ANCHORAGE, Alaska – In the 1970s, there used to be about 1,300 beluga whales in Cook Inlet, delighting locals and tourists alike. Last year, the number was estimated at just 278.
Why their numbers are dwindling has scientists puzzled — and scared. The National Marine Fisheries Service is embarking on a status review to determine if the belugas need the protection of the federal Endangered Species Act.
A listing was rejected in 2000 because then it was believed that overharvesting was to blame. Seven years of strict limits on hunting have proved that theory wrong, said Lloyd Lowry, a professor of marine mammals with the University of Alaska Fairbanks.
"There is something else going on," he said Monday.
The status review will look at possible reasons for the decline. That includes changes in habitat, such as noise from shipping, recreational boating and pile driving. The noise could be interfering with the whales' ability to locate each other and find food.
Scientists also will look at development around the inlet, including the expansion of the Port of Anchorage. Waste discharges from the municipality will be considered, as well as the impact of oil and gas development.
"There are a lot of things we are looking at," said Brad Smith, a biologist with the National Marine Fisheries Service. But so far, he said, nothing jumps out as a likely cause.
"There is no smoking gun," he said.
The fisheries service recently set a harvest limit of eight whales through 2009, alternating a harvest of one and two whales a year. Only Alaska Native subsistence hunters are allowed to kill the whales.
The harvest now is set so low that the population should be growing 2 percent to 4 percent a year, but it's not, Lowry said.
"This population, according to pretty good survey data, is not growing at all," he said.
One cataclysmic event — a large stranding in the inlet's 20-foot tides, perhaps, or an oil spill or tsunami — could push the remaining whale population over the edge, said Lowry.
"Having a small population for a long time is very risky," he said. "If the decline continues we are going to get to very critically low numbers soon."
In contrast to the isolated belugas whales of Cook Inlet, belugas overall are thriving in Alaska, with at least 35,000 to 40,000 animals in four Arctic stocks.
Smith said the status review will be expanded this time. It will include a prediction at what point the inlet whales — considered a genetically distinct population — could go extinct. The last review was done about a decade ago and the data shows the decline.
"It certainly does not look encouraging," Smith said.