Hadal Bait-Attending Fish of the Atacama Trench (Western South America) Including New Snailfish (Liparidae) Species

During a 2018 expedition of the HADES-ERC project to the Atacama Trench (west of South America) Newcastle University’s imaging landers collected over 11,000 five megapixel stills and 100 hours of HD video from bathyal to hadal depths, of which over 8,500 stills and 80 hours were collected from hadal depths. Abyssal deployments (~4000-5500 m depth) were dominated by scavenging grenadiers (predominantly Coryphaenoides armatus), which rapidly consumed the bait. The Abyssal-Hadal Transition Zone (~5900-6500 m depth) was dominated by Bassozetus sp. cusk eels and eelpouts feeding not on the bait itself, but the scavenging amphipods it attracted. Three (likely new) snailfish (Liparidae) species were observed between ~6000 and 7600 m depth. One of the snailfish was successfully captured and has been confirmed to be a new species. It is the first hadal member of the Paraliparis genus and genetic analysis strongly suggests independent radiation into the hadal zone. This further supports that the Liparidae are particularly suited to hadal colonisation. The snailfishes were the deepest observed fish, however deeper deployments were abundant in invertebrates, particularly amphipods, as found in other hadal trenches.