Interactions Between Beluga Whales and Boats in Knik Arm, Upper Cook Inlet, Alaska: Behavior and Bioacoustics

The behavioral studies documented patterns of movement, associations with particular habitats, and behavior of undisturbed beluga whales when passing through and lingering in the narrow reach of Lower Knik Arm (LKA). Patterns of boat movement and activity, and nominal interactions between boats and beluga whales in the LKA, were also documented. Behavioral responses of whales to the physical presence and associated noise of boats were likewise recorded. The potential effects of boat activity, boat noise, and the proposed construction and operation of a bridge crossing lower Knik on the use of marine habitats in upper Cook Inlet and Knik Arm by beluga whales were also evaluated. Pilot supplemental acoustic studies, in collaboration with Dr. Tomonari Akamatsu (Japan National Research Institute of Fisheries Engineering), used a stereo hydrophone array and acoustic data loggers to estimate the number of beluga whales present in observed groups by detecting their vocalizations. The supplemental acoustic studies also estimated the distance to observed beluga whales from the observation boat by triangulating to the sounds produced by the whales.