| Description: |
The National Marine Mammal Laboratory (NMML), in cooperation with the NMFS Alaska Regional Office, the Alaska Beluga Whale Committee (ABWC) and the Cook Inlet Marine Mammal Council (CIMMC), conducted an aerial survey of the beluga whale population in Cook Inlet, Alaska, during 9-15 June 1998. The 39.4 hr survey was flown in a twin-engine, high-wing aircraft at an altitude of 244 m (800 ft) altitude and speed of 185 km/hr (100 kt) along a trackline 1.4 km from shore. This provided complete coverage of coastal areas around the entire inlet (1,388 km) one or more times and 1,320 km of transects across the inlet. Throughout most of this survey, a test of sighting rates was conducted with multiple independent observers on the coastal (left) side of the plane, where virtually all sightings occur. A single observer and a computer operator/data recorder were on the right side. After finding beluga groups, a series of aerial passes were made to allow at least two pairs of observers to make 4 or more counts of each group. The sum of the aerial estimates (using median counts from each site, not corrected for missed whales) ranged from 173 to 192 whales, depending on survey day. There were 57-109 belugas counted near the Susitna River, 42-93 in Knik Arm and 23-42 in Chickaloon Bay, but only one (dead) beluga whale was found in lower Cook Inlet. |