Article

Status after 5 Years of Survival Compliance Testing in the Federal Columbia River Power System (FCRPS)

Authors:
To read the full-text of this research, you can request a copy directly from the authors.

Abstract

Survival studies of juvenile Pacific salmon Oncorhynchus spp. implanted with acoustic tags have been conducted at hydroelectric dams within the Federal Columbia River Power System in the Columbia and Snake rivers between 2010 and 2014 to assess compliance with the dam passage survival standards stipulated in the 2008 Biological Opinion. For juvenile yearling Chinook Salmon O. tshawytscha and steelhead O. mykiss that migrate downstream in the spring, dam passage survival (defined as survival from the upstream dam face to the tailrace mixing zone) must be ≥ 96%, and for subyearling Chinook Salmon that migrate downstream in summer, dam passage survival must be ≥ 93%. Precision requirement stipulates a standard error ≤ 1.5% (i.e., a 95% confidence interval of ± 3%). A total of 29 compliance tests have been conducted at six of eight main-stem dams in the Federal Columbia River Power System, using over 109,000 acoustic-tagged salmonid smolts. Of these 29 compliance studies, 23 met the survival standards and 26 met the precision requirements. Of the six dams evaluated to date, individual survival estimates range from 0.9597 to 0.9868 for yearling Chinook Salmon, from 0.9534 to 0.9952 for steelhead, and from 0.9076 to 0.9789 for subyearling Chinook Salmon. Averages across the six dams exceed the survival standards for all three migrant populations.Received November 9, 2015; accepted February 16, 2016

No full-text available

Request Full-text Paper PDF

To read the full-text of this research,
you can request a copy directly from the authors.

... In recent decades, cooperators within major river basins on the east and west coasts of North America have invested in large-scale studies and monitoring programs, which make use of technically sophisticated tracking systems (McMichael et al. 2010; Thorstad et al. 2012;Leander et al. 2020). These programs have relied on passive integrative transponders and radio-and acoustic-tagging technologies (Skalski et al. , 2002Trancart et al. 2020) to provide rigorous evaluations of structural and operational changes at dams, evaluate the effectiveness of actions, and help guide future decision making (Cooke and Hinch 2013;Skalski et al. 2016a;Munsch et al. 2020). Similar fishtracking studies have been performed in Europe (Aarestrup et al. 2009;Abecasis et al. 2018;Kennedy et al. 2019) and Asia (Makiguchi et al. 2008;Wang et al. 2014;Kim et al. 2016). ...
... Dam operators were required to demonstrate compliance with conservation actions by meeting specific survival thresholds for smolts that were based on rigorous acoustic telemetry studies and statistical analyses (Skalski et al. 2016a). Between 2010 and 2018, 40 passage studies were performed at seven of the eight FCRPS hydroelectric projects, using yearling and subyearling Chinook Salmon Oncorhynchus tshawytscha and steelhead O. mykiss smolts. ...
... The working hypotheses that we evaluated include differences in smolt passage patterns between the hydroelectric projects, specifically the dams in the Snake River versus those in the lower Columbia River, and between fish stocks, specifically the spring and summer migrants. These tagging studies were performed during survival compliance testing under the 2008 FCRPS biological opinion to establish long-term operating conditions for the various hydroelectric projects (Skalski et al. 2016a). Therefore, these analyses are a much-needed synthesis that can also serve as a baseline for comparison with passage compliance under the more recent courtordered spill program. ...
Article
Minimizing the mortality and migration time of juvenile salmon (smolts) passing dams is a longstanding objective in the pursuit of salmon recovery in the Columbia River Basin. We compiled and analyzed 40 juvenile salmonid acoustic‐tag studies that were performed at seven of the eight hydroelectric projects in the Federal Columbia River Power System between 2010–2018. We found the utilization of non‐turbine routes decreased monotonically moving downstream from the Snake River to the mainstem Columbia River dams and associated mortality differed substantially between the dams in the two rivers. Spillways were the predominant passage route at mainstem Columbia River dams, whereas passage through surface weirs and juvenile bypass systems was more common and generally provided higher survival at Snake River dams. Stocks exhibited variable passage behaviors and mortalities, with the estimated probability of an individual passing through all eight dams in the system and never using a turbine route at 0.31, 0.47, and 0.60 for subyearling Chinook Salmon, yearling Chinook Salmon, and steelhead, respectively. Although subyearling Chinook Salmon were generally more likely to pass through a turbine route, they also experienced less turbine‐associated mortality than other stocks, especially steelhead. Notably, the proportion of smolts passing through the spillway relative to the proportion of water through the spillway was lowest at Bonneville Dam, the largest and lowermost dam in the system. Bonneville Dam also stood out as having the highest proportion of smolts passing through turbines, but among the lowest rates of turbine‐associated mortality.
... However, even minor tag failure may be consequential when survival estimates are required to meet specific standards. For example, over the last decade, federal hydroproject operators had to comply with survival threshold and minimum precision criteria (e.g., survival ≥ 0.96 average dam passage survival for juvenile spring Chinook salmon and steelhead with standard error ≤ 0.015) [32]. Even a small degree of bias can be consequential in regulatory studies. ...
... Such studies are designed based on the anticipated life expectancy of the tags and the temporal requirements of the investigation [2]. On the other hand, fish survival studies based on regulatory requirements with mandated survival thresholds will generally need to include formal tag-life studies [32]. Without the ancillary tag-life information, perceived survival estimates calculated by classic release-recapture models will be negatively biased by the presence of tag failure [13,35]. ...
... When actual fish survival is close to the regulatory thresholds, even small bias corrections can be consequential. For example, the compliance threshold for yearling Chinook salmon (Oncorhynchus tshawytscha) and steelhead smolt survival through a hydroelectric project (i.e., reservoir plus dam) in the mid-Columbia River is typically ≥ 93%, with an estimated standard error of ≤ 0.025 [28,29,32]. At federally operated hydroprojects in the lower Snake River and mainstem Columbia River, dam passage survival has a threshold of 0.96 for yearling Chinook salmon and steelhead smolts or 0.93 for subyearling Chinook salmon with a precision requirement of SE ≤ 0.015. ...
