Even though connectivity of rivers may be returned by fishways there is still in many cases crucial lack of reproduction habitats for the species in concern. In Finland, these species are usually salmon (Salmo salar L.) or brown trout (Salmo trutta L.). Traditionally technical (e.g.vertical slot, denil, borland) fishways are constructed for these species and interest is based on species abilities to find the way, swim upstream and on the time spent in passing.

There are, however, numerous examples for natural like fishways or bypass channels (e.g. from Austria, Germany, Switzerland, Denmark, Sweden, Finland) which usually serve as habitat for some species as well. There is a long history of compensation channels or reproduction channels mainly from Canada. By combining these two approaches we end up having natural like stream channel to enable up- and downstream migration and also possibility to host nursery habitat for the key species.

In this work we collected some basic physical information from both existing byspass channels and natural streams which seemed to have equal physical features. These measures were further evaluated in light of known preference values for salmon and brown trout. Results show that good quality habitat values are found in diverse streams and channels. Discharge variability and an option for flow regulation have a clear impact on these measures. These should be taken into account during the planning process in order to maximize the reproduction potential for the target species.