After a summer of successful cleanups, we’re turning our attention to a critical monitoring project: salmon surveys.

Salmon Surveys

Puget Soundkeeper Stewardship Coordinator Gillian Flippo says that survey data will help protect salmon in the future. So, what exactly are we looking for?

Each October, teams of dedicated volunteers survey Longfellow Creek in the Highpoint neighborhood of Seattle. They track coho salmon that enter the Duwamish River from Elliot Bay, and then swim up Longfellow Creek. Volunteers specifically look for salmon experiencing Pre-Spawn Mortality Syndrome (PSM), or death before the ability to spawn.

Coho salmon encounter what Gillian calls a “chemical cocktail” as they migrate through urbanized waterways polluted from stormwater runoff. The chemicals disorient adult coho, causing them to die within hours of contact. Scientists have tried for years to pinpoint which ingredient in the runoff “cocktail” might be responsible. Now, finally, they have some answers.


A team of University of Washington and Washington State University researchers recently pinpointed a chemical called 6PPD-quinone and linked it to Urban Runoff Mortality Syndrome (URMS). URMS describes salmon that die after acute exposure to urban stormwater runoff. It also includes salmon that die before they’re able to spawn. This research comes after years of persistence and effort on the part of Seattle Public Utilities, NOAA Fisheries, US Fish & Wildlife Service, US EPA and Seattle-area Tribes.

6PPD is universally used in tire manufacturing to prevent rubber degradation due to ozone exposure. As 6PPD does its job, interacting with ozone and preventing ozonation, it creates 6PPD-quinone. Soundkeeper supported efforts to secure funding for the Department of Ecology to study 6PPD and report back to the legislature by December 1st, 2021.

It may take time to find conclusive answers on 6PPD-quinone, let alone develop a safe replacement. In the meantime, Low Impact Development (LID) techniques like Green Stormwater Infrastructure effectively control polluted runoff and stop coho PSM.

Is your community implementing salmon-safe solutions, like Green Stormwater Infrastructure? Find out here!