Full Description

"Male oyster toadfish Opsanus tau L produce a long duration, tonal boatwhistle advertisement call, and both sexes grunt, a short duration more pulsatile agonistic call."

"Both sexes were equally likely to grunt, and grunt parameters (sound pressure level (SPL), individual range in SPL, number of grunts, and fundamental frequency) were similar in both sexes. SPL increased with fish size before leveling off in fish >200 g, and fundamental frequency and other parameters did not change with fish size. Number of grunts in a train, grunt duration and inter-grunt interval were highly variable in fish recorded twice suggesting that grunt parameters reflect internal motivation rather than different messages. Grunt production may explain the presence of well-developed sonic muscles in females and suggests that females have an active but unexplored vocal life."

"Territorial males grunt, particularly when guarding eggs, if tethered toadfish (both males and females) and even blue crabs were brought close to the male’s nest (Gray & Winn, 1961). Male toadfish have been found to grunt on top of boatwhistles and grunts of nearby males, an acoustic tag, suggesting a dominance display (Thorson & Fine, 2002a; Mensinger, 2014). Finally grunts have been evoked by electrical brain stimulation in O. beta (Demski & Gerald, 1972; Demski & Gerald, 1974) and O. tau (Fine, 1979; Fine & Perini, 1994). Grunts in O. tau were divided into knock and burst grunts (shorter and longer respectively) and indicate that the fish can vary the number of muscle contractions in a grunt pulse as well as the number of pulses and the timing between pulses."

"Thus males and females were equally likely to produce grunts when held."

"SPL increased nonlinearly from 39 to 78 dB SPL in males and 26 to 78 dB in females. Increase was rapid in both sexes to about 200 g and then leveled off (Fig. 2A)."

"SPLs for individuals ranged from 1 to 14 dB with a mean of 6.6 ± 3.3 dB (SD) in males and 1–14 dB (mean 6.6 ± 3.6 dB) in females."

"Fundamental frequency ranged from 97 to 183 Hz (mean 139.8 ± 18.2 Hz) in males and 106 to 187 Hz (mean 137.3 ± 19.6) in females and did not vary with fish size (r2 = 0.007, P = 0.56) (Fig. 2C). Fundamental frequency was similar between males and females (t52 = 0.49, P = 0.62). Number of grunt pulses varied from 4 to 30 (mean 15.5 ± 8.5) in males and 3 to 32 (mean 14.4 ± 8.0) in females and did not change with fish size (r2 = 0.0004, P = 0.88) (Fig. 2D). Number of grunt pulses per fish was again similar between males and females (t52 = 0.49, P = 0.63)."

"Number of grunts across all fish varied from 6 to 129, and most grunts were rather short with a range in means from 10.3 to 21.3 ms. Inter-grunt intervals within trains were highly variable and tended to be bimodal with bursts of pulses wedged in between longer pauses coupled with a general trend for longer pauses toward the end of a grunt train (hence multimodal) (Fig. 3). Individual, pairs and burst grunts occurred. Means or medians do not adequately describe the intervals, which for fish 5-1 ranged between 18 ms to almost 4 s (Fig. 3)."

"Therefore even when there appear to be trends in qualitative pattern, numbers of grunts and quantitative measurements of their patterning are quite different. The number of grunts from individuals in the two recordings ranged from six and seven grunts (similar), 33 and 55 grunts (somewhat similar), to 73 to 12 (quite dissimilar). Although we suspect some toadfish may exhibit tendencies in the patterning of their grunts, overall the calls are extremely variable and did not demonstrate individual signatures."

"Grunts recorded at Woods Hole, Massachusetts were also variable and described as single, doublet and trains of grunts (Maruska & Mensinger, 2009). All three of these grunt types were emitted in this study, suggesting as in birds (Brown, 1975) different calls can occur in the same behavioral context. Long trains of variable-interval grunts with intervals increasing over time are reminiscent of following grunts evoked after the cessation of electrical brain stimulation (Fine, 1978a). Net grunts recorded by Maruska & Mensinger had an average duration of 178 ms, approximately ten fold longer than ones recorded in this study. Part of this difference could be due to geographical variation (Fine, 1978a; Fine, 1978b) between populations in Virginia and Woods Hole, Massachusetts, the northern limit of the toadfish’s geographical range."

