RMK released 15,000 young salmon into the River Purtse  23.04

Fish from the Põlula Fish Farm were released into the River Purtse, so that the natural spawning of fish would be restored in the river. ‘Historically, the Purtse was one of the best salmon rivers in Estonia. The river was heavily polluted in connection with shale oil production in Kiviõli, which began in the 1930s’, says Kunnar Klaas, Head of the RMK Põlula Fish Rearing Department. He added that even though the water quality of the river has improved since the restoration of independence, problems are posed by the residual pollution that remains on the riverbed and migration barriers.

According to Kunnar Klaas, two year old, and some one year-old young fish, are large enough to be ready to migrate from the river to the sea over a period of a couple of few weeks. Feeding conditions are better for the salmon in the sea than the river. The feeding journey lasts from 2-4 years. During that time the salmon migrate to the middle and southern part of the Baltic Sea. Before leaving the rivers, the young fish memorise the characteristics of their home river with the help of smell memory and return to the same river to spawn when they reach sexual maturity. Approximately half of this year's one year old fish are not yet physiologically ready to migrate to the sea. They will remain in the river for a year and leave for the sea next spring.

Photo: Matti Kämärä, Põhjarannik (Northern Coast)

We placed individual tags on 500 of the two year old fish introduced into the river, which allows scientists to study the migration and growth rate of salmon and to assess fish that are recaptured’, explains Klaas, adding that all introduced fish have had their adipose fin removed in order to distinguish them from natural fish.

‘The river environment is new to farmed and introduced juveniles, and adaptation takes one to two weeks. It must be emphasised that fishing for undersized salmon is prohibited by legislation and a hefty fine may be imposed on those who do so’, says the head of RMK's Fish Rearing Department.

The introduction of fish into the River Purtse is part of the national fish restocking programme and part of the Life IP CleanEST project, managed by the Ministry of the Environment. According to Harry Liiv, Deputy Secretary General of the Ministry of the Environment, the aim of the project is, among other things, to bring life back to those water bodies where it has suffered greatly as a result of human activities. In addition to the cleaning of water bodies and the elimination of residual pollution, the project will also restore the spawning grounds of fish in the rivers of Virumaa within a period of ten years.

‘CleanEST is a targeted pilot project, which explains whether the solutions used for cleaning water bodies can be applied to other objects and how, both in Estonia and in Europe’, the Deputy Secretary General adds.

Nearly 800,000 juvenile salmon have been introduced into the River Purtse since 2005. Larvae, one summer, one-year-old, two summer, as well as two-year-old juvenile fish have been introduced. ‘Monitoring by the Marine Institute shows that the population status is improving. According to current estimates, juvenile salmon should continue to be introduced into the River Purtse for another five years. Once the status of the population has further improved, it will no longer be necessary to support it’, said Kunnar Klaas.

The RMK Põlula Fish Farm is located by the outflow of the Lavi Spring, in Vinni Rural Municipality, in Lääne-Viru County. It is known that fish have been raised by the outflow of the Lavi Spring for more than 120 years.

Photo: Matti Kämärä, Põhjarannik (Northern Coast)

Further information:
Kunnar Klaas
Head of the RMK Põlula Fish Rearing Department
E-mail: kunnar.klaas@rmk.ee
Telephone: +372-527-8245

Mari Sepp
Life IP CleanEST Project Manager
E-mail: mari.sepp@envir.ee
Telephone: +372-522-4166

Agnes Aaslaid
Adviser in the Public Relations Department of the Ministry of the Environment
E-mail: agnes.aaslaid@envir.ee
Telephone: +372-5661-2775

Sille Ader
Head of the RMK Communications Department
E-mail: sille.ader@rmk.ee
Telephone: +372-5666-5896