Hydropower and migratory fish – Actions today

Case: Salmonid trap and transport facility at Montta power plant, River Oulujoki

The trap and transport facility was completed at the end of August 2017 in conjunction with the Montta hydropower plant on the River Oulujoki. We use the trap and transport facility to capture salmon and trout as they migrate upstream; it enables the fish to efficiently and safely bypass the migration barriers. The facility covers the lower portion of the fishway. The salmonid swimming into the facility can be transferred into a tanker truck and transported across several power plant dams to tributaries upstream for spawning. Based on experiences gained elsewhere, this approach results in significantly more broodfish in the spawning areas than if all the necessary fishways between the sea and the spawning areas were built. Fortum has good experiences with transporting landlocked salmon in Sweden on the River Klarälven, which is harnessed for hydropower production.

From the Montta trap and transport facility, fish can also be transferred into reservoirs for fishing, or their roe that has gone through natural selection can be taken to the Montta fish farm where Fortum produces salmon and sea trout for stocking in the River Oulujoki.

The trap and transport facility is a joint project by Fortum, the Muhos, Utajärvi and Vaala municipalities, the North Ostrobothnia ELY Centre, and the Ministry of Agriculture and Forestry to revitalise salmon and trout in the River Oulujoki. The facility has special national significance because the experiences gained from it will be used in migratory fish projects on other constructed rivers.

The trap and transport facility is part of the overall management of fish populations in the River Oulujoki. Fish management is based on the stocking of migratory fish, strengthening the natural life cycle, and developing the quality of the fish to be stocked. In recent years, Fortum has invested over EUR 5.5 million in the modernisation of the Montta fish farm and the construction of the trap and transport facility. The trap and transport facility has also been financed by the Muhos, Utajärvi and Vaala municipalities, and the project has received Finnish Government’s spearhead project funding from the Ministry of Agriculture and Forestry.

Case: River Oulujoki’s migratory whitefish population is strengthening

About ten years ago, the cooperatives of the southern fishing area of the Gulf of Bothnia raised strong concern about the weak situation regarding migratory whitefish in the River Oulujoki. Fortum and the fishing collectives found consensus on strengthening the whitefish population, and as a result Fortum has increased the number of whitefish stocks systematically since 2011. Now the migratory whitefish population in the River Oulujoki is showing signs of strengthening. Fishermen have started catching whitefish, whitefish are migrating upstream, and the roe harvesting necessary for management of the population has been successful.

Management of the whitefish population is based on catching broodfish every autumn at the River Oulujoki delta in the Merikoski rapids. The fertilised eggs are incubated at Fortum’s fish farm in Montta. In spring, the newly hatched fry are stocked in natural nutrition reservoirs to grow and are released as one-summer-old juveniles into the sea. The current number of whitefish stocks is dozens of times bigger than the numbers ten years ago. The stock numbers have grown at the same pace as the strengthening of the population; the needed roe has been collected at the River Oulujoki delta, and the migratory whitefish population has been used for stocking. In practice, the working collaboration has been ensured by the contributions from Oulu Energy and the City of Oulu.

Management of fish populations is long-term work. Migratory whitefish reach maturity at the age of 4-6 years, so it takes some time before an increase in the stock numbers can be seen. In the case of the River Oulujoki’s whitefish population, voluntary measures were started considerably faster than the obligation process. So far, the permit process to update the obligation has taken four year and is still ongoing, but the measures to strengthen the whitefish population are already producing visible results.

Case: Habitat restorations bring juvenile trout to River Vuoksi

Fortum, City of Imatra and the Southeast ELY Centre have worked together to restore the trout habitat in the River Vuoksi in the areas around Fortum’s hydropower plants.

The restoration project started by studying suitable habitats for grayling, trout and salmon in the Finnish part of the River Vuoksi. Modelling and field surveys were used to find several areas that would be suitable for spawning and nursery restoration. In the restoration, water flow is directed to the areas close to the river bank by reshaping the river bed. Then gravel and rocks are spread along shallow areas to provide better areas for spawning and for protecting the juvenile fish.

Recent years have brought restorations to the section of the River Vuoksi between Fortum’s Imatra and Tainionkoski hydropower plants. The restoration plans for 2018 and 2019 target the River Vuoksi downstream from Imatra in the vicinity of Mellonlahti.

Fortum has also participated in the City of Imatra’s urban brook project. Water for the brook, constructed by the City of Imatra and the Southeast ELY Centre, is channelled from the River Vuoksi. The brook provides sheltered areas for growing juvenile trout. At the same time, it functions as a recreational area in the beautiful Koskipuisto Park.

Test fishing from the brook and the habitats created in the River Vuoksi has produced promising results in terms of the number of juvenile fish and the success of the natural spawning.