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 the natural:hatchery composition ratio is 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 will tag 15,000 hatchery spring Chinook on an annual basis.  For FY2013, the managers decided that the number of PIT Tags for spring Chinook could be reduced and still provide the necessary information, with the cost savings to be used in building/replacing PIT antennas at the lower array site in the Tucannon River.  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, 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 and will be analyzed under funding from the LSRCP.

This project will also cover 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. Debris floating down the river during high stream flows in the spring months damage the antennas or require complete replacement on an annual basis.  In addition the Tag Reader (MUX) requires occasional tune-up/service. Also, the current array is located in a remote area where there is no direct power source. A propane Thermo-Electric Generator (TEG) System serves as the power source, and requires approximately 560 gallons of propane annually to operate the site.  If any additional funding is needed for O&M, it will come from LSRCP budgets.