UW News

April 25, 2018

World’s deepest fish named to 10 ‘remarkable new species’ list for 2017

UW News

CT scan of Mariana snailfish

A CT scan of the Mariana snailfish, showing a side view. The green shape, a small crustacean, is seen in the snailfish’s stomach.Adam Summers/University of Washington

The deepest-dwelling fish in the sea just got one more bragging right.

The World Register of Marine Species, or WoRMS, has named the Mariana snailfish one of its 10 “remarkable new species” discovered in 2017. The team that discovered and named the small fish that lives at ocean depths of up to 8,000 meters (26,200 feet) includes Mackenzie Gerringer, a postdoctoral researcher at the UW’s Friday Harbor Laboratories.

The world register announces top marine species lists each year, chosen by a committee of researchers and nominated by marine experts around the world involved with maintaining the register. The Mariana snailfish joins the likes of the Harry Potter “hero” crab, the Californian box jelly and Bob Marley’s intertidal spider in making the 2017 list.

“It is exciting to see the Mariana snailfish on the WoRMS list,” Gerringer said. “It is a remarkable animal, thriving under the amazing pressures and cold temperatures of the Mariana Trench. The impressive diversity of this list serves as a reminder to keep exploring, discovering the incredible organisms with whom we share our planet.”

specimen of mariana snailfish

A specimen of the new species, Mariana snailfish.Mackenzie Gerringer/University of Washington, University of Hawai'i

The Mariana snailfish (Pseudoliparis swirei) doesn’t have the body armor one might imagine to live on the ocean’s floor. The small, translucent, scale-less fishes congregate in groups and feed on tiny crustaceans and shrimp using suction from their mouths to gulp prey. The pressure at the ocean depth they call home is similar to an elephant standing on your thumb.

The snailfish species, discovered by an international team along the Mariana Trench near Guam, is one of about 2,000 new marine species added to the register last year. In total, about 242,500 marine species are documented in the world register, though that doesn’t represent a complete census, researchers say. The oceans cover more than 70 percent of the Earth’s surface, yet still include the least explored regions.

In honor of WoRMS’ 10th birthday, its editors also released a top 10 “astounding” marine species of the last decade list. Some of the showstoppers on that list include the starry sea wanderer jelly, the Palauan primitive cave eel and the squidworm.

The marine creatures appearing on both lists are in no particular order and represent a diversity of animal groups that include fish, crustaceans, jellies, sponges and more. They also draw attention to some of today’s biggest environmental challenges such as invasive species and fragile coral reefs.

“The final candidates feature particularly astonishing marine creatures, notable for their interest to both science and the public,” the WoRMS press release explains. “Each of these marine animals has a story. It may be the among the deepest living or largest fish known, be considered a ‘living fossil,’ an invasive species, the most abundant organism in a habitat, or have remained hidden in plain sight, hoodwinking researchers for decades.”

Read more about the Mariana snailfish discovery in a recent analysis piece written by Gerringer.

Mariana snailfish, the deepest-living fish in the world, are filmed in the Mariana Trench at depths of 7,000 to 8,145 meters. Video courtesy of SOI/HADES/University of Aberdeen (Dr. Alan Jamieson)