Geographic boundaries of Puget Sound and the Salish Sea

Environmental reporter Christopher Dunagan remembers the life and influence of pioneering orca researcher Ken Balcomb.  

Use our interactive map to determine if a geographic feature is within the boundaries of the Puget Sound or Salish Sea watersheds. The Puget Sound region includes the area within the United States while the Salish Sea region* encompasses the entire shaded area. Areas that influence circulation in the Salish Sea or eventually drain into the estuary are marked by broader boundaries.

The Salish Sea Model is a computer model used to predict spatial and temporal patterns related to water circulation in the Salish Sea. It was developed at the United States Department of Energy's Pacific Northwest National Laboratory with funding from the Environmental Protection Agency. It is housed at the University of Washington Center for Urban Waters which is affiliated with the Encyclopedia of Puget Sound.  

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 (see map).

The name Salish Sea was proposed by Bert Webber in 1989 to reflect the entire cross-border ecosystem. Both Washington State and British Columbia voted to officially recognize the name in late 2009. The name honors the Coast Salish people, who were the first to live in the region.

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. 

Where do Protection Island's rhinoceros auklets go to find their food? Scientists hope GPS tags will offer new insight into the bird's still mysterious foraging behavior. Biologist and science writer Eric Wagner reports from the field. 

Research on the sounds and feeding behavior of Puget Sound's southern resident orcas is providing new insight into how the whales respond to underwater noise. A recent online conference brought together some of these findings along with discussions on how to reduce the impacts of noise from vessel traffic.

A series of beluga whale (Delphinapterus leucas) sightings in southern Puget Sound in October 2021, added a new set of records for the species in this region. The 2021 event represents the longest period of time a beluga has been observed so far south of Alaska, in the eastern North Pacific. This may have just been an isolated event of a single extralimital individual. Alternatively, it may suggest a potential range expansion that could portend future increased visits by this species in the Pacific Northwest, especially if warming of Arctic waters continues.

The marine heat wave that struck the Pacific Ocean in late 2013 also caused large changes in temperature in the Salish Sea, but scientists are still puzzling over the impacts of those changes on Puget Sound's food web. The so-called "blob" of warmer than average water was thought to have increased the production of plankton, which potentially benefits creatures like herring and salmon that feed on the tiny organisms. A new paper in the journal Frontiers in Marine Science calls that interpretation into question, pointing to a computer model that links the cause to higher-than-normal river flows in the region.   

Social Science for the Salish Sea (S4) provides a foundation for future research projects, accessible information for planning or management decisions, and synthesized content to inform ecosystem recovery.

An article published in the journal Society & Natural Resources in 2021 describes the results of a geographic literacy survey which shows residents of Washington and British Columbia are largely unfamiliar with the name Salish Sea. The authors discuss the implications of their findings for ecosystem recovery of the region.

An article published in the Journal of Avian Medicine and Surgery in 2021 describes the results of study comparing the effects of season, location, species, and sex on body weight and blood chemistry for free-ranging western and Clark's grebes.

A resident population of minke whales is catching the attention of scientists who want to learn if the elusive mammals are found here year-round. While small compared to their cousins the blue whales, minkes are still among the largest creatures in the Salish Sea.

A 2021 article in the journal JGR Oceans describes circulation and mixing in the Salish Sea. The findings are based on simulations produced by the LiveOcean computer model.

A river spawning species of forage fish known as the longfin smelt is rare and getting rarer in the Salish Sea. Biologists are looking into the mysterious decline of the ‘hooligans’ of the Nooksack.

Years after the appearance of the devastating marine heat wave known as "the blob," scientists are still working to understand how it has affected the Salish Sea. In some ways, they say, it is like the blob never left.

The Salish Sea’s endangered southern resident orcas travel freely across the U.S.-Canada border, unconstrained by political boundaries. But while they don’t require passports, they can still face differing policies and conditions as they go back and forth between nations. We look at some of the ways that the United States and Canada compare in their efforts to protect the whales.

The revival of an Indigenous aquaculture practice has come to the southern Salish Sea. Clam gardens could help First Nations in British Columbia and Washington state address issues of climate change and food sustainability. 

Scientists are using computer models to address complex issues in the Salish Sea like the rise of harmful algal blooms and the movement of toxic PCBs. LiveOcean, Atlantis and the Salish Sea Model are three systems that are changing the game for ecologists and other researchers.

Harbor porpoises declined dramatically in the Salish Sea in the 1970s but their populations have since rebounded, increasing by more than 10% per year in recent decades. A 2020 report for the Encyclopedia of Puget Sound examines harbor porpoise status and trends, natural history and recent policy considerations for the species.

Officially known as West Coast transients but increasingly referred to as Bigg’s killer whales, these marine mammal-eating orcas (Orcinus orca) are spending increasing time in the Salish Sea to consume their marine mammal prey including harbor seals, Steller sea lions, and harbor and Dall’s porpoise. They range from Southeast Alaska to California, but over the last 15 years more members of the population are spending increasing time in the inland waters of Washington State and British Columbia (Houghton et al. 2015, Shields et al. 2018). They have no predators (except perhaps occasionally other Bigg’s killer whales - see Towers et al. 2018), but are at risk from anthropogenic effects, including toxics and noise pollution (Ford et al. 2007).

The first comprehensive guide to the fishes of the Salish Sea is the culmination of more than 40 years of research by University of Washington authors Ted Pietsch and Jay Orr. The new three-volume set includes descriptions and illustrations for every fish species known to have been documented within the Salish Sea, all gathered from an exhaustive search of libraries, aquariums, fish collections and even one restaurant.

A new video series follows local scientists into the water, capturing the adventure behind the research. "Salish Sea Wild" is entering its second season and we interviewed the series host and producers. Among our burning questions: What's it like to have a Steller sea lion chew on your head? 

Washington and British Columbia residents are largely unfamiliar with the Salish Sea. A recent study conducted by the SeaDoc Society and Oregon State University reveals a need to improve geographic literacy and familiarity with the Salish Sea among those communities who share and live alongside this integrated transboundary ecosystem. This summary was provided by two of the collaborators on the survey, David Trimbach of Oregon State University and Joe Gaydos, Science Director at the SeaDoc Society.

A 2019 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. 

Kids around the region are learning about the Salish Sea thanks to a new book that is being offered — in many cases free of cost — to Washington schools and libraries. Explore the Salish Sea by Joe Gaydos and Audrey Benedict inspires the next generation to appreciate and perhaps someday protect the environment close at hand. 

A 2017 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. 

A scientific assessment of current status and future trends in resource abundance and environmental quality in the Strait of Juan de Fuca, Strait of Georgia, and Puget Sound 

The Salish Sea: Jewel of the Pacific Northwest brings together more than 230 extraordinary images of the Salish Sea. But don't call it a coffee table book. Its lush photos are backed by a serious scientific perspective on this complex and fragile ecosystem.