New fish species discovered in deep ocean

Credit: Connor McGaffin/ Credit: Connor McGaffin/

Imagine a deep sea fish. Are you picturing large eyes, sharp teeth, maybe even a light extending from its head? You’re probably seeing something along the lines of an anglerfish, a la Finding Nemo. How about something more translucent, small, and scale-less? “Jelly-like,” even?

The elusive “jelly-like” snailfish is one of many deep sea creatures that makes its home in the oceanic trenches. Its appearance is wildly different from other creatures in the harsh deep-sea environment, and there are over 400 described species of its kind — one of which is the deepest living fish ever recorded, the Mariana snailfish. However, there is an even greater number of undescribed species — a theme common in the study of deep sea creatures and their habitats. But recently, after exploring the depths of the ninth deepest trench in the world, a multinational team of over 40 scientists discovered three new species of snailfish: the pink snailfish, the blue snailfish, and the purple snailfish.

These new species reside in the intense cold and extreme pressure of the Atacama Trench, which lines the coast of Peru and Chile, reaching a maximum depth of about five miles and approximate length of 3,666 miles. The scale-less snailfish are top predators, thriving in this normally inhospitable environment.

In an article by ScienceDaily, Dr. Thomas Linley, one of the team’s UK scientists who hails from Newcastle University, speaks about the adaptations of the Atacama snailfish: “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. Without the extreme pressure and cold to support their bodies, they are extremely fragile and melt rapidly when brought to the surface.”

Dr. Linley is no stranger to snailfish. As part of a similar expedition in 2017, he and a team of researchers from the U.S. and U.K. set out to recover samples of a potentially unique species of snailfish documented by Japanese scientists earlier that year. Their efforts revealed footage of a new species — the Mariana snailfish. Named after the trench it inhabits, the fish was found at a depth of over 26,800 feet and was the deepest living fish ever found.

So how did they manage to document fish nearly five miles deep into the ocean? By using new technology developed by Newcastle University engineers and scientists that allows more efficient exploration of “ultra deep environments” using a unique “lander” system. Two “landers” (types of rovers) were outfitted with HD cameras and traps to hunt the elusive fish. After sinking thousands of feet to the ocean floor, the landers were able to take samples and record the environment. After 12 to 24 hours of waiting, the research team deployed an “acoustic signal” to a trap connected to the lander, triggering weights to fall off the lander so it could float back up to the surface.

The most recent snailfish expedition deployed the landers 27 times at the deepest point of the Atacama Trench, known as Richard’s Deep, to record 100 hours of video and 11,468 photographs. Researchers were able to catch one for observation, carefully monitoring its habitat to ensure its survival. While the process seems lengthy and time-consuming, the results were rewarding: three new species discovered on the floor of the ocean, one of which they were able to capture.

As an extra surprise, the team also recorded an incredibly rare species of long-legged isopods called munnopsids. Isopods, an order of the class crustacean, are a type of invertebrate that look more like bugs than crabs. The most familiar isopod is the pill bug or, as it is colloquially known, the “roly poly.” However, unlike their tiny terrestrial cousins, munnopsids are about the size of an adult human’s hand and they have a unique way of moving about. The creatures swim backwards and upside down, almost paddling with their tummies "before righting themselves on the seafloor and spreading their long walking legs out like a spider,” Dr. Linley remarked. “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.”

These discoveries point to the unimaginable biodiversity that lurks in the deepest parts of our oceans. They serve as an awe-inspiring reminder of how incredibly hardy and tough nature can be, and how life can evolve to not only survive but thrive in those environments. Those interested in experiencing some of this biodiversity can view the captured snailfish at Newcastle University, where it will be featured as part of the Challenger Conference 2018.