A comprehensive report has found that offshore wind developments are not necessarily bad for fish and other marine life, In fact, they may be beneficial. The most risk is at the early stages of construction, when special care needs to be taken not to disrupt spawning grounds. This is usually a question of sensitive timing, and any disruption is generally temporary. The benefits come from trawling exclusion and planned habitat enhancement.
Source : http://data.iucn.org/dbtw-wpd/edocs/2010-014.pdf
