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Why Do Salmon Die in Seattle?


The fact that the nation and world just puts products on the market without basic testing as to their larger ecological effects provides a perfect explanation of the Sixth Extinction.

For decades now, scientists have known something was killing beautiful, adult coho salmon as soon as they hit Seattle’s urban waters, ready to spawn. They had escaped the orcas, the fishermen, traveled thousands of miles, only to be mysteriously killed as soon as they finally reached home.

In a breakthrough paper published in the Dec. 3 issue of Science, a team of researchers revealed the culprit behind the deaths of coho in an estimated 40% of the Puget Sound area — a killer so lethal it takes out 40 to 90% of returning coho to some urban streams before they spawn. It is a killer hidden in plain sight.


More specifically, a single chemical, 6PPD-quinone, derived from a preservative that helps tires last longer.

Through painstaking analysis and building on years of prior research, the team, including researchers from the Center for Urban Waters in Tacoma, the University of Washington and Washington State University, isolated the killer from a witch’s brew of some 2,000 chemicals in roadway runoff.

The chemical is a globally common tire rubber antioxidant. But when it does its job, interacting with ozone in the atmosphere, the chemical transforms to a substance that is highly toxic to coho.

Is there anything our car culture doesn’t destroy?

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