Range Extent CommentsCoastal North Pacific, Mazatlan and Baja California to Vancouver Island (males in fall and winter); breeds on San Miguel, San Nicolas, Santa Barbara, and San Clemente islands in southern California; largest breeding colony is on San Miguel Island; a few pups are born occasionally at South Farallon and Ano Nuevo islands off central California; in Mexico, breeds on the Coronados, Guadalupe, San Martin, Cedros, and San Benito islands off the Pacific coast of Baja California, and there are many smaller colonies on islands in the Gulf of California (Keith et al. 1984, Reeves et al. 1992). Galapagos and eastern Asian populations, sometimes included in this species, are now regarded as distinct species.
Threat Impact CommentsIn the early 1980s, as many as 1500/year may have died as a result of entanglement in gill nets or from being shot by commercial fishermen; such mortality continues at an unknown rate. In the late 1960s and early 1970s, premature births were observed in California, evidently the result of DDT and PCB contamination and viral and bacterial infections (Reeves et al. 1992).