Marine mammal strandings break record in Southeastern Mass. in 2024

The International Fund for Animal Welfare responded to 600 strandings in the region in 2024 and at least two in January 2025.

Southeastern Massachusetts saw a record number of marine mammal strandings in 2024, including 11 large whales and hundreds of dolphins. Local authorities say they have received reports of at least two more large whale strandings — a humpback whale and a sperm whale — in the area this January. 

The International Fund for Animal Welfare, the partner organization authorized by NOAA Fisheries to handle stranded marine mammals in the region, said it responded to 600 strandings in total last year. That’s more than double its annual average.

While the whale strandings are driving speculation about the impact of offshore wind development on these species, NOAA Fisheries officials, IFAW scientists, and many other fisheries researchers say there are no known links between offshore wind activities and whale deaths. 

They say rebounds of certain whale populations and “changing habitat use patterns” are more likely tied to elevated levels of strandings. They have found evidence of ship strikes, fishing gear entanglement, and disease on stranded dolphins and whales. 

Still, these researchers concede that the cause of these deaths is unclear, and more study is needed. 

“What we do know is that coastal marine mammal dynamics have been very different this year,” IFAW veterinarian Sarah Sharp wrote in an email on marine mammal strandings to WCAI. 

“There are many different factors at play right now in our near-shore marine ecosystems and it may take a little time to tease it all out.” 

On Jan. 1, an IFAW team responded to a dead 33-foot male humpback whale in Westport — the first reported local stranding of the year.

The team was able to gather some skin and blubber samples that day, but the whale’s body remained in a good amount of water, even at low tide. So the crew marked its location with a satellite buoy, and conducted an additional necropsy and sampling on Friday, Jan. 3. 

The final necropsy is not yet available, according to an IFAW spokesperson. 

NOAA Fisheries has been tracking elevated mortality levels for humpback whales —  which have been stranding on East Coast beaches — since 2016. 

Researchers do not know exactly why this trend is occurring, but they refer to it as an “unusual mortality event.” 

Federal officials say they have received reports of more than 240 dead humpbacks from 2016 to now, with more than 50 of those deaths reported in Massachusetts. 

NOAA Fisheries and its partner organizations like IFAW conducted partial or full necropsies on roughly half of these whales. Of the whales examined, about 40% had evidence of vessel strikes and fishing gear entanglements. 

Humpback whales are a protected species under the Marine Mammal Protection Act.

Sperm whale stranding

On Jan. 26, IFAW crews responded to reports of a dead female sperm whale on Cuttyhunk Island. The animal was roughly 32 feet long, and weighed 11 tons.

The responders were only able to perform a limited external exam, due to the location of the stranding and the conditions on the beach. The responders were required to be off the island by around 5 p.m. that day.

The IFAW team reported that there were no obvious external wounds present. They anchored and satellite-tagged the whale carcass. Plans for a full necropsy are pending, according to an IFAW spokesperson.

Sperm whales are the largest of the toothed whales, and have one of the widest global distributions of any marine mammal species, NOAA Fisheries researchers said. 

Strandings of sperm whales are rare. Still, they have occurred all around the world. Sperm whales have stranded in Massachusetts before. One stranded in Duxbury in 2023. 

The reasons are still unknown. Some researchers say they believe that topography, ocean noise, marine debris, and oil or manmade contaminant spills could play roles. 

Sperm whales also strand due to vessel strikes and fishing gear entanglements, federal researchers say. Those interactions could be intensifying due to changing ocean temperatures and shifting prey distributions. 

Sperm whales are listed as endangered under the Endangered Species Act and as depleted under the Marine Mammal Protection Act.