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Fishery Bulletin 1 14(1) 
Figure 4 
An example of seasonal periodicity of sound pressure levels (SPLs) in the time series of acoustic data for the 
frequency range <200 Hz recorded at the deepwater site (RHDW) at a depth of 60 m at Riley’s Hump, Tortugas 
South Ecological Reserve, Florida Keys, 2010-2012. Red grouper (Epinephelus morio), black grouper (Mycte- 
roperca bonaci), and red hind (Epinephelus guttatus) all were recorded at this site, but the red hind was the 
dominant sound producer during the period shown. Sound production occurred during all lunar phases, but 
peaks were coincident with the last quarter moon phase. Lunar symbols represent moon phases as follows: new 
moon, #; first quarter moon, t>; full moon, O; and last quarter moon, 3. 
variations of the call of black grouper were identi- 
fied. One variation, BGV1, was composed of a rela- 
tively long, frequency-modulated tonal portion only. 
The other variation, BGV2, was composed of an ini- 
tial, shorter-duration frequency-modulated tone fol- 
lowed by several individual pulses and concluded 
with a longer frequency-modulated tonal portion 
characteristic of the BGV1 (Fig. 5, A-D). The long, 
frequency-modulated tonal portion common to both 
variations (/i=20) had a mean duration of 5.2 s (stan- 
dard deviation [SD] 1.2) and was modulated between 
60-120 Hz at a mean rate of 170 ms (SD 0.03. The 
highest received root-mean-square (RMS) SPL for the 
long, frequency-modulated portion of the call was es- 
timated at 149.9 dB RMS SPL (re: 1 pPa). The high- 
est received RMS SPL for the introductory portion 
of the call only and the overall combined portions of 
the call were 143.3 and 144.3 dB SPL (re: 1 pPa), 
respectively. 
This call type was identified 76 times in the audio 
track of the recordings made with the remote A/V sys- 
tems. Black grouper appeared in the video from the 
A/V systems during 18 of the 76 times either call varia- 
tion was identified and 10 additional times within 25 s 
of the call being made. No other grouper species were 
recorded on video at or near the time during which ei- 
ther variation of this call was produced. Other grouper 
species were verified at these sites by divers during 
visual surveys, including the Nassau grouper, yellow- 
mouth grouper (M. inter stitialis), scamp (M. phenax), 
yellowfin grouper, rock hind ( E . adscensionis), and co- 
ney ( Cephalopholis fulva). 
In most cases, only a single black grouper appeared 
in the video when a call of either variation (BGV1 or 
BGV2) was made and only once was interaction be- 
tween 2 fish recorded (site 12A). On this occasion, one 
fish with a blotched pattern approached another more 
monochromic fish from below and behind and briefly 
made contact as it passed under the rear portion of 
the other’s body. The 2 fish then swam slowly away in 
opposite directions and out of the video frame (Fig. 6, 
A-D). The blotch-patterned fish swam toward the cam- 
era and out of the frame, and within 10 s a relatively 
high amplitude (149.9 dB SPL) BGV1 call was record- 
ed. This behavior could indicate possible courtship, but 
it could also represent a territorial display. 
On the morning that the A/V system that made this 
recording was deployed (27 April 2010) divers reported 
seeing several black grouper at this site (12A) swim- 
ming together in a daisy chain pattern high in the 
water column. Apparent courtship behavior between 2 
black grouper was also observed during a visual survey 
conducted at site RH1 on 19 January 2011. On this 
occasion, a large, light-colored black grouper was ob- 
served to approach a smaller black grouper from be- 
hind and swim alongside it for a few moments and 
then to rub and shake its body against it for about 2 s. 
No sound associated with this behavior was heard by 
divers, but it may have gone unnoticed. Similar court- 
ship behavior of black grouper was described by Paz 
