Evaluation of kurtosis-corrected sound exposure level as a metric for predicting onset of hearing threshold shifts in harbor porpoises (Phocoena phocoena).

Application of a kurtosis correction to frequency-weighted sound exposure level (SEL) improved predictions of risk of hearing damage in humans and terrestrial mammals for sound exposures with different degrees of impulsiveness. To assess whether kurtosis corrections may lead to improved predictions for marine mammals, corrections were applied to temporary threshold shift (TTS) growth measurements for harbor porpoises (Phocoena phocoena) exposed to different sounds. Kurtosis-corrected frequency-weighted SEL predicted accurately the growth of low levels of TTS (TTS 1-4 < 10 dB) for intermittent sounds with short (1-13 s) silence intervals but was not consistent with frequency-weighted SEL data for continuous sound exposures.