TABLE 1.

Mean (±SD) of acoustic features characterising sounds in Parophidion vassali. Isolated specimens allow to distinguish sounds from males (M) and from females (F) in captivity. Fish 1, 2, 3, 5, 6 and 9 were recorded while they were alone in the tank. N refers to the number of sounds (units)

Sound type	Dominant frequency (Hz)	Pulse period (ms)	Sound duration (ms)	Number of pulses
Type A1 (n = 106)	503 ± 82	12.3 ± 0.95	159.0 ± 71.5	14 ± 6
Fish #1 (n = 7) M	368 ± 161	13.7 ± 0.54	137.5 ± 88.7	19 ± 11
Fish #2 (n = 6) M	423 ± 86	13.8 ± 0.47	241 ± 93	17 ± 6
Fish #3 (n = 6) M	437	12.6 ± 0.58	238 ± 88	18 ± 7
Fish #5 (n = 37) M	1734 ± 14	12.8 ± 0.47	201 ± 103	14 ± 8
Fish #6 (n = 6) M	470 ± 87	12.1 ± 0.92	149 ± 52	12 ± 4
Fish #7 (n = 4) M	457 ± 39	13.6 ± 0.54	300 ± 67	21 ± 4
Type A2 (n = 4) M	424 ± 238	35 ± 16	258 ± 136	9 ± 4
Type B (n = 63)	648 ± 109	7.8 ± 0.6	41 ± 16	6 ± 2
Fish #9 (n = 5) F	700 ± 100	8.1 ± 0.1	26 ± 5	4 ± 1