Paraliparis selti, or the Blue Atacama snailfish, lives in the hadal zone (waters deeper than 6,000 m) of the Atacama Trench in southeast Pacific Ocean.
This image of Paraliparis selti was taken by baited camera at a depth of 6,520 m. Image credit: Linley et al., doi: 10.1007/s12526-022-01294-0.
Snailfishes are members of Liparidae, a diverse family of over 400 fish species found in every ocean.
They hold the widest known bathymetric range of any vertebrate family, from the intertidal to the deep trenches.
At least 200 snailfish species are present in the southern hemisphere, and of those, about 150 species are known from the Subantarctic and Antarctic waters.
Only six genera and around 20 species are known from the eastern Pacific off the west coast of South America.
Snailfishes are exceptionally well-adapted to the hadal environment, which is characterized by low temperature (1-3 degrees Celsius), extremely high pressure, and seismic activity.
Between 6,000 to 8,143 m, they dominate the hadal ichthyofauna in at least 10 trenches worldwide.
“They are not at all what we expect from a deep-sea fish. I love to show people that the world’s deepest fishes are actually pretty cute,” said Dr. Thomas Linley, a researcher at Newcastle University.
The only specimen of Paraliparis selti was collected from 6,714 m depth by a baited trap in the Atacama Trench, southeast Pacific Ocean.
“Paraliparis selti doesn’t look like other snailfishes from the hadal zone, these ultradeep regions of the oceans,” Dr. Linley said.
“It has large eyes, a striking blue color, and resembles other species of snailfishes that you would find living in much shallower waters.”
Dr. Linley and colleagues used character trait analysis, micro-computed tomography (micro-CT), and genetic barcoding to show that their specimen belongs to the genus Paraliparis.
“Species in this genus are particularly abundant in the Southern Ocean of the Antarctic and have rarely been seen deeper than 2,000 m,” said Dr. Johanna Weston, a postdoctoral researcher at Woods Hole Oceanographic Institution.
“We were excited to see this result — this is the first time this genus has been found living in the hadal zone.”
“This little blue fish opens up new questions about the relationship between cold temperature and high-pressure adaptation and gives a new understanding of how and when life evolved into the deep,” said Dr. Mackenzie Gerringer, a researcher at the State University of New York at Geneseo.
“It’s a reminder of the unique diversity yet to be discovered thriving in the deepest parts of our oceans.”
The discovery is described in a paper in the journal Marine Biodiversity.
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T.D. Linley et al. 2022. Independent radiation of snailfishes into the hadal zone confirmed by Paraliparis selti sp. nov. (Perciformes: Liparidae) from the Atacama Trench, SE Pacific. Mar. Biodivers 52, 56; doi: 10.1007/s12526-022-01294-0
