Backward swimming in elongated-bodied abyssal demersal fishes: Synaphobranchidae, Macrouridae, and Ophidiidae.

ABSTRACT: The deep-sea demersal fish fauna is characterized by a prevalence of elongated-body forms with long tapering tails. Using baited camera landers at depths of 4500-6300 m in the Pacific Ocean, we observed multiple instances of backward swimming using reverse undulation of the slender body in four species: the cutthroat eel Ilyophis robinsae, abyssal grenadier Coryphaenoides yaquinae, and cusk-eels Bassozetus sp. and Barathrites iris. Backward swimming was used as an escape or repositioning maneuver, reversing for up to seven tail beats before resuming forward swimming in a new direction. The eel I. robinsae reversed with a swimming wave frequency of 0.51-0.95 Hz, wavelength 0.6-0.75 of the body length (L), and large amplitude movements of the head from side to side. C. yaquinae reversed rela

SUBMITTER: Priede IG 

PROVIDER: S-EPMC12327160 | biostudies-literature | 2025 Jul

REPOSITORIES: biostudies-literature