With the wide scale construction of offshore wind farms (OWFs) throughout the entire North Sea, largeareas are permanently being closed to beam trawl fisheries. Beam trawling has affected macrobenthicassemblages for centuries, especially the fragile and long-lived species. Due to the prohibition of beantrawling in many OWFs, opportunities are being provided to investigate the potential recovery of vulnera-ble species and the creation of de-facto Marine Protected Areas (MPAs). The soft-substrate macrobenthiccommunity was investigated from 2008 to 2012, before and after the construction of an OWF in theBelgian part of the North Sea, situated on the Bligh Bank. The fishery enclosed area (±21 km2) withinthe OWF (No Fishery area) was compared with a surrounding control area (±30 km2) where regularfishing activities were registered through vessel monitoring system (VMS) data throughout the period2010–2011. Three years after the exclusion of beam trawl fisheries, subtle changes within the macroben-thic community were observed in the No Fishery area. The benthic mysid shrimp Gastrosaccus spinifer(30 ± 15 ind m−2), tube-building polychaetes Terebellidae sp. (196 ± 151 ind m−2) and the echinodermEchinocyamus pusillus (73 ± 71 ind m−2), sensitive to trawling activities, showed increased abundanceswithin the No Fishery area. With an expansion of the wind farm concession area to 238 km2in the future,the likely increase of dense Terebellidae patches (e.g., Lanice conchilega reefs) within the No Fishery areacould create an ecological important large-scale refugium for higher trophic levels. This study creates abaseline for the evaluation of long-term changes due to the fishing impacts and effects related to the pres-ence of OWFs and highlights the importance of executing long-term monitoring programs in combinationwith targeted research.

Peer Review, Impact Factor

*Biodiversity, North Sea, biodiversty conservation, ecological impact