Article
Full-text available
Acoustic telemetry studies often rely on the assumption that premature tag failure does not affect the validity of inferences. However, in some cases this assumption is possibly or likely invalid and it is necessary to apply a correction to estimation procedures. The question of which approaches and specific models are best suited to modeling acoustic tag failures has received little research attention. In this short communication, we present a meta-analysisof 42 acoustic tag-life studies, originally used to correct survival studies involving outmigrating juvenile salmonidsin the Columbia/Snake river basin. We compare the performance of nine alternative parametric models including common failure–time/survival models and the vitality models of Li and Anderson Theor Popul Biol 76:118–131, (2009) and Demogr Res 28:341–372, (2013). The tag-life studies used acoustic tags from three different tag manufacturers, had expected lifetimes between 12 and 61 days, and had dry weights ranging from 0.22 to 1.65 g. In 57% of the cases, the vitality models of Li and Anderson Theor Popul Biol 76:118–131, (2009) and Demogr Res 28:341–372, (2013) fit the tag-failure times best. The vitality models were also the second-best choices in 17% of the cases. Together, the vitality models, log-logistic, (19%), and gamma models (14%) accounted for 90% of the models selected. Unlike more traditional failure–time models (e.g., Weibull, Gompertz, gamma, and log-logistic), the vitality models are capable of characterizing both the early onset of tag failure due to manufacturing errors and the anticipated battery life. We provide further guidance on appropriate sample sizes (50–100 tags) and procedures to be considered when applying precise tag-life corrections in release–recapture survival studies.
... Efforts to mitigate carryover effects from freshwater that could affect marine survival in these populations have primarily focused on dams. Survival through Columbia and Snake River dams generally now meets recovery targets (>96%) 83 , and cumulative mortality over 500 km of in-river migrating fish (~50%) is similar to that estimated for unregulated rivers of similar length (i.e., Fraser River 84 ). However, slow travel time through slow-flowing reservoirs behind dams, combined with increased surface temperatures in these reservoirs 85 , can potentially result in lower marine survival 86 . ...
Article
Full-text available
Widespread declines in Atlantic and Pacific salmon (Salmo salar and Oncorhynchus spp.) have tracked recent climate changes, but managers still lack quantitative projections of the viability of any individual population in response to future climate change. To address this gap, we assembled a vast database of survival and other data for eight wild populations of threatened Chinook salmon (O. tshawytscha). For each population, we evaluated climate impacts at all life stages and modeled future trajectories forced by global climate model projections. Populations rapidly declined in response to increasing sea surface temperatures and other factors across diverse model assumptions and climate scenarios. Strong density dependence limited the number of salmon that survived early life stages, suggesting a potentially efficacious target for conservation effort. Other solutions require a better understanding of the factors that limit survival at sea. We conclude that dramatic increases in smolt survival are needed to overcome the negative impacts of climate change for this threatened species.
... Fish mortality has been directly attributed to dam passage (Č ada 2001;Muir et al. 2001;Skalski et al. 2002;Schilt 2007;Larinier 2008) and to indirect effects from factors such as predation, migration delay, pathogen transmission, and thermal perturbations Clarkson and Childs 2000;Schreck et al. 2006;Keefer et al. 2012;Colvin et al. 2015). Substantial efforts have focused on developing safe and effective fish passage options for upstream (Clay 1995;Roscoe and Hinch 2010;Bunt et al. 2012;Katopodis and Williams 2012;Pompeu et al. 2012;Williams et al. 2012) and downstream migrants at dams (Ferguson et al. 2007;Schilt 2007;Adams et al. 2014;Shi et al. 2015;Skalski et al. 2016;Fjelstad et al. 2018). Unfortunately, fish passage facilities have often failed to fully mitigate negative effects of dams and their impoundments (Nicola et al. 1996;Caudill et al. 2007;Fukushima et al. 2007;Ferguson et al. 2011). ...
Article
Full-text available
High-head dams are migration barriers for Pacific salmon Oncorhynchus spp. in many river systems and recovery measures for impacted stocks are limited. Trap-and-haul has been widely used in attempts to facilitate recovery but information from existing programs has not been synthesized to inform improvements to aid recovery of salmonids in systems with high-head dams. We reviewed 17 trap-and-haul programs regarding Pacific salmon to: (1) summarize information about facility design, operation and biological effects; (2) identify critical knowledge gaps; and (3) evaluate trap-and-haul as a current and future management tool. Existing programs are operated to address a range of management goals including restoring access to historical habitats, temporarily reducing exposure to dangerous in-river conditions, and reintroducing ecological processes upstream from dams. Information gathered from decades of operation on facility design criteria and fish handling protocols, and robust literature on fish collection and passage are available. While many aspects of trap-and-haul have been evaluated, effects on population productivity and sustainability remain poorly understood. Long-term and systematic studies of trap-and-haul outcomes are rare, and assessments can be confounded by concurrent management actions and broad ecological and climatic effects. Existing data suggest that performance and effectiveness vary among programs and over various time scales within programs. Although critical information gaps exist, trap-and-haul is an important management and conservation tool for providing Pacific salmonids access to historical habitats. Successful application of trap-and-haul programs requires long-term commitment and an adaptive management approach by dam owners and stakeholders, and careful planning of new programs.
... Before this study, the professional judgement of resource managers was that juvenile salmon survival would be very poor through Shasta Reservoir. Under the very high flows during the February release, survival was higher than expected, and similar to that measured at large run-of-the-river dams and reservoirs on the Snake and Columbia rivers (Plumb et al. 2012;Skalski et al. 2016). Under average river flows in November; however, the a priori expectation of poor fish survival to Shasta Dam was supported. ...
... For any remaining dams, regulatory mechanisms provide the ability for survival standards to be im-plemented under the Federal Power Act and Endangered Species Act. Standards sufficient to rebuild stocks have been established for Pacific salmon (National Marine Fisheries Service 2008) and have been shown to be achievable (Skalski et al. 2016). Survival standards for Atlantic salmon have recently been proposed for some facilities (National Marine Fisheries Service 2012b), and our scenarios indicate probable improvement of smolt output by 44% (from Unrestored) if these standards were achieved at all dams in the system. ...
