Aerial Survey of Belugas in Cook Inlet Alaska August 2008
Aerial survey of the beluga population in northern Cook Inlet, Alaska, August 12-14, 2008, to obtain high-resolution video of each group of belugas to determine age structure and number of calves.
NOAA Fisheries conducted an aerial survey of the beluga population in northern Cook Inlet, Alaska, 12-14 August 2008. The survey (16 hours total) covered the coastal areas north of Moose Point and the Native Village of Tyonek. Consistent with previous surveys by NOAA Fisheries made each year since 1993, the August 2008 survey was flown in a high-wing, twin-engine aircraft (AeroCommander 680FL N98UP) at an altitude of 244 m (800 ft) and a speed of 185 km/hr (100 kt). The survey track paralleled the coast (1.4 km offshore) and crossed Cook Inlet on 12 August from just north of Moose Point to North Foreland, and on 13 and 14 August from Point Possession to North Foreland. Each flight coincided with the afternoon low tide. The goal of the surveys was to obtain high-resolution video of each group of belugas to determine age structure (white relative to gray individuals and dark gray calves) and number of calves.
We found belugas in Turnagain Arm, the Susitna delta, and Knik Arm. On 12 August, we videotaped and counted belugas in Turnagain Arm near Sunrise (median count = 29 whales), at the Little Susitna River (median count = 55 whales), at the north end of Eagle Bay in Knik Arm (median count = 2 whales), and near Eagle River in Knik Arm (median counts = 23 whales) for a total median count of 109 whales. On 13 August, we videotaped and counted belugas near Bird Point in Turnagain Arm (median count = 21 whales), along the mudflats of the Susitna River (median count = 69 whales), in the Little Susitna River (median count = 26 whales), and in Eagle Bay, Knik Arm (median count = 61 whales) for a total median count of 177 belugas. On 14 August, we found belugas in the same locations as on 13 August: near Sunrise in Turnagain Arm (median count= 26 belugas), Susitna mudflats (median count = 80 belugas), Little Susitna River (median count = 38 belugas) and Eagle Bay, Knik Arm (median count = 50 belugas) for a total median count of 194 whales. We saw no belugas in Chickaloon Bay during this survey.
The median estimates of belugas seen each day in August 2008 (a quick index of relative abundance not corrected for missed whales) were similar to those documented in August 2007 (181 belugas on 1 August, 141 belugas on 2 August) and in August 2006 (126 belugas on 16 August, 143 belugas on 17 August) but smaller than those in August 2005 (236 belugas on 11 August, 277 belugas on 12 August).