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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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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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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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