Weirs: An effective tool to reduce hatchery–wild interactions on the spawning grounds?

Hatchery-produced salmon and steelhead Oncorhynchus mykiss mitigate for habitat loss and support valuable commercial, recreational, and tribal fisheries. However, excessive interactions between hatchery and wild fish can also cause harm to wild populations. Weirs have been implemented as a management tool to remove returning hatchery-origin Chinook Salmon O. tshawytcha adults to reduce the proportion of hatchery-origin spawners (pHOS) in spawning areas used by their wild counterparts. Using a decade of data since new weirs were implemented, our objective was to evaluate the efficacy of this management approach.