Month: January 2026

Report reveals how urban runoff continues to threaten coho salmon health  

January 27, 2026
Puget Soundkeeper

Link to My Edmonds News article

Pre-spawn mortality – Photo courtesy Puget Soundkeeper


Since 2015, Puget Soundkeeper has monitored coho salmon health in Seattle’s Longfellow Creek, producing data on the impacts of urban pollution on salmon survival. For years, Longfellow Creek has been the epicenter of research studying the effects of 6PPD-quinone — a toxic tire chemical lethal to coho salmon.

According to a Puget Soundkeeper news release, exposure to 6PPD-quinone causes a condition called Urban Runoff Mortality Syndrome (URMS), a disease characterized by symptoms such as disorientation and gasping for air, often killing coho within 24 hours. Furthermore, this chemical has been strongly linked to Pre-Spawn Mortality (PSM), where adult salmon die before successfully reproducing, the news release said.

Puget Soundkeeper’s annual Pre-Spawn Mortality Survey analyzes the spawning success of coho salmon in Longfellow Creek to better understand the impacts of 6PPD-quinone. From October through December, trained volunteers count and dissect returning coho salmon, particularly assessing the presence of eggs and milt to determine whether spawning was successful.

Results from the 2025 study show that 55.5% of coho salmon died before spawning. This aligns with data collected since 2015, which shows that 49-90% of returning salmon die before reproducing each year.

“This level of pre-spawn mortality is devastating,” said Ewan Henderson, clean water program specialist at Puget Soundkeeper. “The dramatic reduction in successful spawning opportunities is a huge blow to our ecosystems, particularly for our resident orcas who already face major challenges as their food sources dwindle.”

According to the press release, Green Stormwater Infrastructure (GSI) projects, such as rain gardens or bioswales, can effectively remove toxins from runoff and prevent harmful chemicals from entering local waters. In addition to GSI projects, a bill (HB 2421) aimed at removing 6PPD from tires was introduced to the Washington State House and Senate Environment Committees last week.

Puget Soundkeeper will be recruiting the next cohort of salmon surveyors in August. More information will be made available on their website.

To learn more about the 2025 Salmon Survey report results, visit pugetsoundkeeper.org/volunteer/salmon-surveys.

Roadway Runoff Induced Acute Mortality in Juvenile Coho Salmon During Spring Storm Events

Ecotoxicology and Public Health
January 5, 2026

By Marlee L. Brown, Nathan Ivy, Melissa Gonzalez, Justin B. Greer, John D. Hansen, Edward Kolodziej, Jenifer K. McIntyre

Abstract

Extensive mortalities of adult coho salmon (Oncorhynchus kisutch), often called “Urban Runoff Mortality Syndrome” (URMS), have been documented during the fall in creeks where water quality has been degraded by roadway runoff. The primary cause of mortality is 6PPD-quinone (6PPDQ; N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine quinone)–an ozone transformation product that forms on all vehicle tires. Laboratory studies have shown that juvenile coho salmon are highly sensitive to 6PPDQ exposure. Unlike adults, juveniles reside in impacted watersheds year-round, including during the spring when 6PPDQ concentrations can frequently exceed lethal thresholds during storms. To assess the potential incidence of URMS in springtime rearing habitats for juvenile coho salmon, we conducted a paired water quality and toxicology study at Miller Creek, a runoff-impacted watershed in Normandy Park, WA, USA. Using a small field facility, three naïve groups of juvenile coho salmon (N = 720) were exposed to either creek water or groundwater (N = 120 per treatment per storm), across three spring storms while comparing water quality and mortality end points. In creek water during exposures, peak 6PPDQ concentrations reached 73–110 ng/L, exceeding reported median lethal concentrations (LC50) for coho salmon. Over each 24–73 h storm exposure period, ∼80% of Miller Creek-exposed juvenile salmon died. No mortality occurred among control fish exposed to groundwater. These results indicate previously unidentified mortality risks for juvenile life stages of coho salmon during spring storms, suggesting substantial and year-round water quality impediments to coho salmon health and recovery across roadway runoff-impacted spawning, rearing, and migratory habitats.

roadway-runoff-induced-acute-mortality-in-juvenile-coho-salmon-during-spring-storm-eventsDownload

Study finds juvenile coho salmon at risk from deadly tire chemical

By Jeff Rice
Puget Sound Institute
Published January 9, 2026

Link to Puget Sound Institute, UW Tacoma article

Juvenile coho salmon. Adobe stock image

Untold numbers of hatchery fish may be dying from exposure to tire-contaminated runoff, according to a new study.

Continue reading “Study finds juvenile coho salmon at risk from deadly tire chemical”

Responding to concerns about drinking water protection, Edmonds Council approves critical areas ordinance

By Teresa Wippel
January 7, 2026

Link to My Edmonds News article

Councilmember Susan Paine, center, makes a point about the critical areas ordinance during a Q&A with staff Tuesday night.

Key takeaways:

  • Michelle Dotsch elected council president, Jenna Nand selected president pro tem.
  • Numerous residents testify in support of a measure they say would better protect the Deer Creek critical aquifer recharge area (CARA) — and council approves it 4-3.
  • Councilmembers sworn in and last year’s council president gets a sendoff.
  • Council votes to increase the city’s transportation impact fees.
Continue reading “Responding to concerns about drinking water protection, Edmonds Council approves critical areas ordinance”

Delay on Critical Areas Ordinance update draws criticism from groups

Edmonds is considering delaying updates to a section of the ordinance that would restrict stormwater wells near its drinking water aquifer.

by Eliza Aronson
January 3, 2026
Link to Everett Herald article

Olympic View Water service area

EDMONDS — The Edmonds Environmental Council and Olympic View Water & Sewer District have raised concerns regarding revisions to the city’s Critical Areas Ordinance, warning that a delay in updating policy surrounding underground stormwater wells could cause the city drinking water to become contaminated.

Continue reading “Delay on Critical Areas Ordinance update draws criticism from groups”