A giant ‘sunbathing’ fish that washed ashore in Oregon turned out to be an unexpected oddity

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Last week, a rare and large species of fish, known as the hoodwinker sunfish or mola tecta, was found washed ashore in Gearhart, Oregon. This discovery was made by beachgoers and confirmed by marine biologists who specialize in studying marine animals.

The hoodwinker sunfish, measuring 7.3 feet in length, was first identified in 2017 and has been occasionally observed near Australia, New Zealand, and the Pacific Northwest. One distinctive feature of this species is the presence of a thick flap of skin instead of a tail, which is split into two parts.

Initially, when Keith Chambers, the general manager at Seaside Aquarium in Oregon, received reports of a circular, gray fish on the beach, he thought it was a common ocean sunfish. However, upon closer examination, he realized it was the rare hoodwinker sunfish.

Although the discovery of this fish may not have been a remarkable moment for Chambers, it holds significance for marine biologists and researchers studying the distribution and behavior of this unique species.
Marine biologist Marianne Nyegaard, who has been studying a unique fish species called mola tecta, noticed something interesting in a Facebook photo shared by an aquarium. The fish in the photo had smooth skin and a two-part tail, which she identified as a mola tecta. Nyegaard, who happened to be visiting Seattle at the time, immediately went to see the fish in person.

“It was an amazing coincidence,” Nyegaard said, laughing. “I can’t seem to get away from them.”

The name “mola” comes from Latin and means “milestone,” referring to the fish’s flat and circular body. These fish are known for floating on the ocean’s surface, a behavior that some scientists jokingly call “sunbathing.” However, Nyegaard explained that this activity serves an important purpose: catching jellyfish and other gelatinous creatures for food.
Sunfish exhibit a unique behavior of diving into colder waters during their hunting activities. Due to their limited ability to regulate body temperature, they rely on the sun to warm themselves up. Interestingly, while these fish float on the surface of the ocean, birds help them by cleaning their skin, feeding on parasites.

The hoodwinker sunfish, in particular, possesses distinct characteristics that set it apart from the ocean sunfish. As the ocean sunfish grows, its skin develops wrinkles, whereas the hoodwinker sunfish always maintains a smooth appearance.

In place of a typical tail, sunfish possess a flap. The ocean sunfish’s flap is characterized by a wavy structure with bony formations, whereas the hoodwinker sunfish’s flap is divided into two parts, allowing independent movement of each section. The purpose behind this difference in tail structure between the two species remains unknown. Some theories suggest that the two-part flap may contribute to steering or agility, but further research is needed to confirm these hypotheses.
According to Nyegaard, sunfish, including the hoodwinker, are still a mystery to scientists. There are a total of five species, but it is unclear how they can coexist in the same location.

It is also uncertain whether the hoodwinker fish found in Australia and New Zealand are connected to those in the Pacific Northwest and have migrated across the equator.

Since its discovery, people have been visiting Gearhart Beach to see the solitary hoodwinker on the shore.

“This is not the first time it has washed up, but it is the largest one to be found,” said Tierny Thys, a marine biologist at the California Academy of Sciences.

“These strandings serve as a reminder that humans occupy only 1% of the vast living space on our ocean planet,” she added. “Encountering one of these incredible creatures is both humbling and inspiring, and it reminds us that there is still so much more for us to learn.”