From a NOAA Press Release:

Beluga whales in Cook Inlet. Credit: Chris Garner, U.S. Army JBER

NOAA Fisheries released today its biennial population estimate for the endangered Cook Inlet beluga whale. Scientists determined that the population size is between 279 and 386 animals, with a most likely estimate of 328 animals. The estimate is derived from data collected during a June 2016 aerial survey. The previous estimate, from 2014, was 340 animals.

Estimates can vary from year to year due to changes in abundance from births and deaths, and may also vary based on weather or oceanographic conditions during the survey, changes in beluga behavior or distribution, and statistical variability in the data.

“Cook Inlet belugas are still in danger of extinction because the population is so small,” said Paul Wade, head of Cook Inlet beluga research at NOAA Fisheries. “The population trend over the last 10 years has been relatively stable compared to the steep decline seen in the 1990s, but there is some evidence the population has continued to decline slightly. We are concerned that the population is not yet increasing towards its former abundance level.”

Scientists from NOAA’s Alaska Fisheries Science Center have been conducting aerial surveys of Cook Inlet for more than two decades to estimate the population of beluga whales. From a small airplane, scientists look for and count beluga whales and make video recordings of the whale groups.

They then analyze the video and observer counts to produce a broad-scale picture of the whales’ distribution and abundance in the inlet in early June. 

Late spring and early summer is when belugas concentrate near river mouths or shallow tidal bays in the northernmost reaches of Cook Inlet, where it is likely they feed on migrating fish, especially eulachon and salmon.

Cook Inlet belugas comprise one of five beluga populations recognized within U.S. waters. NOAA listed Cook Inlet beluga whales as endangered under the Endangered Species Act in 2008. The agency finalized a recovery plan in December 2016 for the iconic species. Cook Inlet beluga whales are one of NOAA Fisheries’ eight Species in the Spotlight—considered most at risk of extinction.

Reports on the survey and the analysis are available online.

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