How do hadal snailfish survive

As the snailfish lives in dark environment, its vision-related genes are primarily lost, which makes them transparent and lose response to visible light. According to He Shunping from the Institute of Hydrobiology, the snailfish feeds on invertebrates.

The researchers dissected a snailfish and found that there were nearly a hundred crustaceans in its stomach, suggesting that it can store food for a long time to cope with food scarcity in the deep sea.

The snailfish sample used in the research was obtained during China's deep-sea expedition to the Mariana Trench in the western Pacific Ocean in Xi meets Mozambican president. Researchers caught several snailfishes to study how they had adapted to the deep sea and compared them to closely-related species living in shallow waters.

Snailfish live in some of the deepest areas of the ocean, known as the hadal zone, between six and 11km below the surface. The zone is thought to be among the most hostile areas on earth, due to high pressure, darkness, cold temperatures and scarce food resources. Lead researcher Wen Wang and colleagues found snailfishes caught in the Mariana Trench had transparent skin, an inflated stomach, soft bones and incompletely-closed skulls, unlike similar shallow sea species.

We named the Mariana snailfish Pseudoliparis swirei in his honor, to acknowledge and thank crew members who have supported oceanographic research throughout history. Hadal snailfish have several adaptations to help them live under high pressure. Their bodies do not contain any air spaces, such as the swim bladders that bony fish use to ascend and descend in the water. Instead, hadal snailfish have a layer of gelatinous goo under their skins that aids buoyancy and also makes them more streamlined.

Hadal animals have also adapted to pressure on a molecular level. Whitman College biologist Paul Yancey , a member of our team, has found that deep-sea fish use a molecule called trimethyl-amine oxide TMAO to help stabilize their proteins under pressure. However, to survive at the highest water pressures in the ocean, fish would need so much TMAO in their systems that their cells would reach higher concentrations than seawater.

At that high concentration, water would tend to flow into the cells due to a process called osmosis, in which water flows from areas of high concentration to low concentration to equalize.

To keep these highly concentrated cells from rupturing, fish would have to continually pump water out of their cells to survive. This means that around 27, feet 8, meters may be a physiological depth limit for fish. There may be fish that live at levels as deep, or even slightly deeper, than the Mariana snailfish.

Different species of hadal snailfish are found in trenches worldwide , including the Kermadec Trench off New Zealand, the Japan and Kurile-Kamchatka trenches in the northwestern Pacific, and the Peru-Chile Trench. Vertebrates living on the surface of the Earth have closed skulls. The skull is made of hard bone and serves the very important purpose of protecting the brain and maintaining a healthy intracranial pressure.

However, this is impossible in the very high pressures of the hadal environment. Most hadal species are boneless, but the snailfish does have bones, so it developed a compromise: a non-closed skull.

Join the ZME newsletter for amazing science news, features, and exclusive scoops. More than 40, subscribers can't be wrong. The creature also exhibits another intriguing adaptation: its bones consist of cartilage rather than being ossified.