Lemhi Effectiveness Monitoring

This is an Intensively Monitored Watershed project. Spring/summer Chinook salmon & steelhead were the project targets; objectives & work are described below:
1. Annual juvenile salmonid abundance surveys using remote-site capture & tagging to estimate brood-year specific production.
Juvenile capture & tagging work was generally effective for estimates of total abundance & abundance by tributary. A total population estimate could not be calculated for salmon in 2015 because high pre-spawn adult salmon encounter rates affected recapture in the mainstem Lemhi. Estimates of total abundance & abundance by tributary were generated. Rotary screw trap operation on the lower mainstem Lemhi initiated in spring of 2011.
2. Estimate juvenile salmonid survival by tributary & mainstem. Estimated salmon survival by life stage & rearing location, including: 1) parr survival from PIT-tagging to emigration in the upper mainstem Lemhi above confluence with Hayden Cr. & in Hayden Cr., 2) overwinter survival in the upper mainstem Lemhi above the confluence with Hayden Cr. & in Hayden Cr., 3) parr/presmolt survival in upper mainstem Lemhi & Hayden Cr. to emigration from Lemhi, 4) overwinter (presmolt to smolt) in lower Lemhi, 5) spring smolt spring survival in upper-Lemhi & Hayden Cr. to emigration from Lemhi, 6) overwinter survival for presmolts rearing downstream of Lemhi, either in the upper-mainstem Salmon or Snake above the hydropower system, & 7) survival of spring smolts from Lemhi to Lower Granite Dam. Steelhead survival estimates not generated as currently unable to distinguish rainbow trout.
3. Annually estimate total adult escapement to Lemhi using in-stream PIT tag detection systems & spatial distribution of salmon spawning in Hayden Cr. through redd surveys. Natural-origin adult salmon & steelhead escapement to Lemhi was estimated. Data from temporary weirs in some tributaries suggest a large portion of steelhead escapement is comprised of hatchery-origin adults. Redd surveys used to identify distribution of salmon spawning in Hayden Cr.. Salmon spawning ground surveys conducted in Lemhi tributaries: Hayden, Little Springs, Big Timber, & Canyon creeks. Total redds in the Hayden Cr. drainage increased throughout the reporting period. No spawning activity was documented other surveyed creeks.
4. Assess status & trend of habitat attributes available to anadromous fish using CHaMP & LiDAR. The efficacy of Experimental Advanced Airborne Research Light Detection & Ranging technology was tested using one impacted reach & one reference reach. The large majority of elevations collected with LiDAR were within + 10cm compared to elevations collected by CHaMP survey.
5. Document change in habitat quantity & quality resulting from restoration:
Only Hayden Cr. retained annual hydraulic connection with the Lemhi in 2008. From 2008 to 2013 all restoration work has doubled tributary stream miles available to anadromous salmonids, resulting in 22% increase in stream area, & 19% increase in pool habitat available to anadromous salmonids. Summer parr rearing capacity estimated to have increased by 62%.
6. Model long-term outcomes of restoration work & evaluate potential of restoration work alternatives. Collect ISEMP & CHaMP data to populate model. This life cycle model relates freshwater productivity as a function of habitat quantity & quality.
7. Estimate adult Chinook migration timing & potential barriers with radio telemetry. 65 fish were radio tagged; 42 arrived in Lemhi; information used to evaluate migration timing & mainstem barriers.
8. Record water temperatures at 17 PIT-tag detection locations. Collected.
9. Install 10 new PIT-tag detection systems in tributaries. Evaluate potential sites for a lower-mainstem Lemhi adult capture facility. Installed 10 PIT-tag detection sites. Evaluated adult trap facility site in lower Lemhi; contract amended for funds to construct the adult trap facility.
Final re

This project will determine how ESA listed species will respond to habitat actions and will help guide future conservation actions using an adaptive management strategy. Once developed, this strategy will be used to assist other sub-basins in Idaho to allocate restoration efforts to more effectively address life-stage specific limiting factors of Chinook salmon and steelhead populations.