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Selected aspects of intensively cultured European whitefish (Coregonus maraena, Bloch) and peled (Coregonus peled, Gmelin)
ŠEBESTA, Roman
Maraena whitefish and peled are considered to be economically important fish species. This Ph.D. thesis deals with testing of selected aspects which show potential for improvement of quality and effectivity of larvae and juveniles of both fish species in recirculating aquaculture systems. The whole Ph.D. thesis includes 9 chapters described in 125 pages. In chapters 2-8, there are described the individual factors which can influence quality of intensive rearing of mentioned fish species. The effect of light intensity and tank wall colour on growth and survival of peled larvae is tested in chapter 2. The effect of different temperature on growth and survival of maraena whitefish larvae is presented in chapter 3. The effect of various stocking density on growth and survival of maraena whitefish larvae is given in chapter 4. The influence of different feeding strategy on survival, growth, and intestine and liver development of maraena whitefish larvae is being shown in chapter 5. The effect of various weaning time and co-feeding duration on growth and survival of peled larvae is described in chapter 6. The effect of variable water oxygen saturation on growth and haematological profile of peled juveniles is shown in chapter 7. The prevalence of deformities in intensively reared peled and comparative morphometry in intensively reared fish compared to pond-reared fish is described in chapter 8. Ph.D. thesis contains important advices which can be used in fishery practise and at the same time they can prevent from elevated fish mortality.
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Využití recirkulačních systémů při odchovu říčních druhů ryb
LEPIČ, Pavel
Using of recirculation systems for rearing of fish is common practice in Western Europe countries. Benefits of this systems are utilized in recovering programs of endangered species of fish. In this work we had paid attention on suitability of RAS for rearing Nase, Vimba bream and Barbel. In the first part two six-month experiments were conducted. The five-month-old nase and vimba bream had been trained on pellet feed and acclimated to four different temperatures. The WT fluctuated in parallel with ambient outside conditions at an average of approximately 4 °C for the inflow system and approximately 15, 18 and 21°C in closed, recirculation systems. The total length and weight were measured at two-week intervals and SGRw, FCR and survival were monitored. We observed a positive effect of higher water temperatures on their growth rate of each species. Both groups (WT 21°C) had the most rapid growth and highest SGRw. Growth rate and SGRw were lowest for each species in group with the ambient temperature conditions. Lower temperature at the level of 18°C gave good results in comparison to rearing in cold water. Individual weight was 3.25 and 4.13 times higher for nase and vimba bream, respectively. The temperature 15°C was chosen with regard to the functioning of the biofilter and in this experiment, it proved to be a minimal temperature suitable for rearing of river fish species in RAS. The economic costs to maintain this temperature is low, but the effect of production considered this level of WT as very less effective in several aspects. To conclude this part, we found intensive winter rearing of nase and vimba bream is an effective way to prepare fish for spring restocking. In the second part we have tested suitability of Vimba bream as a trainer fish for adaptation of pikeperch for commercial pellet diet. One of the basic problems in pikeperch culture in RAS is adapting early life stages to pelleted feed (PF). Our work compares four different ways of adapting 6-week-old pikeperch fingerlings to feeding on a commercial diet. The methods were designated, A - use of trainer fish and direct application of PF; B - use of trainer fish and gradual addition of PF with natural food (NF, chironomid larvae); C - direct application of PF only; D - gradual addition of PF with NF. The growth trial experiment (including adaptation to PF) lasted 14 days by which time all experimental groups were accepting PF. Pikeperch fingerlings in group A grew significantly faster and PF was more readily accepted compared to other groups. Other characteristics observed (total weight increment, FCR) also support the use of trainer fish and direct application of PF for pikeperch in their adaptation to intensive culture. The aim of the final study were to compare the effect of anaesthetics MS 222, clove oil, 2- phenoxyethanol and Propiscin on haematological and blood biochemical profiles in vimba bream. The haematological and blood biochemical profiles of vimba bream anaesthetized with MS 222 (100 mg/l), clove oil (33 mg/l), 2- phenoxyethanol (0.4 ml/l), Propiscin (1.0 ml/l) and non-anaesthetized control group were tested. Each tested group was divided into two subgroups. The first subgroup was sampled immediately after 10-min anaesthesia. Second subgroup was sampled 24 h after 10-min anaesthesia. The 10-min of exposure to the anaesthetics had no effect on the haematological profile of vimba bream. The effect of anaesthetics on biochemical indices of blood plasma was demonstrated. The exposure of the anaesthetics 2-phenoxyethanol and Propiscin influenced levels of glucose, ammonia and the activity of aspartate aminotransferase compared with the control group. The level of triacylglycerols and the activity of lactate dehydrogenase was affected to exposure of MS 222. Based on the results only clove oil had no effect on the haematological and blood biochemical profiles. Other anaesthetics tested more or less affect value of blood biochemical profiles.
