Fig. 3. Aggressive sounds produced by the Hawaiian sergeant fish, Abudefduf abdominalis. (A,B) Sonograms (top) and oscillograms (bottom) show an aggressive >2 pulse sound with four pulses and a 1–2 pulse sound with two short pulses with an interpulse interval of 100 ms. (C) Power spectra of the first pulse of the 2 pulse sound and second pulse of the 4 pulse sound show that both aggressive sound types are broadband, with peak energies of <1 kHz, without prominent harmonic intervals. Power spectra calculated by 128-point FFT (Hanning window). Spectral display settings are Hanning window, 128 point, 75% window width. (D) Aggressive 1–2 pulse sounds have shorter individual pulse and total sound durations compared to the >2 pulse sounds. Data are plotted as means ± s.e.m.