Sound production mechanism in carapid fish: first example with a slow sonic muscle

Abstract

SUMMARY Fish sonic swimbladder muscles are the fastest muscles in vertebrates and have fibers with numerous biochemical and structural adaptations for speed. Carapid fishes produce sounds with a complex swimbladder mechanism, including skeletal components and extrinsic sonic muscle fibers with an exceptional helical myofibrillar structure. To study this system we stimulated the sonic muscles, described their insertion and action and generated sounds by slowly pulling the sonic muscles. We find the sonic muscles contract slowly, pulling the anterior bladder and thereby stretching a thin fenestra. Sound is generated when the tension trips a release system that causes the fenestra to snap back to its resting position. The sound frequency does not correspond to the calculated resonant frequency of the bladder, and we hypothesize that it is determined by the snapping fenestra interacting with an overlying bony swimbladder plate. To our knowledge this tension release mechanism is unique in animal sound generation.

Call properties and morphology of the sound-producing organ in Ophidion rochei (Ophidiidae)

“…Generally speaking, swimbladder sounds have a fundamental frequency ranging from 75 to 300Hz, which would correspond to the muscle contraction rate, placing sonic muscles among the fastest in vertebrates (Rome et al, 1996;Loesser et al, 1997;Connaughton et al, 2000;Fine et al, 2001). The average dominant frequency of pulsed sounds in several carapid species varies between 40 and 340Hz (Parmentier et al, 2003;Lagardère et al, 2005;Parmentier et al, 2006a). We recently discovered that unlike sounds generated by fast sonic swimbladder muscles, sounds in a carapid fish (Ophidiiformes) are generated with slow muscles that require 490ms for a twitch and that tetanize above 10Hz (Parmentier et al, 2006a).…”

Coral reef soundscapes : spatiotemporal variability and links to species assemblages

“…Marine fishes that produce sound may do so in a number of ways, including through the contraction of sonic muscles attached to the swimbladder via the sonic ligaments (Parmentier et al, 2006). In general, most soniferous fishes show limited amplitude and frequency modulation abilities and have small vocal repertoires; however, these species may produce signals that are variable in the time domain for communication purposes (Amorim, 2006).…”

New insights into sound production in <I>Carapus mourlani</I> (Carapidae)

“…This air sac has an anterior thinner zone of its wall called the swim bladder fenestra. This is situated just under the swim bladder plate, which is an osseous enlargement of the third epineural (Parmentier et al 2003a(Parmentier et al , 2006b). During muscle contraction, the thinner zone allows the rostral displacement of the most anterior part of the swim bladder only and the stretching of the swim bladder fenestra (Parmentier et al 2003a(Parmentier et al , 2006b.…”

“…In this situation, the anterior part is transversally stretched, which could affect the sounds produced by the contraction of the primary sound-producing muscles. The increased stiffness of the swim bladder could help to sustain the sound (Parmentier et al 2006b) and/or modulate the call amplitude. This ability may explain the variations in sound amplitude between the different kinds of call.…”