Surveys of beluga whales in Cook Inlet

• Main Authors: David J. Rugh, Kim E. W. Shelden, Barbara A. Mahoney, Laura K. Litzky, Roderick C. Hobbs, Kristin L. Laidre
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 1999
• Subjects: Beluga; Beluga whale; Beluga*; Alaska
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.230.3020; http://alaskafisheries.noaa.gov/protectedresources/whales/beluga/survey/061999.pdf

The National Marine Fisheries Service (NMFS) conducted an aerial survey of the beluga whale population in Cook Inlet, Alaska, during 8-14 June 1999. The 41.5 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) along a trackline 1.4 km from shore, consistent with annual surveys flown each year since 1993. The flights in 1999 included one or more surveys of coastal areas around nearly the entire Inlet and 1,790 km of transects across the Inlet. Paired, independent observers searched on the coastal (left) side of the plane, where virtually all sightings occur, while a single observer and a computer operator/data recorder were on the right side. In addition, each day a different visitor observed from the left side. After finding beluga groups, a series of aerial passes were made to allow at least two pairs of primary observers to make 4 or more counts of each group. Inter-day counts ranged from 75 to160 belugas near the Susitna River (between the Beluga and Little Susitna Rivers), 13 to 43 in Knik Arm, and 17 to 30 in Chickaloon Bay, but no belugas were found in lower Cook Inlet. The sum of the aerial estimates (using median counts from each site, not corrected for missed whales) ranged from 197 to 221 whales, depending on observer. The index count for 1999 is 217, which is slightly higher than the index counts for 1998 (193) but lower than all index counts by NMFS observers between 1993-97.