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Vliv délky světelného dne na příjem krmiva a růst síha peledě (Coregonus peled) v intenzivním chovu
KOS, Martin
The effect of the length of the daylight on growth of in peled (Coregonus peled) juveniles was tested in the intensive culture. Fish of mean body weight 1.82 +- 0.48 g and total length of 65 +- 7 mm were divided into four groups (the ratio of light and darkness 12k12, 16k8, 20k4, 24k0). The experiment lasted for sixty-three days. Every twenty-one days fishes were sampled for biometric measurements. Fish reached mean body weight of 15 +- 4.9 g (12k12); 15.6 +- 4.5 g (16k8); 16.7 +- 4.5 g (20k4); 16.8 +- 5 g (24k0) in experimental groups. The longest total body length was detected in both 20k4 and 24k0 groups (127 +- 11 mm). The lowest one was registered in the 16k8 (114 +- 11 mm). The highest condition coefficient had group 16k8 and lowest was found out in group 20k4. Specific growth rate during the course of the experiment was 3.33 %xday -1 (12k12); 3.28 %xday -1 (16k8); 3.49 %xday -1 (20k4) and 3.43 % xday -1 (24k0). The highest final survival (95.8 +- 1.4 %) was achieved in group 12k12. On the contrary, group 16k8 showed lowest survival of 90.0 +- 4.6 %. There were no significant differences in final survival rate.
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Vliv zvolené strategie na efekt počátečního odchovu jesetera malého (Acipenser ruthenus) v kontrolovaných podmínkách
Dostál, Jan
The thesis summarizes findings from the field of initial rearing of sterlet (Acipenser ruthenus) that are currently available. The results of experimental rearing, which took place in 2014 and consisted of two parts, are included. In the first part, the impact of the exchange rate of the water in the tanks on change of hydrochemical parameters. For the experiment three variants in duplicate were prepared, with different flow rate for each one. The volume of water in the tanks was set to 100 liters and the number of fish was 150 fish/tank. Water change rate within the first variant was set for 1/3 of volume per hour, within the second variant for 1/3 of volume per hour and within the third variant for 3/3 of volume per hour. Each day was measured oxygen content, water temperature and pH, and samples for laboratory analysis were being taken. The results were analyzed by analysis of variance. No statistically significant difference has been found between monitored parameters, therefore these flow rates had no impact on the change of hydrochemical parameters for each variant. In the second part of the experiment was compared the effect of three different feed mixtures on growth parameters and development of fish. The same conditions of the rearing environment were maintained, but stocking density was reduced to 50 fish/gutter and a uniform water change rate of 3/3 volume per hour was set. The first variant was presented feed Aller Bronze 2 mm, the second variant Aller Silver 2 mm and the third variant Biomar Inicio 918 2 mm. At the beginning of the experiment, the fish reached an average piece weight of 29.00 g and FWC 0.44 within the first variant, 29.70 g and FWC 0.43 within the second variant and 29.31 g and FWC 0.41 within the third variant. At the end of the experiment the fish reached monitored parameters with following values: the first variant had the average piece weight of 37.99 g, FWC 0.41, SWGR 0.90 %.d-1, FCR 2.12 kg.kg-1 and PER 1,01; within the second variant, the average piece weight was 40.38 g, FWC 0.41, SWGR 1.02 %.d-1, FCR 1.82 kg.kg-1 and PER 1.18; within the third variant, the average piece weight was 43.51 g, FWC 0.40, SWGR 1.44 %.d-1, FCR 1.44 kg.kg-1 and PER 1.46.
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Water temperature influence on the success of intensive farming of burbot (Lota lota L.)
CHOTĚBORSKÝ, Michal
The aim of this work was to realize the first intensive rearing of juvenile fish of burbot in the Czech Republic (TL = 165.79 +- 18.87, W = 32.91 +- 10.27 g) in recirculation aquaculture system (RAS) at different water temperatures. A total of 9 tanks were used in the three separate RAS systems. For a period of 12 weeks survival (S), specific growth rate (SGR), feed conversion ratio (FCR) and the condition of the fish (FC) was observed at 3 week intervals. The best values of survival (98 +- 0.4%) were achieved in burbots kept at a water temperature of 15 ° C. Survival in the group of fish kept at a water temperature of 18 °C did not statistically differ from the group of fish reared at 15 °C and 21 °C. The SGR value for the fish at a water temperature of 15 °C was (0.7 +- 0.09%.d-1) at 18 °C the SGR value was (0.45 +- 0.1%.d-1) and fish kept at a water temperature of 21 °C reached SGR values of 0.33 +- 0.04%.d-1. The best FCR values (1.27 +- 0.35) were reached also in the group of fish kept at 15 °C. For burbot kept at a water temperature of 21 °C, the FCR value was 2.78 +- 1.17. Based on our results we can conclude that the most appropriate water temperature for rearing juvenile burbot was 15 °C.
