Passage and survival probabilities of juvenile Chinook salmon at Cougar Dam, Oregon, 2012

Abstract

For more information on the USGS-the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment-visit http://www.usgs.gov or call 1-888-ASK-USGS For an overview of USGS information products, including maps, imagery, and publications, visit http://www.usgs.gov/pubprodTo order this and other USGS information products, visit http://store.usgs.gov Suggested citation: Beeman, J.W., Evans, S.D., Haner, P.V., Hansel, H.C., Hansen, A.C., Smith, C.D., and Sprando, J.M., 2014, Passage and survival probabilities of juvenile Chinook salmon at Cougar Dam, Oregon, 2012:: U.S. Geological Survey OpenFile Report 2014-1038, 64 p., http://dx.doi.org/10.3133/ofr20141038/. ISSN 2331-1258 Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.Although this information product, for the most part, is in the public domain, it also may contain copyrighted materials as noted in the text. Permission to reproduce copyrighted items must be secured from the copyright owner. DatumVertical coordinate information is referenced to the National Geodetic Vertical Datum of 1929 (NGVD29).Elevation, as used in this report, refers to distance above the vertical datum. AbstractThis report describes studies of juvenile-salmon dam passage and apparent survival at Cougar Dam, Oregon, during two operating conditions in 2012. Cougar Dam is a 158-meter tall rock-fill dam used primarily for flood control, and passes water through a temperature control tower to either a powerhouse penstock or to a regulating outlet (RO). The temperature control tower has moveable weir gates to enable water of different elevations and temperatures to be drawn through the dam to control water temperatures downstream. A series of studies of downstream dam passage of juvenile salmonids were begun after the National Oceanic and Atmospheric Administration determined that Cougar Dam was impacting the viability of anadromous fish stocks. The primary objectives of the studies described in this report were to estimate the route-specific fish passage probabilities at the dam and to estimate the survival probabilities of fish passing through the RO. The first set of dam operating conditions, studied in November, consisted of (1) a mean reservoir elevation of 1,589 feet, (2) water entering the temperature control tower through the weir gates, (3) most water routed through the turbines during the day and through the RO during the night, and (4) mean RO gate openings of 1.2 feet during the day and 3.2 feet during the night. The second set of dam operating conditions, studied in December, consisted of (1) a mean reservoir elevation of 1,507 ft, (2) water entering the temperature control tower through the RO bypass, (3) all water passing through the RO, and (4) mean RO gate openings of 7.3 feet during the day and 7.5 feet during the night. The studies were based on juvenile Chinook salmon (Oncorhynchus tshawytscha) surgically implanted with radio transmitters an...

Genetic monitoring guides adaptive management of a migratory fish reintroduction program

“…The pattern we observed offered an opportunity for directed adaptive management, whereby managers took action in 2013 to minimize the reintroduction of immigrants (the LSDR method). These measures were taken due to the low recruitment rate estimates (CRRs) provided by our study and interest to limit the impacts of poor juvenile passage through the dam (Beeman et al ., ) to only those salmon associated with past reintroduction. One year's results suggested that this method successfully reduced the trap and transport of immigrants.…”

“…The low CRRs may also be due to the low survival rate to sexual maturity for Chinook salmon [e.g. Smolt‐to‐adult ratios (range: 0–2.2) Claiborne et al ., ] because there are many sources of mortality, such as poor passage through dams (Beeman et al ., ), predation (Collis et al ., ; Sinclair & Zeppelin, ), starvation during outmigration to the ocean (Kareiva, ) or while foraging in the open seas (Parker, ) and mortality prior to spawning (Keefer et al . 2010).…”

“…Managers wanted to limit the trap and transport of immigrants because the existing population of NOR Chinook salmon in the McKenzie River, a likely source of immigrants to the trap, is considered the only ‘genetic legacy’ population of the ESU (HSRG, ), and is thought to present unique genetic and life‐history diversity. Subjecting this legacy population to the potential risks of a novel reintroduction program, with uncertain juvenile dam passage survival (Beeman et al ., ), was unacceptable to local managers. However, managers were amenable to the trapping, transport and above‐dam release of those adult salmon that had been naturally produced through the reintroduction of hatchery fish.…”

A single generation in the wild increases fitness for descendants of hatchery‐origin Chinook salmon (Oncorhynchus tshawytscha)

“…There is no assisted downstream passage for juveniles produced above the dam. Downstream passage of outmigrants through Cougar Reservoir and Dam is associated with high mortality (Beeman et al., 2014; Duncan, 2011; Monzyk et al., 2015; Romer et al., 2016), and is likely a key factor limiting recovery (ODFW and NMFS, 2011). Productivity of the reintroduced population has been continuously evaluated since 2007 using genetic parentage analysis.…”