Article
Full-text available
Dams challenge Atlantic salmon (Salmo salar) conservation, while hatcheries are a common but poorly evaluated recovery tool. We developed a spatially explicit smolt survival model for the Penobscot River, Maine, USA, population. By partitioning survival through dams (with flow dependency), free-flowing river reaches, and the estuary (with dam dependency), the model quantified how these factors influenced the number of fish entering the ocean. Given historical impounded conditions, 74%–22% of hatchery smolts released entered the ocean annually from 1970 to 2012. Of 19.7 million smolts stocked, 7.7 million entered the ocean (39%). Survival was most variable at dams (range 95% to 63%), followed by in-river (range 98% to 70%) and estuary (range 88% to 82%). Overall, lower-river stocking sites resulted in significantly higher numbers at ocean entry because of fewer dam encounters and shorter migrations. Higher flows also resulted in reduced losses. By reconstructing these freshwater and estuary dynamics, the model provides a more accurate estimate of ocean recruitment annually and can be used for scenario planning of future stocking locations relative to predicted flows while being adaptable to new survival rates.
... It has been practice to report 4 decimal places out of concern for complete disclosure. However, as Skalski et al. (2016) report, 25 rather than 23 out of a total of 29 survival studies performed in the FCRPS from 2010 to date would have met the survival threshold if reporting was to 3 rather than 4 decimal places. NOAA and the Action Agencies have discretion to accept studies with small deviations from the standards. ...
Article
Full-text available
An elaborate set of criteria have been developed by fish managers and regulators to assure the accuracy, precision, representativeness, and robustness of survival compliance studies coordinated within the Federal Columbia River Power System in the northwestern USA. Dam passage survival, defined as survival from the dam face to the tailrace mixing zone, must be ≥96 % for spring out migrating juvenile salmonids [i.e., yearling Chinook salmon (Oncorhynchus tshawytscha) and steelhead (O. mykiss)] and ≥93 % for summer outmigrants (i.e., subyearling Chinook salmon). Survival must be estimated with a standard error ≤1.5 %. However, these quantitative benchmarks are only part of a multifaceted set of criteria, including representative dam operations, river discharge levels, and fish selection, along with tests of model validity that must be satisfied. These criteria are illustrated using acoustic-tag survival compliance studies conducted at The Dalles Dam on the Columbia River, 2010–2012. The results suggest evaluation criteria for survival compliance tests must balance the needs for rigor and robustness with the ability to reasonably perform the tests in naturally varying riverine systems.
Article
Full-text available
Two laboratory studies evaluated small Chinook salmon Oncorhynchus tshawytscha (36–99 mm fork length [FL], 0.7–26.7% tag burden) survival, tag retention, and growth (n = 539), and critical swimming speed (Ucrit; n = 241). Fish were implanted with a new active acoustic tag and compared to untagged controls at 12 °C and 17 °C. Across studies no temperature differences were detected. All control fish survived. All tagged fish ≥ 58 mm FL survived and retained their tags. Regression models predicted ≥ 98.6% survival and retention for tagged fish ≥ 58.6 mm FL or ≥ 1.9 g (4.2% tag burden). No growth differences among treatments were identified. Spline regression analysis indicated Ucrit was similar for control and tagged fish that measured ≥ 57.3 mm FL. We recommend tagging salmon ≥ 59 mm FL or ≥ 1.9 g (≤ 4.2% burden), although the guideline should be confirmed in a field setting. Study results represent an important step towards using the new active tag in acoustic telemetry field studies that estimate short-term (30-day) survival of small salmonids.
Preprint
Full-text available
Acoustic telemetry studies often rely on the assumption that premature tag failure does not affect the validity of inferences. However, in some cases this assumption is possibly or likely invalid and it is necessary to apply a correction to estimation procedures. The question of which approaches and specific models are best suited to modeling acoustic tag failures has received little research attention. In this short communication, we present a meta-analysis of 42 acoustic tag-life studies, originally used to correct survival studies involving outmigrating juvenile salmonids in the Columbia/Snake river basin. We compare the performance of nine alternative parametric models including common failure-time/survival models and vitality models of Li and Anderson (2009 and 2013), which characterize demographic heterogeneity in the mortality of populations. The tag-life studies used acoustic tags from three different tag manufacturers, had expected lifetimes between 12 and 61 days, and had dry weights ranging from 0.22 to 1.65 grams. In 57% of the cases, the vitality models of Li and Anderson (2009 and 2013) fit the tag failure-times best. The vitality models were also the second-best choices in 17% of the cases. Together, the vitality models, log-logistic, (19%), and gamma models (14%) accounted for 90% of the models selected. Unlike more traditional failure-time models, the vitality models are capable of characterizing both the early onset of tag failure due to manufacturing errors and the anticipated battery life. We provide further guidance on appropriate sample sizes (50–100 tags) and procedures to be considered when applying precise tag-life corrections in release-recapture survival studies.
Article
Passage of downstream‐migrating fishes through hydropower dams poses a management issue in rivers throughout the world. As such, regulations have been enacted at many locales to understand and limit fish losses by requiring dam passage survival estimation. However, limiting estimates of survival to the dam and immediate tailrace presents a challenge to researchers. In this study, two alternative release‐recapture methods were used to estimate dam passage survival of juvenile salmonids through Lower Granite Dam in the Snake River, Washington State in 2018. One approach, the virtual/paired release (ViPRe) model, has been extensively used in the Columbia/Snake River Basin at federally operated hydroelectric dams, 2010–2014. This existing approach uses three releases of tagged smolts to isolate dam passage survival, defined as survival from the upstream dam face to the tailrace mixing zone, 1‐ to 2‐km downstream of the dam. An alternative approach, the virtual release/dead fish correction (ViRDCt) model, uses one alive release paired with a release of dead‐tagged fish at the dam to estimate the same survival parameter. The alternative estimation approaches were tested on two spring migration stocks, yearling Chinook Salmon and steelhead, and on a summer migrant stock of subyearling Chinook Salmon. The alternative estimates for these stocks were all within one standard error. However, the ViRDCt model produced survival estimates with standard errors 59% smaller than those of the existing ViPRe model and did so using 42% fewer tagged fish and one less downstream acoustic detection array. Because of the reduced sample size, nearly $540,000 less was spent on tags and 4,000 fewer labor hours were required to implement the ViRDCt model compared to the ViPRe model. As such, the ViRDCt model represents a cost‐effective and precise approach to characterizing dam passage survival.
