Aerial Survey of Belugas in Cook Inlet Alaska August 2005
Photographic aerial survey of belugas in Cook Inlet, Alaska, August 11-12, 2005, with the express purpose of documenting the proportion of calves at a time when it was likely that all calves of the year were born.
NOAA Fisheries conducted a photographic aerial survey of belugas (Delphinapterus leucas) in Cook Inlet, Alaska, 11-12 August 2005, with the express purpose of documenting the proportion of calves at a time when it was likely that all calves of the year were born. During the standard abundance surveys conducted in early June, some calves are probably not yet born. The aerial survey in August (10.1 flight hrs) was flown in a twin-engine, high-wing aircraft at an altitude of 244 m (800 ft) on a trackline 1.4 km offshore, consistent with annual surveys for beluga abundance in Cook Inlet as done since 1993. Two observers searched for whales on the left side of the aircraft, and two searched on the right; however, there was no attempt to conduct independent searches. After finding beluga groups, a series of aerial passes was made with three observers counting surfacing whales while paired video and digital still cameras captured images for analyses. The sum of the aerial counts was 236 belugas for 11 August and 277 belugas for 12 August, numbers that represent a rough index of abundance uncorrected for missed whales. The counts from August 2005 were higher than uncorrected estimates from June during the past seven years. Laboratory analyses of the videotapes will determine whether or not the number of whales actually was higher in August than in June 2005.