Revision of the depth record of bony fishes with notes on hadal snailfishes (Liparidae, Scorpaeniformes) and cusk eels (Ophidiidae, Ophidiiformes)

• Published in: Marine biology 2021-11, Vol.168 (11), Article 167
• Main Authors: Gerringer, Mackenzie E., Linley, Thomas D., Nielsen, Jørgen G.
• Format: Article
• Language: English
• Subjects: Abyssal plains; Abyssal zone; Biomedical and Life Sciences; Catadromous fishes; Cyclopteridae; Depth; Eels; Fish; Freshwater & Marine Ecology; Habitat selection; Habitats; Highlight Article; Life Sciences; Liparidae; Literature reviews; Marine & Freshwater Sciences; Marine biology; Marine environment; Marine fishes; Microbiology; Museums; Oceanic trenches; Oceanography; Ophidiidae; Physiology; Records; Trenches; Vertebrates; Zoology
• ISSN: 0025-3162; 1432-1793
• DOI: 10.1007/s00227-021-03950-8

Bony fishes are extremely successful in the marine environment, having evolved into nearly every ocean habitat. However, bony fishes do not seem to inhabit the ocean’s deepest depths, likely due to constraints of pressure adaptation. How deep do bony fishes live? Relatively few studies have examined the deepest living vertebrates, because sampling in hadal environments, depths 6000–11,000 m, is technologically challenging. Here, we review the literature on records of the deepest living bony fishes. Current depth records are held by the hadal snailfish Pseudoliparis swirei (family Liparidae) in the Mariana Trench, collection depth 7966 m, filmed to 8178 m, and the cusk eel Abyssobrotula galatheae (family Ophidiidae) in the Puerto Rico Trench, collection depth 7965 m. Observations of abyssal and hadal fish communities suggest that hadal snailfishes are endemic to trenches but occasionally cross into abyssal areas. On the other hand, cusk eels dwell on the abyssal plains, but can extend their ranges into the trenches. These habitat differences allow both snailfishes and cusk eels to occupy distinct niches in the greatest ocean depths. We then comment on the ecological and physiological significance of these two major hadal families and present recommendations for future research.