Article
Providing efficient downstream passage is critical for improving populations of migratory fishes in impounded river systems. High‐head dams, such as those used for water storage or flood‐risk management, pose unique passage challenges requiring unique solutions. Systems to collect fish in dam forebays, “forebay collectors”, for transport to downstream release locations have been used at some high‐head dams in the western United States since the 1950s. Collection efficiency of these facilities has ranged from nearly zero to 100%, suggesting the need for better understanding of factors affecting performance in these complex environments if they are to be designed and deployed at new sites. We compiled information on environmental, structural, and performance characteristics of seven existing forebay collectors to quantify factors affecting their performance based on a meta‐analysis using a dataset containing 52 separate collection estimates. Covariates included species type (steelhead Oncorhynchus mykiss, Chinook Salmon O. tshawytscha, Coho Salmon O.kisutch, Sockeye Salmon O. nerka), collector inflow, collector entrance area, relative size of the dam forebay, and whether or not nets were used to enhance collection. We found that inflow, the use of lead nets, the size of the collector entrance area, the relative size of the dam forebay, and the interaction between collector entrance and forebay areas were significant predictors of collection performance. There was also evidence for differences between species. Chinook Salmon exhibited the lowest collection rates among the projects we examined while steelhead collection rates were highest. These results provide guidance to design more efficient forebay collectors and improve success of existing systems. This article is protected by copyright. All rights reserved.
Article
In the Pacific Northwest, widespread stream channel simplification has led to a loss of habitat area and diversity for rearing salmon. Subsequent efforts throughout the Columbia River basin (CRB) have attempted to restore habitats altered through land development to recover imperiled salmon populations. However, there is scant evidence for demographic change in salmon populations following restoration. We used a process-based approach to estimate the potential benefit of floodplain reconnection throughout the CRB to Chinook salmon (Oncorhynchus tshawytscha) parr. Using satellite imagery, we measured stream habitats at 2093 CRB stream reaches to construct random forest models of habitat based on geomorphic and regional characteristics. Connected floodplain width was the most important factor for determining side channel presence. We estimated a current CRB-wide decrease in side channel habitat area of 26% from historical conditions. Reconnection of historical floodplains currently used for agriculture could increase side channel habitat by 25% and spring Chinook salmon parr total rearing capacity by 9% over current estimates. Individual watersheds vary greatly in habitat factors that limit salmon recovery, and large-scale estimates of restoration potential like these are needed to make decisions about long-term restoration goals among imperiled populations.
Article
Full-text available
Better understanding of fish behavior is vital for recovery of many endangered species including salmon. The Juvenile Salmon Acoustic Telemetry System (JSATS) was developed to observe the out-migratory behavior of juvenile salmonids tagged by surgical implantation of acoustic micro-transmitters and to estimate the survival when passing through dams on the Snake and Columbia Rivers. A robust three-dimensional solver was needed to accurately and efficiently estimate the time sequence of locations of fish tagged with JSATS acoustic transmitters, to describe in sufficient detail the information needed to assess the function of dam-passage design alternatives. An approximate maximum likelihood solver was developed using measurements of time difference of arrival from all hydrophones in receiving arrays on which a transmission was detected. Field experiments demonstrated that the developed solver performed significantly better in tracking efficiency and accuracy than other solvers described in the literature.
Article
Full-text available
Evidence suggests Snake River stream-type Chinook salmon (Oncorhynchus tshawytscha) experience substantial delayed mortality in the marine environment as a result of their outmigration experience through the Federal Columbia River Power System (FCRPS). We analyzed mortality patterns using methods that incorporated downriver reference populations passing fewer dams, and temporal approaches that were independent of reference populations. Our results from the alternative spatial and temporal methods consistently corroborated with spawner–recruit residuals and smolt-to-adult survival rate data sets, indicating that Snake River salmon survived about one quarter as well as the reference populations. Temporal analysis indicated that a high percentage (76%) of Snake River juvenile salmon that survived the FCRPS subsequently died in the marine environment as a result of their outmigration experience. Through this and previous studies, it is evident that delayed hydrosystem mortality increases with the number of powerhouse passages and decreases with the speed of outmigration. Therefore, a promising conservation approach would be to explore management experiments that evaluate these relationships by increasing managed spill levels at the dams during the spring migration period.
Article
Full-text available
In 2008, the National Marine Fisheries Service completed the sixteenth year of a study to estimate survival and travel time of juvenile salmonids Oncorhynchus spp. passing through dams and reservoirs on the Snake and Columbia Rivers. All estimates were derived from detections of fish tagged with passive integrated transponder (PIT) tags. We PIT tagged and released a total of 18,565 hatchery steelhead O. mykiss, 15,991 wild steelhead, and 9,714 wild yearling Chinook salmon O. tshawytscha at Lower Granite Dam in the Snake River. In addition, we utilized fish PIT tagged by other agencies at traps and hatcheries upstream from the hydropower system and at sites within the hydropower system in both the Snake and Columbia Rivers. These included 122,061 yearling Chinook salmon tagged at Lower Granite Dam for evaluation of latent mortality related to passage through Snake River dams. PIT-tagged smolts were detected at interrogation facilities at Lower Granite, Little Goose, Lower Monumental, Ice Harbor, McNary, John Day, and Bonneville Dams and in the PIT-tag detector trawl operated in the Columbia River estuary. Survival estimates were calculated using a statistical model for tag-recapture data from single release groups (the single-release model). Primary research objectives in 2008 were to: (1) estimate reach survival and travel time in the Snake and Columbia Rivers throughout the migration period of yearling Chinook salmon and steelhead, (2) evaluate relationships between survival estimates and migration conditions, and (3) evaluate the survival estimation models under prevailing conditions. This report provides reach survival and travel time estimates for 2008 for PIT-tagged yearling Chinook salmon (hatchery and wild), hatchery sockeye salmon O. nerka, hatchery coho salmon O. kisutch, and steelhead (hatchery and wild) in the Snake and Columbia Rivers. Additional details on the methodology and statistical models used are provided in previous reports cited here. Survival and detection probabilities were estimated precisely for most of the 2008 yearling Chinook salmon and steelhead migrations. Hatchery and wild fish were combined in some of the analyses. For yearling Chinook salmon, overall percentages for combined release groups used in survival analyses in the Snake River were 80% hatchery-reared and 20% wild. For steelhead, the overall percentages were 65% hatchery-reared and 35% wild. Estimated survival from the tailrace of Lower Granite Dam to the tailrace of Little Goose Dam averaged 0.939 for yearling Chinook salmon and 0.935 for steelhead.
