Full Description

"Sound amplitude is related to speed of swimbladder movement, and slow movements do not produce perceptible sound. Peak sound amplitude overlaps fundamental frequencies of the male’s mating call because of muscle mechanics and not the natural frequency of the bladder."

"Working with spontaneously evoked grunts and low frequencies to 100 Hz in the oyster toadfish, Skoglund (1961) de- termined that sound is generated by muscle-stimulated swimbladder movement and that both of the paired muscles contract synchronously during spontaneous production of the grunt call."

"In his re- view Tavolga (1964) mentions that oyster toadfish sonic muscles are extremely fast and tetanize at 340 Hz. He concluded “The fact that the natural frequency of the swimbladder as an air bubble is in the same order of magnitude as the vibration frequency of the sonic mus- cles undoubtedly aids the efficiency of the system.” Rome et al. (1996) measured isometric contraction of small bundles of sonic fibers dissected from the muscle and found they would complete a twitch in about 10 ms and exhibit complete fusion of force at 150-200 Hz at 16°C and 250-300 Hz at 25°C. Rome et al. (1999) fur- ther state that at 15°C “If stimulated at 60 Hz, a high frequency for vertebrate muscle, it produces nearly separate twitches,” and “At stimulation frequencies of 125 Hz and higher, the swimbladder produces a smooth force record, but force fell rapidly after a peak despite continuous stimulation.”"

"The muscles routinely contract at 200 Hz (range < 150-270 Hz) for 200-400 ms to produce the fundamental frequency of the male’s advertisement boatwhistle call in the York River, Virginia (Barimo and Fine 1998; Fine 1978). Energy in the boatwhistle call is typically below 1 kHz and concentrated at the fundamental frequency and harmonics. Both males and females produce an agonistic grunt call, which consists of irregularly-timed shorter bursts of muscle contraction at lower frequencies than the boatwhistle (Tavolga 1958;Waybright et al. 1990)."

"Twitches, quantified for 23 fish, were extremely rapid (Fig. 2, Table 1). Twitch contraction time, measured with the laser, averaged 4.5 ms, and relaxation was slower (5.1 ms to the zero crossing and 11.8 ms to complete relaxation past the resting position). Using the resting position as the criterion, an average twitch was completed in 9.6 ms. The bladder continued to oscillate more slowly following the twitch, usually for another half cycle, for an average total duration of 38 ms. Therefore, not all bladder movement produced mea- surable sound. The time to peak sound amplitude av- eraged 2.9 ms (less than the contraction time), and the total sound duration averaged 9.3 ms."

Observation Environment Quotes

"Oyster toadfish Opsanus tau were captured in crab pots in the York River, Virginia and maintained in half-strength seawater. Fish were anesthetized in 200 mg I' MS 222, restrained upside down in a Plexiglas tank in an Industrial Acoustics sound-proof booth. Water containing 100 mg!’ of the anesthetic was recirculated into the mouth. The swimbladder (Fig. 1) was exposed completely by a midline incision, which was held open with retractors placed ros- trally, and intestines were pushed aside. The sonic nerve was stimulated using hook electrodes with single 0.1-ms square-wave pulses. Stimulation amplitude was increased until contraction am- plitude saturated to ensure complete fiber recruitment."

Behaviour Description Quotes

"Sound amplitude is related to speed of swimbladder movement, and slow movements do not produce perceptible sound. Peak sound amplitude overlaps fundamental frequencies of the male’s mating call because of muscle mechanics and not the natural frequency of the bladder. "

"The muscles routinely contract at 200 Hz (range < 150-270 Hz) for 200-400 ms to produce the fundamental frequency of the male’s advertisement boatwhistle call in the York River, Virginia (Barimo and Fine 1998; Fine 1978). Energy in the boatwhistle call is typically below 1 kHz and concentrated at the fundamental frequency and harmonics. Both males and females produce an agonistic grunt call, which consists of irregularly-timed shorter bursts of muscle contraction at lower frequencies than the boatwhistle (Tavolga 1958;Waybright et al. 1990)."

"Oyster toadfish Opsanus tau were captured in crab pots in the York River, Virginia and maintained in half-strength seawater. Fish were anesthetized in 200 mg I' MS 222, restrained upside down in a Plexiglas tank in an Industrial Acoustics sound-proof booth. Water containing 100 mg!’ of the anesthetic was recirculated into the mouth. The swimbladder (Fig. 1) was exposed completely by a midline incision, which was held open with retractors placed ros- trally, and intestines were pushed aside. The sonic nerve was stimulated using hook electrodes with single 0.1-ms square-wave pulses. Stimulation amplitude was increased until contraction am- plitude saturated to ensure complete fiber recruitment."

Sound Name Quotes

"Working with spontaneously evoked grunts and low frequencies to 100 Hz in the oyster toadfish, Skoglund (1961) de- termined that sound is generated by muscle-stimulated swimbladder movement and that both of the paired muscles contract synchronously during spontaneous production of the grunt call. "

"The muscles routinely contract at 200 Hz (range < 150-270 Hz) for 200-400 ms to produce the fundamental frequency of the male’s advertisement boatwhistle call in the York River, Virginia (Barimo and Fine 1998; Fine 1978). Energy in the boatwhistle call is typically below 1 kHz and concentrated at the fundamental frequency and harmonics. Both males and females produce an agonistic grunt call, which consists of irregularly-timed shorter bursts of muscle contraction at lower frequencies than the boatwhistle (Tavolga 1958;Waybright et al. 1990)."