CHATHAM — For researchers hoping to understand the death of a stranded whale, sometimes the answer is simple: There is no answer.
That’s not yet the case with the young humpback that stranded on shoals outside Stage Harbor earlier this month, since researchers are still waiting for lab results from tissue samples taken during a postmortem exam. But absent any indication of illness, they don’t have much to go on; the necropsy showed no obvious cause of death for the otherwise healthy juvenile humpback.
“The only surprise was that it was in really good body condition, which is something we rarely see” in stranded whales, said Misty Niemeyer, the stranding coordinator for the International Fund for Animal Welfare’s Marine Mammal Rescue and Research program.
The whale was alive and struggling when it was first spotted on the morning of Nov. 7, high and dry on shoals just south of Crescent Beach, east of the Stage Harbor entrance channel. Supported by the Chatham and Harwich harbormasters, the Coast Guard and the Center for Coastal Studies in Provincetown, the IFAW stranding team worked through the day Saturday to try and free the whale, struggling against strong currents and other challenges. When they returned on Sunday to try again, they found that the animal had died overnight.
Throughout the day Sunday, crews labored to free the 14-ton whale, which was “really difficult to do,” Niemeyer said. Given that most of the 30-foot-long humpback was out of the water even at high tide, “I think it would have been difficult to get the animal out of there regardless” of its ability to swim, she said. The rescue team had trouble imagining how the whale had managed to strand itself, given the lack of open water around it. It is possible that the strong currents in the area washed sand around the animal once it became stranded, locking it in place, she said.
After it had died, the whale was dragged off the shoals and towed to the pier at Old Mill Boatyard, where workers from J.W. Dubis and Sons and Baxter Crane and Rigging lifted it into an 18-wheeler. It was trucked to the Bourne town landfill where the postmortem was performed.
“To us, the biggest surprise that we found out right after this necropsy was that this was still a calf,” Niemeyer said. While the team initially estimated that the animal might have been between two and five years old, they learned that it was even younger, possibly having just weaned.
Matching the Chatham humpback’s distinctive flukes with photos on file, researchers from Bar Harbor Whale Watch and Allied Whale identified the animal as the calf of a humpback named Lynx. Both whales were last seen on Aug. 13 and Aug. 16 on the Grand Manan Banks in the Bay of Fundy.
The necropsy revealed that the whale had no fish in its belly, which makes it less likely that it stranded itself while chasing prey toward the shore, one theory. Investigators found no evidence that the calf had been struck by a boat or had become entangled in fishing gear, two other common causes of death for cetaceans. The exam also showed no signs of chronic illness.
Humpback whales are a federally protected species under the Marine Mammal Protection Act. Populations in the western Atlantic are part of the West Indies population and migrate from the Caribbean along the East Coast of North America. This population is not considered endangered, but other populations of humpbacks in the world are.
Federal fisheries researchers point out that an unexpected die-off of humpbacks, known as an “unusual mortality event,” has been taking place since 2016. Since that time, 24 humpbacks have stranded in Massachusetts waters, among 135 strandings between Florida and Maine.
When older humpbacks die, the causes of death are often obvious, but the death of young whales is less understood, Niemeyer said.
“This animal was probably nursed and cared for very well,” she said. Despite its young and apparently healthy body, the animal may simply have failed to thrive for some reason. “Nature can be harsh,” Niemeyer said.
People who see stranded whales or dolphins are urged to call the IFAW stranding hotline at 508-743-9548, and to keep their distance. In the case of the Chatham stranding, the crews had many well-intended offers of help from passing boaters, but approaching boats not only cause stress to the animal but pose a safety hazard for rescuers, Niemeyer said. “There was also a lot of drone activity” over the rescue operation, which is illegal, she said.
While the three-day rescue attempt, recovery and necropsy took a physical toll on the responders, it is also difficult emotionally.
“This one was really tough,” Niemeyer said. Marine mammal strandings are often fatal. “We know that’s reality,” she said. “But it is always hard. We feel really lucky we have an incredibly dedicated crew” and a large number of partners who help get the job done, she said. “It takes a village to do the work that we do.”