Numbers Drop for Cook Inlet Belugas
Anthony Madden
Katharine Bear Nalven
The pressing need to protect Cook Inlet belugas—our charismatic canaries of the sea up here in Alaska—just became a lot more urgent. The latest abundance survey based on improved survey methods estimated just 279 whales, down from 328 in 2016. The situation is dire and the window of opportunity to save these belugas is closing fast.
The original beluga decline likely resulted from multiple forms of unregulated hunting, which was suspended in 2005. This would explain the slight upward population trend observed until 2010. But in the decade since, the population has continued to decrease. The exact reason remains puzzling. What is known is that the belugas face a host of threats.
Cook Inlet lies off Anchorage, Alaska's largest city, and that means the belugas are exposed to vessel traffic and noise pollution, habitat degradation and contaminants from construction and offshore drilling activities and food limitations. Climate change is also rapidly changing their habitat. But addressing these threats is difficult because scientists do not know how much each threat impacts beluga recovery.
While it would be easy to assume that 49 belugas were lost between counts, the details about this new number aren't as simple as it might seem at first glance. Counting whales in the inlet also isn't easy—imagine counting kids at a pool party, some are underwater, some are in different parts of the pool, some are arriving late to the party, others are leaving, and they are all constantly changing positions.
Laura Morse/NOAA
To make the estimates more accurate, scientists from the National Oceanic and Atmospheric Administration (NOAA), the federal agency tasked with managing this imperiled population, recently changed the way they statistically analyze the data used to count the whales.
In for the Count
NOAA Fisheries
Racetrack flight pattern for counting Cook Inlet Belugas. (NOAA Fisheries AFSC Processed Report 2019-09, Aerial Surveys, Distribution, Abundance, and Trend of Belugas in Cook Inlet, Alaska.)
To count belugas, a team of researchers, composed of two observers and a data recorder, fly a small twin-engine plane over the Cook Inlet. When they spot a group of belugas, the plane circles in a "racetrack" pattern to obtain multiple counts. One observer visually counts the whales and the other records a video.
The data is then statically analyzed to create the abundance estimate for the year, with the video data processed in a program able to correct for situations such as submerged belugas or belugas hidden from view by another beluga. Prior to 2018, scientists statistically analyzed the video data using the mean value of belugas counted. But because outliers can throw off the mean, the median is now used for all acceptable survey days.
Looking back at data and observations made between 2004-2016, the scientists observed that even though population estimates would have been different using the new method, the overall trend observed in the Cook Inlet population remains the same: The population is currently predicted to continue to decline at a rate of 2.3% each year.
Defenders of Wildlife
Defenders is working with agency, non-profit and tribal partners to ensure Cook Inlet belugas get the chance they deserve to recover. With this new sense of urgency, we are forced to think outside the box with more innovative ways to try and solve the mystery of our disappearing belugas. Defenders is here to help usher in this new age of incorporating all types of knowledge, in hopes of bringing these remarkable whales back from the brink of extinction.
The time to ensure protections for this incredible whale is now.
Representative, Alaska
Katy works to protect Alaskan wildlife as Defenders' Alaska Representative.
Wildlife & Wild Places