Eradication of Nonnative Trout with Antimycin-a and the Response of Native Bull Trout in Sun Creek: Two Decades of Restoration in a Small Southern Oregon Watershed

Since 1992, the National Park Service (NPS) and partners have used exclusion barriers, mechanical removal, and antimycin-A to restore bull trout (Salvelinus confluentus) in the Sun Creek watershed.   Nonnative brook trout (S. fontinalis) and brown trout (Salmo Trutta) were eradicated from 14 kilometers of headwater habitat in Crater Lake National Park by 2005, allowing bull trout to increase in abundance and distribution.  During 2012 and 2013, the NPS and Oregon Department of Fish and Wildlife chemically treated an additional 7 kilometers on state forest land downstream.  Initial monitoring indicates recent treatments successfully eradicated nonnatives.  Bull Trout are colonizing the newly renovated reach from upstream, and 85% of the Sun Creek watershed now contains only native fish.  An artificial barrier downstream of the restored area includes a fish trap to allow selective upstream passage of native fish.  Federal, state, and private partners are working in the remainder of the watershed to restore privately owned stream habitat which was modified for irrigation and degraded by grazing.  This long-term project was initiated to conserve bull trout in the national park and has grown into a landscape-scale partnership for restoration of native fish, contributing toward ESA recovery goals in the region.