Rheophile species in the Dutch part of the Berkel In recent years, the European Brook Lamprey (Lampetra planeri) and the Rhine Sculpin (Cottus rhenanus) have been recorded in the river Berkel near Rekken, in the province of Gelderland, not far from the German border. The river Berkel rises in Germany at the foot of the Baumberge, from where it flows in a westerly direction to the IJssel. While parts of the river system have been straightened and substantially damaged, sections of the upper and middle reaches of the Berkel and its tributaries have a natural river morphology with a substrate of gravel, sand and detritus (coarse organic matter). Here, both species can be found. Their presence on the Dutch side of the river where there is hardly any suitable habitat for either species is probably due to them drifting downstream. Brook restoration and improvement of fish migration at weirs along the Berkel and its tributaries offer great potential for further spread of the populations of these typical rheophile species in Germany and the Netherlands.