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Fishery Bulletin 109(3) 
Materials and methods 
Long-term acoustic recording systems (LARS) were 
deployed in estuarine canals at one site in Punta 
Gorda and at three sites in Cape Coral, Florida, to 
document patterns of sound production by black drum 
(. Pogonias cromis) during their spawning season. The 
canals are extensive sea-walled residential systems 
which allow access to the Gulf of Mexico via Charlotte 
Harbor (Fig. 1). One LARS was deployed at the Punta 
Gorda site from 22 March to 3 May 2004, and from 
12 December 2004 to 4 May 2005. At Cape Coral 
sites 1 and 3 (CC1 and CC3), LARS were deployed 
from 12 February to 6 April 2005, and at Cape Coral 
site 2 (CC2) from 12 February to 6 May 2005, and 
from 21 October 2005 to 7 June 2006. These sites 
were selected on the basis of information provided by 
canal-side residents of loud booming sounds produced 
there in the evening during winter months. 
Surface and bottom water temperature data were 
recorded at CC2 during the October 2005-June 2006 
deployment with Hobo® temperature data loggers 
(model UA-002-08; Onset Computer Corp., Bourne, 
MA) programmed to record data at 10-minute in- 
tervals. The surface temperature data logger was 
attached to a buoy and suspended one half meter 
below the surface. The bottom temperature data 
logger was attached to the LARS and recorded data 
at one half meter above the bottom. All LARS were 
anchored and remained positively buoyant one half 
meter above the bottom. Water depth at all sites was 
approximately seven meters, and the bottom was a 
soft muddy composite. During the October 2005- 
June 2006 deployment, the LARS stopped recording 
after the first week and was reprogrammed and 
redeployed on 3 December 2005. With this exception 
all LARS functioned according to schedule during 
deployments. 
Two LARS models were used for recordings: a Per- 
sistor CF2 computer (Persistor Instruments Corp., 
Marston Mills, MA) (sample rate: 2634 Hz) and a 
Toshiba pocket PC model E755 (Toshiba Comput- 
er Corp., Tokyo, Japan) (sample rate: 11,025 Hz). 
Sample rates used for recording were well above the 
frequency range where most of the acoustic energy in 
black drum calls is concentrated (<300 Hz) and there- 
fore aliasing (i.e. under sampling of signals) was not 
a problem (Locascio, 2010). The Persistor-based LARS 
was used for all recordings, except for the 21 October 
2005-7 June 2006 deployment at CC2. High Tech Inc. 
(Gulfport, Mississippi) 96-min series hydrophones were 
used with all LARS (sensitivity: -164dB re: lV/lpPa 
and flat frequency response of 2 Hz-37 kHz). The sensi- 
tivity of each recorder was calibrated with a 0.1 V peak 
sinusoidal signal. 
Each 10-second file was analyzed with a fast Fourier 
transform (FFT) to generate a power spectrum from 
which the band sound pressure level (SPL) in 100-Hz- 
wide bins was calculated. The SPL was greatest in the 
100-200 Hz band and a five-point moving average of 
C ape C oral 
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81" 50 00 
Gulf of 
Mexico 
Figure 1 
Locations where calls of black drum (Pogonias cromis ) were 
recorded in residential estuarine canal systems of Punta Gorda 
and Cape Coral, Florida. The study sites are indicated by 
filled black circles. The three study sites in Cape Coral are: 
CC1 (northernmost); CC2 (central); and CC3 (southernmost). 
data in this frequency range was used for each time 
series analysis. Black drum calls were identified in 
recordings by comparison with previously published 
descriptions by Mok and Gilmore (1983). All data were 
analyzed with MATLAB, version R2007a software (The 
Mathworks, Inc., Natick, MA). 
To be considered a chorus event the SPL was re- 
quired to exceed an arbitrarily defined threshold of 
two standard deviations (SD) above the mean daytime 
background SPL for a minimum of five consecutive 
recordings (i.e., 50 minutes). Mean daytime SPL was 
calculated from 0700 to 1500 hours for each site and 
season separately. Requiring that levels be sustained 
above the threshold for a minimum of 50 minutes con- 
trolled for the infrequent cases where the SPL briefly 
exceeded the threshold during daytime hours because 
of vessel noise, weather, or occasional black drum calls. 
