Spring Chinook Supplementation

Historically the Confederated Tribes of Warm Springs have successfully managed the Warm Springs River as the last remaining run of naturally producing spring run Chinook salmon in the Deschutes River basin. However, the wild population is not currently maintaining itself and is at risk of extinction. The Spring Chinook salmon population has been well below management goals for many years. The numbers of returning adults have exceeded the 1,000 fish escapement above the WSNFH goal in only two years out of past ten. In 2019, 205 adults returned, nearly 82% below the 40-year average. Factors for the downward trend are believed to be poor ocean survival and high water temperatures that have been linked with higher mortalities in returning adults in the Warm Springs canyon. Separate habitat and fish transportation issues are being developed to address these high temperature issues. The current stock is dangerously low and susceptible to expatriation if immediate action is not taken. Therefore, CTWS Fisheries in collaboration with the US Fish and Wildlife Service will implement a supplementation program in 2020 to boost spring Chinook spawning numbers.



Under a separate project, the USFWS will collect and spawn wild supplementation brood and raise juveniles using standard practice. Cost associated with raising these Chinook will be covered by USFWS. A local origin broodstock of 60 pair of adults will be used to produce approximately 150,000 eggs that will be reared at the Warm Springs National Fish Hatchery. Under this PCSRF project, these smolts will be released into upper Warm Springs watershed streams (Figure 1, attached proposal). where historical spawning and rearing occurs in mid-April 2022 to coincide with the release of hatchery smolts. Funds for this project will go to transporting and releasing these fish.



Specific work to be performed under this project at the Warm Springs National Fish Hatchery and Schoolie worksites:



An estimated 150,000 Chinook smolts from the WSNFH group will be transported to the upper Warm Springs River and released near Schoolie, with a planned timeline to occur in mid-April 2022. Funding will also cover implanting pit tags into 10,000 smolts in order to monitor the supplementation results and to determine both juvenile and adult survival from this release

This supplementation plan will help bolster the wild spring Chinook Spawning success, by increasing Warm Springs River spring Chinook outmigrants. Measurable outcomes are increased smolt production from the eggs collected from wild brood, and survival measured by PIT arrays in the Warms Spring River and PIT arrays further downstream in the Deschutes and Columbia basins. The ultimate measure is future increases in returning adults with the goal of meeting or exceeding of the 1,000 adult Chinook return upstream of the WSNFH.