Project Objectives

The OASIS project monitors the status and trends of naturally produced Oregon coastal and lower Columbia River salmonid stocks. The project has four target species: Chinook, chum, coho, and steelhead. Additionally, the program collects information on spawning pacific lamprey. Key metrics include abundance; spatial distribution; temporal distribution; and proportion of hatchery fish within the natural spawning population. 

Side view of a colorful male coho salmon
  • October through January OASIS performs spawning ground surveys for Chinook, chum, and coho salmon. Surveys are conducted at least once every 10 days.

     

  • February through June OASIS conducts spawning ground surveys for Winter Steelhead and Pacific Lamprey. Surveys are conducted at least once every 14 days.

     

  • February through September OASIS performs spawning survey site verification and setup.
 
  • Survey sites include “standard” surveys and GRTS surveys. Standard survey locations were selected, many in the 1950’s, for ease of access and historically high numbers of spawning anadromous fish.
  • Depending on the size of the stream being surveyed, surveyors walk upstream or boat downstream while collecting an assortment of field data.
River with bank covered in snow, small blue boat on the right bank with mountains in the background
Data Collected on Surveys:
  • Number of redds present.
  • Live and dead fish counts (identified by species and sex).
  • Carcass length (MEPS mm).
  • Scale samples.
  • Fin clips and/or tag presence.

     

Metrics Monitored:
  • Abundance. 
    Geographic scale of abundance estimate varies by species, but the target is a point estimate with a confidence interval of +/- 30%.
  • Spatial distribution.
  • Temporal distribution.
  • Proportion of hatchery fish (pHOS) in the naturally spawning population.