Article
Full-text available
Limitations of biotelemetry technology available in 2001 prompted the U.S. Army Corps of Engineers Portland District to develop a new acoustic telemetry system to monitor survival of juvenile salmonids through the Columbia River to the Pacific Ocean. Eight years later, the Juvenile Salmon Acoustic Telemetry System (JSATS) consists of microacoustic transmitters (12 mm long, 0.43 g weight in air), autonomous and cabled receiving systems, and data management and processing applications. Transmitter pulse rate can be user-defined and as configured for this case study was set at 5 seconds, with an estimated tag life of 30 days and detection range of 300 m. Before JSATS development, no technology existed to study movement and survival of fish smaller than 10 g migrating long distances from freshwater and into saltwater. In a 2008 study comparing detection probabilities, travel times, and survival of 4,140 JSATS-tagged and 48,433 passive integrated transponder (PIT)-tagged yearling Chinook salmon (Oncorhynchus tshawytscha; mean fork length 133.9 and 135.3 mm, for JSATS and PIT-tagged fish, respectively) migrating the Snake and Columbia rivers to the Pacific, the JSATS provided survival estimates at more locations with greater precision, using less than one-tenth as many tagged fish as the traditional PIT-tag system. While designed to be optimized for juvenile salmonid survival assessment in the Columbia River basin, JSATS technology may be used in a variety of environments. Information regarding different acoustic telemetry systems from various vendors is presented and discussed relative to the nonproprietary JSATS.
Article
Full-text available
Single-release and modified single-release statistical models were evaluated as means to generate reliable survival estimates from release-recapture studies of migrant salmonid smelts in the Snake and Columbia rivers of the northwestern United States. Monte Carlo simulation studies were used to assess robustness of estimation methods to violations of model assumptions. To field test model assumptions, passive integrated transponder tagged chinook salmon (Oncorhynchus tshawytscha) smelts were released on seven consecutive days in 1993 above Lower Granite Dam on the Snake River. These releases were used to estimate sampling variability of survival estimates for comparison with model-based variance estimates and to assess mixing of detected and nondetected individuals. Field results satisfied model assumptions. The average survival estimate from point of release to the tailrace of Lower Granite Dam (31 km) was 0.902 +/- 0.004 (mean +/- SE). From the tailrace of Lower Granite Dam to the tailrace of Little Goose Dam (60 km) the average survival estimate was 0.859 +/- 0.013.
Article
Full-text available
To estimate survival during barge transport over a distance of 470 km from Lower Granite Dam on the Snake River to a release area downstream of Bonneville Dam (the lowermost dam on the Columbia River), we used a novel adaptation of a release-recapture model with 1,494 acoustic-tagged yearling Chinook salmon Oncorhynchus tshawytscha smolts. Smolts were collected at Lower Granite Dam, received surgically implanted acoustic transmitters, and were divided into three groups: (1) a barge group (R-B) that was released into the raceway with fish that were later loaded into transportation barges (general barge population); (2) a control group (R-A) that was held in a net-pen suspended within the barge hold containing the general barge population until 5-6 h prior to barge evacuation (i.e., fish release into the river), at which time they were confirmed to be alive and then released into the barge hold; and (3) a dead group (R-D) that was euthanized and then released into the barge hold 5-6 h prior to barge evacuation in order to validate a model assumption. Six replicates of each group were loaded onto fish transport barges that departed from Lower Granite Dam between 29 April and 13 May 2010. Detections on acoustic receiver arrays between 70 and 220 km downstream of the barge evacuation site served as the basis for estimation of survival within the barge. The ratio of RB : RA survival from release to river kilometer 153 provided the estimate of within-barge survival. The replicate survival estimates ranged from 0.9503 ((SE) over cap = 0.0253) to 1.0003 ((SE) over cap = 0.0155). The weighted average of the replicate estimates of survival during the barge transportation experience was 0.9833 ((SE) over cap = 0.0062). This study provides the first active telemetry documentation that the assumed survival rate of 98% during the barge transportation experience appears to be justified for yearling Chinook salmon smolts.
Article
Full-text available
We conducted a retrospective analysis of data on the relationship between operating efficiency of Kaplan turbines and direct passage survival of salmonid smolts. A review of a key report instrumental in establishing ±1% turbine efficiency rule for operating Snake and Columbia river hydroelectric stations found a weak association (r = 0.112) but also found misspecification of the turbine efficiency data. At four Snake and Columbia river dams, manipulative studies were performed to investigate the relationship between turbine performance and smolt passage survival, as estimated with balloon-tag releases and recoveries. At all sites, peak passage survival did not coincide with the observed turbine operating efficiency peak. The difference between maximum survival and survival at peak turbine efficiency was as much as 3.2%. However, at three sites, maximum survival was within the ±1% peak efficiency operating rule. A meta-analysis that used balloon-tag survival results from 11 different hydroprojects also found no association between relative turbine efficiency at a site and smolt passage survival (r = 0.0311, P = 0.2640). For the benefit of smolt survival during passage, we recommend managing turbine operations to achieve maximum passage survival rather than focusing solely on peak operating efficiency of Kaplan turbines.
