On the size and index of the scale from of Thymallus thymallus (L.)

Some data on the alteration of the size of the index of the scale from in the onthogenesis of different phyla of Thymallus thymallus (L.) in the basin of the Kama river have been given. Considerable changes of longitudinal and vertical sizes of the scale in seasonal and age depending factors as well as some ecotypical peculiarities have been shown.