Addressing Critical Uncertainties in the Reintroduction of Chum Salmon to Oregon Tributaries of the Columbia River

Historically, chum salmon Oncorhynchus keta represented a significant portion of the salmon and steelhead returns to the lower Columbia River, with peak returns in 1928 estimated at over a million chum salmon.  Beginning in the 1800s, changes to land use significantly degraded the habitats with which chum salmon are associated.  Coupled with harvest rates > 80%, by the 1940s, over 90% of chum salmon populations were extirpated.  In Oregon, recovery efforts began in earnest in 2012 with the initiation of the Chum Reintroduction Project.  The initial focus of the project is on investigating critical uncertainties in the techniques required to re-establish viable chum salmon populations in Oregon tributaries to the Columbia River. In this presentation, I describe (1) our adaptive management approach to achieving recovery goals and (2) experimental reintroductions that were completed in 2013 and 2014. Preliminary results from experimental reintroductions indicate adult outplanting and onsite incubation of eyed-eggs are viable techniques, although the efficacy of each depends on characteristics of the reintroduction site.   As such, the Oregon approach to recovery includes employing a suite of reintroduction techniques in habitats spatially arranged throughout the lower Columbia River in an effort to spread risk and encourage adaptation to diverse environments.