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Comparison of different ways of breeding, nutrition and controlled reproduction of Lota lota
ZÁVORKA, Milan
Based on the results reached after 216 days of experimentation with various breeding types, it can be said that the type of feed is not of paramount importance. This fact is based on the previous adaptation of submitted food, this is especially important for artificial feed. From our point of view, the more important factor is temperature, intensity and method of breeding. Prey selections choices involving 11 species of fish were performed on age groups of different burbot. All groups of burbot preferred the following species: grass carp, pikeperch, tench and stone moroko. The non-preferred species was ruffe. And different preferences were set for common carp, silver carp, burbot, sunfish and also for roach. The study evaluated reproductive parameters in burbot (Lota lota ) and focused on incubation time in two localities. Burbot spawning was observed from January to early February at an average temperature of 1.55 +- 0.9 °C in Borova Lada and 4.78 +- 0.11 °C in Mydlovary. For burbot at the age of 2+, at an average 1166 +- 100 were determined number of swollen eggs per gram. Relative fecundity was at 257260 +- 70678 eggs per kilogram of female. The absolute fecundity was at 24232 +- 6753 eggs.The last parameter evaluated was the incubation period. The average incubation period in the years 2020-2022 was 202 +- 24.55 °D in Mydlovary and 75.8 +- 16.67 °D in Borova Lada. In connection with artificial spawning, in this study, we further point out the possibility of peeling artificially spawn eggs with NaClO, in which we did not observe a negative effect.
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Posouzení možnosti reintrodukce lipana podhorního vysazením uměle odchovaných generačních ryb v předvýtěrovém období
PASTEJŘÍK, Jan
My bachelor s thesis deals with the possibility of reintroduction of the European grayling (Thymallus thymallus) into open waters by stocking artificially bred generation fish in their pre-spawning period. 3-4-year-old broodfish, bred in the pond Hulák in Prachatice, were used for the experiment. Then in the spring the fish were marked and stocked in the parts of FROV JU fishing ground, where fish were previously caught with electric aggregates and the local composition of fish stocks was examined. In the same way, a control catch was carried out also in the autumn - this time there was a main focus on the presence of the European grayling and juveniles. In addition, a follow-up section of the river (outside the experimental sections) was fished out and most fish were caught here. Based on the results of the monitoring, it can be said that in the section of the river where artificially bred generation fish were stocked at least partially successful natural spawning took place. Although the number of caught fish in the autumn was low (11 fish), this approach might be considered as promising in terms of the possibility of supporting the occurrence of the European grayling in open waters and suitable for further testing. Only 6 % of stocked generation fish were caught out 7 months after stocking. The size of these fish was practically the same as when stocked. In case of using this approach within the fishery management, it is necessary to stock generation fish no more than a few weeks before the expected spawning.
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Management generačních ryb candáta obecného (Sander lucioperca) a jeho vliv na produkci jiker a larev
MALINOVSKYI, Oleksandr
This thesis provides an improve to existing reproduction technics through investigation of ecology and physiology features of pikeperch broodstock: (I) Spawning behavior and selectivity to different types of spawning substrates as an important part of the biology of pikeperch species. The main output of the study was revealing of strong selectivity to the spawning site with neither water temperature nor availability of spawning places haven't affected substrate preference of pikeperch broodstock. (II) Spawning in captivity is leads to decrease in physiological status of the pikeperch broodstock, especially in females. It was found that one of the reasons of the decrease was male protective behavior, that in limited space of the reproduction unit is forwarded to female. Separation of the sexes significantly reduces number injuries and improved physiological status of the broodstock. (Ill) The study investigated efficiency of different antifungal agents for pikeperch broodstock. The long term exposure to salt bath in concentration of 2.5, 5 and 10 g L-1 and formaldehyde in concentration 0.015 ml L-1 were found to be highly effective and significantly decreased mortality after spawning. In addition, treatment with salt bath are environmentally friendly and recommended for practical use as an effective way to prevent mortality of pond-cultured pikeperch broodstock. (lV) The provision of live feed is crucially important for proper gametes maturation, particularly in pond-cultured fishes not accepting pellets. The study investigated the effect of temperature on daily biomass of prey consumed by pikeperch broodstock. Significantly increased prey consumption was found after temperature reached 4.5 °C. Females exhibited significantly higher prey consumption rate in compare to male. Study revealed the tendency for pikeperch to consume largest available prey after water temperature reached 8.5 °C.
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Breeding burbot (Lota lota L.)in the Czech Republic
MRÁZ, Luděk
Zabývám se chovem mníka jednovousého různými metodami chovu a to od váčkového plůdku až po ročka (jednoletou rybu) s možným výhledem do budoucna jako s tržní rybou. Také srovnávám poloumělý a umělý způsob výtěru. Krátce se zmiňuji i o chovu v zahraničí především Polsko a Německo. Navrhuji opatření na zvýšení produkce a uplatnění mníka na našem trhu jako konzumní ryby.
