Comparative Morphobiological analysis of Siberian grayling (Thymallus arcticus, Thymallidae) of norhtern and Polar Urals

The characteristic of a number of populations of grayling of Arctic Urals is given. The features of the external appearance of grayling are described. The main diagnostic features of the numerical and plastic figures are shown; polylepidousness of northern populations of grayling is marked, but one can also find a mosaic manifestation of this trait. Most of the parameters characterize the grayling of the Polar Urals as a subspecies of Thymallus arcticus, although interpopulation differences in average values of indicators of morphotype in the region are fixed. The basic elements of grayling biology – the population structure, age, growth, nutrition and reproduction, are described.