National Repository of Grey Literature 13 records found  previous11 - 13  jump to record: Search took 0.01 seconds. 
Evaluation of Efect Mechanicle a Nitrifying Biological Filters in Recirculating Aquacultere Systeme with Intensive Fish Farming.
OLBERT, Karel
Aim of my work is influence of high level breeding of Euroasian perch on quality of water and operation of mechanicle drum filter and fluized bed biofilter. Euroasian perch is reared in recirculating aquaculture systeme. Fish were devide into six groups in dependence on their body weight. Groups of fish with avarage start weight (g) {$\pm$} SD; biomass (kg) 232,9 {$\pm$} 10,0; 15,14 (I), 196,4 {$\pm$} 8,1; 15,32 (II), 139,8 {$\pm$} 6,1; 15,10 (III), 102,4 {$\pm$} 5,5; 15,06 (IV), 59,4 {$\pm$} 5,5; 15,04 (V), 37,7 {$\pm$} 7,5; 15,00 (VI) were put into plastic tank (600l). Three measurement was with fed fish and three measurement with food-deprived fish. Fed day was organised like feeding period (light phase) 12 hours and 12 hours non-feeding period (dark phase). First part of my project was about impact mechanicle filtration to remove solids from water. Mechanical filter can keep the water quality on perfect level for fish farming. Second part was about evaluation of nitrifying biologickle filters. Biologicle filtration was did her function well, because levels of amonia, nitrite and nitrate were keep on optimum values. Third part of my project was about measurement of oxygen consumption and amonia excretion. Was observed significant diurnal changes of oxygen consumption and amonia excretion for fed fish. For food-deprived fish was observed significant diurnal changes of oxygen consuption. Changes of amonia excretion were not significant.
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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