New estimate for Cook Inlet belugas shows hope for endangered population

By Yereth Rosen, Alaska Beacon June 19, 2023
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A gray beluga whale calf and three adults swim together in Cook Inlet. A newly released population estimate shows signs of recovery, or at least stablization, among the endangered whales. The unprecedented marine heatwave known as The Blob is believed to have taken a toll, but the population has increased since that heatwave dissipated. (Photo by Paul Wade/NOAA Alaska Fisheries Science Center)

The number of endangered beluga whales swimming in Alaska’s Cook Inlet increased slightly in the past four years, providing “a glimmer of hope” for a population that crashed in the 1990s and remained at a low number long after that, according to a new estimate released on Thursday by federal biologists.

The latest population estimate for endangered Cook Inlet belugas is between 290 and 386, with a median estimate of 311, the National Oceanic and Atmospheric Administration said. That compares to NOAA’s’ Alaska Fisheries Science Center 2018 median estimate of 279 and a range of 250 to 317 animals.

The new population estimate is based on aerial surveys conducted in the summers of 2021 and 2022.

In a NOAA Fisheries statement, one of the biologists who compiled the new estimate expressed tempered optimism.

An educational sign about endangered Cook Inlet belugas. is seen on March 7 at the small boat launch Anchorage's Port of Alaska. The sign was designed and erected to raise public awareness, part of a wide-ranging strategy to help the endangered whales recover. Cook Inlet belugas' habitat overlaps with a lot of human uses, including those at the port. (Photo by Yereth Rosen/Alaska Beacon)
An educational sign about endangered Cook Inlet belugas is seen on March 7 at the small boat launch Anchorage’s Port of Alaska. The sign was designed and erected to raise public awareness, part of a wide-ranging strategy to help the endangered whales recover. Cook Inlet belugas’ habitat overlaps with a lot of human uses, including those at the port. (Photo by Yereth Rosen/Alaska Beacon)

“While this is certainly encouraging news, it is important to recognize that abundance estimates can vary from year to year due to a number of factors,” Kim Goetz, an Alaska Fisheries Science Center marine mammal biologist listed as the lead author of Thursday’s report, said in the statement.

Cook Inlet belugas numbered about 1,300 in 1979, according to NOAA. The steep decline that started in the 1990s was blamed on overhunting, but even after Indigenous subsistence hunting ceased, the population continued to decline. In 2008, Cook Inlet belugas were listed as endangered.

Now, a slight upturn of less than 1% a year appears to have been happening for at least a few years, according to the new population estimate.

Recent analysis of the past two decades shows that there was likely a steady increase in Cook Inlet beluga numbers from 2004 to 2010, but the population dropped over the next eight years before increasing again.

While the reasons for the 2010-2018 decline are yet unknown, the report said, a likely suspect has emerged: the sustained and unprecedented northeast Pacific marine heatwave that disrupted fish stocks and triggered die-offs in various wild populations.

Informational sign at Anchorage's Earthquake Park, seen on Jan. 27, describes the belugas and salmon found in Cook Inlet. Salmon make up much of the belugas' diet, so the endangered whales suffer when runs are poor. (Photo by Yereth Rosen/Alaska Beacon)
Informational sign at Anchorage’s Earthquake Park, seen on Jan. 27, describes the belugas and salmon found in Cook Inlet. Salmon make up much of the belugas’ diet, so the endangered whales suffer when runs are poor. (Photo by Yereth Rosen/Alaska Beacon)

Among the cascading effects of that heatwave, which became known as The Blob, were a near-total loss in the northern Gulf of Alaska of capelin, an important and oil-rich forage fish; mass die-offs of birds, including Alaska’s biggest die-off of common murres on record; a die-off of large whales; and a sharp decline in Pacific cod, which triggered some Gulf of Alaska commercial harvest closures. Cod are also important to Cook Inlet belugas, the report noted.

There may have also been overlapping human-caused problems for the belugas during the period of decline, said the report. Nonetheless, the increase in abundance since 2018 shows signs that the population is slowly growing or at least stable, the report said.

Cook Inlet belugas live in Alaska’s most populous and developed region. Scientists say they face a myriad of threats and potential disturbances from forces like climate change, habitat degradation, pollution, industrial noise and ship traffic in Alaska.

At the same time, they have also been the subject of numerous conservation and protection efforts. A task force with representatives from multiple government agencies, businesses, academia and other organizations has been guiding recovery work.

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