Since November 2005 a small part of the Dutch Wadden Sea has been closed to bottom-disturbing human activities. The area is situated just to the south of Rottumerplaat and Rottumeroog islands and covers about 7,400 hectares. The purpose of closing this area is to monitor the development of the marine fauna in the Wadden Sea when they are not disturbed by human activities. The monitoring programme focuses on the development of the benthic communities present in the gullies. The benthic fauna in two gullies in the closed area are being monitored and compared with the fauna in two control gullies outside the closed area, where they are under the influence of bottom-disturbing human activities (open gullies). This report describes the interim results 13 years after the area was closed. In line with what has been established earlier, inside the closed area the benthic species composition in the Boschwad gully is somewhat more diverse in mollusc species than in the Schild gully. The benthic fauna in Boschwad differs from all other gullies by having a slightly higher abundance of shellfish (especially cockles, but also Baltic clams) and a different composition of annelid species. The species composition in Schild is more similar to that in the open gullies, possibly as a result of greater natural disturbance (influence of wind and waves on the sediments).