Wind turbines have a positive effect on fish
European Union – 17.04.2012
Wind farms benefit the environment but a new study investigating their impact on marine life in Denmark has discovered that fish also profit from this alternative source of energy. The findings, presented in the National Institute of Aquatic Resources (DTU Aqua) report titled ‘Effect of the Horns Rev 1 Offshore Wind Farm on Fish Communities. Follow-up Seven Years after Construction’, suggest that wind turbines have a positive effect on fish, with some species increasing in number.
The Horns Rev 1 wind park in Denmark is one of the biggest offshore wind farms on this planet, with 80 huge turbines located in relatively shallow water that is teeming with fish. DTU Aqua scientists compiled and analysed data of fish living in the area in question. ‘Our study showed that the turbines have not adversely affected fish life in the area,’ explains lead author Claus Stenberg, a biologist from DTU Aqua.
According to the researchers, the Horns Rev 1-based turbines are sunk deep into the sea floor and are surrounded by a rim of a large pile of stones. This border ensures the protection of the turbines since the sea currents cannot erode deep trenches in the sand. The researchers observed that these stone structures act as artificial reefs as well, giving fish optimal living conditions. Not only do the fish have good shelter and a lot of food, but more and more fish are attracted to the bottom of the rocky sea, which in turn has generated habitats for several new species.
‘Species such as the goldsinny-wrasse, eelpout and lumpfish which like reef environments have established themselves on the new reefs in the area,’ says Dr Stenberg. ‘The closer we came to each turbine foundation, the more species we found. The study shows that wind farms have not been a threat nor of particular benefit to the sand eel. The sand eel is dependent on the fine sand, in which it buries, to live, and the mills did not affect either the sand grain size on the bottom nor had any impact on the number of sand eels.’
The team says this is the first study to evaluate how Danish wind farms affect fish life. But they do not anticipate that the findings will be replicated in the other 11 wind farms found in local waters.
‘Horns Rev is situated in an extremely tough environment with strong wave action, which means for example that seaweed forests, together with the small fish that live in them, cannot establish themselves. We would therefore expect the positive reef effects to be even greater still in a park located for example in the more sheltered Kattegat,’ Dr Stenberg says.
The DTU Aqua researcher goes on to say the research suggests that the Horns Rev 1 is too small to function as a true marine protected area (MPA) because the fish use a much greater area than just the wind farm during their lives. ‘But presumably several parks located close to one another could have a combined positive effect on spawning and the survival of fish fry, as wind farms which are located downstream of each other can act as a kind of dispersion corridor for eggs and larvae,’ he concludes.