Seattle Public Utilities Mami Hara, General Manager/CEO

 

Chinook Salmon

 

Video of a Chinook salmon building a redd (a nest in the stream bed gravel) in the Cedar River about 12 miles upstream of Landsburg.

The Chinook salmon (Oncorhynchus tshawytscha) is the largest of the Pacific salmon and is distributed along the west coast of North America from California to Alaska. Commonly found in large rivers, the abundance of this species in Puget Sound has declined from historic levels. Puget Sound Chinook, including those in the Cedar River, were listed as threatened under the Endangered Species Act in 1999. Read more about chinook salmon life history and ecology on the Seattle Public Utilities Cedar River Biodiversity website.

The Chinook run in the Cedar River is unusual because the juveniles and adults must pass through a large lake as they migrate. The population has been influenced by many factors including the rerouting of the Cedar River into Lake Washington in the early 1900s, the effects of development and ongoing hatchery straying within the Lake Washington basin. Genetically, Cedar River Chinook resemble those in the Green River and those that return to the Issaquah Hatchery.

The Cedar River Chinook primarily rely on mainstem habitat for spawning and incubation. Migration of salmon above the Landsburg dam was blocked in 1901 and renewed in 2003 following the completion of a fish passage facility. Chinook now have about 12.5 additional miles of high quality mainstem spawning habitat.

Spawning occurs in the fall, peaking in October. As the fry emerge from the gravel in late winter, some stay in the river for up to several months, while others quickly move into Lake Washington to grow prior to migrating to sea. Nearly all smolts enter saltwater during their first year of life. Chinook are 3 to 5 years old when they return to the river to spawn.

Goals

Our long term goal for Chinook is to increase the population from current levels. Our specific objectives include:

  1. Protecting water quality through habitat protection measures in the Cedar River watershed
  2. Provide appropriate flows to support Chinook during river residence
  3. Increasing the amount of high quality habitat available to Chinook by opening access to twelve miles of mainstem habitat and five miles of tributary habitat above Landsburg Dam
  4. Acquiring and protecting property adjacent to the Cedar River below Landsburg Dam to reduce the impact of development activities on conditions in this area

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What are we doing for Chinook salmon?

Watershed management practices in the municipal watershed between Masonry Dam and Landsburg to protect water quality, aquatic, riparian and upland habitats and the processes that create and maintain a healthy river.

Construct and operate fish passage facilities at the Landsburg diversion dam to restore fish access to over 20 miles of stream habitat in the protected municipal watershed for the first time since 1901.

Instream flow management practices to promote a healthy river and provide beneficial habitat conditions for all life stages of Chinook salmon.

Downstream habitat protection and restoration along the 22 miles of river below Seattle’s municipal watershed to support flood plain management practices that help create and maintain beneficial habitat conditions throughout the lower river.