Federal wildlife officials are considering deadly measures to keep an Alaska big game animal introduced more than 50 years ago to a remote island in the Aleutians from expanding its range.

The U.S. Fish and Wildlife Service is proposing that caribou swimming from Adak (AY'-dak) Island to Kagalaska (kag-ah-LAS'-kah) Island be killed to prevent a new herd from being established.

Adak Island is 1,300 miles southwest of Anchorage. Caribou were transplanted onto Adak in 1958 to provide sport-hunting for military personnel assigned to a remote naval base formerly located there.

Kagalaska Island is part of the Alaska Maritime National Wildlife Refuge and a short swim away from Adak.

Refuge manager Steve Delehanty (del-ah-HAHN'-tee) says Kagalaska is a wilderness area and caribou would change its vegetation and natural diversity.