Impacts of Vessel Surveys and Tagging Operations on the Behavior of Beluga Whales in Cook Inlet June 1994

In June of 1994, the National Marine Mammal Laboratory conducted a vessel survey of beluga whales in the northwest comer of Cook Inlet, Alaska. The focus of the survey was a radio-tagging study of a portion of the population found near the Susitna River delta. The impacts of the methods used to tag and study beluga whales from vessel platforms were examined. Using techniques similar to those employed by native hunters, beluga whales were isolated from their groups and pursued. Surfacing behaviors were categorized and analyzed based on initial reactions to tagging attempts, duration of tagging attempts, and whether the animals were in undisturbed or actively pursued groups. Behaviors were broken down into two categories: head lifts and slow rolls. The amount of time an animal was visible at the surface during each type of behavior was also examined. Based on analysis of videotaped pursuits, belugas were more likely to head lift during an approach and tagging sequence than to slow roll. In undisturbed groups, times at the surface were significantly different between head lifting and slow rolling animals, and between juveniles and adults displaying slow rolling behavior. Reactions to disturbance were consistent with those observed in other studies. Despite hunting pressures and tagging activities, belugas never abandoned the study area. Site tenacity, demonstrated by this species in other regions, is apparent in the Cook Inlet population.