Ontogenetic change in predicted acoustic pressure sensitivity in larval red drum (Sciaenops ocellatus)

Abstract

Detecting acoustic pressure can improve a fish's survival and fitness through increased sensitivity to environmental sounds. Pressure detection results from interactions between the swim bladder and otoliths. In larval fishes, those interactions change rapidly as growth and development alter bladder dimensions and otolith-bladder distance. We used computed tomography imagery of lab-reared larval red drum (Sciaenops ocellatus) in a finite-element model to assess ontogenetic changes in acoustic pressure sensitivity in response to a plane wave at frequencies within the frequency range of hearing by fishes. We compared the acceleration at points on the sagitta, asteriscus and lapillus when the bladder was air filled with results from models using a water-filled bladder. For larvae of 8.5-18 mm in standard length, the air-filled bladder amplified simulated otolith motion by a factor of 54-3485 times that of a water-filled bladder at 100 Hz. Otolith-bladder distance increased with standard length, which decreased modeled amplification. The concomitant rapid increase in bladder volume partially compensated for the effect of increasing otolith-bladder distance. Calculated resonant frequency of the bladders was between 8750 and 4250 Hz, and resonant frequency decreased with increasing bladder volume. There was a relatively flat frequency dependence of these effects in the audible frequency range, but we found a small increase in amplification with increasing excitation frequency. Using idealized geometry, we found that the larval vertebrae and ribs have negligible influence on bladder motion. Our results help clarify the auditory consequences of ontogenetic changes in bladder morphology and otolith-bladder relationships during larval stages.

Ontogenetic variation in the hearing sensitivity of black sea bass (Centropristis striata) and the implications of anthropogenic sound on behavior and communication

“…otolaterophysic connection; Radford et al, 2013) which would enhance the detection of higher frequencieswould be detectable in these images and dissections. However, even without ancillary structures, a small portion of pressure detection may be transduced through the soft tissue between the swim bladder and the otic capsule, particularly for smaller fishes, therefore improving the bandwidth of hearing (Popper et al, 2003;Salas et al, 2019). This probably explains why the bandwidth extends to 1000 Hz and is not restricted to only 400 or 500 Hz, as is suggested to be the upper end of the purely particle motion component of hearing in fishes .…”

A sciaenid swim bladder with long skinny fingers produces sound with an unusual frequency spectrum

“…Deflation of swim bladder gas via a syringe caused a > 10 dB decrease in auditory thresholds in silver perch and weakfish but had no effect in croaker or spot. Therefore, the swim bladder only aids hearing when diverticula terminate close to the ears 58 , 59 . As with silver perch which can hear to 4 kHz 50 , it is likely that B. microlepis , with two long anterior diverticula 26 , has sensitive high-frequency hearing, which would match the elevated frequency distribution of its sounds.…”

Perspectives on Larval Behaviour in Biophysical Modelling of Larval Dispersal in Marine, Demersal Fishes

“…So, it is often assumed that larvae which lack accessory organs or in which they have not yet developed will be unable to detect swim bladder vibrations [95,96]. However, in small larvae, the distance between swim bladder and ear is so small in many taxa that the ear may well be able to detect (i.e., hear) swim bladder vibrations (e.g., [97]), thus increasing the distance from a sound source that a larva can detect the sound. Sound propagates well underwater, so if larvae can hear sound pressure in this way, the calculated distances over which larvae might be able to hear something like a coral reef are several kilometres [98].…”