Article
Full-text available
Two rearing treatments are used at Lyons Ferry Hatchery to produce yearling (age-1) and subyearling (age-0) fall Chinook salmon Oncorhynchus tshawytscha for supplementing production of wild fish in the Snake River. We compared four indicators of yearling and subyearling postrelease performance, namely, seaward movement, condition factor, growth rate, and survival. A standard rearing treatment was used to grow yearlings slowly for 14 months to sizes of 152–162 mm (mean fork length). A second standard rearing treatment was used to grow medium subyearlings at a moderate rate for 5 months to 84–89 mm. Two modified rearing treatments were used to produce large subyearlings that were grown rapidly to 90–103 mm and small subyearlings that were grown slowly to 70–76 mm. We released yearlings in April and subyearlings in June on the typical supplementation schedule. Seaward movement, condition factor, growth, and survival varied among rearing treatments. Yearlings moved seaward fastest for reasons related to their large size. Yearlings had the lowest postrelease condition factors and growth rates because they were released when temperatures were cool and they moved seaward quickly, spending little time to feed. Yearlings had the highest survival because they were released when the water was cool, they moved seaward quickly, and their large size reduced susceptibility to predation. Small subyearlings moved seaward the slowest because of their small size and slow growth before release. Small subyearlings had the highest postrelease condition factors and highest growth rates because they lingered and were exposed to relatively high temperatures that were favorable for growth. Small subyearlings had the lowest survival because they lingered and were exposed to low flow and warm water for long durations and their small size increased susceptibility to predation. We conclude that fall Chinook salmon performance after release from Lyons Ferry Hatchery is influenced by release date and by rearing treatment effects on size, prerelease growth rate, and postrelease behavior.
Article
Full-text available
Autonomous acoustic receivers are often deployed across a range of aquatic habitats to study aquatic species. The Juvenile Salmon Telemetry System autonomous acoustic receiver packages we deployed in the Columbia River and its estuary were comprised of an acoustic receiver, acoustic release, and mooring line sections and were deployed directly on the river bottom. Detection ranges and reception data from past optimization deployments helped determine acoustic receiver spacing in order to achieve acceptable detection probabilities for juvenile salmon survival estimation. Methods used in 2005, which resulted in a high equipment loss rate, were modified and used between 2006 and 2008 to increase crew safety and optimize receiver deployment and recovery operations in a large river system. By eliminating surface buoys and taglines (for anchor recovery), we experienced a recovery success rate greater than previous acoustic receiver deployment techniques used in the Columbia River and elsewhere. This autonomous acoustic receiver system has optimized deployment, recovery, and servicing efficiency to successfully detect acoustic-tagged salmonids in a variety of river environments.
Article
Full-text available
Precise, up-to-date survival estimates for salmonids that migrate through reservoirs, hydroelectric dams, and free-flowing sections of the Snake and Columbia rivers are essential to develop effective strategies for recovering depressed stocks. To provide this information, survival was estimated for yearling chinook salmon Oncorhynchus tshawytscha and steelhead O. mykiss with passive integrated transponder (PIT) tags that migrated through Snake River dams and reservoirs from 1993 through 1998. A multiple-recapture model for single release groups was used to estimate survival from detections of PIT-tagged fish at dams. The stretch of river over which survival was estimated varied between years, depending on the release site, the number of dams with the capability to detect and rerelease PIT-tagged fish back to the river, the total number of fish marked, and the efficiency of detecting PIT-tagged fish at each dam. Precision of survival estimates varied with the number of fish PIT-tagged and released and the amount of spill at dams with PIT-tag detectors. When spill levels were high, detection probabilities were lower, as was precision. Mortality at bypass outfall sites was not significant at any Snake River dam investigated. Estimated annual average per-project (combined reservoir and dam passage) survival ranged from 86% to 94% for yearling chinook salmon and from 88% to 92% for steelhead. Survival estimates were higher for both species in years when spill was used specifically to pass fish through nonturbine routes. Over the same stretches of river in years with similar flow conditions from 1970 through 1975, per-project survival estimates typically averaged 57–71% for yearling chinook salmon and 77–90% for steelhead. From 1993 to 1998, survival estimates for fish released from Snake River basin hatcheries to the Lower Granite Dam tailrace indicated that substantial smolt mortality occurred before fish entered the hydropower system. For each hatchery, estimated survival varied each year, and estimates from different hatcheries to Lower Granite Dam varied inversely with the distance fish traveled.
Article
Full-text available
From 1987 to 1992, we evaluated a fish bypass system at Bonneville Dam Powerhouse 2 on the Columbia River. The survival of subyearling Chinook salmon Oncorhynchus tshawytscha released into the system ranged from 0.774 to 0.911 and was significantly lower than the survival of test fish released into turbines and the area immediately below the powerhouse where bypass system flow reentered the river. Yearling and subyearling Chinook salmon and yearling coho salmon O. kisutch released into the bypass system were injured or descaled. Also, levels of blood plasma cortisol and lactate were significantly higher in yearling and subyearling Chinook salmon that passed through the bypass system than in fish released directly into a net located over the bypass exit. This original system was then extensively modified using updated design criteria, and the site where juvenile fish reentered the river was relocated 2.8 km further downstream to reduce predation on bypassed fish by northern pikeminnow Ptychocheilus oregonensis. Based on studies conducted from 1999 to 2001, the new bypass system resulted in high fish survival, virtually no injuries to fish, fish passage times that were generally similar to water travel times, and mild stress responses from which fish recovered quickly. The mean estimated survival of subyearling Chinook salmon passing through the new bypass system was 0.946 in 2001, which was an usually low-flow year. Survival, physical condition, passage timing, and blood physiological indicators of stress were all useful metrics for assessing the performance of both bypass systems and are discussed. The engineering and hydraulic criteria used to design the new bypass system that resulted in improved fish passage conditions are described.
