Survival of Subyearling Fall Chinook Salmon in the Free-flowing Snake River and Lower Snake River Reservoirs in 2003 and from McNary Dam Tailrace to John Day Dam Tailrace in the Columbia River from 1999 to 2002, 1999-2003 Technical Report.
- National Marine Fisheries Service, Northwest Fisheries Science Center, Fish Ecology Division, Seattle, WA
We report results from an ongoing study of survival and travel time of subyearling fall Chinook salmon in the Snake River during 2003 and in the Columbia River during 1999-2002. Earlier years of the study included serial releases of PIT-tagged hatchery subyearling Chinook salmon upstream from Lower Granite Dam, but these were discontinued in 2003. Instead, we estimated survival from a large number of PIT-tagged fish released upstream from Lower Granite Dam to evaluate transportation from Snake River Dams. During late May and early June 2003, 68,572 hatchery-reared subyearling fall Chinook salmon were PIT tagged at Lyons Ferry Hatchery, trucked upstream, acclimated, and released at Couse Creek and Pittsburg Landing in the free-flowing Snake River. We estimated survival for these fish from release to Lower Granite Dam tailrace. In comparison to wild subyearling fall Chinook salmon PIT tagged and released in the free-flowing Snake River, the hatchery fish we released traveled faster and had higher survival to Lower Granite Dam, likely because of their larger size at release. For fish left in the river to migrate we estimated survival from Lower Granite Dam tailrace to McNary Dam tailrace. Each year, a small proportion of fish released are not detected until the following spring. However, the number of fish released in 2003 that overwintered in the river and were detected as they migrated seaward as yearlings in 2004 was small (<1.0%) and had minimal effect on survival estimates. We evaluated a prototype floating PIT-tag detector deployed upstream from Lower Granite reservoir to collect data for use in partitioning travel time and survival between free-flowing and reservoir habitats. The floating detector performed poorly, detecting only 27 PIT tags in 340 h of operation from a targeted release of 68,572; far too few to partition travel time and survival between habitats. We collected river-run subyearling Chinook salmon (mostly wild fish from the Hanford Reach) at McNary Dam, PIT tagged them, and released them to the tailrace as part of an evaluation of transportation from McNary Dam in 2002. Estimated survival in 2002 from the tailrace of McNary Dam to the tailrace of John Day Dam was 0.746 (s.e. 0.036). For migration years 1999-2002, we found that in the reach from McNary to John Day Dam reach, travel time was shorter (migration rate was greater) and survival probabilities were greater when flow volume was greater. Survival was also correlated with water temperature: warmer water was associated with decreased survival, and there was an apparent survival threshold at about 19.3 C (above this temperature survival decreased substantially).
- Research Organization:
- Bonneville Power Administration (BPA), Portland, OR (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- 00004922
- OSTI ID:
- 889640
- Report Number(s):
- DOE/BP-00004922-5; R&D Project: 199302900; TRN: US200619%%730
- Country of Publication:
- United States
- Language:
- English
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