By Devon Stark, Communications Intern

The Pacific Northwest has always been known for its large salmon populations. However, since the late 19th century, the number of fish in the region has declined drastically. Currently, six of eight Pacific Northwest “salmonid” species subtypes are listed as “threatened” or “endangered” under the Federal Endangered Species Act.

These changes are due in large part to human overfishing, as well as environmental degradation, climate change, and habitat loss in the last century. Below is a brief history of these issues and their effects on Pacific Northwest salmon populations.

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Women cooking salmon on the Muckleshoot Reservation, Auburn. ca. 1950. Image courtesy of Museum of History and Industry (Seattle), the Seattle P-I Collection

Before 1850, Native American Indians fished, traded, and sold most salmon because they weren’t used by the EuroAmericans. However, after the development of salmon canning technology, which increased the market potential for salmon, big companies like Hudson Bay Co. took over fishing in the Northwest. Salmon populations rapidly declined.

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Interior of a Puget Sound salmon cannery, ca. 1906. Image courtesy of University of Washington, Albert Henry Barnes Collection

In the 1890s and 1900s, regulations were set attempting to preserve salmon populations, but were largely unsuccessful. Hatcheries were established to raise fish in captivity and keep populations up with mandatory escapement numbers each salmon run season, with varying success. As salmon populations continue to decline, fewer and fewer are available to be commercially and privately fished each year.

New genetic tools allowed scientists to understand the great diversity within wild salmon populations that can’t be recreated in hatcheries.  The importance of preserving existing wild populations, and restoring naturally spawning populations, provides the ability of salmon populations to adjust to changing environmental conditions.

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Puget Sound salmon catch, ca. 1900. Image courtesy of Museum of History and Industry (Seattle)

Historic estimates for Chinook salmon populations are in the hundreds of thousands. In fact, some sources estimate that in the early 1800s, total salmon populations would have been in the millions. Current runs are a small fraction of this number.

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A comparison of 5-yr (2000-2004) average Puget Sound Chinook salmon populations to historical estimates (EDT estimates). Graph courtesy of NOAA, 2007, accessed at Encyclopedia of Puget Sound

In 1999, salmon in Washington, California, Oregon, and Idaho were already extinct in as much as 40% of their former spawning areas.

Salmon populations suffered from more than overfishing. Most varieties of Puget Sound salmon migrate from the small creeks in which they were born to rivers and freshwater lakes like Lake Washington, to esturaries, and along our shorelines to  the Pacific Ocean. At the end of their life, they return back to their birth stream to spawn and die.

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Salmon life cycle. Image courtesy of NOAA Fisheries

The healthiest habitats for salmon spawning are cool streams and creeks with lots of woody debris and clean gravelly patches where salmon can safely deposit their eggs. In recent years, a combination of factors. including water diversions, has eliminated much of this critical salmon breeding ground.

Duwamish River and Harbor Island - Before and After

These images show the drastic loss of salmon habitat in Seattle’s Duwamish River Basin. On the left, you see historic conditions – with a meandering river and large Estuary. On the right, you see a straightened river, and the man-made “Harbor Island” where the estuary once was. Courtesy of Seattle Parks and Recreation and Flickr user J Brew, respectively

Specific to urban areas, research on Lake Forest Park, WA states that “fisheries biologists believe a long list of destructive forces —over-fishing, stormwater runoff, the “hardening” of stream banks with stone or concrete, siltation from upstream development, pollution from lawns, the loss of wetlands, changes in the temperature of ocean currents – all have converged to kill off the fish in urban streams around Puget Sound.”

Thus, it is key to improve conditions for salmon in the immediate future. Many cities in Washington have already begun efforts to reduce pollution and restore populations.