Baseline Hearing Measurements in Alaskan Belugas

Due to the opening of the Northwest Passage and interest in Arctic resources, naval activities (amongst others) and ocean noise are increasing in northerly beluga waters. Through data acquired in a capturerelease project, this work examines the frequencies and sound levels to which wild belugas are sensitive. A standard audiogram is being determined from the wild samples, noting the variation between animals and the audiogram of maximal sensitivity. This will be compared to available hearing data from captive belugas, evaluating any differences and potentially combining the two data sets. The hearing curves will be appraised relative to demographic and health-related meta-data from the animals from which the measurements were made. Through these data analyses we seek to: 1) define the natural and baseline hearing abilities and variability in belugas, 2) place the results in the context of potential ecological influences and that of anthropogenic noise, and 3) evaluate the validity of captivebased hearing data in relation to wild animals.