DISCUSSION

• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Arctic; Arctic Ocean; Northwest Passage; Beluga; Beluga*; Climate change; Delphinapterus leucas; Northwest passage
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.297.2137; http://www.fakr.noaa.gov/protectedresources/whales/beluga/acoustics/bbbelugas_castellote_etal2013audiograms.pdf

Belugas (Delphinapterus leucas) have been identified as Arctic ecosystem sentinels because they are broadly dispersed, high trophic feeders and are likely to be negatively impacted by climate change. They are highly dependent on hearing and underwater sound to enact key biological activities such as forage for prey, communicate with conspecifics and navigate. Therefore, understanding how noise might affect their sensory ecology is a priority to encourage their survival and address the broader potential acoustic impacts within the Arctic. Ocean noise levels are increasing in the Arctic due to an increase in human activities, which are related to the interests in Arctic resources and the opening of the Northwest Passage. This is of concern because several beluga populations are endangered and considered strategic stocks. Their hearing sensitivities are unknown. The work presented here describes for the first time how wild belugas hear. OBJECTIVE To describe the hearing sensitivity of temporarily restrained Bristol Bay belugas using auditory evoked potential (AEP) techniques for the range 4-180 kHz in the shortest time possible. METHODS 1) Solitary belugas were captured using a 300-ft. long net, 15-ft deep with 21 in. mesh deployed from an 18 ft. aluminum skiff with a 70 hp outboard assisted by an additional two to four support boats. Animals were restrained with a combination of a tail rope, head hoop net, and a modified canvass sling. 2) Sinusoidally amplitude modulated (SAM) tone-bursts were