A new small blue snailfish is altering our understanding of the world’s deepest fishes. An international team of scientists studied the Atacama Trench in 2018, an expansive trench that runs along the west coast of South America as a deep underwater valley that mirrors the Andes Mountains. The team, which included scientists from Newcastle University, used free-falling landers to sample the sparse deep-sea creatures near cameras and baited traps. Two lander systems from Newcastle University recorded three types of hadal snailfish, one of which was distinct from the others.
The small blue fish, seen from 6,000 to 7,600 m depth, does not resemble other hadal snailfish. With its large eyes and striking color, it resembles other species of snailfish found in much shallower waters. The researchers used a 3D x-ray technique called microcomputed tomography (micro-CT) and DNA barcoding to determine where the new species fit within the snailfish family.
We have been wondering for some time just what makes this type of fish so good at living deep. Maybe it was a series of lucky accidents, a chance fluke, that happened in one lineage. Finding this new species tells us that it’s bigger than that. Lightning struck twice and there is something special about this Family.
Dr. Thom Linley
To the team’s surprise, the new species appears to be a distinct Atacama Trench coloniser. The new species is a member of the genus Paraliparis. Species in this genus are particularly abundant in the Antarctic Southern Ocean and are rarely found deeper than 2,000 meters. Significantly, this is the first time this genus has been found living in the hadal zone.
The team named the new species Paraliparis selti, meaning blue in the Kunza language of the indigenous peoples of the Atacama Desert. The description is published in the journal Marine Biodiversity.
Study lead author, Dr Thom Linley, a visiting researcher at Newcastle University said: “I find this family of fishes absolutely fascinating. They are not at all what we expect from a deep-sea fish and I love to show people that the world’s deepest fishes are actually pretty cute.
“For me to get a camera down to where these animals live, it’s made of inches thick stainless steel and sapphire glass. It then films these delicate and beautiful animals perfectly adapted to this extreme environment. With engineering-built force we can only clumsily visit these animals for a short time.
“We have been wondering for some time just what makes this type of fish so good at living deep. Maybe it was a series of lucky accidents, a chance fluke, that happened in one lineage. Finding this new species tells us that it’s bigger than that. Lightning struck twice and there is something special about this Family.
“Paraliparis selti is a fantastic opportunity to learn about what allows fish to live so deep. We couldn’t tell which traits were just part of the lineage and which were the deep-sea secret sauce if we only studied one.”
The new species may have evolved from cold-adapted species of the Southern Ocean. This little blue fish raises new questions about the relationship between cold temperature and high-pressure adaptation, as well as a new understanding of how and when life went deep.
