The main objective of the research is to assess how the Atlantic salmon population is recovering and in what conditions it lives. For the Arkhangelsk region, Atlantic salmon is not just a valuable commercial species, but also an important indicator of the state of northern rivers: its well—being directly reflects the ecological health of the watercourse.
The scientists conducted control fishing using spinning rods and fishing nets, and in the spawning and growing areas they considered the fry to be a special device. This comprehensive approach allows us to obtain comparable data and not miss key abundance indicators at different stages of the fish life cycle. The catches included not only juvenile salmon, but also grayling, pike, perch and other fish. This information is also important: it helps to create a more complete picture of the river's ichthyofauna and understand how different species interact in the same ecosystem.
At the same time, the researchers collected samples of phyto‑ and zooplankton, zoobenthos, to understand how rich the river's food supply is. Planktonic and bottom—dwelling organisms are the basis of the nutrition of juvenile salmon, and their number, species composition and biomass directly affect the survival and growth rates of fish. The scientists also recorded hydrometeorological data and measured the oxygen level in the water: the dissolved oxygen content is one of the key factors determining the suitability of the environment for salmon life, especially during the development of eggs and fry.
The collected materials will help to compare the current salmon abundance and the state of the food supply with historical data accumulated in VNIRO funds over the previous decades. This comparison allows us to see long-term trends: whether the population is growing or decreasing, whether habitat conditions are changing, whether the timing of spawning or migration is shifting. On this basis, experts will be able to prepare a forecast of the salmon stock for the Arkhangelsk region and provide scientifically sound recommendations for the conservation and restoration of the species, including for planning fish protection and compensation measures.
VNIRO Press Service
