Example AEP traces recorded in response to high frequencies.

<p>Examples of AEPs (with FFT analysis) elicited at 3 kHz from a silver carp <b>(A)</b> and 5 kHz from a bighead carp <b>(B)</b>; upper traces were taken at sound pressure levels above the hearing threshold while the lower traces represent a baseline recorded at sound pressure levels below the hearing threshold.</p

Mean sound pressure and particle motion thresholds for each species at all frequencies examined.

<p>Letters indicate significant groups and * indicates significantly lower mean thresholds (ANOVA P < 0.05). BHC = bighead carp; SVC = silver carp; CC = common carp.</p

Particle acceleration thresholds (dB re 1 ms^-2) for the bighead, silver, and common carp.

<p>Each threshold was derived using a tri-axial accelerometer and are reported as the combined magnitude vector of the x, y, and z-axes Data are reported as mean (± SD).</p

Acoustic characterization of the experimental tank.

<p><b>A)</b> Acoustic impedance (ratio of sound pressure level to particle motion level) at three sound pressure levels (119, 130, and 145 dB 1 μPa SPL_rms) for all frequencies examined. There are no apparent resonances at any of the frequencies. <b>B)</b> Particle acceleration levels for each of the x, y, and z magnitude vectors at 130 dB re 1 μPa for all frequencies examined.</p

Low-pass filtered broadband sound.

<p>Spectrogram (left) and power spectrum (right) of the unfiltered (top) broadband sound used by Vetter et al. [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0192561#pone.0192561.ref014" target="_blank">14</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0192561#pone.0192561.ref015" target="_blank">15</a>] and Murchy et al. [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0192561#pone.0192561.ref010" target="_blank">10</a>] to deter bigheaded carp. Bottom spectrogram and power spectrum represent the same broadband sound with a 5 kHz low-pass filter applied using Audacity (version 2). Spectrograms were generated using MatLab (version 9.3) and power spectra were analyzed in Audacity.</p

Audiogram for bighead, silver, and common carp.

<p>Each data point represents the minimum sound pressure level (SPL; dB re 1 μPa SPL_rms) necessary to invoke an AEP response at each frequency examined (100 Hz– 5 kHz). Data are plotted as mean ± SD. Silver carp had the lowest thresholds of the species examined.</p

Example auditory evoked potentials (AEP) recorded from a bighead carp at 500 Hz.

<p>Averaged AEP traces <b>(A)</b> and FFT analysis <b>(B)</b> at six different sound pressure levels, including below the hearing threshold (86 dB re 1 μPa SPL_rms). FFT peaks are two times the stimulus frequency (1000 Hz). Hearing threshold was 89 dB re 1 μPa SPL_rms for this bighead carp.</p

Example auditory evoked potentials (AEPs) recorded from a silver carp at 500 Hz.

<p>Averaged AEP traces <b>(A)</b> and FFT analysis <b>(B)</b> at six different sound pressure levels, including below the hearing threshold (80 dB re 1 μPa SPL_rms). FFT peaks are two times the stimulus frequency (1000 Hz). Hearing threshold was 83 dB re 1 μPa SPL_rms for this silver carp.</p