Salmon Population

Data Table


Coho salmon are important indicators of the overall health of the Deschutes River and an important cultural and economic asset of local tribes and Thurston County. Based on the specie's life cycle, there are three distinct Coho salmon runs (cohorts) on the Deschutes River.

Smolt populations for all three runs have seen extreme losses. The fewer smolts (young) that leave the freshwater system mean fewer adults returning to spawn. Reasons for this population decline include landslides destroying critical spawning habitat during winter storms, low adult returns, and high summer stream temperatures combined with low summer stream flows. Factors that contribute to higher than average Coho salmon smolt population include high summer streamflows and mild winter streamflows.

Increasing the Salmon Population

Water quality and habitat concerns that affect Coho and other salmon populations include high water temperatures, high pH, low dissolved oxygen, sediment, and fecal coliform. Steps that can be taken to increase the salmon population include:

  • Restoring key habitat to increase shading and lower stream temperatures
  • Addressing nutrient and fecal coliform concerns from septic systems
  • Increasing outreach and education for general watershed stewardship concerns
  • Reducing growth in sensitive areas of the watershed
  • Reducing clearing in areas with steep slopes that are susceptible to landslides
  • Conserving water during drought periods


Washington Department of Fish and Wildlife