Complex work was carried out from May 18 to June 16 and included: search and delineation of natural spawning grounds of the White Sea herring, counting of laid eggs; ichthyoplankton survey, zoo- and phytoplankton sampling; collection of biological material on White Sea cod, White Sea herring and flounder; sampling for hydrochemical indicators, samples to assess pollution of the habitat of aquatic biological resources with petroleum products, aluminum and phenols. The work program necessarily included basic studies of hydrological indicators.
The estimate for seeding spawning grounds with White Sea herring caviar in 2024 can be assessed as average. There was no mass hatching of herring larvae in 2024, due to the abnormally cold year (water temperature at the beginning of the third ten days of May was 3-4 °C), followed by a sharp rise in water temperature to 9 °C and a drop to 5 °C after the storm, These environmental conditions negatively affected the development of herring embryos. Herring larvae were sporadically observed along the water's edge in coastal waters.
Employees of the Northern Branch took the following fish species for biological analysis: White Sea herring, White Sea cod, river flounder, polar flounder, and limanda flounder. In Chupa Bay, a larger number of herring was recorded compared to last year; accordingly, more pinnipeds and beluga whales were spotted, both single individuals and groups.
Compared to last year, the amount of significant catches shifted by about 2 weeks until the beginning of June; in May, the composition of the catches was marked by single catches both in net fishing gear and with spinning rods. The bulk of the catches were White Sea cod, the share of the catches was 51%, White Sea herring was 28%, other species were significantly smaller, the smallest species - polar flounder - less than 1%. Cod spawned within the average long-term period; in river flounder and limanda there was a delay in the development of reproductive products and, accordingly, spawning.
The collected material will be used to assess the abundance of aquatic biological resources, prepare forecast materials, substantiate the raw material base of fisheries, as well as develop measures to regulate fisheries.
VNIRO press service