ANCHORAGE, Alaska (AP) -- Sea otters used to frolic and feed in reefs near Cold Bay just off the western end of the Alaska Peninsula.
''That place used to be lousy with sea otters,'' said Douglas Burn, a U.S. Fish and Wildlife Service biologist with the sea otter program in Anchorage. ''To not see them there, clearly something is wrong.''
The sea otters of Southwest Alaska could be ''circling the drain,'' Burn said Wednesday.
The ''why'' remains largely a mystery to biologists who are alarmed at recent aerial surveys that show a dramatic decline in sea otters in a huge area along Alaska's coastline.
They already knew that sea otters in the 1,000-mile-long Aleutian Island chain -- extending from the Alaska Peninsula -- had declined by about 70 percent.
New aerial surveys done in 2000 and 2001 to parallel a study done in 1986 have set off more alarm bells. They show that densities are low in the six major island groups of Southwest Alaska, said Angela Doroff, another biologist in the sea otter program.
Between 1986 and 2000, sea otters in the northern Alaska Peninsula declined between 36 percent and 56 percent to 5,756 animals. The decline was even more startling in the southern Alaska Peninsula where numbers between 1986 and 2001 declined between 91 percent and 92 percent to just 1,844 sea otters.
Between 1994 and 2001, sea otters in the Kodiak archipelago declined 40 percent to 5,893 animals.
''We have no evidence that the decline is stopping,'' said Rosa Meehan, head of Fish and Wildlife's marine mammal program in Anchorage. ''We had a red flag before. We have a much bigger red flag now.''
Estimates put the number of sea otters in Alaska at about 74,000 -- down from approximately 100,000 in the mid-1980s. About 90 percent of the world's sea otters live in coastal Alaska waters.
While sea otters in Southwest are declining sharply, populations in Southeast and Southcentral appear to be either stable or increasing.
Biologists are considering a number of possible factors, including starvation, disease and contamination. But predation by killer whales is the best guess, in part because biologists are finding so few carcasses.
''Something is taking them out,'' Burn said.
Killer whales may be going after sea otters because there are fewer Steller sea lions to hunt, said Marilyn Dahlheim, a biologist with the National Marine Mammal Laboratory in Seattle, which is conducting a three-year study to count killer whales in an area of Southwest Alaska.
During a six-week trip in July and August, biologists spotted 15 or 16 groups of killer whales. In 1992 and 1993, 12 groups of whales were spotted each year during similar trips.
''We really don't have a good handle on population size,'' Dahlheim said.
Scientists are taking skin samples to determine which whales are resident and which are transient. Resident whales feed primarily on fish, while transients feed on marine mammals.
Other factors could be at work as well, Meehan said. Scientists are also looking at recent climate changes, such as El Nino.
Biologists will be taking a close look at the few places in Southwest Alaska where sea otters are now concentrated, including sheltered areas on the north and south sides of Adak Island.
Alaska's sea otters are capable of making dramatic comebacks. They were hunted nearly to extinction at the turn of the century with numbers in the United States and Russia dwindling to about 2,000 before commercial hunting was banned in 1911.
Fish and Wildlife biologists in Anchorage want to include all of Southwest Alaska's sea otters as a candidate species for protection under the federal Endangered Species Act, Meehan said.
The decline of sea otters is part of a bigger problem, Burn said. It is more evidence -- along with declines in sea lions and spectacled eiders -- that the Bering Sea ecosystem is ''out of whack.''
On the Web:http://alaska.fws.gov/ea/sotter/index.html.
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