The giant fin whale likely died at sea, officials told local news outlets, noting that it had been spotted floating in the water about eight miles offshore before it arrived.
It is thought the creature may have been dead for two to three days, although the cause of death was unclear.
It showed no outward signs of trauma, Tony LaCasse, the New England Aquarium’s media relations director, told reporters, adding that facility's marine mammal team and experts from the International Fund for Animal Welfare were still investigating why it died.
Once the investigation is complete, Mr LaCasse said, local officials would bury the animal onsite. He added that the results could take months to finalise.
The local police department posted a picture of the whale on Facebook, warning locals to stay away from the area as the investigation was conducted. In the photo, the mammal could be seen dwarfing the official vehicle driving alongside it.
Fin whales – a common sight in the waters around Massachusetts – are the second largest whale species in the world, according to the National Oceanic and Atmospheric Administration (NOAA). They can weight up to 80 tons, and reach up to 85 feet.
Jennifer S. Goebel, a NOAA public affairs officer, told the Cape Cod Times there are approximately 2,700 fin whales in the North Atlantic and Gulf of Mexico. There have been 116 cases of whales found stranded or floating on the East Coast between 1992 and 2016, according to the organisation’s data.
In some cases, whales strand themselves due to sickness, injuries or navigational errors. In New England, whale deaths are usually caused by collisions with ships or fishing gear.
This was the second fin whale to wash ashore in the area in the last two weeks, The Patriot Ledger newspaper reported.