The regulation of osmotic and ionic balance in fish reproduction and in the early stages of ontogeny

On the basis of the modern literature data we analyzed the influence of the level of salt concentration and ion composition in a fish habitat during the processes of reproduction. The results of studies of the mechanisms of the reaction of fish to gamete hypo- and hyperosmotic stimulus in the external aqueous environment, as well as the role of mineral and organic osmolytes in the adaptation of mature eggs of fishes in the external environment, depend on the hydrochemical and hydrological conditions of the spawning grounds. The paper provides information about the features of the endocrine regulation of oocyte maturation in fish spawning in different hydrological conditions and the importance of humoral factors in the pathological process of the maturation of fish oocytes. The main scientific and practical aspects of the formation of the phys mechanisms that regulate the water-salt balance is the early ontogeny of fishes are discussed.