Aerial Survey of Belugas in Cook Inlet Alaska August 2010
Aerial survey of the beluga population in northern Cook Inlet, Alaska, August 17-20, 2010, 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, 17-20 August 2010. 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. The survey (16 hours total) covered the coastal areas north of Point Possession and Beluga River. Consistent with previous surveys by NOAA Fisheries made each year since 1993, the August 2010 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 surveys occurred during the low tide when possible.
We found beluga groups in the Susitna delta (from the Beluga River to the Little Susitna River) and in Knik Arm and Turnagain Arm every day. On the 17 August survey, we video-taped and/or counted 7 beluga groups: near Sunrise in Turnagain Arm (median count = 44), mid Knik River off Birchwood Airport (median count = 9), scattered across Goose Bay and Knik River (median count = 35), a lone whale on the shoreline near Windy Point, 3 whales lost in rain squalls at the Susitna River, a scattered group at the Ivan River (median count = 29), and in the mouth of the Beluga River (median count = 7). On the 18 August low tide, we videotaped and/or counted 5 beluga groups: in Eagle Bay (median count = 50), the Little Susitna River (median count = 7 whales), at Beluga River (3 large, white whales), and in Turnagain Arm (median count = 62 whales near Sunrise and 32 whales near Rainbow) for a total median count of 154 belugas. On 19 August low tide, we coordinated efforts with LGL’s boat-based photo-identification project, counting and videotaping a beluga group then alerting the LGL team to the group to begin their photo-id effort after we departed the area to find another group. Belugas were again in Eagle Bay (median count = 73) and the Little Susitna River (median count = 95), along the east tributary of the Susitna River (median count = 17), and in Turnagain Arm ((median count = 48 whales near Gull Rock, 29 whales near Sunrise, and 4 whales near Bird Point) for a total median count of 266 whales. On 20 August, we again coordinated with LGL, videotaping and counting belugas in Eagle Bay (median count = 27) and the Little Susitna River (median count = 14). We saw no belugas in Chickaloon Bay during this survey.
The median estimates of belugas seen each day when the entire upper inlet was surveyed in August 2010 (a quick index of relative abundance not corrected for missed whales) were similar to surveys in 2009 (196 on 11 August, 212 on 12 August, and 197 on 13 August), 2008 (109 belugas on 12 August, 177 on 13 August, 194 on 14 August), 2007 (181 belugas on 1 August, 141 belugas on 2 August) and in 2006 (126 belugas on 16 August, 143 belugas on 17 August), and 2005 (236 belugas on 11 August, 277 belugas on 12 August).