A large, disk-shaped fish that is “famous for looking odd” gained global media attention after it washed up on a Santa Barbara County beach, thousands of miles away from its known habitat in the Southern Hemisphere.
The fish found on Devereux Beach along UC Santa Barbara’s Coal Oil Point Reserve on Feb. 19 measured 7 feet long and 7 feet wide. It had no tail and no teeth, and sharp fins that are used to flap like a bird under water.
Scientists first thought it was an ocean sunfish commonly seen in the Santa Barbara Channel, but with the help of an online crowd-sourced animal identification site called iNaturalist, an expert based in Australia realized it was actually a hoodwinker sunfish and it was really, really rare.
Only one other sighting of the species has been confirmed in the Northern Hemisphere, a sunfish that was originally misidentified and stored in a museum after it was found on a Dutch Island in 1889.
After the discovery of the recently beached specimen, some people speculated in comment sections that the hoodwinker sunfish’s journey to the Americas was yet another example of animals expanding habitat due to warming waters caused by climate change.
Another possibility offers to inspire awe and wonder: that mysteries still abound in the vast ocean, and the fish may have been swimming in the Pacific all along.
After all, this species of sunfish — Mola tecta — was only first discovered by scientists in 2014 and documented in 2017. How is that possible in a time when it seems that humans have explored and named every inch of the earth?
In fact, when scientist Marianne Nyegaard wrote about her discovery and identification of the fish, she said, the “new species had been hiding in plain sight for centuries.” Yes, the largest bony fish in the sea had gone undetected.
Research identifies sunfish
As part of her Ph.D research, Nyegaard analyzed more than 150 samples of sunfish and in 2009 found one that didn’t fit any known species. Armed only with skin samples, she had no idea what the fish looked like. She scanned pictures looking for any indication of a difference from the known species.
She got a break in 2014, when fisheries in New Zealand and Australia hauled in a fish with a small structure on its back. That ended up being the crucial defining feature of the hoodwinker that had hidden among the others: a “back-fold” connecting the halves of their back fin. That’s a small distinction to identify on a fish that’s already elusive.
A photo of that part of the body is what sealed the deal that the Santa Barbara County sunfish was well beyond its territory.
“With the fish so far out of range, I was extremely reluctant to call it a hoodwinker without clear and unambiguous evidence of its identity,” Nyegaard told the UC Santa Barbara Current, adding that she didn’t want to be hoodwinked by a stranded sunfish.
Ultimately, more information is needed to determine why the fish ended up on the Isla Vista beach.
“It’s not uncommon for sunfish to wander really far. In the future, we will understand whether this fish occurs regularly off the coast of California or whether this is a one-off,” Nyegaard said.
Research of the wandering creature has already begun.
According to a Facebook post from the Coal Oil Point Reserve, samples of the fish were saved for future research or sent to labs, including the Eliason Lab that studies how fish are physiologically adapted to their environments and how they respond to environmental change. That lab received several parts, including the heart and the otoliths, organs in the inner ear that allows an organism to perceive gravity and movement.
Other body parts were frozen, like the left eye and the ovary. Several sections of intenstine were packed on ice to be examined by a parasitology course. Also collected were “multiple bags of tapeworm-laden mucous that dripped from the intestines during dissection.”