When a university intern stumbled upon a seven-foot fish washed up on the beach at the University of Santa Barbara's (UCSB) Coal Oil Point Reserve on February 19, 2019, scientists assumed it was the mola mola sunfish. One of the world's heaviest known bony fishes, the species, found in tropical and temperate waters around the globe, is common in the Santa Barbara Channel.
It was only when UCSB associate professor Thomas Turner posted images on iNaturalist, an online scientific database to identify species, that the researchers realized this was a rare mola tecta, or "hoodwinker," sunfish, which has never been seen in North America.
Australian marine scientist Marianne Nyegaard, who helped make the classification, said she suspected the washed up creature might be a hoodwinker when she saw the first images. However, the sunfish expert needed more evidence to make a definitive decision and asked Turner to send additional photos. "When the clear pictures came through, I thought there was no doubt. This is totally a hoodwinker," the researcher told CNN. "I couldn't believe it. I nearly fell out of my chair."
And she should know. It was, after all, Nyegaard who first found and named the fish. In 2009, while analyzing over 150 skin samples of sunfish for her Ph.D. thesis, the researcher came across one that did not resemble any previously identified specimens. Her suspicion that it may belong to a new species was confirmed in 2014, when a fisherman caught a sunfish with a distinct back flap called a "clavus," which are not found on the common sunfish. It took another three years for the expert to certify that it was a new species.
The mola tecta, which means "hidden" in Latin, can be found in the warm coastal waters of Australia, New Zealand, South Africa, and perhaps Chile. It is larger and heavier than other sunfish species, weighing about two tons, and does not have the same protruding snout characteristic of the more common mola mola. The only other time a hoodwinker has appeared outside of the Southern Hemisphere was in 1889, when one washed up in the Netherlands. That specimen, also misidentified as a mola mola, was preserved in a museum's collection and only correctly reclassified as a mola tecta after Nyegaard's discovery of the species.
Not surprisingly, UCSB scientists are incredibly excited at this unprecedented opportunity to conduct an extensive analysis of this rare fish. The team has extracted portions of the fish's intestines to get a better idea of the hoodwinker's diet and its place in the ocean's ecosystem. They have also removed its heart and otoliths–organs in the inner ear that allow the fish to perceive gravity and movement underwater–to determine how it adapts to its environment.
UCSB zoology professor Armand Kuris says, "Opportunities to study any sunfish are few and far between. Especially the elusive hoodwinker, which was first described in 2017. It’s the first time someone has looked at an identified hoodwinker sunfish.”
The scientists are unsure if the dead fish drifted off-course and swam the almost 12,000 miles from its Southern Hemisphere habitat, or if hoodwinkers are common in the waters around California and have just managed to stay hidden all these years.
Resources: latimes.com, edhat.com, cnn.com