Over 36 Salmon Spotted In Miller & Walker Creeks, But Many Are Dying, Possibly From “Pre-Spawn Mortality”

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Our friend Dennis Clark, Miller/Walker Creek Basin Steward for King County, alerts us that over 36 salmon have been spotted in Miller and Walker Creeks.

Here’s his report:

With the rains of fall comes another age-old marker of the turn of the seasons: the salmon are returning to Highline.  Since October 10, at least three dozen coho salmon have returned to Miller and Walker Creeks.  Coho have been reported multiple times in Normandy Park, Burien, and as far upstream as SeaTac.  On Tuesday, Josh Feigin, an environmental specialist at the Port of Seattle, saw at least seven fish in Miller Creek on the airport property.

Some adult trout have been seen to pass upstream of this Miller Creek waterfall, which is about 5 feet high.

Remarkably, three of the fish made it past a substantial waterfall near S. 157th St. that usually prevents further upstream fish passage.  The coho began their upstream migration from Puget Sound following the first fall rains and appear to come in spurts with each succeeding rainfall.

While these are fairly good numbers for early in the season, the news is not all good.  Coho salmon on Miller Creek are suffering from what is termed “pre-spawn mortality.”  Otherwise seemingly healthy fish are dying before they can spawn.  Their deaths are preceded by bizarre swimming in which the fish literally throw themselves out of the water.  I witnessed this disturbing behavior on Friday when a fish jumped over my boots before dying (more info here).  It seems that as the rains gradually wash the pollutants that accumulated over the summer off the streets, fewer fish succumb to this phenomenon (and where do these pollutants go when “washed away”? Read more info here).

While the exact cause of pre-spawn mortality is unknown, it is likely linked to some combination of pollutants associated with modern industrial life.  While research continues, Burien residents can avoid or reduce pollution that is known to harm salmon such as car wash soap (wash your car at a commercial car wash or while parked on the lawn), leaking oil (fix oil leaks promptly), and pesticides (limit use or choose alternatives safer for kids, pets, and fish).

Despite these problems, the presence and persistence of salmon that begin and end their epic lives right here in Burien is a compelling reminder of the amazing world we share.  If you observe fish in the streams, please let Stream Steward Dennis Clark know by e-mail or at 206-296-1909.

Here’s a photo Dennis took Oct. 23rd of a male and female salmon at Miller Creek in Normandy Park:

Here are some photos courtesy Brett Fish showing the various stages of “pre-spawn mortality”:

A female coho has flung herself out of the stream and is flopping on the gravel bar.

Here the coho has come to her side and died in the shallows. Periodically her mouth would briefly gape open. She was visibly swollen with eggs that she will not have a chance to lay.

Determining whether a dead fish found suffered from pre-spawn mortality is not certain but if milt (sperm) or eggs are present, it is possible that is the cause. Brett cut this dead male open, revealing that the testes – the two white organs in the center of cavity – are still full of milt.

More information is available at Dennis’ excellent blog here.

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4 Responses to “Over 36 Salmon Spotted In Miller & Walker Creeks, But Many Are Dying, Possibly From “Pre-Spawn Mortality””
  1. Jim Branson says:

    Dennis, thank you for the report, and thank you for the work you do.

  2. Rainycity says:

    Thats a good thing you are doing Dennis,
    That one shot of that hen dying there, doesn`t look like shes even hardly changing color yet.

  3. dluxe says:

    Everyone that lives in the Puget Sound region should absolutely watch the PBS Frontline that featured Puget Sound; “Poisoned Waters”

  4. Jen McIntyre says:

    FYI: NOAA Fisheries has been coordinating a regional effort to document and understand coho pre-spawn mortality (PSM) for the past 7 years. With our partners (King County, US Fish & Wildlife Service, Seattle Public Utilities, Wild Fish Conservancy), we have been working on a comprehensive paper which details what we have learned thus far on the extent, frequency, and possible causes of PSM. Meanwhile, interested parties may view the following web-based summary of the study:


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