Rare Video Shows "Sea Serpent" Oarfish in Shallow Water

A pair of rarely seen, bizarre deep-sea creatures, thought to have been the inspiration for historic tales of "sea serpents," were captured on a video (see above) posted online Monday.

The footage, filmed by staff from Chicago's Shedd Aquarium, shows two giant oarfish (Regalecus glesne) swimming near a beach in shallow water in Baja, California.

"It was one of the most stunningly beautiful fish I've ever seen," says Tim Binder, vice president of collection and planning for the Shedd Aquarium, who recorded much of the video. It was shot in early March in a remote area north of La Paz, near Isla San Francisco.

The giant oarfish is the world's longest bony fish and can reach a length of 56 feet (17 meters) and weigh up to 600 pounds (270 kilograms). The fish had bright silver patterns with blue spots and a dramatic crown. "They had an undulating way of swimming; it was very graceful," says Binder.

Beached and Expired

Binder says the fish swam around for 20 to 30 minutes. "They just kept trying to beach themselves," Binder says. Eventually, they did flop up on the beach; after that, "it didn't take long for them to expire."

Because of their large size, and because the trip was not a collecting expedition—it was an ecotourism expedition for aquarium members—Binder's team were not able to take the specimens for study.

Although the behavior has been documented before, scientists can't explain why the fish beached themselves. Such beachings are most common in areas near upwellings of water from the deep. The area where the oarfish were recorded fits that description, Binder says.

Still, the odds of being on this remote beach at that moment were negligible, and the chance encounter provided, he says, "quite a spectacular opportunity."

The Oarfish's Strange History

Oarfish were first described in 1772, but are rarely seen because they live at depths estimated to be around 3,300 feet (1,000 meters).

The silvery fish, sometimes called the "king of herrings" because of their resemblance to the smaller fish, are named oarfish because of their long pectoral fins, which resemble oars. They are also known as ribbonfish because of their slender form, or rooster fish because of their crown of fins.

In October 2013, staff at the Catalina Island Marine Institute found the body of a dead 18-foot-long (5.5-meter-long) oarfish in Toyon Bay on California's Catalina Island.

It took 15 people to haul the giant beast onto shore.

In June 2013, National Geographic reported on a rare video, taken near the Gulf of Mexico in 2011, of a swimming giant oarfish in the deep.

Not much is known about the oarfish's conservation status because it is so difficult to study. The fish are occasionally pulled up as bycatch in fishing nets. They are thought to occupy a broad range, and to feed on krill, small crustaceans, and squid.

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