10,000 to >1,000,000 individuals
Comments: Estimates from the mid- to late 1980s suggested populations of 6000-7000 in the Kuril Islands, 2000-2500 in the Commander Islands, and 2500-3000 off Kamchatka, giving a total western Pacific population of 10,500-12,500 (Riedman and Estes 1990, Reeves et al. 1992). In the 1980s, the total population from Prince William Sound to the Kuril Islands was about 150,000 (Riedman 1990). For the Aleutian Islands, the minimal population estimate was 8,742 sea otters in 2000 (Doroff et al. 2003).
Alaska had 100,000-150,000 in the mid- to late 1980s (Reeves et al. 1992), and the current population probably also is in this range (USFWS 1995 stock assessment). Prince William Sound population in late 1980s was about 14,000, of which an estimated 2800 were killed as a result of the Exxon Valdez oil spill (Raloff 1993). From an original 402 individuals translocated in the 1960s, the population in southeastern Alaska increased to more than 3500 in five populations by 1987 (Reeves et al. 1992); 1988 estimate was 4520 (See Riedman and Estes 1990).
In 1984, the population off west coast of Vancouver Island, British Columbia, was 345 (descended from 89 that were translocated from Alaska, 1969-1972) (MacAskie 1986); 1987 count was 380 (see Riedman and Estes 1990). In 1995, the minimum number along the coast of British Columbia was 1522, including 135 near Goose Island (Watson et al. 1997).
Otters were transplanted from Alaska to Washington in 1969 and 1970; population increased from 36 to 94 between 1981 and 1987 (Matthews and Moseley 1990); 211 were counted in Washington in July 1989 (Jameson, in Riedman and Estes 1990, Reeves et al. 1992).
See also record for subspecies nereis of California (about 2,505 individuals in 2003).