Nonnative brook trout exist in high numbers in the Upper Malheur. The introduced fish poses serious threats to the long term viability of bull trout because of its ability to outcompete and hybridize with the native. Resource competition and hybridization between the two species is documented in the Upper Malheur. Brook trout threats, along with other environmental and anthropogenic factors, have imperiled the native in the Upper Malheur and led to the population being classified as having a “high risk” of extinction. As identified by the Malheur River Technical Advisory Committee (TAC), brook trout are the primary limiting factor to bull trout recovery. Accordingly, Federal Recovery Criteria for the Upper Malheur River Core Area includes brook trout removal as a high priority and an immediate action necessary to achieve full recovery and delisting. Additionally, reducing the effect of brook trout on bull trout is strategized under Objective 4.1 of the NPCC Subbasin Plan.

BPT has taken the lead in implementing this management action.  Implementation of mechanical methodology to control brook trout in the Malheur River began through this project in FY2011. BPT considers current use of mechanical methodology and baseline data collection as “Phase I” of suppression efforts, as approved in the FY2012 Categorical Review of Resident Fish projects. BPT staff has been working on "Phase II" of the brook trout removal efforts alongside the agencies comprising the TAC. This Phase II approach is proposed to consist of barrier installation and rotenone treatments.  “Phase II” will be contingent upon the results and baseline establishment in “Phase I” (e.g., barrier site selections, success of electrofishing/weir removal efforts, etc.), and the continued collaboration between tribal, state and federal agencies in the TAC.

These efforts in FY2017 coincide with additional projects funded by other sources: use of eDNA to detect changes in abundance of brook trout and to monitor resulting trends in bull trout (NRCS funding); development of NEPA analysis for long term treatment of High Lake (U.S. Fish and Wildlife Service Tribal Wildlife Grant); and empirical investigation of the complete range of brook trout in the basin in order to evaluate eradication options (U.S. Forest Service Funding).  This project also has attracted substantial in-kind contributions through interagency collaboration.

Work elements in the FY2017 SOW were approved in the FY2013-2017 Categorical Review by NPCC and successfully vetted through the ISRP.