Belgium has allocated a 238 km2 zone in the Belgian part of the North Sea (BPNS) to offshore renewable energy production, for example offshore wind farms. At present 109 turbines are operational in the BPNS. In the next few years several hundreds of new turbines will be up and running. A monitoring is being conducted to assess the potential impacts on the marine environment. Although the number of wind turbines during the first six years of the research was relatively limited in the BPNS, some clear effects have been observed. 1. Higher numbers and larger individuals of certain benthic and demersal fish and invertebrates have been observed in the wind farms. These species seem to profit from the high food availability and the absence of fisheries in the farms.2. The steel and concrete foundations of the wind turbines form new habitat in a sandy sea bottom area. These foundations are overgrown very quickly by high numbers of benthic organisms. Many species are known to us from nearby rocky shores; others are exotic.3. Some fish species, like Cod and Pouting, are strongly attracted to the foundations of the wind turbines. These fish mainly feed on organisms growing on the foundations.4. Some bird species, like Northern Cannet, Common Guillemot and Razorbill, avoid the wind farms. Others, like Lesser Black-backed Gull, Common Tern and Sandwich Tern, are attracted to it. The high numbers of prey fish are probably causing this attraction. Collisions with wind turbines are of concern for bigger gulls like the Lesser Black-backed Gull.5. The excessive under water noise during piling disturbs Harbour Porpoises, the only common cetacean in Belgian waters, up to a distance of 20 km. It is not yet clear if the Harbour Porpoises are attracted by the many prey fish near the wind farms, once the operational phase starts.These results show that there are positive and negative effects of offshore wind farms. Future research should focus on the understanding of these effects so that we can optimally support the future policy and management. There is also a need to assess how these effects will evolve once all planned wind turbines in Belgium {ca. 530) and in the entire North Sea {ca. 14.000) will be installed. The assessment of the cumulative effects of all these wind turbines will be the biggest scientific challenge for the future monitoring. |
