title: Comment on "silent research vessels are not quiet" [J. Acoust. Soc. Am. 121, EL145-EL150].
abstract: The recent paper by Ona et al. [J. Acoust. Soc. Am. 121, EL145-EL150] compared avoidance reactions by herring (Clupea harengus) to a traditional and a "silent" research vessel. Surprisingly, the latter evoked the strongest avoidance, leading to the conclusion that "candidate stimuli for vessel avoidance remain obscure." In this Comment, it is emphasized that the otolith organs in fish are linear acceleration detectors with extreme sensitivity to infrasonic particle acceleration. Near-field particle motions generated by a moving hull are mainly in the infrasonic range, and infrasound is particularly potent in evoking directional avoidance responses in several species of fish. The stimuli initiating vessel avoidance may thus include infrasonic particle acceleration.
authors.affiliation: Department of Molecular Biosciences, University of Oslo, PO Box 1041 Blindern, NO-0316 Oslo, Norway. olav.sand@imbv.uio.no
authors.forename: Olav
authors.initials: O
authors.lastname: Sand
authors.forename: Hans Erik
authors.initials: HE
authors.lastname: Karlsen
authors.forename: Frank R
authors.initials: FR
authors.lastname: Knudsen
mesh_terms: D000818:Animals; D001362:Avoidance Learning; D001522:Behavior, Animal; D005398:Fisheries; D005399:Fishes; D010037:Otolithic Membrane / Q000502:physiology*; D012767:Ships; D014465:Ultrasonics