© Ted GikasThe humpback whale found washed up on Sharp Park Beach in Pacifica.
Over the weekend, academy scientists performed a necropsy on the subadult female humpback whale discovered on Sharp Park Beach in Pacifica. Giancarlo Rulli, a spokesperson for the Marine Mammal Center, said the whale was "in an advanced state of decomposition" when scientists first visited Saturday and difficult to get to because of the high tide. Scientists returned Sunday and were able to perform the necropsy.
After collecting data, photos, measurements and samples from the carcass, they found that lacerations on her body appeared to be consistent with "an interaction with orcas," which was the likely cause of death, said Moe Flannery, the California Academy of Sciences' senior collections manager.
The whale was "missing her tongue, had rake marks, and had tissue damage around her jaw."
Humpback whales are one of the most endangered whale species, with some 2,900 along the coastlines of Washington, Oregon and California and between 35,000 to 40,000 individuals around the globe, according to the Marine Mammal Center.
"This is the time of year when humpback whales are feeding in the San Francisco Bay Area, so it is not uncommon to have several strandings," Flannery said.
Researchers from the Marine Mammal Center have determined that malnutrition, entanglement, trauma from shrimp strikes and orca predation are among the most common factors leading to whale deaths and subsequent stranding, but sometimes the cause can remain unknown. In the Bay Area, the institution works in partnership with the California Academy of Sciences to respond to reports of the deceased animals. This year, they performed necropsies on seven gray whales, all part of an ongoing unusual mortality event, two humpback whales and one Hubb's beaked whale, a deep-sea species rarely seen alive or dead.
One local who saw the whale stretched out in the sand next to the Pacifica Pier early Saturday evening said it appeared to have been there for several hours.
"You could smell it from the end of the street," he said.
Some San Francisco residents were similarly puzzled to find another marine mammal at Fort Funston that same day. Ben Blatteis was going for a jog when he found a shiny gray sea creature laying on its side on the beach. It had dark fins and a white underbelly and appeared to be about 4 feet long.
"What is this? [A] baby whale?" he wrote in a post he shared on Reddit.
Users were quick to say that it looked like a harbor porpoise, a small and shy species of cetacean that's frequently spotted swimming underneath the Golden Gate Bridge.
"This is like the third one I've seen this week," one said.
Rulli confirmed that the Marine Mammal Center and the California Academy of Sciences have "received several calls" over the past two weeks from people reporting harbor porpoise deaths between Alameda, Ocean Beach and the Marin Headlands. In the past year, they've responded to 10 carcasses, including eight along Bay Area shorelines and two in the Watsonville area, though Rulli noted that the numbers of dead harbor porpoises statewide and locally are running behind the normal historical average.
Marine Mammal Center response volunteers were dispatched to Fort Funston on Saturday to verify the deceased animal's presence on Saturday and ultimately decided to leave it on the beach to naturally decompose.
"Fort Funston is tricky logistics-wise because gaining beach access from the nearest parking lot is down a very steep cliff and would have required a large team of responders to perform the task of hauling it up," Rulli said.
Though the deaths of the whale and the harbor porpoise are likely not connected, the harbor porpoise does also face natural risks like malnutrition and trauma from predators. However, it's not orcas they need to steer clear of but aggressive bottlenose dolphins. The Marine Mammal Center's cetacean field research team is studying the harbor porpoise population's abundance, distribution, social behavior and calving success following their 65-year absence from the bay.
Rulli said the porpoise was gone by Sunday afternoon and likely washed away with the high tide. Skylar Knight, a spokesperson for the California Academy of Sciences, said the whale remained ashore on Sharp Park Beach as of Monday afternoon, but that the carcass would be towed away if it was still there Tuesday.
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