Nine large-whale strandings in the region over the past six weeks, and an “unusual” increase in humpback whale stranding deaths since 2016, has federal wildlife regulators concerned about the pattern, but they said there is no evidence that new offshore wind survey activity is to blame.

The nine whales that have washed up on beaches along the Atlantic coast, including New Jersey and Long Island shores, since Dec. 1 consisted of seven humpback and two sperm whales, said Sarah Wilkin, coordinator of the Marine Mammal Health and Stranding Response Program of the National Oceanic and Atmospheric Administration’s Fisheries Office of Protected Resources.

Recent deaths of humpbacks are part of what the government terms an unusual mortality event for the species that has seen 178 stranding deaths since January 2016. Wilkins said there also are unusual mortality events for the North Atlantic right whale and minke whale.

“Unfortunately, it’s been a period of several years where he have had elevated strandings of large whales,” she said. “But we’re still concerned about this [increase] over the past six weeks or so.”

In a briefing on the whale deaths Wednesday, officials from the federal Bureau of Ocean Energy Management were quick to note that an uptick in offshore wind survey work doesn’t appear to be to blame.

“We do not have evidence that would support a connection between the survey work and these recent stranding events, or any stranding event in the last several years,” said Benjamin Laws, deputy chief for the permits and conservation division, NOAA Fisheries Office of Protected Resources. The surveys use sounding devices that can have an effect on whales, but the equipment is said to be less damaging than other such equipment used for oil and gas exploration.

Of the roughly half of the whales that could be examined in a necropsy since 2016, about 40% showed evidence of “human interaction,” including a vessel strike or “entanglement,” NOAA said. “To date, no whale mortality has been attributed to offshore wind activities,” an official said.

But concern about impacts of wind farms was enough to prompt Sean Hayes, chief of the National Marine Fisheries Service protected species unit, to write a letter to BOEM’s lead biologist last May to express concern about one planned wind-farm’s potential impact on the endangered right whale. Newsday obtained the letter through a Freedom of Information Act request.

“The development of offshore wind poses risks to these species, which is magnified in southern New England waters due to species abundance and distribution,” Hayes wrote, citing increased noise, vessel traffic, “habitat modifications” and other factors. He requested creation of a “conservation buffer” and other modifications to projects to further protect right whales.  

But officials Wednesday noted other factors could be drawing whales into more perilous waters. The whales “may be following their prey, which we’re hearing from our partners are reportedly close to shore this winter,” NOAA said.

One wind-farm opponent said uncertainty around the deaths calls for more study. "We need a moratorium" on vessel survey work until the impacts are known, said Bonnie Brady, executive director of the Long Island Commercial Fishing Assoc., which opposes wind farms on fishing grounds.