ANCHORAGE - The number of endangered Steller sea lions counted between the Gulf of Alaska and the tip of the Aleutian Chain has increased again, according to new data from the National Marine Fisheries Service.
The increase is in the second in four years.
"I think we're seeing a turnaround in this Steller sea lion population," longtime federal biologist Tom Loughlin told more than 200 scientists and others at the opening session of the Sea Lions of the World conference in downtown Anchorage last week.
"There's something going on out there, and I think it's because we're seeing the very opposite of what happened in the '60s, '70s and '80s."
The western population may have increased 6 percent to 7 percent since 2002, based on counts of the sea lions at more than 250 sites conducted by a team from the Southwest Fisheries Science Center during aerial surveys in June.
That's similar to the increase reported two years ago when the fisheries service documented the first overall rise for Aleutian sea lions in nearly three decades.
Conditions along Alaska's vast coast may be shifting but it's too soon to know whether sea lions will keep the rebound going, several agency biologists said.
"Two counts in four years doesn't scientifically establish a clear population trend," said Doug DeMaster, director of the Alaska Fisheries Science Center.
"I think it's still a 'wait and see' situation," said Lowell Fritz, who oversaw the count. "Maybe we're just seeing a new lower level of stability. At the very least, I think we can say the decline has slowed if not stopped in almost all of the areas."
The number of Steller sea lions between Kodiak Island and the tip of the Aleutian Chain plunged between the 1960s and 1980s for unknown reasons. Before the rate of decline eased in the 1990s, a region that once supported more than 200,000 sea lions had bottomed out at an estimated 35,000 animals. The population was listed as endangered in 1997.
This crash has confounded scientists for two decades. No single cause has been pinpointed and theories abound.
Many scientists say a complicated series of events must be involved, beginning with a shift from an ocean dominated by small forage fish to one teeming with pollock. Some biologists have argued that the changes made it harder for young sea lions and cows in some areas to find enough nutritious food.