February 9, 2023 — Offshore wind development in US East Coast waters has been blamed for a flurry of dead humpback whales off New Jersey and New York. But what do — and don’t — we know?
Since 2016 there has been an unusually high incidence of humpback whale deaths on the US East Coast: a total of 180 animals, of which about 40 percent had evidence of entanglement in fishing gear or being struck by vessels. The US National Marine Fisheries Service works with other organizations to examine dead whales found at sea or beached to determine the cause of death. The other cases remain undiagnosed because of decomposition, the inability to tow the whale ashore, lack of access to the whale, or an indeterminate cause.
Investigations of large whale mortalities can take many months, but NMFS has stated that the recent mortalities show no relation to offshore wind development. So what are the potential risks for whales of offshore wind development?
Marine mammals are sensitive to noise, which can result from weather events, earthquakes, and human sources, such as sonar, bottom drilling and coring, seismic air guns, and explosions. The effects can range from behavioral change to temporary or permanent hearing loss, and occasionally mortality. Most deaths related to acoustic exposure have been in toothed whales and dolphins related to sonar. There has been no recent evidence of humpback or other baleen whales dying from noise exposure.