From 2015 the author has regularly visited a tidal channel in Vijfsluizen (between Vlaardingen and Schiedam) which is connected to the Nieuwe Maas. In the past water from a peat meadow was discharged into this tidal channel. The tidal channel has a brackish character and features some interesting mollusc species including Assiminea grayana which appears as ‘threatened’ on the Dutch Red list.