Aerial audiogram for a juvenile male Steller sea lion obtained using psychophysical methods. Thresholds for three individual sessions per frequency (from Table I) are shown with open circles. The contour of the mean of the three session thresholds is shown by a solid black line.
Aerial audiograms for three species of otariid obtained using psychophysical methods: 1Moore and Schusterman, 1987, California sea lion (n=1), northern fur seals ; 2Babushina et al., 1991, northern fur seal ; 3this study.
Ambient noise in (a) the sound-attenuating chamber used for the behavioral audiogram and (b) the surgery room in which the ASSR audiogram was conducted. Noise levels for the ASSR audiogram were further attenuated by headphones placed over the subject’s ears. Power spectral density levels are derived from 1-min unweighted recordings using 1/3-octave band analysis. The 10th, 50th, and 90th percentiles of the noise level distribution are shown in addition to the . Note the positive skew of the noise level distribution in the surgery room due to the intermittent activity of the anesthesia ventilator.
A comparison of the aerial audiogram from a juvenile male Steller sea lion with underwater audiograms from one male and one female Steller sea lion (this study; Kastelein et al., 2005). All audiograms were obtained using psychophysical methods. (a) Audiograms are compared in terms of sound pressure by converting the underwater thresholds to dB re . (b) Audiograms are compared in terms of estimated sound intensity by converting all sound pressure thresholds to dB re (assuming plane-wave propagation conditions).
A comparison of aerial hearing sensitivity measured using psychophysical and ASSR methods with the same juvenile male Steller sea lion.
Aerial hearing thresholds for a juvenile male Steller sea lion obtained using psychophysical methods. The mean thresholds are the average of the three consecutive session thresholds reported. Also shown are the average false alarm rates for each frequency and the order in which testing occurred for each frequency.
Aerial hearing thresholds for a juvenile male Steller sea lion, obtained using the ASSR method. Thresholds are defined as the last statistically detectable ASSR response.
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