Hearing ability in three clownfish species

Abstract

SUMMARYClownfish live in social groups in which there is a size-based dominance hierarchy. In such a context, sonic cues could play a role in social organisation because dominant frequency and pulse length of sounds are strongly correlated with fish size. Data on the hearing ability of these fish are, however, needed to show that they have the sensory ability to detect the frequencies in their sounds. The present study determines the hearing sensitivity in three different anemonefish species (Amphiprion frenatus, Amphiprion ocellaris and Amphiprion clarkii), and compares it with the frequencies in their calls. The frequency range over which the three species can detect sounds was between 75 and 1800 Hz, and they were most sensitive to frequencies below 200 Hz. During sound production, dominant frequency is clearly related (R=0.95) to the fish size, whatever the species. Dominant frequency extends from 370 to 900 Hz for specimens having a size between 55 and 130 mm. The best hearing sensitivity of small specimens were found to be lower than the dominant frequency of their own calls. However, they were found to be close to the dominant frequency of larger fish calls. The interest of juveniles lies in localising the adults and thus their location on the reef.

Auditory evoked potential audiograms in post-settlement stage individuals of coral reef fishes

“…Presence or absence of response to sounds of different intensities and frequencies allows the measurement of AEP thresholds. The experimental setup was similar to that used for previous studies (Parmentier et al, 2009;Colleye et al, 2013). No anesthetics or neuromuscular-blocking drug were used during the AEP recordings.…”

“…The presentation of sound stimuli and the determination of thresholds followed the detailed description given by Parmentier et al (2009). Stimuli were tone bursts of 50 ms in total duration gated with a Hanning window.…”

Further insight into the sound-producing mechanism of clownfishes: what structure is involved in sound radiation?

“…Sound duration and frequency are known to be morphologically determined signals strongly related to fish size Parmentier et al, 2009;Colleye et al, 2011), which suggests that both acoustic features are subject to a morphological constraint. Considering the positive relationship existing between fish size and swimbladder volume (Fig.4A), it appears that the swimbladder could be the structure responsible for the size-related variations in acoustic features.…”

“…Thus there exists a need for further understanding of sound radiation in clownfishes, especially regarding the anatomical structure(s) involved. Some acoustic features such as dominant frequency and pulse duration are signals directly related to body size in clownfishes Parmentier et al, 2009). …”

“…In the croaking gourami, Trichopsis vittata, sound duration increases during ontogeny whereas dominant frequency decreases (Henglmüller and Ladich, 1999). In weakfishes (Connaughton et al, 2000), pearlfishes (Parmentier et al, 2006b), damselfishes (Myrberg et al, 1993;Lobel and Mann, 1995) and clownfishes Parmentier et al, 2009), pulse duration increases and dominant frequency decreases in larger fishes. Grey gurnards and weakfishes produce sounds by contracting sonic muscles attached to the swimbladder.…”