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Rozvoj zooplanktonu v rybnících s produkcí rychlených stádií hospodářsky významných druhů ryb
PECHA, Oldřich
This master thesis was focused on zooplankton development in ponds with advanced fry rearing of economically important fish species. For the purpose of my study, we sampled pond cascade that is managed by Štičí líheň - ESOX, spol. s r.o. in the village Liderovice, near Tábor. In this particular pond cascade, the annual production of advanced fry of economically important fish species takes place, namely pike, pikeperch, carp, tench and grass carp. Importantly, pond cascade is used several times during one growing season, and zooplankton is the main food source of all early stages of rared fish. For the production of advanced fry of fish served 3 ponds, which were released and refilled 2-3 times a season. Fourth pond served as a control stocked with one year old carp throughout the whole season. The water from an upper pond in the cascade served as zooplankton inoculum to a lower pond after the pond harvesting. Statistical analyses showed that the fry of different fish species in ponds lying in the same cascade does not affect the composition of zooplankton after restocking and water refilling. The only difference we noticed was in the treatment with pikeperch, which partially does not share the food base of other monitored species.We also found out, that the occurrence of Cyclops vicinus, Daphnia magna, D. ambigua or D. pulicaria was positively correlated with increased P-PO4 concentrations. We also confirmed that pond ecosystem can effectively retain nutrients from basins and use them for its production. As was shown after a short rain when the measured concentration of total phosphorus in the inflow in our pond system was 0.50 mg/L, on the contrary in the last pond of our cascade we measured values below 0.08 mg/L. High transparency was maintained in the whole cascade throughout the monitoring period, and an adequate economic profit was generated. Such management can be applied to only a few ponds (systems).
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Hematologické vyšetření ryb po antiparazitární léčbě
JANÍK, Jan
The aim of this bachelor's thesis was to consider the effect of chosen anti-parisitics on hematological indicators in the blood of fish and consequently study the effect of this medicaments on parasitic disease of lens caused by tremato-da Diplostomum spathaceum. Grass carps infected with trematoda were exposed to broad-spectrum anti-parasitics - praziquantel for 24 hours in the concentrations 2 mg.l-1 and 10 mg.l-1 and also in the benzimidazole derivatve - fenbendazole in the concentration 25 mg.l-1. Afterwards blood was taken from the fish and following indicators were stated - red blood cell (RBC), white blood cell (WBC), hematocrit (PCV), hemo-globin (Hb), mean corpuscural volume (MCV), mean corpuscural hemoglobin (MCH), mean corpuscural hemoglobin concentration (MCHC). Another step was to examine the lens and consider the effect of medicaments on metacercariae of Diplostomum spathaceum. Based on the results it was clear that there was a statistical decrease in the amount of erythrocytes (p<0.05) when using fenbendazole in the concentration 25 mg.l-1. Furthermore the results showed that when the concentration of pra-ziquantel was higher (10 mg.l-1), there was considerable increase in the middle colored concentration (p<0.05). The other indicators did not differ from the pa-rameters of the control groups. This examination showed only small statistically insignificant aberration, which was given by the low initial prevalence of Diplostomum spathaceum in the examined fish.
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Comparison of survival, growth rate and overall breeding of grass carp (Ctenopharyngodon idella) juveniles in pond and recirculating aquaculture system during winter time.
PECHER, Petr
The study compared survival and growth rate in grass carp (Ctenopharyngodon idella) juveniles in pond and recirculation aquaculture system (RAS) during winter time. The juveniles of grass carp were stocked to 5 tanks and three ponds during 2013 and 2014. In the RAS, the fish were fed by dry pellets and rearing was in constant temperature. In the pond, the temperature and feeding were only natural. In the RAS, the survival rate was significantly higher 97.79 % 0.52 % compared to 10.94 % 11.42 % in the pond. At the end of experiment, the weight of fish, Specific growth rate (SGR) and Fulton coefficient (FK) was significantly higher in RAS in comparison with the pond. The results showed that the rearing of grass carp is more effective in RAS in comparison with pond during winter time.
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