Assessing substrate addition of offshore wind farms by fractal dimensions

Abstract

Offshore wind energy is a renewable technology able to deliver significant energy in a sustainable manner, able to satisfy more than 4% of EU electricity consumption by 2020. The installation of offshore wind farms incorporates new material and substrate to the marine biota. These new structures are located on the seabed and can function as artificial reefs (AA) by providing hard substrate and rocky microhabitats incorporate and provide shelter for the growth of species bound to the substrate (fouling). Wind farms may have a role similar to that of Fish Aggregating Devices (FADs), influencing the spatial redistribution of pelagic and migratory species. It is therefore crucial to assess the potential of offshore wind parks as areas that act as aggregation of benthic resident species and pelagic species. Experimental set-up with a combination of FADs and benthic artificial reefs has been deployed at 30m depth to test influence of substrate aggregation on fish species. Fractal dimensions have been calculated to test correlations among number of species and fractal coefficient. The results are of benefit to future ore platforms in order to increase available substrate for aggregation of species