Dataset: Harris Creek May 2015 Acoustic Time Series: raw files
Deployment: Bohnenstiehl_hydrophone_2015

Beginning in May 2015, a short-term effort was initiated to record ambient underwater sound at high temporal resolution, at restored and unrestored oyster reefs within a large-scale oyster restoration site in Harris Creek, MD. This was accomplished using a low-power SoundTrap recorder and hydrophone (Ocean Instruments New Zealand).

The instrument was strapped vertically to a metal post and positioned ~0.15m above the seafloor and approximately 1.0-3.5 m below mean lower low water (MLLW) at all sites.

Recordings began 5/6/2015 at 12:00 and ended 6/1/2015 at 10:00. The instrument was programmed to record for 130 seconds every 15 or 30 minutes at a 96 kHz sample rate. The SoundTrap analog signal is digitized at a fixed rate of 288 kHz. A digital anti-alias filter, with a cutoff frequency of 0.45 times the desired sample rate, is then applied before decimation. Consequently, at our sample rate of 96 kHz, the useable (-3 dB) bandwidth of these recordings is 0.020-43.0 kHz. In total, 16,185 separate 2-minute recordings were made as part of this monitoring initiative.

The data may be read into MATLAB using functions included in MATLAB.

Example:
% Set calibration
cal=10^(STcalibration/20);

[y,fs]=audioread(‘filename.wav’); %read in audiofile
y=y(fs*5:end) %remove first 5 seconds that have calibration sound
y=(y-mean(y))*cal; %demeaned and response correct to uPa