Steller sea lions in far western Alaska continue to do a disappearing act, with already distressed numbers slipping further in some areas, according to a federal survey.
"Clearly we are seeing steep declines still way out west in the western Aleutians," said Lowell Fritz, a biologist at the National Marine Mammal Laboratory in Seattle.
For instance, only 43 sea lions were counted this summer at Buldir Island at the end of the Aleutians, half the number of four years ago. In the 1980s, thousands were spotted, he said.
Fritz said Wednesday the western population stretching from Yakutat to the far western Aleutian Islands is "hanging in."
The National Marine Fisheries Service conducted its aerial survey _ the first complete survey since 2004 _ over a two-day period in June when adult and juvenile sea lions are most likely to be onshore to give birth and breed.
The survey found that Steller sea lion numbers in the western population are either stable or declining slightly. The eastern population continues to increase.
The survey found the biggest declines were in the central and western Aleutians, where populations declined 30 percent and 16 percent respectively.
The western population is now thought to be about 45,000, down from perhaps 250,000 in the late 1960s and early 1970s. The population was listed as endangered in 1997.
The eastern population, which extends from Alaska's Cape Saint Elias into California, now stands at between 45,000 and 51,000 animals. The population was declared threatened in 1990. It has more than doubled.
Most of the world's sea lions live along Alaska's vast coastline. There are believed to be about 16,000 across the Bering Sea off Russia's coast.
About $160 million has been spent on Steller sea lion research in recent years with the goal of stopping the declines. While scientists do not know why sea lions in some areas of Alaska are in trouble, certain things have become less plausible, Fritz said. Those things include killer whale attacks, disease and contaminants, he said.
What scientists have determined is that the number of sea lions being born appears to be down. "Something is preventing them from getting born," he said.
