Comprehensive work was carried out from May 14 to June 15 and included searching for and outlining natural spawning grounds of the White Sea herring, counting the laid eggs, ichthyoplankton survey, sampling zoo- and phytoplankton, collecting biological material on commercial fish species. Samples were also taken to assess hydrochemical indicators and pollution of the habitat with oil products, aluminum and phenols, and hydrological conditions were monitored. It should be noted that on June 1, the water temperature in the bay was 3-4 degrees lower than long-term values, although in general the winter and early spring season in 2025 was warmer than last year.
No significant catches were noted during the entire period of work. The catch was mainly made up of White Sea cod (50%), up to 20% of the catch was of flounder fish, the share of herring did not exceed 10%, and the remaining species were present in the catches in much smaller quantities or singly. Two species: toothed smelt and European eelpout were noted in similar collections for the first time. During the work, the branch specialists performed a biological analysis of White Sea herring, cod, river flounder, polar flounder and limand, as well as whitefish. It was established that cod spawned within the average long-term period, while river flounder and limand had a delay in the development of sexual products and, accordingly, spawning.
During the observation period, marine mammals were repeatedly noted in Chupa: pinnipeds and beluga whales - both single individuals and groups with cubs.
In addition to field work, the branch specialists held a meeting with the staff of the White Sea Herring Research Institute of the Russian Academy of Sciences, during which they spoke about the research conducted by the Northern Branch. A large number of clarifying questions were asked, and the audience demonstrated interest. It should be noted that such meetings contribute to the development of connections and interactions between related organizations.
The material collected as a result of the work will be used to assess the efficiency of reproduction of the White Sea herring, the number of aquatic bioresources, prepare forecast materials, substantiate the raw material base of fisheries, and develop measures to regulate fisheries.
Press service of VNIRO