The effect of loading on disturbance sounds of the Atlantic croaker Micropogonius undulatus: Air versus water

Abstract

Physiological work on fish sound production may require exposure of the swimbladder to air, which will change its loading (radiation mass and resistance) and could affect parameters of emitted sounds. This issue was examined in Atlantic croaker Micropogonius chromis by recording sounds from the same individuals in air and water. Although sonograms appear relatively similar in both cases, pulse duration is longer because of decreased damping, and sharpness of tuning (Q factor) is higher in water. However, pulse repetition rate and dominant frequency are unaffected. With appropriate caution it is suggested that sounds recorded in air can provide a useful tool in understanding the function of various swimbladder adaptations and provide reasonable approximation of natural sounds. Further, they provide an avenue for experimentally manipulating the sonic system, which can reveal details of its function not available from intact fish underwater.

Developmental variation in sound production in water and air in the blue catfish Ictalurus furcatus

“…Sharpness of tuning increases in water. Many of these differences parallel findings from Atlantic croaker recorded in both media (Fine et al, 2004). Peak frequency in croaker sounds does not differ between air and water because it is determined by sonic muscle contraction-relaxation time, which is not affected by acoustic loading.…”

Distress sounds of thorny catfishes emitted underwater and in air:characteristics and potential significance

“…In contrast to stridulation sounds, duration of drumming sounds did not decrease with time. Fine et al (Fine et al, 2004) found a longer pulse duration in drumming sounds emitted in water in the sciaenid Micropogon undulates, but no change in sound duration.…”

“…This change in sound duration and subsequently pulse periods is probably due to muscle fatigue. This indicates that in distress sounds temporal patterns are less important for communication than they are in reproductive behaviour (Myrberg et al, 1978;Fine et al, 2004).…”

“…Ladich (Ladich, 1997) observed that characteristics of stridulation and drumming sounds of doradids and pimelodids recorded in air and underwater were basically similar, but ratios of peak-to-peak amplitudes and ratios of total sound duration of stridulation and drumming sounds in the two media differed significantly. Fine et al (Fine et al, 2004) conducted a study on disturbance sounds (drumming sounds) of the Atlantic croaker Micropogonius undulates, where they compared characteristics of sounds produced in air and water. Their study showed that pulse duration became longer in water, whereas the dominant frequency was unaffected.…”

“…In catfish, the relationship between sound duration, dominant frequency and sound intensity to body size has been described (AbuGideiri and Nasr, 1973;Kaatz, 1995;Ladich, 1997;Pruzsinszky and Ladich, 1998;Fine et al, 2004;Lechner et al, 2010), but is not known whether the sound medium has an influence on these relationships.…”