Dams, weirs, pipes and different constructions create barriers in our rivers which prevent them from functioning naturally. Consequently, the ecosystems are altered and this affects the more sensitive species living in them (semi-aquatic mammals, such as the European mink or the desman, and fish, such as the Atlantic salmon), which find their distribution area reduced or fragmented. This forces the groups to reproduce among themselves, leading to genetic isolation which, in conjunction with other associated effects, weakens their ability to cope with other pressures and places the continuity of the species in danger.

In order to solve this situation, the different public bodies in charge of river management in the Basque Country and Navarre have decided that intervention with regard these obstacles should be adopted as their chief course of action. In addition to the work performed in this direction in each of the two communities, a number of cooperation projects have also been implemented, culminating in LIFE IREKIBAI.