Anthropogenic noise and sound production by beluga whales (Delphinapterus leucas) in Cook Inlet, Alaska during early August 2007.

Abstract

The beluga whale population in Cook Inlet, Ak, has a limited range centered near the Port of Anchorage and was declared endangered in 2008. One potential threat to the belugas recovery is anthropogenic noise, which may disrupt communication and normal behaviors. This project used a boat‐based single hydrophone system to evaluate noise levels at several locations in Cook Inlet on 6 days from 2–14 August, 2007. Belugas were encountered twice, at the Port of Anchorage and near the Little Susitna River. Recorded vocalizations were analyzed to develop a provisional description of the whales’ repertoire. Call frequencies ranged from 381 Hz to 24 kHz (the limit of the recording system), with most energy at frequencies above 2 kHz. Most vocalizations were similar to call types of other beluga populations. Broadband and 1/3‐octave band levels were evaluated for noise from tidal flow and ships at the Port of Anchorage. Vessel noise levels were highest below 0.5 kHz, but frequencies ranged to greater than 8 kHz (dis...