Artificial reproduction of the European grayling (Thymallus thymallus Linnaeus, 1758) in the rivers of the Carpathian region

Рurpose. To develop scientific bases for reproduction of European grayling populations by the Carpathian River basin in artificial and natural conditions. Method ology. Fishery volumes were determined on the basis of indicators of development of the natural forage base of river systems. Actual weight gains in the younger age groups and estimated mortality rates. Natural mortality coefficients were calculated from the parameters of the Bertalanffy equation, which was determined on the basis of the actual size and age parameters of the grayling. Survival of seagrasses was determined on the basis of the calculated coefficient of natural mortality in the first year of life and the ratio of survival of different age groups, which for larvae and seagulls weighing 5 g was 3.7. Findings. The analysis of the available data shows the fundamental possibility of introducing a viable European grayling youth to replenish the reproductive nucleus of the natural population, which in turn will create objective prerequisites for population growth and create prospects for viewing the conservation status. The parameters of the Bertalanffy equation, calculated on the average size and age parameters of the grayling of the Transcarpathian rivers, were: K (year-1) - 0.297; L∞ (cm) - 36.9; t0 (year) - 0.168. natural mortality, differentiated by age, and, accordingly, annual mortality rates. On the basis of this, the indicators of instantaneous natural mortality, differentiated by age, and, accordingly, indicators of annual mortality were determined. The potential accumulation of grayling ichthyomas can be determined on the basis of the total annual mortality and the actual weighting by size classes. The baseline stocking index can be used as a baseline weighted area (based on area). Yew, which is 418.6 copies. / ha of annuals. The bioproductive potential of the rivers of the Carpathian region allows to increase fish productivity on the European grayling by an average of 8.6-21.2 kg / ha. For this purpose, during the four-year period, it is necessary to fish the Tisza River basin with a grayling of at least 5 g with a total amount of 620.5 thousand. Ex. per year. and the Prut River Basin - 122,000 copies. per year. Originality. Methodical approaches for determining quantitative indicators of grayling activities are substantiated. Practical value. The practical implementation of the obtained results will be carried out during the reproduction and cultivation of viable planting material, regulation of quantitative and qualitative indicators of fishing.