The Salish Sea extends across the U.S.-Canada border, and includes the combined waters of the Strait of Georgia, the Strait of Juan de Fuca, Puget Sound Basin and the San Juan Islands.
The boundaries of Puget Sound and the Salish Sea are not always consistently defined by scientists and government agencies. This article clarifies the distinctions between oceanographic and watershed-based definitions of these geographic areas.
Northern elephant seals were hunted heavily in the 19th century and believed to be extinct by 1892. However, a small remnant population (~50–100 animals) off the western coast of Mexico grew to populations in the United States and Mexico to at least 220,000 individuals as of 2010. Elephant seals are distributed in the central and eastern North Pacific Ocean, from as far north as Alaska down to southern Baja California. Sightings of elephant seals were once considered rare in the Salish Sea, but increasingly single individuals are known to haul out onto sandy beaches on Smith, Protection, and Whidbey Islands. In 2010, a local breeding population established itself along the lower west side of Whidbey Island in Puget Sound.
Harbor seals were hunted from the 1870s to 1970s until they were protected in the United States by the 1972 Marine Mammal Protection Act and in Canada under the 1970 Marine Mammal Regulations in the Fisheries Act. The inland Washington harbor seal stock is estimated to be over 12,000, while the Strait of Georgia sustains approximately 39,000 harbor seals. Key threats include human disturbance, habitat degradation, loss of prey, and interaction with fishing gear and boats.
Steller sea lions use Puget Sound as a feeding area from autumn through spring when they are not breeding in British Columbia and Alaska during summer. While the Western Stock of the species is considered Endangered under the US Endangered Species Act (ESA), the Eastern Stock, which occurs in Puget Sound, is increasing in numbers and not listed under the ESA.
California sea lions have become common in Puget Sound in non-summer months. The overall trend for the population has been a dramatic increase in numbers since the species was protected in 1972. They are opportunistic feeders that often target herring and juvenile salmon and steelhead species in Puget Sound.
A 2023 report from the Puget Sound Ecosystem Monitoring Program presents an overview of selected recent monitoring and research activities focused on toxic contaminants in the Salish Sea.
