Harbor porpoise necropsied today
May/17/17 06:57 AM
Brand new Seal Sitters (SSMMSN) volunteer Judy, trained this past Saturday, was out for a hike near West Seattle’s lighthouse yesterday afternoon when she came across a fresh-dead harbor porpoise on the pebbled beach. Having just learned that SSMMSN responds to reports of all marine mammals, dead and alive, she contacted the proper authorities and SS First Responder Lynn arrived on scene, shortly after our hotline @ 206-905-SEAL (7325) received the report.
Cascadia Research Collective was immediately called and confirmed they wanted the porpoise for necropsy. First Responders Robin, David and Ralph arrived and photos were texted to Jessie Huggins, stranding coordinator for Cascadia. Based on initial review of photos sent by Seal Sitters, it appears the adult female is either pregnant or recently gave birth. Plans were set in motion for biologist Erin Keene and a former intern to drive a truck up from Tacoma to collect the perfect specimen.
With the help of several members of the public (also environmental stewards), the approximately 125-150 lb porpoise was rolled onto a tarp, carried off the beach and up into a private driveway, where she was picked up by the Cascadia team shortly after 6pm. Thanks so much to homeowner Margaret who allowed us access thru her property, making the transfer off the beach much shorter and kudos to those who helped carry the heavy porpoise.
The stunning porpoise showed no obvious injuries, aside from nicks on flippers. Possible predation by transient orcas is always a concern, especially with the recent heightened transient presence in Central and South Puget Sound, and internal hemorrhaging from such an attack could still be present (often times, prey is rammed and not consumed). However, it seemed more likely that cause of death was related to pregnancy complications or disease.
In the Pacific Northwest’s Salish Sea, harbor porpoise calving typically occurs in the summer months. On May 1, 2013, SSMMSN responded to a dead neonate on the shoreline along Beach Drive. Harbor porpoise numbers have greatly rebounded in Puget Sound, after nearly disappearing in the 1970s. Cascadia and WDFW Marine Mammal Investigations collaborated on a study of 20 year aerial surveys of Washington waters. Read more about the species’ return in this recent paper. An additional resource can be viewed here on NOAA’s website.
The necropsy was performed by Cascadia today. The female was indeed pregnant, but probably a month or two away from full term. There was no trauma or evidence of pregnancy complications, but an underlying disease that may have caused early termination of pregnancy can’t be ruled out. Neurological disease is suspected and will be further evaluated histologically. A moderate lungworm infection was found, which is fairly typical for this particular species, but can also be a symptom of a more significant disease process.