ABSTRACT
Two species of sea lions inhabit the waters along the west coast of North America. The most abundant, the northern or Steller sea lion, ranges from California northward to Alaska with greatest numbers in Alaskan waters. From late May into July, the northern sea lion hauls out on rocky beaches of islands and isolated headlands primarily to give birth and mate. Generally, in September, sea lions return to land and haul out to molt. Nonbreeding males feed during the breeding season, as do parturient females to maintain lactation. A second species, the California sea lion, inhabits the waters from Mexico northward to Canada. Adult males generally migrate northward, and females remain near their breeding island or migrate southward after the breeding season. Sea lions can best be counted and minimum census or population estimates made by aerial surveys during the breeding and molting season.
