Dead Fish Tell no Lies - Longfellow Creek Salmon Study - Puget Soundkeeper Alliance

“This one is definitely symptomatic” Kathryn Davis, Puget Soundkeeper Stewardship Coordinator called out. The bright adult female coho salmon was displaying the classic “death dance” of a fish in trouble. Disorientation, gaping mouth, and an inability to swim are classic signs of a scary phenomenon playing out in urban creeks around Puget Sound. Among the commotion were dead fish along the banks of Longfellow Creek, a stark reminder of what is ahead for this fish in trouble.

Longfellow Creek is a rare gem – one of the few major creeks that flows year-round within Seattle city limits. It covers approximately four miles in the West Seattle neighborhood, ending in the Duwamish River. Restoration efforts that began in the 1980s have revitalized much of the watershed, and coho salmon now return every year. But despite the work that has been done to improve habitat for native species, many of these salmon die before they can spawn. They are poisoned by undiluted stormwater runoff, a toxic brew containing heavy metals, motor oil, fertilizer chemicals, and other contaminants that wash off roadways and parking lots directly into the creek.

Soundkeeper Chris Wilke cuts open a dead female salmon to see if it has spawned.

Surveys by NOAA scientists over the last ten years reveal a high pre-spawn mortality (PSM) rate, frequently over 80 percent. This is in contrast to rural creeks, where only about one percent of salmon die before spawning. Late fall, when the salmon return to their home waters, is prime time for heavy rains that carry toxins directly into their path. In a brief survey at Longfellow Creek during early November, Soundkeeper staff documented five live and ten dead salmon. Of those, seven were female and five still had eggs inside, a 71% mortality rate.

Soundkeeper will continue to do spot surveys at Longfellow Creek throughout the spawning season, but simply cataloging the impact isn’t enough. Polluted stormwater runoff is the largest source of toxic pollution to Puget Sound and surrounding waterways. Soundkeeper is involved in stormwater regulation on a number of levels – scrutinizing stormwater permits as they are issued and reissued, advocating for stronger regulations on stormwater discharge, enforcing the Clean Water Act, and supporting active solutions such as rain gardens, biofiltration, and permeable pavement. Research done at Washington State University has shown that biofiltration may be the key to saving these fish.

A sign to discourage dumping in storm drains that lead directly to local watersheds.

Soundkeeper has won or settled over a dozen court cases that changed the standards for stormwater permits, requiring green infrastructure solutions for all new development in Washington and stronger treatment standards for industrial sites, and we constantly spread the word about this important issue through outreach and education.

There are many things you can do on an individual level to improve the situation for stormwater pollution in Puget Sound – for more information, visit King County’s page on stormwater.

  1. […] dying off in excessive numbers earlier than they may spawn. One report centered on West Seattle’s Longfellow Creek, the place every year, as much as ninety p.c of the feminine salmon had been dying earlier than […]

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