Meet the Biologist: Jay Davis

Salmon restoration in the Pacific Northwest and specifically the Puget Sound in Washington has long been a complex conservation problem. Jay Davis, a contaminants toxicologist who works in the U.S. Fish and Wildlife Service office in Lacey, Washington has been working on this problem for much of his career.

Jay and his partners have been studying how rain that first collects on land and streets, washes into creeks and rivers and causes a huge problem for fish. Specifically, this storm water runoff kills coho salmon and invertebrates, which are critical food supplies for other species of salmon.

Jay and a team of researchers used runoff from the streets of Seattle to test its effect on coho salmon, and they found it was quite toxic. Jay, along with his partners at NOAA National Marine Fisheries Service, Washington State University and the Suquamish Tribe have worked for almost a decade to understand the causes and potential solutions for mortality in adult coho salmon returning to urban streams, causing behavioral abnormalities, and ultimately death before these fish even have a chance to spawn.

They found that mixtures of metals and petroleum hydrocarbons – conventional toxic constituents in urban storm water – were not enough to cause the mortality by themselves. But, untreated highway runoff collected during nine distinct storm events was universally lethal to adult coho. More importantly, mortality was prevented when highway runoff was first treated by soil infiltration, a conventional green storm water infrastructure technology, before it reached the waterbody.

Based on this research, they were able to link toxic storm water runoff from highways, parking lots, and other developed surfaces that enter urban streams during seasonal rains to a 90 percent mortality rate of female coho. And if the females die before spawning, then they cannot support other salmon and predators in the ecosystem.

Jay found that inexpensive filtration of urban runoff through simple columns of sand and soil, a process called bioretention, can completely prevent the toxic effects on fish. Running the storm water through a basic treatment system before it enters the creek or the river cleans the water "up so much that it doesn't harm fish anymore." The treatment, which Pacific Northwesterners call a "rain garden," cleans the water naturally. These rain gardens now appear quite regularly throughout urban neighborhoods in the Puget Sound and through the Pacific Northwest.

Largely as a result of this scientific work Jay fostered by working with others, Washington's Puget Sound Partnership, the state agency leading the recovery of Puget Sound, formally identified urban storm water runoff as the largest on-going threat to the Puget Sound ecosystem. This is leading to both legislative and on-ground approaches to address non-point sources of contamination responsible for salmon mortality.

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