Abstract
What you should know:
- Almost all marine animals rely on sound for their key biological needs, including communication, orientation and navigation, predator avoidance, and feeding.
- One of the offshore wind noise-producing activities that has a significant potential to impact marine animals is pile driving. Impact pile driving is a method used to install monopile and jacket wind turbine foundations. Regulatory agencies require that offshore wind developers minimize and mitigate effects that could lead to auditory injuries or behavioral disturbance via a range of monitoring and mitigation strategies.
- Public concern that noise from offshore wind pre-construction activities is contributing to whale deaths along U.S. beaches is not supported by any scientific evidence. While offshore wind activities during pre-construction do produce noise, most of these sounds are less impactful than those produced by other human activities and emit at far lower intensities than marine activities used in oil and gas or military applications
- The most common sources of mortality and injury to marine animals are collisions with boats or becoming entangled with ropes that are used to secure and mark fishing gear. To reduce the risk of lethal collision, vessels that are used for offshore wind activities are required to observe various speed restrictions. Further, offshore wind survey vessels must have dedicated protected species observers (PSOs) or a trained lookout on board watching for marine mammals and sea turtles, a requirement that goes above and beyond most other marine activities.
- While not conclusively demonstrated in field studies, some marine animals and their prey may be sensitive to changes in electromagnetic fields (EMFs) from subsea cables. Other disturbances, such as dredging or effects on currents, may cause these animals to temporarily avoid the wind farm areas or have a negative effect on key food sources. This is discussed further below and in Coastal and Marine Habitats.
- Technology applications and installation methods used by offshore wind developers can significantly reduce the intensity of these impacts and help to mitigate negative effects. Restorative measures can also be taken to help reestablish habitats, while the artificial reefs that develop around turbine structures have the potential to improve localized biodiversity and ecosystem health.