Scientists have discovered what seems to be three entirely new species of snailfish at some of the most extreme depths of the Pacific Ocean.
The trench is about 3,600 miles long, 40 miles wide, and drops to depths of 26,460 feet. By contrast, the deepest known part of the ocean, Challenger Deep in the Mariana Trench southeast of Guam plunges down 35,800 feet.
The three new species were spotted at a depth of about 24,600 feet, near the bottom of the 26,460-foot deep trench.
The snailfish are not typical deep-sea dwellers, which tend to have huge mouths, giant teeth, and often, bioluminescent lures.
Instead, the snailfish look—as the name implies—like snails without shells, sort of undersea slugs. They lack even defensive scales.
“There is something about the snailfish that allows them to adapt to living very deep—beyond the reach of other fish they are free of competitors and predators,” said Dr. Thomas Linley, a professor at Newcastle University and a participant in the expedition.
“As the footage clearly shows, there are lots of invertebrate prey down there and the snailfish are the top predator, they seem to be quite active and look very well-fed,” Dr. Linley continued.
“Their gelatinous structure means they are perfectly adapted to living at extreme pressure and in fact, the hardest structures in their bodies are the bones in their inner ear which give them balance and their teeth.”
The three different species are so far differentiated only by color—the pink, the blue, and the purple Atacama Snailfish. Only one specimen was recovered and brought to the surface—the rest were identified by video or photographs.
The scientists believe the fish they saw are a new species of snailfish (Liparidae), with three color variations.
Studying the recovered specimen presents its own challenges, even on the surface.
“Without the extreme pressure and cold to support their bodies they are extremely fragile and melt rapidly when brought to the surface,” Dr. Linley explained.
Another Rare Animal Sighted
Along with discovering what are, potentially, three new species of snailfish, the expedition also caught video of another rare creature, called a Munnopsid. Munnopsids are small-bodied, spindly-legged animals about the size of a human hand.Munnopsids propel themselves through the water with small fins on their stomachs, but when near the sea bottom, the creatures flip over and walk on their legs.
“We don’t know what species of munnopsid these are but it’s incredible to have caught them in action in their natural habitat—especially the flip they do as they switch from swimming to walking mode,” said Dr. Linley.
Specialized Gear for Deep-Water Research
Scientists and technicians from Newcastle University have spent five years developing specialized equipment to study ocean life at extreme depths.They created what they call a “lander,” a device which can drop to the extreme depths of the deepest ocean trenches and take high-definition video and still pictures, and also capture sea life with baited traps.
The bait attracts whatever life forms inhabit the region, and the cameras capture images—in this case more than 100 hours of video and 11,468 still photos.
The landers have proved their worth in more than 250 ultra-deep descents so far.
The landers are dropped overboard without a lead line or power cord—they are completely self-contained. It can take up to four hours to sink to the bottom. The scientists generally wait 12–14 hours, then send an acoustic signal which tells the lander to release the weights which hold it down. The lander then rises to the surface and is collected.
