Fish and Wind Farms Living in Harmony (Marine Life Thriving!)

 
Fish are living happy and content lives — in fact they are thriving — in and around one of the world’s largest offshore wind farms in Denmark, according to a new report from the National Institute of Aquatic Resources in Denmark.

The Horns Rev 1 wind park off the coast of Anholt in Denmark is nearly ten years old, located in shallow water no deeper than 20 meters, and was visited by researchers from DTU Aqua (National Institute of Aquatic Resources in Denmark) even before the park was built so that they could conduct a survey of the fish life in the area.

Seven years later, biologists have compared the data from then to now in an effort to determine the effect the park has had on the marine life.

“Our study showed that the turbines have not adversely affected fish life in the area,” says biologist Claus Stenberg from DTU Aqua.

Thriving, and introducing new species

The more than 80 turbines installed at Horns Rev 1 are sunk deep into the seabed and surrounded by a massive collection of stones, which prevents the sea currents eroding deep trenches in the sand around the turbines.

But these stones aren’t just providing protection for the turbines, but the fish as well.

The study suggests that these stone structures are now acting as artificial reefs. There’s an abundant supply of food and shelter from the current, and the rocks make for an attractive location for those fish who like a rocky bottom.

“Species such as the goldsinny-wrasse, eelpout and lumpfish which like reef environments have established themselves on the new reefs in the area — the closer we came to each turbine foundation, the more species we found,” says Claus Stenberg.

The researchers were also intent on determining how fish species that live on large fine-grained sane banks would be affected by the introduction of the turbines, species that include the sand eel, a very important fish for the Danish fishing industry.

“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 DTU Aqua biologist concludes.

Horns Rev 1 is not necessarily typical of other wind farms, but in a good way

Researchers do not believe that the conditions they found at Horns Rev 1 will necessarily be replicated at the other 11 wind farms located throughout Danish waters; they believe that those other farms will fair much better.

“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,” says the DTU Aqua scientist.

Another interesting turnabout is that Horns Rev 1 has now become a sort of mini protected area since the area has been closed off to all fishing activities. It’s too small to have any significantly positive effects on local fish stocks, but in the future, interconnected farms may change that.

“Our studies suggest that the Horns Rev 1 is too small to function as a true marine protected area (MPA), because over their lifecycles the fish utilize a much greater area than just the wind farm. 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,” says Claus Stenberg.

Source: DTU Aqua, National Institute of Aquatic Resources in Denmark