- Amanda Colbert
This week, we continue further down the coast to explore the Columbia-Snake Rivers and their connection to northwest salmon and Southern Resident orcas.
The Columbia River headwaters originate in Columbia Lake, British Columbia, and travel 1,253 miles from its source to its mouth where it meets the Pacific Ocean at Astoria, Oregon. By volume, the Columbia River is the 4th largest river in North America, traveling through four mountain ranges and draining more water into the Pacific Ocean than any other river in North or South America. Historically, 10-16 million wild salmon and steelhead would move into the Columbia River aimed at spawning sites upriver. Certain salmon runs would travel as far inland as some of the tributary waters in British Columbia, Canada.
The Snake River headwaters originate from the western side of Wyoming in the Rocky Mountains, flowing due west through Idaho before making a sharp turn north along the Idaho/Oregon state line. The Snake flows 1,078 miles until it meets the Columbia River at the Tri-Cities in Washington State and is the largest tributary waterway of the Columbia. The Snake River watershed covers roughly 108,000 square miles and spans six states including Wyoming, Idaho, Nevada, Utah, Oregon, and Washington. Historically, 2-4 million wild salmon and steelhead would move into the Snake River aimed at spawning sites as far inland as Central Idaho. The Snake River basin once produced roughly half of all spring Chinook returning to Columbia basin rivers and tributaries. These “Springers” were/are highly desirable to tribes and fishermen because of their high-fat content, and vital to the Southern Resident orcas for the same reason.
These two rivers unify a large portion of the Pacific Northwest, with drainage basins spanning portions of seven U.S. states and British Columbia, in Canada. Historically, the Columbia and Snake Rivers provided unobstructed, optimal, and pristine habitat for the wild salmon and steelhead returning to spawn. Today, man-made pressures, dams, and environmental challenges have pushed wild salmon and steelhead populations to the brink, with the Federal Government currently listing 12 of the 13 salmon populations found in this river system as being “high risk” for extinction.
With the precipitous decline of salmon in the Columbia-Snake River system comes the compounded effects of decreased food availability for the Southern Resident orcas who have relied especially on the Chinook that enter the Columbia-Snake in the spring. The winter/spring period is an especially critical time for Southern Residents, with Chinook salmon typically less available, naturally, during this lean time. Continuing to reduce what winter/spring resources are available has contributed to the overall continued decline of their population.
Resources: https://www.worldatlas.com/articles/where-does-the-snake-river-begin-and-end.html |https://www.klriver.org/faq/where-does-the-columbia-river-start-and-stop-best-solution.html | https://today.oregonstate.edu/archives/2008/oct/new-study-salmon-smolt-survival-similar-columbia-and-fraser-rivers | https://stateofsalmon.wa.gov/salmon-101/salmon-history-and-timeline/#pattern2_4 |https://www.americanrivers.org/river/snake-river/