Executive SummaryThis report presents the results of an evaluation of juvenile Chinook salmon (Oncorhynchus tshawytscha) behavior at Cougar Dam (CGR) on the south fork of the McKenzie River in Oregon in 2010. The study was conducted by the Pacific Northwest National Laboratory (PNNL) for the U.S. Army Corps of Engineers, Portland District (USACE). The overall goal of the study was to characterize juvenile salmonid behavior and movement patterns in the immediate forebay of the Water Temperature Control (WTC) tower of the dam for USACE and fisheries resource managers use in making decisions about bioengineering designs for long-term structures and/or operations to facilitate safe downstream passage for juvenile salmonids.We collected acoustic imaging (Dual-Frequency Identification Sonar; DIDSON) data from March 1, 2010, through January 31, 2011, to evaluate juvenile salmonid behavior year-round in the immediate forebay surface layer of the WTC tower (within 20 m, depth 0 to 5 m). From October 28, 2010, through January 31, 2011, a BlueView acoustic camera also was deployed in an attempt to determine its usefulness for future studies and to augment the DIDSON data. A total of 277 days of DIDSON and 65 days of BlueView data were collected during the study period. Because of the large amount of data recorded by the acoustic cameras each day and the cost for analysis, it was not feasible to analyze all of the acquired data. Instead, in consultation with USACE personnel, we processed a total of 45 separate 24-hour periods of DIDSON data covering every month throughout the 11-month study; some months included more sub-sampled days than others to cover special circumstances, such as, different forebay elevations and the presence of large numbers of juvenile fish. Two different 24-hour periods were processed for the BlueView data for the feasibility study. A basic observation of fish, that is, a single fish or a school of fish, in the sample volume was termed an "event." The data were analyzed to characterize a fish abundance index, fish size patterns, movement direction, diel and seasonal behavior patterns, schooling, and predation.Juvenile salmonids were present in the immediate forebay of the WTC tower throughout the study (March 2010 through January 2011). The juvenile salmonid (hereafter, called "fish" unless otherwise noted) abundance index was low in early spring (<200 fish per sample-day), began to increase in late April, and peaked on May 19 (6,039 fish). A second peak was observed on June 6 (2904 fish). Screwtrap estimates obtained from the Oregon Department of Fish and Wildlife (ODFW) of juvenile Chinook caught in the tailrace of the dam show comparable numbers, with estimates increasing in the spring and peaking in early June (~2400 fish). The fish abundance index began to decrease in early June and remained low in the summer months (<100 fish per sample-day). During the fall and winter, fish numbers per subsample date varied with a peak on November 10 (1881 fish) and a minimum on December 7 (12 fish). A second...
Pacific Northwest National Laboratory (PNNL) and subcontractors conducted an acoustic-telemetry study of juvenile salmonid fish passage and survival at Bonneville Dam in 2010. The study was conducted to assess the readiness of the monitoring system for official compliance studies under the 2008 Biological Opinion and Fish Accords and to assess performance measures including route-specific fish passage proportions, travel times, and survival based upon a single-release model. This also was the last year of evaluation of effects of a behavioral guidance structure installed in the Powerhouse 2 forebay. The study relied on releases of live Juvenile Salmon Acoustic Telemetry System tagged smolts in the Columbia River and used acoustic telemetry to evaluate the approach, passage, and survival of passing juvenile salmon. This study supports the U.S. Army Corps of Engineers continual effort to improve conditions for juvenile anadromous fish passing through Columbia River dams.v PrefaceThe U.S. Army Corps of Engineers (USACE) Portland District, contracted with the Pacific Northwest National Laboratory (PNNL), in Richland, Washington, to conduct an acoustic-telemetry survival study at the Bonneville Dam in 2010. The PNNL assembled a study team consisting of staff from PNNL, the Pacific States Marine Fisheries Commission (PSMFC), and the University of Washington. The Portland District provided all funding and oversight.This final report presents behavioral and fish passage results for tagged yearling and subyearling Chinook salmon smolts and juvenile steelhead as part of a survival study conducted at Bonneville Dam during 2010.This report was originally published in December 2011. It was revised in August 2012 to address review comments from the Studies Review Work Group of the USACE's Anadromous Fish Evaluation Program. One important change was to revise the fish collection section to clearly present numbers and percents of fish rejected, excluded, tagged and released alive or dead, and to list the sum of extra fish that were collected but not needed to fulfill the daily tagging quota. The fish passage efficiency statitics were added to Tables ES-2 and ES-3. A paragraph describing comparisons of spill treatment and day and night effects in summer and Table 6.8 were added to Section 6.6. We also added tables of subyearling Chinook survival results for combinations of day, night, and spill level to the appendices. We did not accept the recommendation of one reviewer to limit reporting to single-release survival estimates and to avoid using passage survival through the Bonneville Powerhouse 2 Corner Collector as a virtual reference release to make surrogate estimates of paired-release survival. All capture histories and single-release survival results were the primary focus of this report and were tabled in the Executive Summary and appendices. Estimation of surrogate paired-release survival estimates was a reasonable and informative exercise that was retained for readers that might be interested, but those estimates...
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