PCCS recently participated in the post-mortem effort to discern the cause of death of a humpback whale known to scientists as Beacon. What follows is a summary of activities that are typically conducted by qualified participating organizations whenever a large whale washes ashore.

On Saturday, December 11, Larry Bessinger, a trained volunteer with the Cape Cod Stranding Network (CCSN) found the carcass of a dead humpback whale at Newcomb Hollow Beach.

When large whale strandings occur on the Lower Cape, PCCS helps the stranding network by following up on the report and beginning the documentation process. "I looked for evidence of human interaction, a high priority for the stranding network," explains PCCS research assistant Moriah  Bessinger.  "Was the whale hit by a ship, or was it entangled?" she asks.  No recent evidence of human interaction was found in her initial investigation, but Moriah did see healed entanglement scars on the whale.   This is not uncommon and PCCS research on live whales indicates that more than half of the local population has scarring indicative of previous entanglements.

Bessinger also took basic measurements, such as a single straight-line length of the entire animal, and she measured the girth, flipper length and fluke width of the whale. 



A skin sample was also taken, just in case the tide took the carcass back out to sea overnight.   The Provincetown Center for Coastal Studies maintains an extensive genetic archive of the local humpback whale population, in conjunction with geneticists at the University of California at Berkeley.  Identifying features were not yet visible because of the orientation of the carcass when it ran aground.  If it were to wash back out to sea overnight, genetic analysis could still provide the identity of the individual that died.

PCCS later worked with representatives of the Cape Cod Stranding Network and the National Park Service to set the anchor that would help to prevent the overnight tide from carrying the carcass back out to sea.

The National Park Service provided permission to perform an on-site necropsy the following day.   With daylight gone, everyone adjourned for the night.

On Sunday, December 12, the necropsy team, led by the Cape Cod Stranding Network, met at the site before sunrise.   Strandings are unusual events that draw the attention of scientists, managers and the public.  In addition to CCSN and PCCS, the group included representatives from the National Marine Fisheries Service (NMFS) and National Park Service (NPS), interns from the Whale Center of New England (WCNE) and scientists from Woods Hole Oceanographic Institution (WHOI.)

Jooke Robbins, director of PCCS humpback whale research, was on site with her research assistant, Amy Kennedy.  "Our role was to provide as much insight as we could from our research on the live population, to look for evidence of entanglement, to obtain samples to assist in our own research to help us better understand how the whale lived, and to assist CCSN with the labor of the necropsy," Robbins explained.

One of the first tasks was to expose the underside of whale's tail.  The pattern of pigmentation on a humpback whale's tail is unique to each individual, much like the fingerprints of a human.  Since  the mid-1970s, PCCS has photographed and cataloged humpback whales in the  wild.  With the tail exposed, PCCS scientists were able to identify the dead humpback as Beacon, a 6-year-old female who frequented Cape Cod waters.

Humpback whales are an endangered species.  In the North Atlantic, they number approximately 12,000 animals.  Robbins said Beacon was part of the Gulf of Maine feeding population, which ranges from Cape Cod to Nova Scotia.  Had she not died, Beacon would be preparing to migrate to the West Indies, which is where this population mixes with other North Atlantic animals to mate and calve.

"Based on her age and length, she would have been reaching sexual maturity," explained Robbins.  "Our last sighting of her was during a research cruise on November 2 and there was nothing unusual about her at that time."

Most humpback whale deaths go unwitnessed.   For those who studied Beacon in the wild, her stranding provides a piece in the puzzle of large whale mortality.  It also provides opportunities to better understand her life. Beacon was part of a study on humpback whale reproduction, and Robbins hoped that reproductive organs would be in good enough shape to determine whether she was mature and/or pregnant.

Unfortunately, cetacean carcasses do not always yield up their secrets.  Necropsy team members were disappointed to find that the internal organs had already undergone substantial decomposition.  This is not uncommon.  The black skin and thick blubber layer of cetaceans causes internal organs to heat quickly, even in winter.  So, while investigators obtained as many samples and data as they could get, they have to assume that many of their questions about this stranding will probably remain unanswered.