Coho Reintroduction in the Wenatchee and Methow Basins: Using a Phased Approach to Re-Establish Extirpated Populations

By the end of the 20^th century, indigenous natural coho salmon no longer occupied the mid- and upper-Columbia river basins. Several factors contributed towards this extirpation, which included but were not limited to construction and operation of mainstem Columbia River hydropower projects, habitat degradation, release locations, harvest management, hatchery practices and genetic guidelines. 

Studies of the feasibility of reintroducing coho in the Wenatchee and Methow subbasins began in 1996 and demonstrated that the vision held by Yakama Nation was possible. Two goals from which to determine the feasibility of reintroducing coho to mid-Columbia tributaries; 1) whether a broodstock could be developed from lower Columbia River coho stocks whose progeny can survive in increasing numbers to return as adults to the mid-Columbia region and 2) initiate natural reproduction in areas of low risk to sensitive species and in other select areas to study the risks and interactions with sensitive species.

Once feasibility goals had been met, a conceptual plan for these subbasins was developed to emphasize broodstock development and a transition towards natural production.  Distinct stages were created to guide the reintroduction efforts, which consisted of Broodstock Development I and II Phases, Natural Production Implementation Phase, and Natural Production Support Phases I and II.  This phased approach is an attempt to develop a local population over time through encouraging local adaptation to areas predicted by modeling to be successful for coho while focusing on decreasing domestication selection and increasing overall fitness in the natural environment. The program is designed to be discontinued after a minimum of five generations of natural production supplementation, unless it can be demonstrated that continued supplementation is needed to prevent extirpation from once again occurring.