When a team of underwater explorers made the deepest dive ever on a wreck earlier this year, the news was broadcast worldwide. A team from Caladan Oceanic found the USS Johnston, which sank in an intense naval battle in 1944, to be surprisingly well preserved, its guns still pointing in the direction of the enemy. A few days before making their record trip, the explorers had yet made a new descent to the seabed, a dive that finally ended in a few kilometers.
Although they failed to find the wreck that day, they I found something else.
After footage of the excursion arrived, Alan Jamieson, a deep sea researcher at the University of Western Australia, sat in his office on the expedition ship, scrolling through frame after frame without incident, looking for anything that might be interesting.
The two-person submersible, piloted by Victor Vescovo, the American investor who founded Caladan Oceanic, appears to have slipped little more than mud – and more mud – on its long journey through the Philippine Trench, which lies 6,200 meters below the surface, east of the Philippines.
But then, for a few seconds of video, something strange moved in the distance. Jamieson rewound and replayed the short sequence. And even.
On his screen, caught in the light projected by the submersible, was a fuzzy but recognizable shape: a squid. He was sailing just above the seabed a mile and a half deeper than anyone who had ever seen a squid before.
Jamieson quickly cut a snippet of the footage and some stills, and sent them to Mike Vecchione, a zoologist at the Smithsonian Institution. From the contours of the creature, Vecchione could tell it was a magnapinnid. Also known as the bigfin squid, due to the large fins sticking out of their mantle, magnapinnids are among the most mysterious squid in the world.
“They are really weird,” said Vecchione. “They are drifting with their arms outstretched and those very long, skinny spaghetti-like extensions hang below them.” Microscopic suction cups on these filaments allow the squid to capture their prey.
But the squid that Jamieson and Vecchione saw in the footage captured 6212 meters below the ocean’s surface is a small one. They estimate his coat was 10 centimeters long, about a third the size of the largest known magnapinnid. And the characteristic long extensions seen on other magnapinnids did not appear anywhere in the video. It could mean, Vecchione said, that that big-finned squid was a young one.
The find is fascinating because of what it involves, says Bruce Robison, a deep sea ecologist at the Monterey Bay Aquarium Research Institute. Squids, being top predators, depend on a complex ecological web, and therefore finding a squid at these depths suggests that many other life forms must be out there somewhere to support it, he says.
If big-finned squids commonly inhabit this part of the ocean at different stages of their lives, it could make them vulnerable to certain human activities. “Sediment plumes and disturbances caused by seabed mining could have a real impact on these populations,” says Robison.
Images of the USS wreckage Johnston left Jamieson with similar concerns. Although the trench dug by the stricken ship was made 77 years ago, “it looks like it fell yesterday,” he says.
There are signs of marine life in the nearby sediments, but not in the gouge itself, suggesting that when the seabed at such depths is disturbed, as would be the case during mining operations, it may repel marine organisms for decades.
Finding a squid so deep suggests that there is much to protect in these poorly understood expanses. Jamieson, for his part, says he’s always trying to challenge the perception that the deepest parts of the ocean are lifeless.
This isn’t the first time Jamieson and Vecchione have documented a species at extraordinary depths. In 2020, the couple released a study into the deepest octopus ever sighting, which was also made possible by Caladan Oceanic expeditions. And, around the same time they found the bigfin squid, the company also captured images of a jellyfish in the Philippine trench at an astonishing depth of 10,000 meters.
“We saw the deepest jellyfish ever,” says Jamieson, who can’t contain a laugh of excitement. He is now working on an article that will also officially describe this discovery.