch is very likely the change of preferences...
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Spatial distribution of the European catfish Silurus glanis influenced by familiarity
Fořt, Martin ; Slavík, Ondřej (advisor) ; Kozák, Pavel (referee)
One of the key elements of animal social behaviour is the recognition of individuals on the basis of previous experience. This relationship is called familiarity and affects individual's behaviour. We know many examples of familiarity-based behaviour among fish. Many results show that familiarity is advantageous. Familiar individuals are less aggressive, forage more, make more cohesive shoals and grow faster. We tested the influence of the familiarity on the spatial distribution of juvenile wels catfish Silurus glanis from two unfamiliar groups, which were held in separate tanks. In a laboratory experiment was the spatial distribution of individuals monitored in the artificial stream by using passive integrated transponders. Shelters, which were occupied by individuals, were placed in the stream. Two groups of fish were subsequently added into the experiment under conditions of limited or unlimited shelters. These groups came from the same tank (so they were familiar) or from different tanks (so they were unfamiliar). 1080 individuals were used in this experiment and over three million individual fish positions were recorded. We discovered changing levels of activity under different conditions. When we compared activity of original and additional individuals, we measured higher level of activity in...
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A behaviour of the European catfish Silurus glanis in the mating season and for rest of the year with focus on social interactions among individuals
Lüftner, Radek ; Slavík, Ondřej (advisor) ; Randák, Tomáš (referee)
Reproduction ability is the key factor for survival and dispersal of every species. There is, however, only limited information about reproduction of large-bodied fish. Males of European catfish, our biggest native fish, build nests in vegetation and mate there later with females. After succesful mating male guards the nest and takes care of eggs and fry. According to literature, the act of reproduction should take place at nights with water temperature from 18 to 24 řC. However, available records about reproductive behaviour are outdated, fragmentary or come from aquacultures. Thus, a study was designed to evaluate behaviour of European catfish in their natural environment in the Berounka river using radiotelemetry, the results of which I processed in this thesis. Spatial distribution of catfish was followed during the whole year, with special attention on separating mating season from the rest of the year. The goal was to determine conditions characteristic for the mating period and to verify that catfish in the field indeed reproduce in pairs. For this purpose, 10 adults were tracked for two-year period (2002-2004) in the Berounka river by radiotelemetry. Exact positions of all individuals were followed in fourteen-day cycles. In every tracking episode, the position of an individual fish was...
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Hormonal induction of artificial stripping of the female European catfish (Silurus glanis)
BORKOVEC, Tomáš
The optimalization way of hormonal induction ovulation females European catfish Silurus glanis was the aim of experiment with the help of hormonal preparate on the base functional of the analogue GnRH. Fish with females were fish out in the ponds early in june and injected by hormonal preparates CPE, Dagin and Ovopel. Was monitoring latency time in dependency of water temperature, percent of ovulated females, relative weight of ovulated eggs, fertilization eggs and hatching performance.
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