Salmon have lived here for millions of years

By Carol Savonen

The earliest fossil evidence for the ancestors of Pacific Northwest salmon and trout dates back to the Eocene, about 40 million years ago. About six million years ago, when saber-toothed tigers roamed the landscape, salmon were evolving into the species we know today.

Humans have used salmon for food in the Pacific Northwest for thousands of years, since the end of the last Ice Age. Commercial harvest data reveals early Pacific Northwest salmon runs were most likely the most productive salmon fisheries in North America.

"The physical environment of the Pacific Northwest made all of this possible," explains Oregon State University historian William G. Robbins in The Northwest Salmon Crisis: A Documentary History, published by the Oregon Sea Grant program in 1996.

". . . the [Columbia] river serves as a natural funnel, providing a water highway through which four varieties of salmon . . . passed upstream to spawn."

This "funnel" also made it relatively easy for humans to catch them with nets, spears, traps and poles. Salmon supported up to 100,000 people in this region for thousands of years.

Salmon faced major physical disruptions long before humans came to North America. Great volcanoes have shaken and erupted for millennia, sending mud flows and pumice into rivers and streams. Massive ice sheets and their meltwaters influenced many of the familiar landforms in our region: the Columbia Gorge, the scablands of eastern Washington and the flat, silt-filled valleys of the Willamette Valley. Little is known about salmon during the Ice Age. But scientists think that they took refuge in areas not covered by ice or affected by unstable rivers and coastlines, such as southern Oregon, California and the Queen Charlotte Islands of British Columbia.

About 9,000 years ago, after the end of the last Ice Age, the Pacific Northwest slowly became more favorable for salmon. Sea levels stabilized, creating more stable river mouths and estuaries. Upwelling currents in the Pacific carried nutrients for salmon food.

Archaeologists have studied ancient Indian sites around the Pacific Northwest. By analyzing and dating piles of clam shells and fish bones, the scientists concluded that large numbers of salmon were used by humans as long as 9,000 years ago. The fish probably were more plentiful during cooler, wetter climate periods and less plentiful during warmer, drier periods.

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