Article
Full-text available
Safe fish passage through hydroprojects is of paramount importance in the Pacific Northwest of the United States where anadromous runs of salmon smolts pass through as many as nine dams on the Columbia River on their way to the ocean. Minimum survival standards through the dams or hydroprojects (i.e., reservoir and dam) have been established by the 2008 Federal Columbia River Power System (FCRPS) Biological Opinion or by Habitat Conservation Plans (HCPs) in order to protect salmon stocks. These federal requirements have prompted the need to conduct scientifically and statistically rigorous and precise smolt survival studies at federally and publicly operated hydroprojects throughout the Snake- Columbia River Basin. Successful studies have been the cooperative results of regulators, hydro managers, fish biologists, engineers, and biometricians working together to conduct these high value investigations. Rock Island Dam, Washington, is used as a case study where a total of 17 release-recapture studies were conducted over a nine-year period on three salmonid species to assess compliance with HCP survival standards.
Article
Full-text available
There is an unprecedented need to preserve and restore aquatic and riparian biological diversity before extinction eliminates the opportunity. Ecological restoration is the reestablishment of processes, functions, and related biological, chemical, and physical linkages between the aquatic and associated riparian ecosystems; it is the repairing of damage caused by human activities. The first and most critical step in ecological restoration is passive restoration, the cessation of those anthropogenic activities that are causing degradation or preventing recovery. Given the capacity of riparian ecosystems to naturally recover, often this is all that is needed to achieve successful restoration. Prior to implementation of active restoration approaches (e.g., instream structures, channel and streambank reconfiguration, and planting programs), a period of time sufficient for natural recovery is recommended. Unfortunately, structural additions and active manipulations are frequently undertaken without halting degrading land use activities or allowing sufficient time for natural recovery to occur. These scenarios represent a misinterpretation of ecosystem needs, can exacerbate the degree of degradation, and can cause further difficulties in restoration. Restoration should be undertaken at the watershed or landscape scale. Riparian and stream ecosystems have largely been degraded by ecosystemwide, off-channel activities and, therefore, cannot be restored by focusing solely on manipulations within the channel. While ecological restoration comes at a high cost, it also is an investment in the natural capital of riparian and aquatic systems and the environmental wealth of the nation.
Article
Full-text available
Since 1987, millions of juvenile salmonids (smolts; Oncorhynchus species) in the Snake and upper Columbia rivers have been tagged with Passive Integrated Transponder (PIT) tags, and detected at hydroelectric projects as theymigrate downriver to the Pacific Ocean. Since the late 1990s, detection of PIT-tagged adults has been possible at some dams. Existing release-recapture models are designed for either juvenile data or adult data, but not both.We present amigratory life-cycle release-recapture model that follows tagged individuals from their release as juveniles through their return migration as adults, accounting for downstream barge transportation of juveniles, right-censoring due to known removals at dams, and adult age at maturity. This branching model estimates river survival, age-specific probabilities of adult return, and relative effects of smolt transportation on survival. Performance measures are defined using model parameters. We analyze a dataset of 58,447 PIT-tagged summer Chinook salmon released in 2000 in the Snake River. For nontransported fish, juvenile survival from passage at Lower Granite Dam to Bonneville Dam was estimated at 60.3% ([^(SE)] = 8.1%\widehat{SE} = 8.1\% ), and the ocean return probability to Bonneville was estimated at 4.5% ([^(SE)] = 0.7%\widehat{SE} = 0.7\% ). The smolt-to-adult ratio (SAR) for the entire release group was estimated at 2.0% ([^(SE)] = 0.09%\widehat{SE} = 0.09\% ), and perceived inriver adult survival was estimated at 87.1% ([^(SE)] = 1.7%\widehat{SE} = 1.7\% ).
Article
Full-text available
The high detection rates of acoustic- and radio-tagged fish greatly improve the ability of an investigator to obtain information on survival and movement of fish with fewer tags. The trade-off, though, is a greater dependence on the individual tag performance, as each tagged fish in a smaller study represents a greater proportion of the outcome. This reduction in release size, due to the increase in detection capability, places a greater emphasis on the need to accurately gauge the status of the tagged fish. Should a tag fail while a smolt is migrating through the study area, the release-recapture model cannot discern the difference between smolt death and tag failure. If the release-recapture models are not adjusted for the probability of tag failure, the estimates of smolt survival will therefore be negatively biased. This article presents a semiparametric approach for adjusting survival estimates from release-recapture studies for tag failure, and provides subsequent estimation of sampling variance and its contributing components.
Article
Full-text available
Fish can become entrained at water withdrawal locations such as fish bypasses, hydroelectric turbines, and power plant cooling water intakes. Accordingly, the size of a fish entrainment zone (FEZ) is often of interest to fisheries managers and facility operators because of the need to protect fish from injury or mortality. This study developed a new technique to map the FEZ, defined here as the region immediately upstream of a portal where the probability of fish movement toward the portal is greater than 90%. To map the FEZ, we applied a Markov chain analysis to fish movement data collected with an active fish tracking sonar. This sonar device locked onto and followed fish targets, recording their positions through a set of volumetric cells comprising the sampled volume. The probability of a fish moving from one cell to another was calculated from fish position data. These probabilities were used to populate a Markov transition matrix. In 2000, we developed and applied the technique using data on salmon smolts migrating near the ice/trash sluiceway at The Dalles Dam on the Columbia River. The FEZ of the sluiceway entrance as determined with this procedure was approximately 5 m across and extended 6–8 m out from the face of the dam in the surface layer 2–3 m deep. In conclusion, using a Markov chain analysis of fish movement data, we were able to describe and quantify the FEZ of the sluiceway at The Dalles dam. This Markov chain analysis could be used in a comparative before/after study to look at changes in FEZ caused by engineered structures. The technique is generally applicable to bio-engineering efforts aimed at protecting fish populations affected by water withdrawals.
