A milky, turquoise, phytoplankton bloom in Hood Canal visible from space. Natural color MODIS image from Landsat 8 acquired July 24, 2016. Photo: NASA Earth Observatory

Does Puget Sound need a diet? Concerns grow over nutrients

As the region's population grows, scientists say we can expect to see increasing amounts of nitrogen and other elements flowing into Puget Sound. Known as “nutrients” these elements are naturally occurring and even necessary for life, but officials worry that nutrients from wastewater and other human sources are tipping the balance. That could mean big problems for fish and other marine life, gradually depleting the water of oxygen and altering the food web.


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Sediment Quality in Puget Sound: Changes in chemical contaminants and invertebrate communities at 10 sentinel stations, 1989–2015

A 2018 report from the Washington State Department of Ecology presents results from 27 years of sampling sediments and benthic invertebrates at 10 long-term stations throughout the greater Puget Sound area every year from 1989 through 2015.

The Budd Inlet sewage treatment plant. Photo courtesy of LOTT Clean Water Alliance

Sewage treatment plant in Olympia a leader in nitrogen removal

A regional sewage-treatment system in Thurston County has helped contain  low-oxygen problems in Budd Inlet as the population continues to grow. The system cleans up some of the effluent for replenishing groundwater supplies.

The rapid growth of a red-orange algae, Noctiluca scintillans, dramatically colors the waters of Puget Sound near Edmonds on May 16, 2013. Such algae blooms have been seen more frequently in recent years. Photo: Jeri Cusimano via WA Ecology (CC BY-NC 2.0)

Dead plankton leave clues to a food-web mystery

High amounts of elements such as nitrogen can cause blooms of phytoplankton that sometimes trigger perturbations throughout the food web. This occurs most often in the spring and summer after the long, dark, cloudy days of winter begin to fade.

A sharp boundary appears as sediment-laden freshwater is discharged from British Columbia's Fraser River into the Salish Sea. Fresh water, which is less dense than salt water, spreads in a shallow (approximately 1 m deep) plume at the sea surface. Photo: Ed McNichol, Ocean Networks Canada (CC BY-NC-SA 2.0)

Puget Sound circulation triggers low-oxygen conditions at different times and in different places

The amount of oxygen in the Salish Sea is dependent on water circulation which distributes chemical elements such as nitrogen through the system.

Image describing low oxygen "dead zones"; image courtesy of NOAA

How the state assesses low oxygen in Puget Sound

Under the federal Clean Water Act, states are required to assess the quality of their surface waters and compile a list of polluted water bodies. The law mandates cleanup plans to address pollution and other water-quality problems. This article describes how this process works in Washington state for dissolved oxygen. 

Glaucous-winged gulls. Photo courtesy of James Hayward.

Daily and annual habitat use and habitat-to-habitat movement by Glaucous-winged Gulls at Protection Island, Washington

A 2017 paper in the journal Northwestern Naturalist looks at distribution patterns for Glaucous-winged Gulls across associated habitats in the Salish Sea.  

Harbor Seals sunning on intertidal rocks of Puget Sound. Photo: Tony Cyphert (CC BY-NC-ND 2.0)

Study would explore changes to protections for seals and sea lions

As wildlife managers work to recover Puget Sound’s diminished Chinook population, a proposed white paper is expected to review the impacts of some of the salmon's chief predators. The study would include a section on potential management of seals and sea lions, prompting open discussion of a long taboo subject: Could officials seek to revise the Marine Mammal Protection Act — or even conduct lethal or non-lethal removal of seals and sea lions in some cases? Such actions are hypothetical, but we look at some of the ongoing discussions around the issue as prompted by a new resolution from the Puget Sound Leadership Council. 

Southern Resident killer whales and boats. Photo courtesy of NOAA

Soundwatch: Eighteen years of monitoring whale watch vessel activities in the Salish Sea

A December 2017 article in the journal PLOS One reports that incidents and violations among whale watching vessels have increased in the Central Salish Sea since 1998.

