This project monitors the effectiveness of B-run steelhead hatchery (supplementation) releases in the Clearwater River subbasin by providing: 1) hatchery (supplementation and conventional) monitoring on B-run steelhead (Oncorhynchus mykiss) releases, 2) incorporation and validation of PIT tag array-based status and trend estimates of adult abundance, 3) descriptive biological data on natural-origin returns and 4) facilitation of a run reconstruction of Snake Basin steelhead to known and unknown areas. Carried out by co-managers (Nez Perce Tribe and Idaho Department of Fish and Game), this project plays a critical role in increasing the understanding of two populations of B-run steelhead in the Clearwater River major population group, the Lolo Creek and the South Fork Clearwater River (SFCR) populations.
This project evaluates the efficacy of supplementation by 1) monitoring the population abundances of Lolo Creek and SFCR steelhead, 2) assessing the relative productivity, survival and behavior of natural and hatchery fish in Lolo Creek and 3) comparing the relative performance of supplementation and conventional hatchery steelhead in the SFCR. Furthermore, the spatial distribution of returning natural, supplementation, and conventional adults in the SFCR are being investigated to determine spatial overlap in the spawning distribution of these fish and to verify or refute the presence of a velocity barrier to returning steelhead in the SFCR. Working in coordination with collaborators in the Snake River Basin (U.S. Fish & Wildlife Service, The Shoshone-Bannock Tribe, Oregon Department of Fish & Wildlife, and Washington Department of Fish & Wildlife) the data collected through the activities of this project is being integrated with other monitoring projects to account for the final disposition of adults upstream of Lower Granite Dam for the purposes of run reconstruction.
In addition to these activities, this project incorporates a suite of tagging technologies to improve the information available on the status of steelhead populations in the Clearwater River subbasin. Supplementation juveniles are coded wire tagged to distinguish these individuals from natural fish as adults. Juveniles are PIT tagged at the Lolo Creek and SFCR screw traps to determine juvenile abundance and survival through the hydrosystem using mark-recapture analyses. Finally, a subset of the adults returning to SFCR are captured (utilizing Separation by Code at Lower Granite Dam and the help of volunteer anglers) and tracked to evaluate their spatial distribution in the SFCR via radio telemetry.