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Induction and optimalization out-of-season spawning of spawners pikeperch (Sander lucioperca)
VLČEK, Jakub
In total, 21 pairs of pikeperch brood stock were divided into three groups and used during two out-of-season and one seasonal semi-artificial spawning. The only differences among these three groups were the length of cold water period (CWP) and spawning date. Group of earlier spawning (A) CWP = 122 days, Group of normal spawning (B) CWP = 149 days, Group of late spawning (C) CWP = 223 days). Dates of spawnings A 11.3., B 26.4., C 13.6). There were observed and assessed the main production parameters such us latency, successful spawning, fertilisation and hatching rate etc. in each group and spermatozoa quality (sampled one day after the observed spawning). In Group A and B, 100 % of fish successfully spawned. Fertilisation rate was 59.4 % (Group A) and 80.3 % (Group B). Much worse results were obtained in Group C. Only 42.9 % of fish spawned and the fertilisation rate was zero. There was no difference among the three groups in spermatozoa quality parameters. It means that the poor fertilisation rate in Group C was caused by low egg quality. According to our results we can say that it is possible to successfully spawn pikeperch earlier (before the main spawning season) with comparable result to the natural spawning season. However, it is necessary to find some better way for female stimulation to provide higher egg quality and subsequently higher fertilisation rate.
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Reproduction Burbot burbot (\kur{Lota lota}) and incubation of eggs at different temperatures in service
MIKEŠOVÁ, Lucie
The study evaluated the reproductive performance in Burbot burbot (Lota lota L.) and compared the incubation period at two locations. It was confirmed that the burbot wipes at the end of December and beginning of January with an average temperature of 1,93 ? 0,8 ° C. It was found that the content of the eggs in one gram is 3325 ? 248 pieces eggs and 1 ml is 1434 ? 24 pieces of eggs. Also, to evaluate the size of eggs before and after swelling. Size before swelling was 0,814 ? 8 mm and the swelling 0,838 ? 7,1 mm. Further, the absolute and relative fecundity and GSI, the absolute fecundity was 289,279 ? 204,759 pieces of eggs, the relative fertility of 763,523 ? 110,061 pieces of eggs per kilogram of body weight of fish and GSI was 23,15 ? 3.9%. The last parameter was rated incubation period. The incubation period was Vodňany 178,4 ° D and Borových Ladách 145,4 ° D.
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Optimization of artificial spawning of pikeperch (Sander lucioperca) using HCG and new ways of removing artificial stickiness of eggs before incubation.
BLECHA, Miroslav
The object of the thesis is to experimentally find the most suitable method of artificial spawning of pikeprech, using hormonal stimulation of ovulation in females hormonal medication containing HCG. After scraping of the broodstock and after artificial fertilization of eggs obtained experimentally test new methods of artificial stickiness removing of eggs and then evaluate the success of artificial incubation of stripped, fertilized and unstickeness eggs of pikeprech. Experiments that are part of the thesis have been divided into several sub-experiments. In the first experiment was observed effect of different doses of hormonal Chorulon, containing the active substance HCG, the basic indicators of reproductive females. Was evaluated as spawning synchronization, spawning success, the number of spontaneous spawnings, fertility of females and hatching rate of eggs. The used HCG doses were 250, 500, 700 and 1000 IU per kilogram of body weight. All eggs were deprived of stickiness using a mixture of talc and milk. In the second experiment was carried out comparing different types of removes stickiness solutions. Here was evaluated especially time and labor intensity and the influence of various solutions on fertilization and hatching rate of eggs. In this trial was all pikeperch females injected the same amount of HCG hormone 500 IU per kilogram of body weight. Tested solutions was a mixture of talc and milk, just eggs wash water and the solution of various concentrations alkalase. The amount alkalase was 0,5; 1; 1,5; 2 and 5 ml, which are mixed with distilled water, so that the total volume of the solution was 1000 ml. The third experiment was supposed to simulate the pilot plant mass propagation of pikeperch females. All females received the same amount of hormone 500 IU of HCG per kilogram of body weight. All eggs were deprived of stickiness using a mixture of talc and milk. In the last experiment was one of the methods tested, which could limit the number of spontaneous spawning during the artificial spawning of pikeperch. To prevent spontaneous spawning were selected females (all were injected with 500 IU of HCG per kilogram of body weight) sewing genitourinary papilla. The incubation of eggs collected during all the experiments were used Zugské bottle.
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Spawning of domesticated eurasian perches in controlled conditions of fish breed
TRNKA, Petr
The eurasian perch (Perca fluviatilis Linnaeus, 1758) is considered as very perspective species for breeding at intensive aquaculture, where was successful domesticated. Consumption of eurasian perch is increased at present. The greatest grow of consumption is mainly in countries of alpine region and in Scandinavian countries. The aim of experiment was monitor and character spawning of domesticated eurasian perch in controlled conditions of breed. It was determinated fertility and then fertilization of eggs. The next aim was make incubation of fertilization eggs and determinate hatching. After hatch was determinated total length of larvae and its quality by the help of osmotic shock. Domesticated eurasian perch is spawned without problems in controlled conditions of breed. The resulting data of domesticated perch are worse than date of non-domesticated perch in some spawning characteristic. This problem will resolve with gaining knowledge about spawning of eurasian perch. The greatest problem is hatching of eggs, which is very low during spawning of domesticated perch.
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