Full Description

"Sounds are made only by males; females do not have sound-producing apparatus."

"In tanks, during courtship activity, it was reported that drumming began around dusk and the rate intensified significantly through the evening until spawning (Guest and Lasswell, 1978). The drumming call was made up of a burst of pulses with dominant energy in the 240–1000 Hz range. Pulses were of 70–100 ms duration and calls were irregular in pulse repetition rate (pulses/s). The first two interpulse intervals were greater than others in a typical call (Guest and Lasswell, 1978). In the field, red drum sounds were also produced between 18:30 and 21:30. This was in the form of either a low-frequency rumble with a prominent energy peak at approximately 150 Hz or a clearly distinguishable call made by individuals or small groups of red drum (Holt, 2008)."

"In the floating cage (Station 2) with 31 specimens, the daily sound production of males (3–5 years old, 1–7.7 kg) at the end of the spawning period (but still spermatic) was estimated at between 2118 and 4554 sounds/day. Sounds were produced throughout the day but the production was not uniform. Chorus activity began to increase after midnight and peaked from 06:00 to 09:00. Call numbers then diminished regularly before an increase to a smaller second peak at noon. The sound production then decreased regularly until 18:00 and very few sounds were recorded after sunset and overnight. This activity pattern was observed each day (Fig. 1)."

"At the end of the spawning period, trains of calls recorded at Stations 1 and 2 comprised between one and seven pulses (n = 400 calls), with most sounds having three or four pulses. The sound duration was positively related to the number of pulses (R^2 = 0.9478, y = 0.0979x _ 0.0112), highlighting the constant rate of pulse production."

"Fig. 2. Characteristics of the calls produced by Sciaenops ocellatus. A: Oscillogram of a train made of four pulses. B: power spectrum of a single pulse (upper line). The grey zone corresponds to the recorded ambient noise before or after sound emissions. (1): Call duration; (2): pulse period; and (3) pulse duration."

"Analysis of sound characteristics was conducted on sounds recorded in floating cages. Data were collected on calls having three or four pulses. Each pulse had three high-amplitude half-cycles sometimes followed by decaying lower amplitude oscillations (Fig. 2). Most energy occurred in the first cycle, and the amplitude of the second cycle decayed by about half. Pulses lasted between 9 and 42 ms (mean ± S.D. = 23 ± 4 ms, n = 700 sounds from 33 specimens) and we did not observe significant differences in the pulse duration due to its position in the call (Shapiro–Wilk, H = 0.33; p = 0.95). The first period (time between the first and second pulse) was significantly longer (151 ± 18 ms, n = 200) than the other periods (140 ± 14 ms, n = 200 for the second period and 142 ± 16 ms, n = 100 for the third period). The sound spectrum of a pulse contained energy with a wide bandwidth, between 50 and 750 Hz. The dominant frequency ranged from 78 to 157 Hz (105 ± 32 Hz, n = 200) and did not show harmonics (Fig. 2)."

"In 9-monthold males, sonic muscles are present but they are apparently not functional because no sound was recorded in this group."

"In both tanks and field studies, most of the acoustic activity in S. ocellatus has been reported as occurring mainly at the end of the day, from 19:00 to 22:40 (Guest and Lasswell, 1978; Holt, 2002), and as corresponding to spawning events (Falguière, 2011; Holt, 2008; Holt et al., 1985)."

"We did not observe reproduction during our recordings but our results indicate that the highest rate of activity took place between 06:00 and 09:00 and not at dusk as it is usually the case during the spawning period."

"In the red drum, each muscle twitch is assumed to produce individual pulses with the cycle of each pulse giving the dominant frequency of the sound (Lagardère and Mariani, 2006)."

Observation Environment Quotes

"The study took place in Martinique between February 5 and March 25. Fish were recorded in tanks and in floating cages placed in open sea."

"Recordings of fish in floating cages (30 m3) were performed at three stations"

"Recordings in tanks were made at the Ifremer Station located in the Bay of Robert."

Behaviour Description Quotes

"In tanks, during courtship activity, it was reported that drumming began around dusk and the rate intensified significantly through the evening until spawning (Guest and Lasswell, 1978). "

"In these conditions, it was only possible to count the number of pulses per call. This shows at least that stress conditions can also induce sound production in this species.' 'Males (10 specimens, 5–8 years old, 2–6.4 kg) in a shifted period tank (i.e. outside the reproduction period) only made 156 sounds/day. This allows the hypothesis of relationships between courtship and sonic activities."

"Data recorded during spawning activity (Guest and Lasswell, 1978; Holt, 2002) and from unpublished results (Beauchaud, pers. com.) indicate that the number of pulses/sound would be higher (up to nine on average) during spawning activity than outside (three to four in this study). This shows that the rate of acoustic activity of S. ocellatus can be related to the spawning period (Lagardère and Mariani, 2006; Locascio and Mann, 2011; Locascio et al., 2012; Ramcharitar et al., 2006; Tellechea and Norbis, 2012; Tower, 1908; Veerappan et al., 2009)."

Sound Name Quotes

"Although this species is known for its drumming sounds (Fish and Mowbray, 1970), paradoxically only very few studies have investigated this aspect of their biology. In tanks, during courtship activity, it was reported that drumming began around dusk and the rate intensified significantly through the evening until spawning (Guest and Lasswell, 1978). The drumming call was made up of a burst of pulses with dominant energy in the 240–1000 Hz range. Pulses were of 70–100 ms duration and calls were irregular in pulse repetition rate (pulses/s). The first two interpulse intervals were greater than others in a typical call (Guest and Lasswell, 1978). In the field, red drum sounds were also produced between 18:30 and 21:30. This was in the form of either a low-frequency rumble with a prominent energy peak at approximately 150 Hz or a clearly distinguishable call made by individuals or small groups of red drum (Holt, 2008)."

"Chorus activity began to increase after midnight and peaked from 06:00 to 09:00."