Science

Newly Identified Mariana Snailfish Is The Deepest Ever Fish In The Sea

How would you react if a full-grown elephant stood on your thumb? Yeah, the human body cannot withstand intense pressure. But a tiny snailfish found in the Mariana Trench near Guam spends all its life under the same level of pressure as an elephant standing on your thumb. After extensive study, a group of researchers at the University of Washington and the University of Hawaii has identified the Mariana snailfish as a new species and given it a scientific name.

Mariana Snailfish
Image Credit: ZooTaxa / Mackenzie Gerringer (screenshot)

The Mariana Snailfish was first spotted three years ago

The Mariana Trench is the deepest stretch of ocean on the planet. The two-inch-long Mariana snailfish has a scaleless body that is so translucent that you could see its liver. It was found swimming deeper than 8,000 meters. Findings of the study were published on November 28 in the journal ZooTaxa. The little creature lives in a dark ocean region called the hadal zone.

Researchers led by Mackenzie Gerringer of the University of Washington sent cameras and traps deep into the sea, obviously because human divers cannot go where the Mariana snailfish are generally found. The study was conducted over a three-year period. It would usually take the cameras and traps about four hours to reach where the creature lives.

The Mariana snailfish was first captured on camera in 2014, and was found again earlier this year at the extreme depths. Scientists believe the creature lives happily so deep underwater because there are lots of prey but few predators. The species is endemic to the Mariana Trench. Scientists found that the snailfish feeds on crustaceans that get caught in the trenches.

Further research in such extreme depths could lead to more surprising discoveries. The Mariana snailfish is the deepest known fish in the sea. There could be more fish living even deeper waiting to be discovered. The deepest parts of the sea extend to about 11,000 meters. There are more than 350 known species of snailfish living at different depths.

The Mariana snailfish is different from others because of its structure and physiology. It has a combination of dorsal and anal fins that you wouldn’t find on any other snailfish. The species is named Pseudoliparis swirei, after the HMS Challenger officer Herbert Swire. Swire is the one who discovered the Mariana Trench in 1875. The Trench is also known as the Swire Deep. Mackenzie Gerringer said in a statement, “It takes a lot of people to keep a ship running and we wanted to sincerely thank them.”

Why fish are not found at the deepest ocean levels

The Mariana snailfish’s eggs are pretty large, measuring about a centimeter in width. Gerringer said there are huge limitations to life in these trenches. The snailfish lives about 8,000 meters deep, meaning it has to handle water pressures equal to the weight of more than 1,600 elephants. Not many species on the planet can do that. The snailfish has evolved adaptations to extreme pressure levels to keep its “enzymes functioning and membranes moving.”

Immense pressure could be a reason why fish haven’t been found in the deepest parts of the ocean. There are a wide variety of creatures that could live at extreme depths such as microbes, sea cucumbers, foraminifera, and odd decapod shrimp. But it’s difficult for the fish to survive there because they might, biochemically, not be able to withstand the effects of pressure on proteins below 8,200 meters, according to another study published in the PNAS.

So far, scientists have only reported their observations about the species’ existence and appearance. They are yet to talk about why it evolved distinct physical features such as the anal and dorsal fins.