Background The Ina basin, in Western Pomerania, Poland, is home to several Natura 2000 sites. Since 2006, a project to restore the population of Atlantic salmon (Salmo salar), a species listed in Annex II of the Habitats Directive, has been taking place in the Ina river. Atlantic salmon reproduction and the first stages of development need to take place in clear, cool and well-oxygenated rivers and streams. To spawn, salmon need large stretches of gravel and rocky-gravel substrate where they dig out nests and hide eggs. The past installation of large numbers of hydrotechnical structures in the Ina basin has made it difficult or even impossible for salmon to migrate to their spawning grounds. This situation, combined with the straightening of the river along a section from the town of Recz to the river mouth, has had a negative impact on the salmon population and the biodiversity of the Ina basin. Objectives The project aims to conserve and improve biodiversity in the Ina basin’s water ecosystems that are located in Natura 2000 sites. It will achieve this mainly by linking them within a blue ecological corridor. An additional objective involves restocking salmon populations in the Ina basin. These objectives will be reached by performing the following actions: Clearing migration routes in the Ina river and its major tributaries by building ‘fish passes’; Creating artificial spawning grounds and enlarging the area of natural spawning grounds for salmonids; and Planting trees along 20 km of the river bank to create shaded areas and lower the water temperature.Creating inter-linked blue ecological corridors will help facilitate large scale protective measures for currently isolated Natura 2000 sites. All the problems occurring in the Ina basin (including ecological barriers in the form of old hydrotechnical structures, lack of spawning sites and disappearance of the old river beds) are typical of most of the salmon rivers flowing into the Baltic Sea. Therefore, this project aims not only to solve the problems in the Ina basin but also to demonstrate transferable solutions for reconstructing functional water ecosystems for migratory fish species. Expected results: The project expects to achieve the following: To clear the channel of the Ina river and its major tributaries; To create artificial spawning grounds, increasing the number of fish that inhabit the Ina river, and improving the population of Atlantic salmon; and To provide detailed records of fish migration, specifying when and where Atlantic salmon (and other fish species) access the spawning sites. These records will enable the beneficiary to perform more successful protective actions.