Variability of siberian sculpin <Emphasis Type="Italic">Cottus sibiricus</Emphasis> (Cottidae,Sorpaeniformes)

The morphometric characteristic is composed and special traits of the biology of seven populations of the Siberian sculpin Cottus sibiricus from three large river basins of Siberia are considered (the Lena, Yenisei, and Ob basins). The studied populations demonstrate a rather wide range of variation of biological characteristics and exterior characters. The fish from different water bodies differ in longevity, growth rate, term of maturation, and, as a consequence, in definite size. However, there is no geographic regularity in this variation. Morphometric investigations also demonstrated the absence of clear geographic variation at a relatively high intrapopulational polymorphism. With consideration of the obtained data, it may be concluded that in spite of internal heterogeneity there are no reasons for subdivision of the Siberian sculpin into geographic forms (subspecies).