Aerial Survey of Belugas in Cook Inlet Alaska May 2006
Aerial survey of upper Cook Inlet, Alaska, May 2-3, 2006, to document beluga distribution, record calf sightings relative to other seasons, and test new survey equipment.
NOAA Fisheries conducted an aerial survey of upper Cook Inlet, Alaska, 2-3 May 2006 with the intention of: 1) documenting beluga distribution; 2) recording calf sightings relative to other seasons; and 3) testing new survey equipment. The 7.1 hr survey was flown in a twin-engine, high-wing aircraft at an altitude of 244 m (800 ft) and speed of 185 km/hr (100 kt), consistent with NOAA Fisheries' annual abundance surveys for Cook Inlet belugas. The flights in May included coastal searches of most areas within 1.4 km of the shoreline around the northern portion of Cook Inlet and some transects well away from shore.
After sighting a beluga group, a series of aerial passes was made to mark the group location and to make quick aerial counts. Unlike June surveys, when groups are generally large, concentrated, and close to shore, belugas in May were in very small, widely scattered groups, some of them well offshore making them hard to find. The beluga distribution in early May appeared to be similar to winter/spring observations (November-April) made in previous years and in sharp contrast to the summer/fall distribution (June-October) when whales are in dense groups in shallow water. Although the total number of belugas seen (43 whales in two days) is small, no calves were observed, suggesting that this May survey preceded the calving season. With the small, scattered nature of beluga groups, cameras could not be tested directly on whales. However, broken river ice provided an ideal test of camera performance because ice color ranged from white to black (similar to belugas) with crisp, uniquely identifiable ice edges, which helped in pair-wise comparisons between images.