In autumn 2011 a first survey of the mollusc fauna of the coastal gun battery near Durgerdam, North-Holland, the Netherlands was carried out. This military installation was built at the end of the 19th century on a tiny, uninhabited island in the former Zuiderzee North-East of Amsterdam and formed part of the ‘Defence Ring around Amsterdam’. Only 21 terrestrial gastropods and 7 aquatic mollusc species were found during the survey.