The Yakima Coho Project and the Yakima Fall Chinook Project are components of the Yakima/Klickitat Fisheries Project (YKFP).   The YKFP is a project designed to use artificial propagation in an attempt to re-establish, supplement, or increase natural production and harvest opportunities of anadromous salmonids while maintaining the long-term fitness of the target population, and while keeping ecological and genetic impacts on non-target species within specified limits.  The planning, implementation, and evaluation of this project were initially guided by the framework developed by the Regional Assessment of Supplementation Project (RASP 1992), but are currently being reviewed for compliance with the recommendations of the Hatchery Scientific Review Group for the Columbia Basin.  The YKFP is designed as an experiment to resolve uncertainties associated with supplementation.  As a "laboratory," the YKFP will help determine the role of supplementation in increasing natural production of anadromous salmonids.  Both controlled experiments and monitoring and evaluation of natural populations contribute information.    

Consistent with the Pacific Northwest Power Planning Council's (NPPC) Fish and Wildlife Program (NPPC 1994), the objectives of the YKFP are to:
• Enhance existing stocks of anadromous fish in the Yakima and Klickitat river basins, while maintaining genetics and ecological resources.
• Reintroduce stocks formerly present in the basins.
• Apply the knowledge gained through supplementation throughout the Columbia River Basin.
Overall Project objectives are achieved while adhering to all relevant environmental laws and regulations, including National Environmental Policy Act (NEPA) and Endangered Species Act (ESA) requirements
    
The YKFP endorses an adaptive management policy, which allows for Project objectives and strategies to change as new information becomes available from Project experiments, monitoring and evaluation, and literature reviews.  

Wild stocks of coho salmon (Oncorhynchus kisutch) were once widely distributed within the Columbia River Basin.  However, coho salmon probably became extinct in the Yakima River in the early 1980s.  For this reason, efforts to restore coho within the Yakima basin have relied largely upon releases of hatchery coho because wild stocks did not exist to supplement.  Hatchery coho releases began in the Yakima basin in 1983 with the first release of 324,000 Little White Salmon hatchery smolts.  At that time, the program was primarily for harvest augmentation.  

The goal of Yakima Coho Project is to determine the feasibility of re-establishing a naturally spawning coho population and a significant fall fishery for coho within the Yakima River Basin, while keeping adverse ecological impacts within specified limits.  The current status of the program indicates that some natural production is occurring, but the population is driven by the hatchery component.  In order to increase the opportunity for increased local adaptation, the program is planning to increase the number of naturally produced adults that will be used in the broodstock of the hatchery component.

The Yakima Klickitat Fisheries Project's (YKFP) ongoing fall Chinook research program aims to test the application of supplementation principles to the two lower Yakima River fall Chinook populations, the mainstem and Marion Drain stocks.  The Marion Drain stock spawns in Marion Drain.  Marion Drain is a man-made 19-mile irrigation return ditch constructed in the early 1900's.  The other Yakima stock, the "mainstem stock", is the most abundant stock in the Yakima sub-basin.  The mainstem stock is genetically similar to the composite stock of upriver bright (URB) fall Chinook in the Columbia River, and the Marion Drain stock is similar to Snake and Deschutes River fall Chinook. Genetic sampling has determined that the stocks are not distinct; the differences detected in 2006 are likely the result of the particularly small sample sizes available from Marion Drain.

Another component of the Fall Chinook program is to evaluate the feasibility of reestablishing the early fall/summer run population in the Yakima River between Wapato and Naches.  Summer run Chinook eggs are collected at Wells dam and transferred to Prosser/Marion Drain for incubation and early rearing, to be released into the lower Naches River.