On a recent weekend this fall, while one group of Coastal Studies students was deploying research gear from an 88-foot schooner, another group was having an equally unusual field trip experience in the far reaches of the Gulf of Maine: necropsying a humpback whale.
The whale carcass had washed ashore last year on New Brunswick’s Kent Island archipelago, home to the Bowdoin Scientific Station. In collaboration with Grand Manan Whale and Seabird Research Station, BSS director Damon Gannon led students from the classes Biology of Marine Mammals and Biology of Marine Organisms through a postmortem examination of the 38-foot juvenile male humpback, known in whale photo ID catalogues as “Harmonic.”
As participant Christine Walder ’15 observed, “it was a one-of-a-kind experience.”
I was struck with a sense of wonderment at how absolutely massive this animal was – and Harmonic wasn’t even full-grown. The sheer amount of muscle on the body suggested a hugely powerful animal. Whales have so much muscle tissue that much of it doesn’t articulate to the skeleton directly (as it would in most mammals), but rather to a tendinous sheath surrounding the body. I cut through the sheath and just a portion of the whale’s muscle as I worked to expose a rib that was about the size of my arm. In the process, I removed slab upon slab of dark red meat as blood and oil oozed from the newly opened gash. The stench of a year-old, partially decomposed carcass did nothing to dampen my enthusiasm for this encounter with one of the elusive giants of the ocean. And I certainly have a newfound respect for anybody who spends time working with dead cetaceans! –Christine Walder ’15
Ship strikes and entanglement with fishing gear are the most common causes of death for humpbacks, which are classified as endangered. While Harmonic’s body shows no evidence of entanglement, its belly-up position has so far prevented researchers from searching the dorsal side for signs of blunt-force trauma or lacerations from a ship strike. Another possible source of mortality is the naturally occurring red tide toxins that humpbacks ingest with their food.
I worked to expose the pyloric stomach, which was concealed within yards and yards and pounds and pounds of intestine. As I cut through the connective tissue that held the intestines in place, the intestines poured out of the whale, often rupturing and issuing air that smelled both of rotting flesh and low tide. The stomach itself was underwhelming, just a sac filled with digestive juices, but it probably would have been more interesting had we dissected the humpback when it was fresh. The otoliths (inner ear bones) of fish are the last to break down in the stomach, so, had we found some, we could have learned about the whale’s diet. My lasting impressions were of magnitude, awe, and slight nausea. Sitting knee deep in whale intestines is certainly one of the best ways appreciate the size of the animal, even if it was a juvenile when it washed ashore. My last reminders of it are the smell that will not leave my backpack and clothes, and a golf ball-size barnacle (Coronula diadema, endemic to humpback whales) that fell off of the whale’s tail. –Jackson Bloch ’15
Besides investigating potential causes of death – and taking advantage of the rare opportunity to learn about whale anatomy firsthand – the students also collected a pectoral fin for the nearby Grand Manan Whale and Seabird Research Station museum, which will eventually display the full skeleton. Obtaining the skeleton of a carcass that probably weighs 20 tons is an enormous task, Gannon noted, and plenty of labor still remains. “Much of the work done during this trip was intended to make it easier to collect bones in the future,” he said.
Read about more goings-on in the rapidly expanding Coastal Studies program at Bowdoin.
