21 August 2025

Whitefish spawning run: research by VNIRO scientists on the Severnaya Sosva River

Specialists from the Tyumen branch of the Russian State Research Center “All-Russian Research Institute of Fisheries and Oceanography” (VNIRO) have begun key monitoring studies of the season – studying the spawning migration of whitefish species in the Ob-Irtysh basin.
 
Scientific studies are being conducted simultaneously on several main spawning rivers. For three weeks now, specialists from the Nikita Laboratory of Fisheries Ecology have been conducting a survey of the migrating ichthyofauna in the Northern Sosva.
 
Peled and tugun – Sosva herring are actively going to spawn, whitefish-pyzhyan is starting their spawning run, and schools of whitefish producers are expected in the Northern Sosva in September. Of the partial group of fish, ide, roach and dace are actively going to winter.
 
Scientists of the industry conduct research on the branch's own vessel, and here, on board - in the field laboratory, they conduct primary processing of hydrobiological samples and perform biological analysis of fish: they record the length, weight of individuals, filling of the gastrointestinal tract, readiness for spawning. The age of each fish will be determined by the scales in the stationary laboratory.
 
The comprehensive scientific accounting of the floating stocks of valuable commercial ichthyofauna in the Northern Sosva will last two months. During this time, specialists will conduct hydroacoustic surveys every day at different points of the river. Its data will provide information on the concentration of floating stocks and the number of fish going to spawn and wintering grounds.
 
Press service of VNIRO