"Grunts recorded from identified males that were boatwhistling in the York River, VA fish varied from 48 to 147 ms in duration (Barimo & Fine, 1998), supporting the hypothesis that the grunts reflect different internal states of the fish under courtship and distress situations."

"Although fish sounds typically increase in amplitude and decrease in frequency with fish size (Myrberg, Ha & Shamblott, 1993; Henglmuller ¨ & Ladich, 1999; Connaughton, Taylor & Fine, 2000; Wysocki & Ladich, 2001; Ladich, 2007; Lechner, Wysocki & Ladich, 2010; Tellechea et al., 2010a; Tellechea et al., 2010b), toadfish grunts differ in some ways from this pattern. SPL increased with size to 200 g and then unexpectedly stabilized."

"We believe that the current study provides the first explicit demonstration that swimbladder size does not affect sound frequency although boatwhistle choruses recorded in the field (Fine, 1978b) contained fundamental frequencies that varied over as little as 10 Hz, therefore pointing to the same conclusion."

"Incidence of grunting as well as number of grunts, grunt duration, inter-grunt interval and sound pressure level were similar in males and females. It is clear that both sexes possess a similar grunt repertoire under these conditions."

Observation Environment Quotes

"Oyster toadfish were collected in the York River, VA and kept in sea tables with running York-River water under ambient photoperiods at the Virginia Institute of Marine Science (VIMS). Other fish were transported to Virginia Commonwealth University (VCU) and kept in five 120 L tanks in half-strength artificial sea water (18h) under a 14:10 LD cycle at 22 _C."

Behaviour Description Quotes

"Male Opsanus tau and O. beta produce a long-duration tonal courtship boatwhistle call, which functions in male-male competition and female attraction (Fish, 1954; Tavolga, 1958; Fine, 1978b; Edds-Walton, Mangiamele & Rome, 2002; Thorson & Fine, 2002b). "

"Male oyster toadfish Opsanus tau L produce a long duration, tonal boatwhistle advertisement call, and both sexes grunt, a short duration more pulsatile agonistic call. "

"Territorial males grunt, particularly when guarding eggs, if tethered toadfish (both males and females) and even blue crabs were brought close to the male’s nest (Gray & Winn, 1961). Male toadfish have been found to grunt on top of boatwhistles and grunts of nearby males, an acoustic tag, suggesting a dominance display (Thorson & Fine, 2002a; Mensinger, 2014). Finally grunts have been evoked by electrical brain stimulation in O. beta (Demski & Gerald, 1972; Demski & Gerald, 1974) and O. tau (Fine, 1979; Fine & Perini, 1994). "

"In this study we examined the effects of size and sex on grunt incidence and parameters by recording individual male and female oyster toadfish held in air (net grunts) to describe ontogenetic changes and potential sex differences. "

"Grunts recorded from identified males that were boatwhistling in the York River, VA fish varied from 48 to 147 ms in duration (Barimo & Fine, 1998), supporting the hypothesis that the grunts reflect different internal states of the fish under courtship and distress situations. "

"Even though male toadfish produce a courtship boatwhistle and possess larger sonic swimbladder muscles than females, both sexes are equally likely to grunt under distress conditions."

Sound Name Quotes

"Male oyster toadfish Opsanus tau L produce a long duration, tonal boatwhistle advertisement call, and both sexes grunt, a short duration more pulsatile agonistic call. "

"Territorial males grunt, particularly when guarding eggs, if tethered toadfish (both males and females) and even blue crabs were brought close to the male’s nest (Gray & Winn, 1961). Male toadfish have been found to grunt on top of boatwhistles and grunts of nearby males, an acoustic tag, suggesting a dominance display (Thorson & Fine, 2002a; Mensinger, 2014). Finally grunts have been evoked by electrical brain stimulation in O. beta (Demski & Gerald, 1972; Demski & Gerald, 1974) and O. tau (Fine, 1979; Fine & Perini, 1994). Grunts in O. tau were divided into knock and burst grunts (shorter and longer respectively) and indicate that the fish can vary the number of muscle contractions in a grunt pulse as well as the number of pulses and the timing between pulses. "

"We believe that the current study provides the first explicit demonstration that swimbladder size does not affect sound frequency although boatwhistle choruses recorded in the field (Fine, 1978b) contained fundamental frequencies that varied over as little as 10 Hz, therefore pointing to the same conclusion."