An integral part of the technological preparation of artificial cultivation of brine shrimp in saline water is a set of preliminary experimental work to assess the quality of cysts. It has been shown that during the winter period, activation of Artemia cysts occurs from the initial hatching values of 5-10 % to 72-99 %. The most optimal salinity range for hatching nauplii is a salinity of 20-30 g/l. With an increase in salinity above these indicators, hatching decreases. The size of hatching of Artemia depends on the salinity of a natural reservoir. In reservoirs with salinity of 50-80 g / l, higher hatching rates were obtained than with salinity of 150-160 g/l. Higher hatching rates are observed when using natural lake water for incubation. During incubation of cysts in a standard solution and fixed salinity and temperature conditions, the development rate of various stages of nauplii from the beginning of the opening of cysts (breaking stage) and pre-nauplius to active nauplii is shown. After 1.5–2 h after the mass appearance of pre-nauplii, they completely change into the nauplius stage.
This paper presents the results of a study of the macrocomponent composition of 15 salt lakes of the Pavlodar region. For the first time, based on the data of the chemical composition and pH of the waters, the geochemical classification of the lakes of this region has been proposed. The study shows that the majority of the analyzed objects are lakes of chloride type with sodium cationic composition.
Artemia cf. parthenogenetica Bowen and Sterling, 1978 is widely distributed in the saline lakes of Northern Kazakhstan. Female Artemia can easily be recognized by a brood pouch full of cysts before being released. The number of cysts can be used to estimate both individual reproductive performance and the entire population. During the studies involving Artemia reproductive performance, it was observed that throughout the growing season, in the water bodies, there were females whose well-developed brood pouches were partially filled with cysts. Thus, we were confronted with a question about the relevance of using females with partially filled brood pouches to determine the reproductive performance of Artemia. The number of cysts in a full brood pouch and a partially filled brood pouch revealed consistent differences in the following statistical indicators: average reproductive performance, coefficient of variation, and average minimum and maximum reproductive performance. As the percentage of females in the population with cysts not yet ready to be released increases, the percentage of females with partially filled brood pouches decreases. The general conclusion is that the use of females with partially filled brood pouches underestimates the valid value of average reproductive performance and also changes the pattern of the reproductive performance distribution. The obtained results prove that only females with a full brood pouch should be used when assessing the reproductive performance value of Artemia.
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