Population Viability Improvements Following the Removal of a Hatchery Program in Salmon River (Oregon)

Fisheries agencies have relied on hatchery production to meet harvest and supplementation objectives for 150 years, and once in place, such programs usually have become institutionalized.  A number of recent genetic studies and meta- and retrospective analyses have documented reduced productivity of wild salmon and steelhead that interbreed with hatchery-reared fish, raising concerns about the long-term viability and recovery of at-risk stocks. In 2007 the Oregon Department of Fish and Wildlife discontinued a coho salmon hatchery program at Salmon River to support recovery of a “threatened” wild coho population in the Oregon Coast ESU. This decision constituted a unique management “experiment” allowing direct measurement of the wild population response following the discontinuation of a decades-old hatchery program. We quantified the response of two generations of coho salmon from the 2006 through 2011 brood years; spawner to recruit ratios shifted from a fraction of to equal that in neighboring populations, spawn timing moved closer to historic timing, and survival rates and life history diversity increased. Our results documented a rapid improvement in multiple population viability metrics within two generations, indicating that discontinuing a hatchery program can be an effective management action to meet conservation and harvest goals.