Acoustic data

Sound particle motion and pressure recordings for Ferrari et al 2018 School is out paper. Methods:

Acoustic recordings:

Sound pressure was recorded with an
omnidirectional hydrophone (HiTech
HTI-96-MIN with inbuilt preamplifier; sensitivity -165 dB re 1V/μPa; frequency
range 2 Hz–30 kHz; High Tech Inc., Gulfport MS) and a solid-state recorder (Zoom
H2 recorder; sampling rate 44.1 kHz; Zoom Corporation, Tokyo, Japan). The
recorder was fully calibrated using pure sine wave signals generated in SAS Lab
(Avisoft, Germany), played on an mp3 player, measured in line with an
oscilloscope. Particle acceleration was recorded with an accelerometer (M30,
sensitivity 0–3 kHz, manufactured and calibrated by GeoSpectrum Technologies,
Dartmouth, Canada; recorded on a laptop via a USB soundcard, MAYA44, ESI
Audiotechnik GmbH, Leonberg, Germany).

Acoustic analysis:

Acoustic recordings were analysed in
MATLAB v2013a. Fast-Fourier
Transforms were used to transform time domain recordings into the
frequency domain before power spectral density was calculated with a window
length of 1024 using a Hamming window on 1-min samples of ambient and
boat sounds in the tank compared with original recordings made in the lagoon.
This allowed
comparison of sound levels across the frequency range 0-3 kHz.
Sound levels are only considered up to 3 kHz due to the upper limit of the sensitivity
of the accelerometer. This frequency range is likely to cover the hearing range
of most fish.

Figure
Legend:

Figure x. Sound pressure (left) and particle
acceleration (right) power spectral densities of ambient and boat sounds in the
tank compared with original recordings made in the lagoon. Sampling rate of
recordings = 44.1 kHz, window length = 1024. Each line on the figure represents
the mean level from 60 x 1-s Hamming filtered windows for the frequency range
0-3 kHz.