Name: Helen Bailey
Address: NOAA/NMFS, Southwest Fisheries Science Center, Environmental Research Division, 1352 Lighthouse Avenue, Pacific Grove, CA 93950-2097, USA
Marine renewable developments have raised concerns over impacts of underwater noise on marine species, particularly from pile-driving for wind turbines. Environmental assessments typically use generic sound propagation models, but empirical tests of these models are lacking. In 2006, two 5 MW wind turbines were installed off NE Scotland. The turbines were in deep (>40 m) water, 25 km from the Moray Firth Special Area of Conservation (SAC), potentially affecting a protected population of bottlenose dolphins. We measured pile-driving noise at distances of 0.1 (maximum broadband peak to peak sound level 205 dB re 1 μPa) to 80 km (no longer distinguishable above background noise). These sound levels were related to noise exposure criteria for marine mammals to assess possible effects. For bottlenose dolphins, auditory injury would only have occurred within 100 m of the pile-driving and behavioural disturbance, defined as modifications in behaviour, could have occurred up to 50 km away.
Financial support for this study was provided by the EU DOWNVInD project, with additional logistic and financial support provided by Talisman Energy (UK) Ltd. and Scottish & Southern Energy.
Moray Firth, NE Scotland
- To determine accurate estimates of received sound levels from pile driving for offshore wind at a range of distances from the source
- To determine the validity of the propagation model and predicted received levels in the environmental assessment
- To determine the potential impacts on marine mammals based on noise exposure criteria and in comparison with local background noise measurements
After the recording, it was evident that the sound extends over a large area. Also, the impact could be greater when larger wind farms are installed over longer periods of time. The dangerous effects are most likely to occur within 100 meters from the site. If a larger project was constructed over several months, could lead to potential avoidance by harbor porpoises from 20 km away.
Bailey, H.; Senior, B.; Simmons, D.; Rusin, J.; Picken, G.; Thompson, P. (2010). Assessing Underwater Noise Levels during Pile-Driving at an Offshore Windfarm and its Potential Effects on Marine Mammals. Marine Pollution Bulletin, 60(6), 888-897. https://tethys.pnnl.gov/publications/assessing-underwater-noise-levels-during-pile-driving-offshore-windfarm-and-its