NOTE:  Work to PIT tag hatchery spring Chinook and natural-origin steelhead will not be started until WDFW receives written notice to proceed from the COTR with a copy to the Contracting Officer for the official contract file.

Tucannon River summer steelhead and spring Chinook are considered primary populations in the Snake River Basin, but both are considered depressed based on estimated numbers of natural origin spawners from WDFW redd counts.  However, redd count data from summer steelhead surveys are limited in scope and effectiveness due to survey conditions in the spring. Further, the only permanent fish trapping facility (Tucannon FH) is located 37 miles up the basin, and natural:hatchery composition are biased because of where hatchery mitigation fish are released in the Tucannon River.  However, unlike for summer steelhead, redd count surveys for spring Chinook in the Tucannon are very effective, with 25-35% of the carcasses recovered providing excellent estimates of the natural:hatchery composition.  

Recently, adult summer steelhead population estimates have been derived from PIT tags, confirming that the population is critically depressed.  Further, the PIT tag data have shown that both summer steelhead and spring Chinook from the Tucannon River migrate to, and remain above, Lower Granite Dam through the spawning season. This hydrosystem effect on natural origin summer steelhead and spring Chinook from the Tucannon River needs to be monitored further so managers can decide the most appropriate actions to recover these populations in the Tucannon River.

This project will expand the current efforts of PIT tagging on natural origin summer steelhead smolts in the Tucannon River, and hatchery origin spring Chinook smolts in the Tucannon River, and assist in the WDFW operation/maintenance of the lower Tucannon River PIT tag array. WDFW will attempt to PIT tag ~3,000 natural origin steelhead, and tag 25,000 hatchery spring Chinook on an annual basis. Based on the number of fish tagged and expected smolt-to- adult survivals, WDFW estimates that between 40-60 adults will return from each release group over the two (steelhead) or three (spring Chinook) year return cycle. These data, and especially for fish returning to the Tucannon River, will provide the basis for monitoring the status of the depressed steelhead population over time, and for assessing the straying of summer steelhead and spring Chinook above Lower Granite Dam.  Data from all PIT tagged fish (steelhead and spring Chinook) will be uploaded as required to the PTAGIS database.

A portion of the funding for this project will also cover some of the costs associated with the operation/maintenance of the Tucannon River PIT Tag Array, from which population estimates and proportions of fish straying outside of the Tucannon River can be determined. We anticipate that debris floating down the river could sometimes damage the antennas which would require repair, and the Tag Reader (MUX) may require occasional tune-up/service. Also, the current array is located in a remote area where there is no direct power source. A propane Thermoelectric generator system serves as the power source, and requires approximately 550 gallons of propane annually to operate the site.