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2017 Addendum — Ocean Acidification: From Knowledge to Action

The Washington Marine Resources Advisory Council has released an addendum to the 2012 report Ocean Acidification: From Knowledge to Action. The original report established a statewide strategy for addressing ocean acidification in Washington. The addendum identifies updates based on emerging science and management practices and is intended to be a companion to the 2012 report. 

Steller Sea Lion (Eumetopias jubatus). Photo by NOAA Fisheries.

Year-round algal toxin exposure in free-ranging sea lions

Sea lions living along the coast of Washington are at risk from harmful algal blooms throughout the year, according to a 2017 study published in the Marine Ecology Progress Series.

Harbor porpoise. Photo courtesy of the National Park Service.

Group characteristics, site fidelity, and photo-identification of harbor porpoises, Phocoena phocoena, in Burrows Pass, Fidalgo Island, Washington

A 2017 paper in the journal Marine Mammal Science examines harbor porpoise group structure and site fidelity in the Salish Sea. 

Puget Sound marine Waters 2016 report cover

2016 Puget Sound Marine Waters Overview

The Puget Sound Ecosystem Monitoring Program has released its sixth annual Marine Waters Overview. The report provides an assessment of marine conditions for the year 2016 and includes updates on water quality as well as status reports for select plankton, seabirds and fish.

A dying female coho salmon in the Lower Duwamish spotted by Puget Soundkeeper volunteers in October 2017. Photo: Kathy Peter

What is killing the coho?

Researchers are trying to determine which chemicals in stormwater are contributing to the deaths of large numbers of coho salmon in Puget Sound. It has prompted a larger question: What exactly is in stormwater anyway?

Harbor seal photographed by Andreas Trepte. Available through a Creative Commons Attribution Share Alike 2.5 license.

Influence of human exposure on the anti-predator response of harbor seals (Phoca vitulina)

A 2017 paper in the journal Aquatic Mammals reports that harbor seals in the Salish Sea are less concerned about predators when they become habituated to humans. 

A young resident killer whale chases a chinook salmon in the Salish Sea near San Juan Island, WA. Sept 2017. Photo: (CC BY-SA 2.0)

Seals and sea lions may be slowing salmon recovery, hurting orcas

Increased consumption of Chinook salmon by seals and sea lions in the Salish Sea “could be masking the success of coastwide salmon recovery efforts,” according to a new study published in the journal Scientific Reports. Endangered resident orcas are said to be declining in part due to a lack of available Chinook, the orcas' preferred prey.

2017 State of the Sound report cover

2017 State of the Sound

The 2017 State of the Sound is the Puget Sound Partnership’s fifth biennial report to the Legislature on progress toward the recovery of Puget Sound by 2020. The document reports on both the status of the Partnership's recovery efforts and the status of a suite of ecosystem indicators.

The Vechey residence and bulkead (circa 2013) before the restoration project. Photo courtesy: John Vechey

With sea-level rise, waterfront owners confront their options

Climate change could cause sea levels to rise more than four feet in some parts of Puget Sound, leaving shoreline residents with some tough decisions. Experts say fighting the waves with conventional seawalls may not be the answer.

Olympia high tide, Dec 28, 2010. Photo: Johanna Ofner (CC BY-NC-SA 2.0)

Average high tides are creeping higher in Puget Sound

The average worldwide sea level has increased more over the past 150 years than during the previous 1,500 years, experts say, and the seas continue to rise at an ever-increasing pace.

GIS is used to illustrate sea-level rise scenarios in downtown Olympia. Story map by City of Olympia:

Local governments begin to plan for higher tides

Planning for rising seawater in Puget Sound has often focused on public property such as roads, buildings and utilities. Now local governments are looking more closely at private property despite regulations based on traditional flooding history.

A plane releases chemical dispersant to break up an oil slick on the water surface below. Photo courtesy of the National Commission on the Deepwater Horizon Oil Spill and Offshore Drilling.

