For downstream migrations there is not yet a satisfactory solution. This was the common opinion of the gathered expert at the Symposium of the international commission for the protexction of the rhine in Bonn/ Germany in november 2005. Thus some soltution are to be shown in this section.
Also there ist no fishway for the upstream migration that would help essential fishes that are willing to move downstream, besides the total breakdown of a hindrance. This means that there is to think of both Fishways for upstream and downstream migration when thinking of improvemtn for fishmovements. Especially in the surroundings of hydropowerstations this is essential because normally the main flow, which the fishes follow leads directly into the turbines and damaeges a certain percentage of the fishes.
Thus the width of the screens is a very important criteria. As a postulation screnn should not be wider than 10 mm for Atlantic Salmon smolts and 15mm for Silvereel (A.anguilla)