Renewable hydropower and active environmental management


Finnish hydropower is a carbon-neutral form of energy that is produced in an efficient and reliable manner, respecting the environment. Hydropower is Finland's number one renewable power source.

We at Pohjolan Voima and its hydropower company PVO-Vesivoima have been actively and determinedly caring for and developing the aquatic environment for almost forty years. This means that we have restored shorelines, handled regulation in a manner that takes into account different needs, stocked and transported fish, and participated in projects aiming at the restoration of migratory fish stocks. In addition to taking care of our obligations, we have participated in voluntary environmental management projects and tasks.

We work in close cooperation with the authorities, NGOs and local residents. We are always trying to find ways to improve dialogue and cooperation with our different partners in order to better care for our shared aquatic environment.

Our current hydropower production is highly automated. Modern technology boosts production, expands the power plants’ service lives and provides environmental and energy efficiency benefits. We can further reduce our environmental impact by continuously developing our operations.

Pohjolan Voima carries the responsibility for fish stock management in the Iijoki river and sea area 

The Iijoki river is one of Finland’s most popular recreational fishing waters, partly due to the stocking of fish. Pohjolan Voima’s hydropower company PVO-Vesivoima carries the responsibility for the stocking of fish in the Iijoki river and sea area, and in two lakes. PVO-Vesivoima is responsible for some of the Kemijoki river main channel and sea area obligations, as well as for one lake.

PVO-Vesivoima is responsible for 17% of the Kemijoki river main channel and sea area obligations, as well as for one lake. The stocking has been designed based on how many fry the fish in the area usually produce.
Annual fishery fees are also paid in the Iijoki headwaters, in the Irnijärvi and Kostojärvi regulation lakes’ area.

Salmon, trout and migratory lavaret at the river mouth

The Iijoki river fish management obligations were determined in a separate decision linked to the power plant licences in 1980. Fry of salmon, sea trout and lavaret, which are ready to migrate, are planted at the mouth of the river. Freshwater fish are planted in the river area to compensate for the losses of lavaret and trout coming from the sea. Brown trout, grayling and freshwater lavaret are planted in the lakes.

At present, Pohjolan Voima spends €1.7 million per year to plant fish.

Transport of river lamprey

In the Kemijoki river, PVO-Vesivoima Oy and Kemijoki Oy have invested in the catching of river lamprey at Isohaara. Due to the continuing deficit in the Kemijoki river, PVO-Vesivoima Oy and Kemijoki Oy have increased the volume of river lamprey being caught at the Isohaara power plant. The results from new catching locations and methods have been encouraging, but the catching of river lampreys needs to be further developed. New solutions are currently being planned.

Migratory fish spearhead project in Iijoki river

We participate in a migratory fish stock project in the Iijoki river. The project was started in 2017. The action plan of the three-year project includes the following:

  • Fishway for Raasakka power plant
  • Downward migration solutions for smolt (young salmon and trout)
  • Fry transplanting programme
  • Fish transfers
  • Measures to be implemented in old riverbeds of Raasakka and Maalismaa

Coordinated by the Oulu Regional Council, participants of the project include the Ministry of Agriculture and Forestry, several municipalities in the region, the Iijoki water system fishing area and Metsähallitus. The project is part of the nature policy spearhead project of the Finnish Government.

Fish transfers are an essential part of the restoration of migratory fish stocks

Fish transfers are an important measure to promote the restoration of migratory fish stocks in constructed rivers.
Pohjolan Voima has participated in and funded a migratory fish transfer project in the Kemijoki river by the Lohijokitiimi association. The transfer of live salmon past power plant dams to the best breeding spots will continue in the Iijoki river.

The transfer of salmon from the Iijoki river mouth to breeding areas around halfway up the river started during a cooperation project called Vaelluskalat palaavat Iijokeen (“Restoring migratory fish to Iijoki river”) in 2008–2010. Success of the natural breeding of the salmon was verified by equipping some fish with radio transmitters and by means of electric pulse fishing.

The fish transfers were continued by the Vaelluskalat palaavat Iijokeen 2015–2017 project. The catching of live salmon to transfer them past five power plant dams to the best breeding areas in the Iijoki river will be continued. The project coordinator is the Centre for Economic Development, Transport and the Environment for North Ostrobothnia. In addition to PVO-Vesivoima, participants of the joint project include the municipality of Ii, the city of Oulu, the town of Pudasjärvi, and the fishery associations of Southern and Northern Ii.

Fish stock management also involves monitoring

PVO-Vesivoima’s fish stock management obligations also include the monitoring of the success of the stocking and the variation of the fish stock in terms of species. Monitoring partners include professional and recreational fishers in each area. They write down what they have caught.

The information is collected from the accounts of partner fishermen with whom agreements have been signed and from replies by a larger group of fishermen. The information is compiled into three- and five-year reports that are published on the Pohjolan Voima website in Finnish.

The monitoring also includes the taking of fish samples. Atlantic salmon, lavaret and river lamprey samples are annually taken from the Iijoki sea area, and grayling and trout samples are taken from the river area. In the lake area, lavaret and vendace samples are taken every three years. The samples are analysed to study the health of the fish.

Fish farms grow the fry

Voimalohi Oy grows the fry PVO-Vesivoima needs to meet its obligations. The owners of Voimalohi are PVO-Vesivoima and Kemijoki Oy.

The health, condition and physiological quality of the fry are continuously monitored at the fish farms.

Fish management obligations

Iijoki sea area

Atlantic salmon 310,000
Sea trout 28,000
Migratory lavaret 1,200,00
River lamprey transport 60,000

Iijoki river area

Brown trout        20,000
Freshwater lavaret      650,000

Iijoki and Kemijoki lake areas




Suolijärvi lakes

Freshwater lavaret








Brown trout









The freshwater lavaret obligation in the Kosto area, 62,000, was converted to a fishery fee based on a decision of the Northern Finland Environmental Permit Authority in 2002.

Kemijoki sea and river area

Pohjolan Voima’s share, 17% of the obligation

Atlantic salmon


Sea trout


Brown trout


Migratory and freshwater lavaret




River lamprey transport, 50% of the obligation









Kemijoki Oy carries the responsibility for the other Kemijoki river fish stocking obligations.

The species, size and number of fry can be changed based on a joint decision with the authority in charge in order to achieve the best results. This will not change the value of the fish management obligation. For example, no lavaret has been stocked in the Iijoki river area since the mid-1990s. The lavaret obligation was mainly replaced with grayling and trout.