Scientists from NOAA’s Alaska Fisheries Science Center today announced that the 2014 abundance estimate for the endangered Cook Inlet beluga whale population is 340 animals, a slight increase over the 2012 survey when the population was estimated at 312 whales.
“To determine whether a population is recovering or declining, the small changes from survey to survey don’t tell us as much as the trend over a period of 10 to 20 years,” said Rod Hobbs, a population biologist with the Cetacean Assessment and Ecology Program at the Alaska Fisheries Science Center. “Estimates can vary from year to year based on weather, oceanographic conditions, changes in beluga behavior or distribution and statistical variability in the data.”
The population estimates have been as low as 278 whales and as high as 375 during the past decade. The overall population trend for the past 10 years for Cook Inlet beluga whales shows them not recovering and still in decline at an annual average rate of 0.4 percent, indicating these whales are still in danger of extinction in the foreseeable future.
For over two decades, scientists with NOAA’s Alaska Fisheries Science Center have been conducting aerial surveys of Cook Inlet. From a small airplane, scientists look for and count beluga whales and make video recordings of the whale groups. The video and observer counts are analyzed to produce a broad-scale picture of the whales’ distribution and abundance in the inlet in early June.
In Cook Inlet, belugas concentrate near river mouths or shallow tidal bays during late spring and early summer in the northernmost reaches of the inlet. It is likely that the whales gather in these areas to feed on migrating fish, particularly eulachon and several species of Pacific salmon.
Reports on the survey and the analysis (PDF, 63 pages)
The Cook Inlet beluga whale, one of five beluga populations recognized within U.S. waters, was listed as endangered under the Endangered Species Act in 2008. NOAA designated critical habitat for the population in April 2011. NOAA is currently developing a recovery plan for Cook Inlet beluga whales, and continues to fund research on this population.