Vukovar-Srijem County, located in the eastern Croatia, holds a significant nature potential represented by the Spačva basin lowland (lowland forest and waters). There are three major rivers (Sava, Bosut, and Danube) and several other water bodies that contribute to the potamodromous fish species life cycle. The insight into potamodromous fish habitats is a first step in their understanding, improvement, and species conservation.

For this reason, the SWIM project conducts the assessment of these habitats in collaboration with local authorities and fishery associations. The approach includes main tributaries of the Bosut River which are Biđ, Spačva, Studva, and Berava. The findings will be compiled into a "Blue Document" and, along with findings from other projects (DaWetRest, EcoDalli, RETFOR), will serve as a roadmap for planning future restoration activities for migratory fish species and their habitats in the region.