Video above: FOX 5's Christelle Koumoue in a Dec. 10 report on the dead whale.
SAN DIEGO (KSWB) — Over a month after a massive fin whale was found dead on the shore of Pacific Beach in San Diego, its carcass is still moving around the waters near Southern California — along with its suspected killer.
Scientists with the National Oceanic and Atmospheric Administration have been tracking the 52-foot female juvenile whale using a special GPS buoy attached following its second tow by crews since it was rolled off the beach and into the ocean in early December.
In the weeks that followed, the whale has been picked up drifting hundreds of miles in an almost circular motion — first northward towards the islands off the coast of Los Angeles county, then back down south through San Diego to Mexican waters.
"It's essentially following a current that we call the Southern California Eddy that creates a kind of circular motion," said Justin Greenman, assistant stranding coordinator with NOAA's Fisheries Office of Protected Resources. "It appears that at least it's been caught in that for a little bit."
The main purpose for this monitoring, Greenman explained, has been to see where the decaying whale is headed in real-time in order to alert any boats whether the body may be moving in their direction or to notify beach crews that it is moving back inshore.
The information collected from her drifting also gives oceanographers additional data to feed into models for predicting the movement of the ocean when working to address things like oil spills or stranded vessels.
While she has been floating with the current, the whale's movement has mirrored that of the creature who scientists believe may be the culprits in her death: the pod of eastern tropical Pacific orcas that has been sticking around in Southern California over the last few weeks.
The fin whale, whose body was still very fresh when it became beached, was discovered about a day before the pod was first spotted hunting off the coast of Palos Verdes on Dec. 11.
Scientists were not able to conduct a necropsy of the fin whale, but this timing on top of visible rakes on her flippers and the flukes that scientists say is inconsistent with human-inflicted marks, has led scientists to assume that an interaction with the orca pod may have been what led to her untimely death.
"We know that we've seen them hunting on other cetaceans, small dolphins as well as newborn gray whales," Greenman said. "It's not out of the picture for them to at least try to take down this fin whale."
At the very least, he says that the fin whale's marks could indicate that she "encountered orcas and they had perhaps been given a chase or harassed" before moving closer to the shore and away from open waters — a typical behavior when whales are attacked.
However, fatal killer whale attacks on fin whales that are actually recorded are relatively rare, with one recently published study noting only 12 reported between 1982 and 2021 — the vast majority in the Gulf of California.
That includes a 2011 incident when fisherman near Coronado Island saw a pod pursuing a fin whale in Northern Baja waters for over two hours, and another in 2019 when an "apparently healthy" adult became stranded on a beach alive after a group of eight orcas chased it there.
The only recorded killer whale attack on a fin whale that turned deadly in the waters off the coast of California, according to the study, was a "likely fatal" in 2019 near Morro Bay when four killer whales were observed from a fisheries research vessel hunting one for nearly half an hour.
Killer whales do not often target fin whales, a species that is second only to the blue whale in size. The types of orcas that hunt other mammals more frequently go after smaller creatures like dolphins, seals or gray whale calves, according to the California Killer Whale Project.
It is usually the more aggressive pods — a trait passed down from the matriarch of the group — that turn to the larger cetacean species, including those that might select a fin whale as potential prey to feast on.
The pod currently swimming around Southern California has been observed multiple times by whale watching groups to their simultaneous wonder and horror while the orcas hunt dolphins and a several young gray whales.
Jessica Rodriguez, education and communications manager at Newport Landing & Davey’s Locker Whale Watching, said that she would not put trying to take down a fin whale past this pod, even though most of their predation has been on the smaller mammals.
"They would have to be pretty hungry and very ambitious to do that, because these whales can be hundreds of thousands of pounds," Rodriguez explained, adding that they would likely have coordinated with each other to take down a whale the size of the one that washed up in Pacific Beach.
"They are called the wolves of the sea for that reason," she continued, "they hunt in packs and they work together."
It still appears that the killer whales plan to stick around in Southern California to hunt for a little while longer, with even more Orange County sightings of the same pod on Jan. 4 and Jan. 9. A video of the whales from the latest sighting can be viewed in the player below.
As for the body of the fin whale, Greenman says it will eventually sink back down to the seafloor sometime in the near future. How quickly that might happen depends on how much predation happens to the animal.
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