Oil dispersant effectiveness and ecological consequences in San Juan County marine waters

A 2017 report from the University of Washington summarizes current scientific knowledge on chemical oil spill dispersants and their potential impacts on shoreline habitats in San Juan County, Washington. 

Ptilosarcus gurneyi (with a striped  nudibranch) off Whidbey Island, WA;  photo by Jan Kocian.

The Orange Sea Pen

The Orange Sea Pen, also called the Fleshy Sea Pen or Gurney’s Sea Pen, resembles a colorful autumn tree waving in the “breeze” of moving water currents. Article courtesy of the Washington Department of Ecology's Eyes Under Puget Sound series. 

Image of tidal motion in SSM (72 hr animation, April 06); Exaggerated vertical scale to visualize SSM domain-wide tidal motion

The Salish Sea Model

The Salish Sea Model is used to predict spatial and temporal patterns in the Salish Sea related to factors such as phytoplankton, nutrients and Dissolved Oxygen. It is a collaborative effort between the Pacific Northwest National Lab, the Washington State Department of Ecology and U.S. Environmental Protection Agency.

Fragile shell. Joe Doe (CC BY-NC-ND 2.0)

Using mineralogy and higher-level taxonomy as indicators of species sensitivity to pH: A case-study of Puget Sound

Scientists from NOAA's Northwest Fisheries Science Center (NWFSC) developed publicly searchable database of nearly 3,000 Puget Sound species to study whether species having calcium carbonate shells are more or less vulnerable to ocean acidification. Their findings published in the journal Elementa question previous assumptions that shell-building organisms are more vulnerable.

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Water sampling and testing for formaldehyde at Northwest fish hatcheries

Formaldehyde is often used to control parasites on hatchery salmon and trout. The U.S. Environmental Protection Agency and the Washington State Department of Ecology conducted a joint study of formaldehyde concentrations in effluent from hatcheries in the Pacific Northwest. 

English Sole (Parophrys vetulus) in Puget Sound. Photo: biodiversityguy

PCBs in fish remain steady while other toxics decline

A new study shows a surprising decline in some toxic chemicals in Puget Sound fish, while levels of PCBs increased in some cases. Scientists say the study shows that banning toxic chemicals can work, but old contaminants remain a challenge as they continue to wash into Puget Sound.

WDFW biologists sorting and measuring fish from PSEMP's index sites in the Duwamish River and near the Seattle Waterfront. Photo: WDFW

Monitoring helps to reveal hidden dangers in the food web

Toxic chemicals have been showing up in Puget Sound fish for more than a century, but consistent testing over the past 30 years has helped to reveal some unusual patterns of pollution.

Screenshot of archived SSEC 2016 website at

2016 Salish Sea Ecosystem Conference

The 2016 Salish Sea Ecosystem Conference took place April 13-15 at the Westin Bayshore in Vancouver BC. Over 1100 scientists and policy experts attended.

Dean Toba, a scientific technician with the Washington Department of Fish and Wildlife, operates the agency’s screw trap on the Skagit River. The trap helps biologists estimate the number of juvenile salmon leaving the river each year. Photo: Christopher Dunagan, PSI

Are we making progress on salmon recovery?

In recent decades, hundreds of millions of dollars have been spent to restore habitat for Puget Sound salmon. In this article, we look at how scientists are gauging their progress. Are environmental conditions improving or getting worse? The answer may depend on where you look and who you ask.

Salmon smolts. Photo courtesy of Governor's Salmon Recovery Office

State of the salmon in watersheds 2016

A biennial report produced by the Governor's Salmon Recovery Office provides stories and data about salmon, habitat, and salmon recovery in Washington, including Puget Sound.

Spiny Dogfish (Squalus acanthias), a species typically found in Puget Sound marine waters. Image courtesy of NOAA.

The pelagic (open water) food web

The marine habitat of Puget Sound can be divided up into nearshore, benthic (associated with the sea floor), and pelagic (open water) habitats. This article focuses on the pelagic habitat within the Puget Sound. This article was prepared as part of the 2015 Puget Sound Fact Book produced by the University of Washington Puget Sound Institute. 

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