While on a snorkel tour on the Great Barrier Reef, marine biologist Jorja Gilmore spotted something peculiar. In the water in front of her danced a paper-thin, elongated silvery fish. Perplexed, she called over master reef guide Tahn Miller to see if he knew what it was, writes Phil Brandel for the Australian Broadcasting Corporation (ABC).
"At first I couldn't quite place what species of fish it was, but then I saw the shiny mercury-coloured body, two predominant eyes and the ultra-fine dorsal fin running head to tail, undulating like mini waves propelling through the water," Miller tells Marina Trajkovich from 9News. "I knew we had come across something rarely seen on the Great Barrier Reef. Luckily, I had my camera and started to film straight away.”
But the fish wasn’t in any of the guidebooks onboard, so the team reached out to a network of reef guides to see if anyone could identify it. One suggested it might be an oarfish, an elusive creature usually found in the deep ocean, per ABC.
The team contacted Tyson Roberts, a former research associate at the Smithsonian Tropical Research Institute in Panama and oarfish expert. Roberts confirmed the fish was a juvenile Regalecus russelli, an oarfish species that can grow more than 25 feet long. The individual seen on the Great Barrier Reef had about a foot long body but was about 3 to 6 feet with its fins, per 9News.
"This is the first record of this species on the Great Barrier Reef and on the eastern seaboard of Australia," Roberts tells ABC. "There have been other oarfish recorded in south-eastern Australia, but they are the Regalecus glesne species, which lives in cold water and has two dorsal fin crests above the head, differing from the individual spotted at Opal Reef."
Dead adult oarfish periodically wash up on beaches. In 2013, two Regalecus glesne were found in Southern California within less than a week of one another. Live oarfish sightings are more rare, reports Steven Hill for Field and Stream. Earlier this year, beachgoers spotted a live 12-foot oarfish in New Zealand, but the fish died shortly after.
Oarfish can be found at depths of more than 3,000 feet in the ocean, but they sometimes get washed into shallower waters, Wave Length Reef Cruises writes on Instagram. The one spotted on the Great Barrier Reef was swimming at a depth of about 6 feet.
"It's amazing that the ocean still has secrets to reveal, just when you think you've seen it all, magic happens,” Miller tells ABC. "There were about 40 people in the water that day and we were all very lucky to experience it."