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Vliv obsádky na dynamiku hydrochemických parametrů v systému intenzivního chovu lososovitých ryb
Teplý, Martin
Aim of the thesis was to evaluate the influence of fish stock on the hydrochemical parameters of the water in Recirculating systems. A part of the work was elaboration of the literature review on the topic. In the experimental part was performed several trials under laboratory and practical conditions. The first trial aimed on comparison of hydrochemical parameters between recilculating system with biological filtration and recirculating system without biological filtration. There was studied a content of nitrogen compounds. The content of ammonia nitrogen was higher in the system without filtration (0.2 -- 1.0 mg.l-1) than in the system with biological filtration (0.1 -- 0.4 mg.l-1). In the system with the biological filtration was higher a content of the nitrite nitrogen ranged from 0.14 to 0.16 mg.l-1. In the system without filtration ranged content of nitrite nitrogen from 0.01 to 0.1 mg.l-1. In the next trial was monitored a development of the hydro chemical parameters in recirculating systems after their launch. Two monitoring was made. In the first three weeks was observed increased content of ammonium nitrogen, after its reduction increased nitrite nitrogen. These compounds were sufficiently degraded roughly after a one month. The third trial was aimed on changes in recirculating systems during 24 hours. Monitored were contents of nitrogen compounds, oxygen and pH. The lowest content of ammonium nitrogen was registered at night. The biggest increase of ammonium nitrogen was found after feeding of the fish. Content of nitrite nitrogen increased during monitoring due to biological degradation of ammonium nitrogen in filter. The biggest decrease of oxygen was registered after fish feeding. Oxygen decreased op to 10 percent. The pH continuously decreased during monitoring due to CO2 production of fish and biological processes in filter.
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The effect of temperature on feed intake and growth of peled (Coregonus peled) in intensive culture.
VÁLEK, Pavel
The effect of water temperature within the range from 13 to 25 °C was tested on two weight cohorts of fish (age 74 and 230 days post hatch) during two subsequent growing experiments. Significantly better growth rate within the temperature range from 19 to 22 °C was observed in younger fish (initial body weight 0.60 +- 0.04 g). The mean individual weight at the end of the experiment was followed 5.19 +- 1.59 (13°C), 8.16 +- 2.08 (16 °C), 9.78 +- 2.50 (19 °C), 9.06 +- 2.75 (22 °C) and 4.70 +- 2.13 g (25 °C). Significantly lower survival (29.6 +- 6.3 %) was monitored in fish reared at 25 °C. Significantly higher growth heterogeneity (CV 50.1 +- 5.1 %) was observed in fish reared at 25 °C in comparison with the other groups. Significantly better growth rate within the temperature range from 16 to 22 °C was observed during second experiment on older juveniles (initial body weight 13.7 +- 2.9 g). Final mean body weight in appropriate group was observed as followed 25.2 +- 6.8 (13 °C), 30.3 +- 7.1 (16 °C), 29.7 +- 8.0 (19 °C), 30 3 +- 8.8 (22 ° C) and 23.9 +- 5.5 g (25 °C) at the end of the experiment. Fish reared at temperatures 22 and 25 °C showed significantly lower survival rate (70.8 +- 18.8 and 40.8 +- 6.3 % respective) in comparison with the other groups.
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Adaptation of Intensively Bred Juvenile Fish of Pikeperch (\kur{Sander lucioperca}) to a Pond Condition
CHOTĚBORSKÝ, Michal
The aim of this study was to evaluate the adaptability of juvenile fish of pikeperch (Sander lucioperca) artificially bred in the recirculation system, which were planted to experimental ponds. Within this study of adaptability, the survival rate of planted fish and their growth in determined period was observed. Later, after several months of breeding the pikeperch in experimental ponds, the returnable adaptability was evaluated, when the fish from ponds were returned to the recirculation system, where they were adapted back to the controlled breeding conditions and artificial feed. Again, the survival rate and growth of adapted fish was evaluated.
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Impact of teperature, fish size and feeding on oxygen consumption and ammonia excretion in the african catfish (Clarias gariepinus)
KOMENDOVÁ, Jana
Aims of this thesis were to assesed the impact of feeding, temperature of water and fish size on ammonia excretion and oxygen consumption in Clarias gariepinus in recirculating system. Fish were divided in 8 weight categories from 21 to 2495 g. Experiments were performed under four temperatures: 22°C, 25°C, 28°C and 30°C. Fish were acclimatized, light conditions were: 14 hours of light period and 10 hours of dark period. Feeding was provided fed four times a day. Starved fish were measured. Measurements were held every two hours. Oxygen consumption was measured by multimeter and ammonia excretion using Nessler?s method. Average daily oxygen consumption in fed fish was dependent on temperature and average individual weight of fish, varied from 10.5 to 96.6 mg O2/kg/h and in hungry fish from 4.3 to 61.8 mg O2/kg/h. TAN excretion varied from 0 to 59.9 mg TAN/kg/h in fed fish and from 0 to 60.8 mg TAN/kg/h in hungry fish. Oxygen consumption increased with increasing temperature. Ammonia excretion was very unstable at all temperatures in all weight categories. Fish had higher ammonia excretion in light period of experiment.
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