In the 20th century, populations of both salmonid fishes and pearl mussels were severely affected. Much damage in Karelia was caused by extensive timber rafting via its major rivers. Logs plowed up the riverbed, destroying salmon eggs and young mussels. The final blow after which salmonids and pearl mussels went extinct in the Suna was hydropower engineering and commissioning of the second Suna Hydroelectric Power Station. The river flow was regulated by a dam near the village of Girvas, causing some channels and salmon spawning grounds to lose water and become unsuitable as spawning and nursery habitats.
Restoration of a spawning and nursery area in the river began in 1997. Under the leadership of ichthyologist Dr. Yuri Smirnov, head of the Karelian Fisheries and Biological Resources Administration (Karelrybvod) Vyacheslav Movchan, and the then director of the nature reserve Alexander Sukhov, a program was developed to clear the riverbed of timber rafting debris. A half a hectare site downstream of the Kivach waterfalls was selected. A rapid was constructed there, placing boulders and filling the area with outwash pebbles and gravel. Salmon were released several times to restore the population. Eventually, natural fish spawning at this site not only resumed but proved highly productive.
With the salmon population restored, it became possible to return pearl mussels to the Suna River within the reserve, as well. This is because at the larval stage (glochidia) the mollusk must parasitize the gills of young salmon. Glochidia attach themselves to the gills and spend their first winter there. In spring, a small but fully developed mussel drops off to settle on the riverbed. This means that in rivers lacking salmon reproduction the development of pearl mussel populations is also impossible. The work to restore the mussel population began within a grant project in 2012, involving employees of the Institute of Biology KarRC RAS – Evgeny Ieshko, Alexey Veselov, Vyacheslav Shirokov, and Igor Shchurov. Three hundred mollusks were transferred from the pearl mussel colony of the Nemina River, also in the Lake Onega catchment, to a site in the Suna River. By 2013 already, the first young salmon infected with glochidia were spotted. In 2020, specialists found the first young pearl mussels on the riverbed.
Thus, populations of both the Atlantic salmon and the freshwater pearl mussel in the Suna river stretch within the Kivach Nature Reserve have been restored. Currently, the pearl mussel colony numbers over 400 individuals. There occurs natural breeding of salmon from Lake Onega.
In 2025, the Kivach Nature Reserve applied for the project “Through Time: Pearl Mussel and Salmon – Together Forever”. Early in 2026, this conservation project became one of the winners of the grant competition of the Presidential Fund for Nature. The grant agreement with the fund was signed in early April.
The main objective of the project is to assess the current state of the previously established mussel colony and the juvenile salmon population in this river stretch, downstream of the Kivach waterfalls. To keep up juvenile salmon numbers, the project will release ten thousand fingerlings (age 0+) of landlocked salmon into the Suna River within the reserve boundaries. Additionally, the tourism infrastructure will be improved to raise awareness of the need to preserve the unique natural heritage of Karelia.
The project will try out a non-invasive technique (i.e., without removing the animals) for detecting juvenile Atlantic salmon and freshwater pearl mussels. The application of the environmental DNA assay technique, which detects genetic signatures of mussels and fish in water samples, is expected to enable monitoring of the numbers and wellbeing of pearl mussels and salmon during as well as after the project.
Photos: Alexandra Sukhova / Kivach State Nature Reserve
