|Editions | myCNN | Video | Audio | Headline News Brief | Feedback||
Aleutian otters take a nosedive
The number of sea otters in Alaska's Aleutian Islands has plummeted since the early 1990s, a recent survey by the U.S. Fish and Wildlife Service reveals.
The sea otter population in the area has declined 70 percent since 1992 and 95 percent or more throughout much of the archipelago since the 1980s.
The biologists surveyed 78 of the islands using a twin-engine aircraft.
"We have known for some time that populations of sea otters were declining in certain areas of the Aleutians" said Jim Estes, a scientist with the Western Ecological Research Center in Santa Cruz, California. "The survey chronicled the geographic extent of that decline. Prior to that, we only had spot surveys."
Historically, sea otters were abundant throughout the coastal regions of the north Pacific Ocean. Extensive commercial harvesting for the otter's teddy bear skin brought them to the brink of extinction at the turn of the century.
In 1911, the International Fur Seal Treaty gave the remaining isolated populations of sea otters protection from further commercial harvest.
Following the treaty, otters made a successful comeback in the Aleutian Islands. By the 1960s the Aleutians harbored the world's greatest concentration of sea otters. A survey conducted in the 1980s by the Alaska Department of Fish and Game estimated that there were 55,000 to 100,000 sea otters in the area.
That number has declined dramatically to only 6,000 otters, according to the recent survey. The cause of the decline is a subject of controversy.
"This is another indication that the Berring Sea ecosystem is undergoing immense changes," Estes said.
Many biologists suspect that the ground-fishing industry may be indirectly responsible for the otters' decline.
Ground fisheries have removed vast amounts of fish from the ecosystem, Estes said. Seals and sea lions are suffering from that.
In the absence of their traditional food source of Stellar sea lions and harbor seals in western Alaska waters, killer whales have been preying on an increasing number of otters, Estes concluded in a 1998 study.
Previous work over the past several decades reveals that the otters are dying in the water, explains wildlife biologist Douglas Burn. "If it was disease or starvation, you would expect to see a lot of dead otters on the beach. It is likely that the otters are being preyed upon at sea."
Estes calculated that a killer whale on a steady diet of sea otters could consume as many as 1,825 otters in a year. "It wouldn't take a remarkable number of whales to have an impact on the sea otter population," he said.
"Our recent data will lead the Fish and Wildlife Service to consider a need for listing the otters under the Endangered Species Act" Estes said. "No other marine mammal has declined as precipitously."
Analysis: The debate over drilling in America's wildest refuge
RELATED ENN STORIES:
California sea otters not down for the count
|Back to the top||
© 2001 Cable News Network. All Rights Reserved.|
Terms under which this service is provided to you.
Read our privacy guidelines.