Puget Sound ecosystem

Category: Marine and Oceanic Biomes.

Geographic Location: North America.

Summary: A marine estuary linked to the Pacific Ocean, this biome is a waterway of exceptional beauty and ecological diversity, but is threatened by pollution, shoreline degradation, and population pressures.

Located in the northwest corner of Washington State, Puget Sound is at once a tidal basin, an estuary, and an inland sea. The sound is an arm of the Pacific Ocean linked to the ebb and flow of marine tides through the Strait of Juan de Fuca and Strait of Georgia. Freshwater enters the system through 19 river basins that drain the Cascade Mountains to the east and the rugged Olympics to the west. Puget Sound is the largest marine estuary on the west coast of the United States, and second only to Chesapeake Bay nationally. Its 2,500 miles of convoluted shoreline is nearly fractal in its complexity.

From sandy bluff to pebbled beach, from saltwater marsh to freshwater estuary, the ecology of Puget Sound is as diverse as the ways in which water meets shore. Much of that shore has been altered by human development, resulting in a significant loss of habitat. Toxic chemicals and other pollutants have tainted the once pristine waters, contributing to pressure on threatened salmon populations and other marine organisms. With over 4.1 million people living along this unique inland sea, and substantial growth expected in its future, the health of the Puget Sound ecosystem will remain dependent on coordinated conservation strategies.

Today, the shores of Puget Sound are punctuated by the drone of fog horns, the whistle of trains, and the rhythmic lapping of waves—but 11,000 years ago, there was only the groan of ice as the Vashon lobe of the Fraser Glacier retreated into Canada, leaving a deep north-to-south-running trough. The waterway that filled this trough was called Whulj or Whulge, meaning the saltwater before us in the dialect of indigenous tribes collectively called the Coastal Salish.

In 1792, Peter Puget, for whom the Sound was named, served as second lieutenant to Captain George Vancouver aboard the English ship Discovery. Puget led an expedition to explore the intricate system of bays, narrows, and inlets of the sound in search of a hypothetical inland passage. In 1990, a proposal to rename Puget Sound and adjoining Canadian waters the Salish Sea was met with a mixed response. However, many of the rivers that feed into the sound honor the region’s rich Native American heritage including the Nisqually, Puyallup, Skagit, Stillaguamish, and Duwamish.

Puget Sound is a place of vistas, of broad bays, and narrow inlets, above which rise low forested hills, sprawling cityscapes, and on clear days, the snow-capped peaks of Mt. Baker, Mt. Rainier, and the Olympic Mountains. The dugout canoes of the Salish tribes have given way to kayaks, sailboats, fishing boats, tugboats, cargo ships, super tankers, submarines, and an extensive system of state-run ferries that serve local recreation, national defense, and international commerce. Beneath the surface, Puget Sound is a mixture of deep basins and higher sills—a topography as varied and complex as that of the terrestrial landscape. Depths average 450 feet (137 meters), and range from 900 feet (274 meters) near the mounded green jewels of the San Juan Islands in the north, to 300 feet (91 meters) in the muddy-bottomed inlets of the southern sound near Olympia. Twice daily, heavy tides circulate water through an intricate system of channels, passages, bays, and inlets including Budd Inlet, Nisqually Reach, The Narrows, Elliot Bay, and Deception Pass.

Biota

The ebb and flow of the tide flushes nutrients and pollutants alike over diverse habitats including subtidal, intertidal, and shoreline zones collectively called the marine near-shore. Limpets, mussels, oysters, crabs, anemones, sea stars, jellies, chitons, and tube worms are but a few of the thousands of invertebrates reliant on healthy near-shore environments. Shallow eelgrass beds, such as those of Padilla Bay, are crucial to juvenile salmon and other wildlife.

In areas with sufficient current, forests of bull-kelp, with medusa-like heads of flattened fronds, shelter a variety of Puget Sound denizens including shark, sculpin, and rockfish—which can live up to 100 years in these cold waters. The giant Pacific octopus is an elusive predator of rocky habitats here, and a favorite of recreational scuba-divers. Sandy sediments conceal flounder, English sole, and other flatfish.

Overall, the sound supports more than 200 species of fish, 100 seabird species, and 14 species of marine mammals including orcas or killer whales, endangered on the south sound. Canary and yellow-eyed rockfish were listed as threatened on Puget Sound in 2022—as are populations of steelhead, chum, and Chinook salmon; the latter is vital to tribal, recreational, and commercial fisheries, and an iconic symbol of the region.

