Published on: 01/01/08
Review of the reef effects of offshore wind farm structures and their potential for enhancement and mitigation
The purpose of this report is to review the likely reef effects of offshore wind farm (OWF) structures focussing on two aspects of their physical presence: firstly, the likely reef effects on fish, shellfish and other marine biota and secondly, the potential to enhance the reef effect for commercially significant species. The report begins with a literature review of the factors which control colonisation of structures in the marine environment, and describes the characteristics of the subsequent succession and climax communities. Predictions of the enhanced habitat opportunities for commercially important species (such as mussels, lobster, crab and finfish) associated with OWFs in the UK, were then considered. We used a combination of existing data resources and an understanding of the life cycles, food requirements and physiology of the target species, together with simple mathematical considerations, to assess whether such opportunities might present themselves, either through provision of shelter or rocky substrata on which to settle, and/or adequacy of food supply. We have extended our analysis to include some preliminary observations on the aquaculture potential of OWFs. The report also considers the potential offered by the footprints of OWF, together with their turbine structures and associated scour protection, to enhance the opportunities for local fisheries, either through enhanced habitat opportunities for commercial species or through the development of ‘no-take’ areas. As a general rule, our analysis shows that for each Round 2 OWF site identified, we are able to recommend, on the basis of predictions from existing data, the development of commercial activities which are likely to yield useful outcomes and identify others which are unlikely to succeed. However, more detailed site based investigations would be needed to verify the predictions before developing any enterprise commercially. The following table summarises the potentially enhancing/mitigation effects of OWF structures and their associated scour protection for individual species, and provides further comment on potential with regard to fisheries management measures. These tentative assessments can be updated as further information becomes available to ground-truth the predictions.