Snake River Basin steelhead (Oncorhynchus mykiss) are listed as threatened under the Endangered Species Act. Yet little tributary specific status and trend information of A-run aggregates upstream of Lower Granite Dam exists. The NOAA Fisheries Service determined that there are at least five populations of A-run and five populations of B-run steelhead in the Snake River Steelhead ESU. The Imnaha River is host to one of the Snake River A-run steelhead populations.
We propose to quantify adult steelhead escapement into the Imnaha River Subbasin and describe the population's spatial distribution within the subbasin. A properly monitored Imnaha steelhead population will contribute towards understanding the status and viability of the entire Snake River ESU and informed management decisions. In addition, NOAA Fisheries Service calls for monitoring and evaluating the viability of component populations using four complimentary criteria for "Viable Salmonid Populations". These are the monitoring priorities for Imnaha steelhead highly recommended by the Collaborative Anadromous Workshop in the Snake Basin strategy that will relate performance at the population scale to risks affecting the persistence of the entire DPS (Distinct Population Segment).
Therefore, researchers from the Nez Perce Tribes Department of Fisheries Resources Management have relied on numerous contemporary documents to develop a monitoring project that will implement the VSP monitoring recommendations, apply the RME objectives found in the 2009 Fish and Wildlife Program, address critical uncertainties from the Council's 2006 Columbia River, and execute reasonable and prudent alternative (RPA) 50.6 in 2008 Federal Columbia River Power System Biological Opinion documents. This fast track proposal, along with other related projects in the Imnaha Subbasin, will use floating weirs, fixed weirs, resistivity weirs, and PIT tag array methodology. Results from these multiple methods will provide natural and hatchery adult abundance, distribution, life history, and genetic information in the Imnaha River drainage.