The Yakima River Coho Re-Introduction Study is an ongoing study aimed at assessing the best possible strategies for full scale reintroduction. Beginning in 1999, an in-basin brood stock development program was begun. Using donor stocks from Lower Columbia River Hatcheries, a wide range of genetics was introduced into the Yakima Basin. Currently, an in-basin coho stock has been developed and they are reared at the Yakama Nation Salmon Hatchery in Prosser Wa. In 1999, Phase I was implemented and in 2005 was completed. Phase I was published in American Fisheries Society in February 2007. Results from the success of Phase I raised many new exciting questions. Therefore, Phase II was developed and authorized in 2007 and is currently being implemented.

Phase I results showed promise in recovering an extinct species using an out-of-basin fish source. The success was almost immediate. After in-basin coho were established in the Prosser hatchery, the smolts showed higher survival rates than new out-of-basin smolts and have continued to outperform out-of-basin coho smolts. Adult returns have been steady and increasing since 1999. Large areas of new habitat have been seeded using acclimated smolts, and returning adults. Tributaries are now consistently producing coho. The wild coho in the Yakima River has been established, and returns have been over 1,000 adults in 6 out of 9 years. Using these results, Phase II was developed and implemented.

Phase II in the reintroduction plan uses a variety of techniques to study possible full scale recovery. Development of in-basin brood stock has continued and large acclimation sites are still in use. However, the focus shifted to experimenting on techniques to recover individual tributaries. Pit tagged summer parr are being released into select tributaries to identify quality rearing habitat. Hatchery adults are being outplanted into tributaries to monitor spawning conditions. Mobile acclimation techniques are being tested on two tributaries. Also, radio tags are being inserted into returning pit tagged adults for fidelity studies. These techniques are all being currently monitored and assessed.

The results from Phase I and II will guide a Yakima Basin Coho Master Plan that will outline the reintroduction strategies for the future.