Locascio and Burton: A passive acoustic survey of fish sound production at Riley's Hump 
109 
Time (s) 
Figure 5 
Examples of acoustic recordings of black grouper (Mycteroperca bonaci) sounds made at site 12 at Ri- 
ley’s Hump, Tortugas South Ecological Reserve, Florida Keys in April 2012: (A) in waveform and (B) as 
a spectrogram of black grouper call variation 1 (BGV1), which is frequency modulated between 60-120 
Hz at a rate of about 0.2 s. Average duration of this variation was 5.2 s (SD 1.2, n=20), and highest 
received levels recorded were 149.9 dB SPL (re: 1 pPa). (C) Waveform and (D) spectrogram of black 
grouper call variation 2 (BGV2), which contains an introductory portion composed of a short frequency- 
modulated period followed by individual pulses and then the longer frequency-modulated portion com- 
mon to BGV1. The BGV2 call was uncommon in field recordings. How the context of the 2 call variants 
differs is unknown. The longer frequency-modulated end portion of the BGV2 call is truncated because 
the programmed 10-s recording period elapsed during the call. 
