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.
One concern is the potential effects of turbulence around towers in the water — posed by seabed scouring, greater mixing, and alteration of thermal layers — which has the potential to change the ecology of surface waters that are significant food sources for fish and whales. This needs further study to truly understand its significance.
Most important, there is an increased risk of whales being struck by vessels that are surveying for, constructing, or maintaining offshore wind structures. Such a strike would result in trauma that may or may not be lethal to a whale. Vessels should be mandated to slow to 10 knots in whale habitat. However, according to NOAA Fisheries, “There are no specific links between recent large whale mortalities and currently ongoing surveys for offshore wind development.”
State and federal managers must find a balance between the need to address climate change through the use of renewable energy and the safety of whales. Offshore wind energy development is driven by the need to reduce fossil fuel consumption, greenhouse gas production, and consequent global warming which the United States is failing to control.
Consumer demand that enables the fishing and marine transportation industries leads to whale mortality. Our wants and needs are the driving force for vessel strikes and fishing gear entanglements that are killing whales. We must rebalance our behavior by demanding supply chains that harvest and deliver in ways that are sustainable for both industries and the resources they directly and indirectly exploit. Doing so will enable a healthy ecosystem, thriving whales, a cooler planet, and socioeconomic justice for jobs in all these competing activities.
Meanwhile certain commentators are suggesting — without evidence — that offshore wind development has been killing these whales to stoke the fires of climate change denial.
Michael J. Moore is director of the Woods Hole Oceanographic Institution Marine Mammal Center and author of “We Are All Whalers.”