The Effects of River Restoration and Watershed Land Use on Fish Populations

The dredging of river beds and the different forms of watershed land use, such as agriculture, forestry and peat production, alter the discharge of rivers and local flow conditions. The increased sediment and nutrient loading resulting from changes in runoff influences the amount and condition of habitats suitable to river fish in many ways.

Photo: Pauliina Louhi

To increase the amount of habitats suitable to fish in our country, extensive river restorations have been carried out, the effects of which are only partially known. Improving the habitat of fish populations requires action not only in river channels, but in watersheds as well. Restorations targeting watersheds have sought, for example, to decrease the sedimentation into waterways and stabilize the strong fluctuations in discharge in the underlying waterways resulting from forest drainage.

Because the different restoration actions and the restocking that is often connected with them also require significant financial resources in many cases, it is important to determine the effects of restoration measures on the state of the river populations by scientifically reliable follow-up and evaluation methods.

In the theme - The Effects of River Restoration and Watershed Land Use on Fish Populations research

• Research data will be produced on the restorations carried out in river beds and river basins and the effects of land use on fish, lotic invertebrate communities and the structural heterogeneity of the rivers.
• Data will be produced on the opportunities for the fishing industry as well as recreational use of flowing waterways in urban areas.
• The significance of discharge, and the variables closely connected to it, to the welfare of river fish will be established.
• The possible effects of changes in the discharge of rivers based on climate change predictions on the welfare of river fish populations will be evaluated.

Research projects

• Effects of stream restoration on fish populations, benthic invertebrates and stream function
• Restoration possibilities of urban streams
• The effects of land use changes on biota of running waters
• Energetic consequences of hydropeaking conditions on Atlantic salmon (Salmo salar L.) fry  

Further information:

Ari Huusko, Finnish Game and Fisheries Research Institute

Teppo Vehanen, Finnish Game and Fisheries Research Institute

Pauliina Louhi, University of Oulu (first name.last name@oulu.fi)

Ari Saura, Finnish Game and Fisheries Research Institute

Text version