Scientists have completed their research into the fish fauna of the Yenisey River estuary. Rosneft's Tamura corporate programme provided support for the expedition. The studies concluded the series of fieldwork conducted as part of the environmental programme.

The Tamura project was launched in 2024 and is scheduled to run until 2027. Scientists are studying the Kara subpopulation of polar bears, wild reindeer and valuable species of birds and fish in western Taymyr. The data collected will help update information on the condition of key fauna species in the Far North.

The primary objective of the new expedition was to study the current state of the fish fauna in the estuary of the Yenisey River and its food supply during the summer.

The expedition assembled leading researchers from the Lomonosov Moscow State University Centre for Marine Research, the Murmansk Marine Biological Institute of the Russian Academy of Sciences, and Rosneft's Arctic Research Centre. Specialists conducted a biological assessment of the Yenisey’s most widespread and precious fish species, including muksun, whitefish, and omul.

The first stop for the expedition was the most remote net-setting station in the Tanalau River area. The research vessel proceeded along the Yenisey, concluding its journey in Dudinka. In total, the scientists completed work at six stations, and the expedition covered a distance of over 500 kilometres. The work was conducted in a number of areas, including the main riverbed itself, as well as the major branches – Ushakov and Tolstaya Zemlya – and its tributaries, including the Bolshaya Kheta, Tanalau and Muksunikha.

Key size and weight indicators, as well as feeding characteristics, were determined for each species. This data will make it possible to evaluate the condition of the fish during their feeding migrations, assess their habitat conditions, and significantly complement the findings obtained during the 2025 studies.

In addition, the research team attended the Fisherman's Day celebrations in the Nosok settlement on the banks of the Ushakov branch. Ichthyologists carried out a comprehensive biological analysis of the fish caught during the Taymyr Fishermen competition, and also interviewed local residents to gather information about their catches – fish numbers, species diversity and catch dynamics over the last few years.

Once the fieldwork has been completed, the collected samples, including scales and fins, will be sent to specialist laboratories for office analysis. As fish grow, annual growth rings form on their scales and fins. These rings can be used to determine the age of the fish and reconstruct the characteristics of their individual growth. To evaluate the species composition of the fish, molecular genetic testing of water samples will be conducted.

The initial stage of work studying the Yenisey River's precious fish species in 2025 comprised a comprehensive suite of research, including an assessment of the population status of the most precious fish species and the environmental conditions of their habitats, but during the autumn period. Scientists covered over 600 km of the Yenisey estuary, including its most vital and major tributaries—the Bolshaya Kheta, Pelyatka, Dudinka, Tanalau, and Muksunikha rivers.  A biological analysis of the fish was performed in an on-board laboratory. Research locations were selected following a review of ichthyological and hydrobiological studies published over the past 90 years.

Rosneft pays special attention to biodiversity conservation, implementing the most extensive Arctic research programme since Soviet times. Since 2012, 65 expeditions have been conducted, during which scientists have studied the hydrometeorological, geological, and biological features of the region. It has been the source of a unique body of information on Arctic climate, nature and wildlife.

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Rosneft
July 10, 2026