Differential response of macrozoobenthos to marine sand extraction in the North Sea and the Western Mediterranean

Sublittoral benthic coastal communities of the North Sea and of the Western Mediterranean were studied before and after sand extraction between 1993 and 1995 at borrow sites in Denmark, The Netherlands, and Spain. Recolonization of disturbed areas was fast owing to the rapid increase of opportunistic species. At the North Sea sites, the benthic community largely recovered within 2-4 years, whereas in Spain recovery is expected to take longer. The response of zoobenthos to sand extraction is discussed, taking into account differences in site characteristics, extraction methods, and recovery time of the habitats. The effects on the benthic community appear to be related to the physical impact on the sea door. Small-scale disturbances in seabed morphology and sediment composition result in short-term effects on the benthic community. However, larger disturbances mainly caused by sediment composition may have a prolonged effect, particularly in low dynamic systems such as those present in the Mediterranean. (C) 2000 International Council for the Exploration of the Sea.