Full Description

"Male courtship calls are produced nocturnally and consist of trains of 10 to 40 pulses that increase in amplitude and decrease in rate before exhibiting alternating periods of ca. 84 and 111_ms. Each pulse includes an unusual waveform with two parts. Pulse part 1 is a single cycle followed by a longer duration pulse part that exhibits gradual damping."

"Chorus began 30–45min after sunset and ended 30–45min before sunrise (Fig.1). In each case, sound production peaked for 120min from 20:00 to 22:00h. Calling diminished to low levels or even silence during the night and increased to a smaller second peak before sunrise, around 05:00h. In these conditions, it was impossible to give a precise account of the number of callers. However, sounds were recorded during different nights at different places, and we obtained sounds having different intensities. This allows us to be confident that the recordings correspond to the calls of different specimens. Calls consisted of between nine and 43 broad-band pulses (Fig.2), and number of pulses per call correlated with call duration (R2=0.96, P<0.001; Fig.3). The pulse period and amplitude increased gradually during the first eight pulses, separating the call into two parts: call part 1 (cp1) and call part 2 (cp2; Fig.4). The pulse period in cp2 exhibited a saw-like profile (Fig.4B, Fig.5), alternating between short (85.8±0.2ms) and long (113.7±0.4ms) periods that differed significantly (t345=60.46, P<0.001). Pulse length was 25.5±4.6ms (N=237). The pulse waveform consisted of two parts, pulse part 1 (pp1) and pulse part 2 (pp2; Fig.4). The pp1 waveform consisted of one major cycle that lasted 6.9±0.2ms (N=81), and pp2 exhibited a sinusoidal waveform with an exponential decay that lasted 21.4±2ms (N=77). The duration of pp1 was more fixed (CV=3.2%) than for pp2 (CV=12.4%). Pulse energy was concentrated in two frequency bands of relatively similar amplitude (Fig.6): 226±1Hz (N=209) and 410±1Hz (N=209). Above the second band, energy decreased rapidly from about 450Hz to about 900Hz."

"Calls were produced only during the night, and the fish were caught at the place of recordings, in 75cm of water on a sandy bottom."

"The pulse of O. rochei is made of two parts, starting with a low-amplitude onset before a longer high-amplitude part (Fig.4C)."

"The pulse rate presents two periods in alternation in the second part of the sound train (cp2 in Fig.4): 84 and 111ms. It could be encoded as follows: ababab, where ‘a’ corresponds to the first period of 84ms and ‘b’ to the second period of 111ms. A way to have a constant period (c) is to add a and b."

Observation Environment Quotes

"Calls were recorded in a sandy area in the Cetina Estuary near the town of Omis in Croatia (43°26N, 16°41E). Water depth was about 2_m and temperature about 23°C."

Behaviour Description Quotes

"Male courtship calls are produced nocturnally and consist of trains of 10 to 40 pulses that increase in amplitude and decrease in rate before exhibiting alternating periods of ca. 84 and 111_ms. Each pulse includes an unusual waveform with two parts. Pulse part 1 is a single cycle followed by a longer duration pulse part that exhibits gradual damping."

Sound Name Quotes

"Male courtship calls are produced nocturnally and consist of trains of 10 to 40 pulses that increase in amplitude and decrease in rate before exhibiting alternating periods of ca. 84 and 111_ms. Each pulse includes an unusual waveform with two parts. Pulse part 1 is a single cycle followed by a longer duration pulse part that exhibits gradual damping.' 'Chorus began 30–45min after sunset and ended 30–45min before sunrise (Fig.1)."