Apr 20, 2012

New ocean windfarm fishery impact study: drop in local species; increases in exotics.

Gulf of Maine fishermen wondering what changes offshore windfarms proposed off Maine portend for the future of their fisheries got sobering news from across the Atlantic recently.  

According to the Danish Energy Authority, a seven year study of the Horns Rev #1 ocean windfarm  in the southern North Sea reveal lasting changes to the mix of fish and invertebrate species inhabting the area.    

In the report "Effect of the Horns Rev 1 Offshore Wind Farm on Fish Communities:" researchers Simon B. Leonhard, Claus Stenberg  and Josianne St√łttrup write that setting up and operating the 80 turbine ocean windfarm 12 kilometers off Denmark has: reduced local biodiversity and abundance, and has failed to attract additional pelagic and dermeral fish to the windpark's structure-filled environment.  

This is in marked contrast to articles based on  the wind industry's  media releases about the report, which characterize  the marine ecosystem as "Thriving Around Wind Farms".

Excerpts from the report: published by  Denmark's  National Institute of Aquatic Resources: DTU Aqua Report No 246-2011:
"The introduction of...Horns Rev Offshore Wind Farm to the sand banks characteristic of the southern North Sea resulted in changes in the fish abundances and community and in species diversity."

"Fish redistributed from being generally more abundant in the Control area before the establishment of the offshore wind farm to more similar fish abundance in Impact and Control area seven years later.

 "In contrast to the hypothesis that wind farms would attract pelagic and demersal fish species to the farm area, fewer fish of the different fish species were caught in the windfarm area after deployment. "  

The study found declines in the Danish sand eel fishery within the windpark, accompanied by increased biomass of the less commercial desirable  goldsinny wrasse 

Also noted was  a  drop in  current speed  of nearly 15%  and a 3 percent drop in wave height, in the lee of the Horns Rev I wind farm. This is the "wind shadow", as described in another report about Horns Rev 1)

An important distinction.   Horns Rev 1 is in fairly shallow (20 meters deep), high energy waters with a predominantly sandy seafloor. The effects on the Gulf of Maine's ecosystems of floating deepwater windfarms as proposed by DeepCwind Consortium and  Statoil,  may be markedly different.

No comments: