Imnaha River Smolt Survival and Smolt to Adult Return Rate Quantification (Imnaha River Smolt Monitoring Program) BPA Project Number Nez Perce Tribe Department of Fisheries Resources Management Authors: Jay A. Hesse, Peter J. Cleary, Michael L. Blenden, and Paul A. Kucera

Associated Projects Fish Passage Center Smolt Monitor Program by non-federal Entities –In-season (real time) flow (spill) management –Hydrosystem configuration effectiveness/impact assessment –Long-term (time series) trend monitoring (status) Lower Snake River Compensation Plan Evaluation Studies –Hatchery Performance and Effectiveness

Project Background Smolt Emigration Studies began in 1993 at Cow Cr. (rkm 7) with funds from the Lower Snake River Compensation Plan (LSRCP). Participation in the Fish Passage Centers Smolt Monitoring Program began in 1994 as part of BPA Project < Project funding was obtained directly from BPA in 1998 < Major study design changes were proposed, but not funded, in 2002 for year round monitoring and obtaining smolt-to-adult returns for natural chinook salmon

Current Goals < Imnaha Smolt Monitoring - Provide emigration information to the Fish Passage Center while maintaining a time series of steelhead survival and arrival data to Lower Granite Dam, Lower Monumental Dam, and McNary Dam. <LSRCP - Provide information about juvenile chinook salmon biological characteristics, behavior and emigration timing, and survival and arrival timing to Snake River dams and McNary Dam.

Funded Objectives Describe emigration timing from the Imnaha River Monitor Imnaha River fish arrival timing and travel times to and through the mainstem Snake and Columbia rivers Estimate survival natural and hatchery fish from the Imnaha River subbasin to and through the mainstem Snake and Columbia rivers Provide information to the Fish Passage Center, Lower Snake River Compensation Plan Program, Northeast Oregon Hatchery Monitoring and Evaluation Program (NEOH M&E), and PTAGIS

Located 7 km from the confluence of the Snake River Below all but one major tributary Situated on private property Study Area Imnaha River Juvenile Fish Trap

Approach Juvenile Chinook Salmon and Steelhead Emigrant Trapping (March 1 – June 15) PIT Tag Chinook Salmon and Steelhead –Weekly release groups of –Season-wide sample size of 11,000 chinook salmon and 5,000 steelhead –Passage route control (SbyC) PIT Tag Interrogations of Smolts and Adults at Mainstem Dams and the Imnaha River

PIT Tagging Goals

Logistical Limitations <Sample Period: Normally October 15 to November 15, and March 1 to June 15 for a migration year. <Trapping Equipment: Screw traps are labor intensive and are not fished during periods when debris and discharge are excessive. <Funding: year round trapping require increased labor, supplies, and improved housing.

Smolt Emigration Timing Natural Chinook Natural Steelhead Hatchery Chinook Hatchery Steelhead

Juvenile Hatchery Chinook Salmon Emigration Timing Imnaha River

Size at Emigration 2003 Imnaha River Steelhead

Size at Emigration 2003 Imnaha River Chinook Salmon

Imnaha River Natural Juvenile Chinook Salmon Arrival Timing at Lower Granite Dam

90% Arrival Timing of Steelhead at Lower Granite Dam (1994 to 2003)

90% Arrival Timing of Chinook Salmon at Lower Granite Dam (1992 to 2003)

Weekly Survival of Hatchery Steelhead from the Imnaha River to Lower Granite and Lower Monumental Dams in 2003

Season-wide Juvenile Steelhead Survival Estimates to Lower Granite Dam Imnaha River

Season-Wide Juvenile Survival Estimates to McNary Dam Natural and Hatchery Steelhead 1998 to 2003

Post Release Survival Hatchery Chinook Salmon (Gumboot Acclimation Facility to Mouth of Imnaha River)

Season-wide Juvenile Chinook Salmon Survival Estimates to Lower Granite Dam Imnaha River

Season-Wide Juvenile Survival Estimates to McNary Dam Natural and Hatchery Chinook Salmon 1998 to 2003

Summary Tributary-specific contribution to Fish Passage Center Smolt Monitor Program basin aggregate monitoring. Maintains a time series of tributary-specific juvenile survival estimates to and through the Snake and Columbia river hydrosystem. –Natural chinook salmon survival to Lower Granite Dam range from 76 to 91%. –Hatchery chinook salmon survival to Lower Granite Dam range from 67 to 80%. –Natural steelhead survival to Lower Granite Dam range from 82 to 90%. –Hatchery Steelhead survival to Lower Granite Dam range from 64 to 89 %. Primary data and survival estimates available real time on line at and Annual reports posted at

Future Direction <Representative Juvenile Trapping and Marking (Year-Round) <Provide estimates of juvenile emigrant abundance at Imnaha rkm 7 <Measure the SAR for Imnaha River natural chinook salmon and steelhead from the Imnaha River to the Imnaha River, from Lower Granite Dam to Lower Granite Dam, and from Lower Granite Dam to the Imnaha River <Measure Juvenile survival to Lower Granite Dam (and McNary Dam) <Estimate Imnaha River natural chinook salmon and steelhead smolt equivalents at Lower Granite Dam

Questions?