By Jim Magowan
Turnagain Times Correspondent
The National Oceanic and Atmospheric Administration announced this month that the most recent count of the endangered Cook Inlet beluga whale population is estimated to be 321, down from last year's estimate of 375.
The decline of 54 whales is alarming to scientists.
The Cook Inlet beluga is a unique and isolated sub species of the five beluga whale stocks that live in Alaska waters.
The Cook Inlet whales' habitat includes Knik Arm and Turnagain Arm–feeding grounds that provide the whales with a critical food supply. Summer salmon is the beluga's primary source of nutrition that sustains them through the winter months.
The current estimate of the number of Cook Inlet belugas is believed to be within 18 percent of the actual number of whales.
The good news is that the population could be as high as 456. The bad news is it could be as low as 226, and, regardless of the actual number of whales, National Marine Fisheries Service biologists are convinced that there is a downward trend in whale numbers.
An aerial count of Cook Inlet belugas was conducted by NOAA in June.
A female, stranded in July, led NMFS to initiate a follow up count of “grays,”(juveniles) in August and this has been done for the past five years.
“Paired cameras are used, one shooting wide angle views and one zooming in, to see more detail,” said Barbara Mahoney, a beluga specialist with the National Marine Fisheries Service (the NOAA agency involved in beluga studies).
“Gray belugas are hard to see from the air and are better identified in the photographs,” she said. “The babies swim close to their mothers and are difficult to see. By identifying a particular ‘white' or adult whale in a group and zooming in it is often possible to see a baby swimming close to it.”
“Other complicating factors in counting whales,” Mahoney added, “are that some whales do not surface as often as others and when they travel in large groups it is more difficult to get an accurate count.”
In many wild populations it is relatively easy for researchers to estimate the number of young because there is usually a constant ratio of young to mature animals.
However, this is not the case with beluga. The ratio of young to mature animals seems to fluctuate too much to use adult numbers as an index of the number of young.
With data indicating a declining population, agencies are going to try to reverse the trend by reducing other factors that may be contributing to the population decline.
Pollution and habitat loss are being studied. Habitat loss can have a direct impact on the Cook Inlet belugas by physically altering the habitat making it unusable by the whales.
Mahoney said other factors like noise in Cook Inlet and killer whale predation of beluga calves may have an impact.
Noise could deter the whales from using critical habitat, and killer whales may decrease calve numbers, but Mahoney said there is no direct data supporting that theory.
In the late ‘70s and early ‘80s, biologists were shocked to find that grizzly predation on newborn moose calves, not wolf predation, was primarily responsible for moose population decline.
Is it possible that killer whales could be serious predators on beluga calves? Is it possible that disease is a factor, and could there be an epidemic among Cook Inlet belugas? These are questions beluga researchers are trying to answer.
Natural hazards in the shallow waters of Turnagain and Knik Arm can also pose life-threatening situations for the beluga.
On Oct. 9, Mahoney responded to a call reporting a dead pregnant female beluga on the Knik Arm mud flats, near the Coastal Trail. As of this writing the cause of death had not been determined.
The National Marine Fisheries Service is expected to issue a critical habitat proposal this month. As part of the proposal, Turnagain Arm is considered an important feeding area for the Cook Inlet beluga and will likely be designated an area of critical habitat.
The designation will mean that any activity that may affect the beluga's habitat must be reviewed and approved by NMFS.
“There is not much activity in Turnagain Arm that might affect critical habitat,” said Mahoney. “There is some proposed mining in the Hope area on Resurrection Creek that might require review.”
Critical habitat designation may also influence future decisions by the Department of Transportation for Seward Highway construction projects. Highway construction could raise issues of pollution and noise in Turnagain Arm from blasting that could affect the whales.
The agency reviewed the Cook Inlet beluga population in 2000 and determined that a listing under the Endangered Species Act was not warranted. Instead, the whale was designated as depleted under the Marine Mammal Protection Act at that time.
But in October 2008, the NFMS listed the Cook Inlet beluga as “endangered” under the Endangered Species Act.
A significant factor in the Cook Inlet belugas decline, studies concluded, was native subsistent hunting of the whales. The harvesting of belugas is believed to be a leading factor in the dramatic decline of the beluga population.
In 1999 unregulated hunting of Cook Inlet belugas was stopped, but that did not cease the population decline, which reached an all time low of 278 in 2005. Between 1999 and 2006 five beluga whales were taken for subsistence in Cook Inlet.
In the 1980s, the population of Cook Inlet belugas was estimated at 1,300. The population was nearly cut in half in 1994 to 653 and four years later in 1998 was nearly cut in half again to 347 whales.
The recent drop in population numbers of the Cook Inlet belugas is a clear indication to scientists that they are in a rush with time.
Determining the causes of the whales' decline is critical for protective measures to be implemented in order to save the belugas from extinction.
Ken Smith contributed to this article.
