Portland, Deadly 6PPD-Q And Coho: Reasons For Hope

The mystery of why urban coho are dying before they can spawn is most strongly associated with Seattle.

It’s where the condition was first seen (Longfellow Creek above the lower Duwamish) and where the cause of the mortality (6PPD-quinone, a tire preservative that reacts with ozone and gets washed into streams) was first identified by scientists from Washington State University and the University of Washington.

Exposed to the chemical during fall rains, coho quickly die.

But an Oregon Fish and Wildlife Commission workshop last week showed that Portlanders and Oregonians are well aware of the problem, including junior US Senator Jeff Merkley (D), who has called for tire companies to replace the preservative, and, what’s more, they appear to have doable near-term solutions in mind.

Along with Washington’s response, it left me a lot more optimistic about a depressing problem I’ve been following for years. A decade ago, my family and I even did our tiny little miniscule share by having a bioswale installed to filter street runoff that otherwise dumped straight into a pipe to a Lake Washington tributary.

Bioswales’ simple soil mix of bark, compost and other materials is remarkably good at capturing 6PPD-q and rendering stormwater far safer for the salmon.