Conserving the Nature of America

News Release

Sea Otters Decline Throughout the Aleutian Islands in Alaska

June 29, 2000


Division of Public Affairs
External Affairs
Telephone: 703-358-2220

The U. S. Fish and Wildlife Service (Service) recently surveyed sea otters in the Aleutian Islands and confirmed that the population has declined dramatically. The sea otter population in the Aleutians has declined 70% since 1992, and 95% or more throughout much of the Archipelago since the 1980s. An estimated 6,000 sea otters remain in the Aleutian Islands today.

Historically, sea otters were abundant throughout the coastal regions of the north Pacific Ocean from northern Japan to Baja California, Mexico. Extensive commercial harvests of sea otters for fur began in the mid-1700s and continued until the sea otter population was at the brink of extinction. In 1911, the International Fur Seal Treaty provided protection from further commercial harvest to the isolated remnant populations of sea otters.

In the Aleutian Islands, which form the boundary between the Bering Sea and the north Pacific Ocean, two small sea otter populations were known to have survived the commercial harvests for fur. The remnant population of sea otters in the Aleutian Islands began to grow and reoccupy their former range. The first systematic aerial surveys of sea otters in the Aleutian Islands were conducted by the Service during 1959-1965. Sea otters were thriving and the greatest concentration in the world was located in the central Aleutian Islands. In the 1980s the Alaska Department of Fish and Game estimated there were from 55,000 to 100,000 sea otters in the Aleutian Islands.

Nearly three decades had passed before the entire Archipelago was again surveyed by aircraft in 1992. Within the 27 year interim, the population grew and the range expanded to include the eastern and western most islands, which had contained few, if any, sea otters in the early 1960s. In the central Aleutians however, the sea otter counts of several islands declined by over 50% and, in a few cases, the decline was as high as 90%. The 1992 overall population of 19,104 sea otters concerned biologists because it was far below what they expected for the Aleutian Islands. During the 1990s, severe local declines in sea otter abundance were documented in portions of the central Aleutians by the U.S. Geological Survey (USGS). The recent findings from our aerial sea otter survey in spring of 2000 confirm the widespread nature of these declines. The areas most severely affected are those islands located in the central Aleutians.

Population studies of sea otters conducted in the Aleutian Islands over the past several decades demonstrate that the declines are likely a result of increased adult mortality. A recent increase of interactions between sea otters and killer whales indicates predation may be a leading cause of the observed population decline. In the Aleutians, Native subsistence harvest of sea otters has and continues to be intermittent and localized occurring at very low levels and therefore is an inconsequential source of mortality.

The Service will take the following steps to determine the full range of the sea otter decline in the Bering Sea and western Alaska. The Service will be expanding survey efforts to include the Alaska Peninsula and Kodiak Archipelago and has joined the World Wildlife Fund in supporting surveys of the Commander Islands in Russia to determine the geographic extent of the decline. The Service will continue to support annual surveys to document population trends of select islands of the Aleutians; these surveys will be conducted by USGS and the Alaska Sea Otter and Steller Sea Lion Commission (TASSC), in conjunction with local tribes. Through a cooperative effort, the Service, TASSC, and USGS are evaluating the genetic discreteness of sea otter populations within Alaska. An international meeting of scientists will be held this fall to share and review recent data pertaining to the population status of sea otters in the United States and Russia. A final report of the Aleutian aerial survey results is scheduled to be available in the fall of 2000.

The U.S. Fish and Wildlife Service is the principal Federal agency responsible for conserving, protecting and enhancing fish, wildlife and plants and their habitats for the continuing benefit of the American people. The Service manages the 93-million-acre National Wildlife Refuge System which encompasses more than 520 national wildlife refuges, thousands of small wetlands and other special management areas. It also operates 66 national fish hatcheries, 64 fishery resource offices and 78 ecological services field stations. The agency enforces Federal wildlife laws, administers the Endangered Species Act, manages migratory bird populations, restores nationally significant fisheries, conserves and restores wildlife habitat such as wetlands, and helps foreign governments with their conservation efforts. It also oversees the Federal Aid program that distributes hundreds of millions of dollars in excise taxes on fishing and hunting equipment to state fish and wildlife agencies.

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