EMBRYONIC DEVELOPMENT OF CHINESE CYPRINIDS PELAGOPHILES UNDER CONDITIONS OF ARTIFICIAL REPRODUCTION IN UZBEKISTAN

Abstract

The embryonic development of Cyprinids pelagophiles introduced into Uzbekistan from water bodies of China in the early 1960s was studied. In Uzbekistan, the main is the artificial reproduction of the species with gonadotropic stimulation of maturation and incubation of eggs in apparatuses. The rate of embryonic development is somewhat higher than the rate of development in the Yangtze River, which is explained by the design of the water supply system, which provides a more constant water temperature without its daily fluctuations. The water heated in the pond is pumped into tanks above the incubation shop (capacity 90 tons), where the water also warms up and does not have time to notice cool down during the night period in May-June. The design was influenced by the experience of fish farmers in the mass reproduction of herbivorous fish, there are no night temperature drops as in the conditions of the river (for example, in the Yangtze) and as it was in the 1960s - 1990s. The rate of embryonic development of silver carp eggs in the hatchery of the Research Institute of Fish Breeding begins to affect the stage of embryo hatching and increases towards the transition to exogenous nutrition. Under local conditions, more than 10-15 generations of the species have changed. Embryonic development proceeds normally. At a water temperature of 20 - 24 ° C, embryos hatch after 32 hours.