ARKHANGELSK, August 3. /TASS/. Ichthyologists for the first time assessed the population of brown trout (Salmo trutta) in reservoirs of the Bolshoy Solovetsky Island of the Solovetsky Islands Archipelago (Solovki), the Laverov Federal Research Center for Integrated Arctic Studies (the Russian Academy of Sciences' Urals Branch, Arkhangelsk) told TASS. Most likely, humans have introduced this type of fish to the Solovetsky lakes, since initially the local ichthyofauna was quite poor.

"Solovki lakes historically have been reservoirs with rather low fish productivity. At the same time, the archipelago's ichthyofauna species composition is wide," the center said. "Some fish species were introduced during the pre-revolution times and during the Soviet times. While working on the archipelago, ichthyologists finally clarified that the brown trout (Salmo trutta) has settled on the Bolshoy Solovetsky Island."

The scientists conducted a genetic analysis, and prepared a scientific article for the Reports of the Russian Academy of Sciences. Life Sciences magazine. The center's Director, corresponding member of the Russian Academy of Sciences, Ivan Bolotov noted that those were the Solovetsky Monastery monks who had planted trout into the archipelago's waters.

"I would like to explain that trout can have be both of a migratory form, that is fish capable of migrating between marine and fresh waters, feeding in the sea, and of a sedentary form, living only in streams, in fresh waters," the scientist continued. "In our case, this is a sedentary form, which is commonly called brook trout. Its origin is not absolutely clear, but according to archival and historical data from the late 19th and early 20th centuries, monks have introduced brook trout into the lake-canal system. [Those are] stormy, deep enough streams, suitable for trout."

Back in the Soviet times, the brown trout's settlement did not happen. Brook trout grows to a relatively small size, as streams parameters limit the growth. The Solovetsky trout may be maximum 30-35 cm long. As for migratory trout, it may grow more: to up to 70-80 cm in length and up to 15 kg in weight.

Solovki anthropogenic load studies

The ichthyofauna study is part of assessing the anthropogenic impact on the Solovki ecosystem. Russia's Deputy Prime Minister Dmitry Chernyshenko supervises the Solovetsky Archipelago's conservation and development. In compliance with his instructions, the Russian Ministry of Science and Higher Education has been calculating the maximum anthropogenic load on the Solovetsky Archipelago. This work is underway at three subordinate institutions: the Laverov Federal Research Center for Integrated Arctic Studies (the Russian Academy of Sciences' Urals Branch), the Russian Academy of Sciences' Karelian Scientific Center, and the Lomonosov Northern Arctic Federal University (NArFU).

The Laverov Center's specialists have been conducting research on the Bolshoy Solovetsky Island for the third year now. They are working in a wide range of areas, assessing the anthropogenic impact on the ecosystem. Over the current year, the research focuses on hydrobiology, geo-botany, entomology, flora, ichthyology and other aspects. Experts are collecting materials for comparative assessment of various plant and animal populations in natural habitats and in areas near sightseeing routes.

"The ichthyologists have traditionally worked on three lakes that are in close proximity to the village of Solovetsky (settlements Svyatoe, Pityevoe, Bannoe) and they are experiencing the greatest anthropogenic impact due to the tourist flow. The work included sampling to assess fish habitat conditions: hydrochemistry of water and sediments, food supply (communities of invertebrates - zooplankton and zoobenthos). The experts have assessed also the freshwater ichthyofauna conditions. The samples now are at the stage of laboratory processing," ichthyologist and Director of the Arkhangelsk center's Institute for Socio-Economic and Bio-Resource Research Alexander Novoselov told TASS. Experts have not recorded strong effects of human activity on the Solovki's freshwater fish, the ichthyologist noted.

The Arkhangelsk center's interdisciplinary approach, which also includes work of sociologists, will determine critical levels for tourist flows. Russia's Ministry of Science and Higher Education will submit figures for 2026 to the Russian Federation's government.

The Lomonosov Northern Arctic Federal University's specialists are engaged in research of man-made load, in the problem of pollutants discharges from infrastructure facilities in the village of Solovetsky. The Karelian Scientific Center studies the ecological state of the marine coastal waters and in the Blagopoluchiya Bay.