Growth of the Whitefish Coregonus lavaretus (Salmonidae: Coregoninae) in the Ural Tributaries of the Pechora River

Abstract

For the first time, we represent a comparative characteristic of the growth of, presumably, the freshwater form of the whitefish Coregonus lavaretus in the Ural tributaries of the Pechora River. The growth rate of the whitefish in the studied rivers varies significantly, which testifies the assumption of existence of several local groups in the Pechora river system, confined to different parts of the river basin. In the Ilych and Kosyu rivers as well as in the upper reaches of the Pechora River (Northern Urals), the calculated body lengths and linear growth rates do not differ significantly. Similar growth rates have been observed for the whitefish from the plain tributaries of the Pechora (lower reaches of the Kosyu and Usa rivers). In the rivers of the Subpolar Urals, the variability of whitefish growth rates is significantly higher. The specific growth rate of the subadult whitefish positively correlates with the benthos biomass in the watercourse (ρs = 0.57 according to Spearman, p = 0.04), while the dependence on climatic conditions is less significant.