Conservation and Threats

Puget Sound was designated an Estuary of National Significance by the U.S. Environmental Protection Agency (EPA) in 1998; however, the area is imperiled by pollutants, shoreline degradation, and a growing population. The Washington State Department of Ecology has identified 1,400 toxic clean-up sites within one-half mile (0.8 kilometer) of the sound. Bottom sediments, particularly those near urban centers like Seattle, are contaminated with oils, heavy metals, and other pollutants from decades of industrial activity. Toxic compounds have migrated through the sound’s food chain to concentrate in the tissues of high-level predators.

The EPA routinely monitors toxins found in fatty tissues in harbor seals, and tracks liver lesions in English sole. Harbor seals on Puget Sound proper are seven times more contaminated with toxic chemicals than those found in Canada’s nearby Strait of Georgia. Orca whales resident to the south sound carry more PCB (polychlorinated biphenyl) contaminants than any other mammal monitored world-wide.

The human impact on the Puget Sound ecosystem has been extensive, and the population is expected to climb. Roughly two-thirds of Washington State’s residents live along this dynamic waterway, the majority in the dense urban corridor between the cities of Everett and Tacoma. Stormwater runoff from these urban areas is another significant source of pollutants. Sewage contamination has contributed to ongoing shellfish closures in a region noted for recreational clamming and commercial oyster beds.

Along the fjord-like inlet of Hood Canal, a portion of the sound treasured for its recreational and scenic attributes, runoff of fertilizers and a growing population has compounded problems of low dissolved oxygen. Following massive fish die-offs in the early 2000s, Hood Canal was identified as Washington’s first Aquatic Rehabilitation Zone.

In addition to Hood Canal, more than 70 percent of estuaries, eel-grass beds, salt marshes, and other critical habitats have been impacted by development along Puget Sound’s shores. Armoring of the shoreline with bulkheads and seawalls to protect residential and commercial properties has disrupted natural processes that contribute sediments to beaches. Species such as the sand lance or candle-fish, which makes up the bulk of the food base for juvenile Chinook salmon, rely on intertidal sand or sand-gravel beaches for spawning—and this habitat is now quite disrupted.

Conservation

Segments of natural shoreline, and access to state-owned submerged saltwater lands, have been preserved in over 80 state and regional parks around the biome. Federal refuges, including three national marine estuaries at Nisqually Delta, Skagit Bay, and Padilla Bay, have been the focus of concerted restoration efforts, much of which was influenced by the need to protect habitats vital to Chinook salmon species listed as being "in crisis" by the U.S. Fish and Wildlife Service in 2020 despite being listed under the Endangered Species Act (ESA) for more than 20 years.

Efforts to restore Chinook salmon populations on Puget Sound have had positive impacts on ecosystem protection in general, as native vegetation and water quality have been restored or improved with local and region-wide initiatives that began with the Shoreline Management Act of 1971. In 1996, federal, state, tribal, and local governments combined to form the Puget Sound Action Team, which set priorities for restoration and conservation efforts.

The Puget Sound Initiative, proposed by Washington’s governor and passed by the legislature in 2005, seeks to reinforce the ongoing commitment of public, business, environmental, and government sectors whose cooperation is key to protecting the unique natural resources of Puget Sound. The Initiative set in motion coordinated funding, research, monitoring, education, and conservation efforts. For the millions who will live along this complex waterway, a personal connection to the Sound, along with a sense of collective responsibility, is essential to preserving the ecological diversity that has made this region unique.

A 2020 report on climate change issued by the Puget Sound Institute indicated that the area has already begin to deal with increased temperatures, reduced snowpack, higher winter streamflows, lower summer streamflows, and sea level rise. The report indicated that to meet the 1.5-degree Celsius temperature-rise limit set by the Paris Agreement, global emissions from 2010 need to be reduced by 45 percent by 2030 and to net zero by 2050.

Bibliography

Dunagan, Christopher. "New Report Describes Anticipated Climate-Change Effects in Washington State." Puget Sound Institute, 6 Feb. 2020, www.pugetsoundinstitute.org/2020/02/new-report-describes-anticipated-climate-change-effects-in-washington-state/. Accessed 30 Aug. 2022.

"Endangered Species Act Coverage for Puget Sound Fisheries." Washington Department of Fish and Wildlife, 2022, wdfw.wa.gov/fishing/management/puget-sound-management-plan. Accessed 30 Aug. 2022.

Kruckeberg, Arthur R. The Natural History of Puget Sound Country. Seattle: University of Washington Press, 1991.

Masson, D. and P. Cummins. “Observations and Modeling of Seasonal Variability in the Straits of Georgia and Juan de Fuca.” Journal of Marine Research 62 (2004).

Puget Sound Partnership. “Leading Puget Sound Recovery.” Washington State Government. http://www.psp.wa.gov.