Article
Full-text available
In 2001 the U.S. Army Corps of Engineers, Portland District (OR, USA), started developing the Juvenile Salmon Acoustic Telemetry System, a nonproprietary sensing technology, to meet the needs for monitoring the survival of juvenile salmonids through eight large hydroelectric facilities within the Federal Columbia River Power System (FCRPS). Initial development focused on coded acoustic microtransmitters and autonomous receivers that could be deployed in open reaches of the river for detection of the juvenile salmonids implanted with microtransmitters as they passed the autonomous receiver arrays. In 2006, the Pacific Northwest National Laboratory began the development of an acoustic receiver system for deployment at hydropower facilities (cabled receiver) for detecting fish tagged with microtransmitters as well as tracking them in two or three dimensions for determining route of passage and behavior as the fish passed at the facility. The additional information on route of passage, combined with survival estimates, is used by the dam operators and managers to make structural and operational changes at the hydropower facilities to improve survival of fish as they pass the facilities through the FCRPS.
Article
Full-text available
The mortality of salmon smolts during their migration out of freshwater and into the ocean has been difficult to measure. In the Columbia River, which has an extensive network of hydroelectric dams, the decline in abundance of adult salmon returning from the ocean since the late 1970s has been ascribed in large measure to the presence of the dams, although the completion of the hydropower system occurred at the same time as large-scale shifts in ocean climate, as measured by climate indices such as the Pacific Decadal Oscillation. We measured the survival of salmon smolts during their migration to sea using elements of the large-scale acoustic telemetry system, the Pacific Ocean Shelf Tracking (POST) array. Survival measurements using acoustic tags were comparable to those obtained independently using the Passive Integrated Transponder (PIT) tag system, which is operational at Columbia and Snake River dams. Because the technology underlying the POST array works in both freshwater and the ocean, it is therefore possible to extend the measurement of survival to large rivers lacking dams, such as the Fraser, and to also extend the measurement of survival to the lower Columbia River and estuary, where there are no dams. Of particular note, survival during the downstream migration of at least some endangered Columbia and Snake River Chinook and steelhead stocks appears to be as high or higher than that of the same species migrating out of the Fraser River in Canada, which lacks dams. Equally surprising, smolt survival during migration through the hydrosystem, when scaled by either the time or distance migrated, is higher than in the lower Columbia River and estuary where dams are absent. Our results raise important questions regarding the factors that are preventing the recovery of salmon stocks in the Columbia and the future health of stocks in the Fraser River.
Article
We evaluated the impact of predation on juvenile steelhead Oncorhynchus mykiss and yearling and subyearling Chinook Salmon O. tshawytscha by piscivorous waterbirds from 11 different breeding colonies in the Columbia River basin during 2012 and 2014. Fish were tagged with both acoustic tags and PIT tags and were tracked via a network of hydrophone arrays to estimate total smolt mortality (1 – survival) at various spatial and temporal scales during out-migration. Recoveries of PIT tags on bird colonies, coupled with the last known detections of live fish passing hydrophone arrays, were used to estimate the impact of avian predation relative to total smolt mortality. Results indicated that avian predation was a substantial source of steelhead mortality, with predation probability (proportion of available fish consumed by birds) ranging from 0.06 to 0.28 for fish traveling through the lower Snake River and the lower and middle Columbia River. Predation probability estimates ranged from 0.03 to 0.09 for available tagged yearling Chinook Salmon and from 0.01 to 0.05 for subyearlings. Smolt predation by gulls Larus spp. was concentrated near hydroelectric dams, while predation by Caspian terns Hydroprogne caspia was concentrated within reservoirs. No concentrated areas of predation were identified for double-crested cormorants Phalacrocorax auritus or American white pelicans Pelecanus erythrorhynchos. Comparisons of total smolt mortality relative to mortality from colonial waterbirds indicated that avian predation was one of the greatest sources of mortality for steelhead and yearling Chinook Salmon during out-migration. In contrast, avian predation on subyearling Chinook Salmon was generally low and constituted a minor component of total mortality. Our results demonstrate that acoustic and PIT tag technologies can be combined to quantify where and when smolt mortality occurs and the fraction of mortality that is due to colonial waterbird predation relative to non-avian mortality sources.Received November 4, 2015; accepted February 1, 2016
Chapter
Supplementation is one of the strategies that may be used for restoring natural production of anadromous salmonid populations in the Columbia River Basin. Depending on the particular circumstances, supplementation may be used by itself or in conjunction with other management strategies for restoring natural production such as habitat restoration and maintenance, improvement of tributary and mainstem river passage survival, improvement of estuarine and ocean survival, and harvest management by escapement objectives to allow the population to optimally seed available habitat. Above mainstem dams, all measures may need to be employed simultaneously to achieve success.
Article
A three-year study from 1998 to 2000 was performed at the Wells Hydroelectric Project on the Columbia River, Washington, to assess compliance with the Habitat Conservation Plan survival standard for project passage equal to or greater than 0.93 for salmonid smolts. For annual juvenile project survival estimates to be valid, the Habitat Conservation Plan requires the studies to measure the survival of juvenile fish migrating through the reservoir, forebay, dam and tailrace associated with a project. It also requires the study to take place during the normal smolt migration period (April—May). Valid survival estimates must also have estimated standard errors (SEs) less than or equal to 0.025. Paired release-recapture studies using PIT-tagged yearling Chinook salmon (Oncorhynchus tshawytscha) and steelhead (O. mykiss) smolts produced successive annual survival estimates of 0.997 (SE = 0.015), 0.943 (SE = 0.016), and 0.946 (SE = 0.015) with a three-year mean of estimated survival of 0.962. A 10-year follow-up study to determine continued compliance with the survival standard produced an estimate of 0.954 (SE = 0.013) in 2010 using PIT-tagged yearling Chinook salmon smolts. The Wells Project was the first hydroproject in the Columbia-Snake River Basin to meet its survival standard for outmigrating salmonid smolts, and Public Utility District No. 1 of Douglas County was also the first to subsequently conduct and successfully meet a 10-year recertification.
Article
High survival through hydropower projects is an essential element in the recovery of Pacific salmon Oncorhynchus spp. populations in the Columbia River. High dam passage survival is also a regulatory requirement under the 2008 Biological Opinion (BiOp; established under the Endangered Species Act) on Federal Columbia River Power System operation. The BiOp requires dam passage survival to be at least 0.96 and at least 0.93 for spring and summer out-migrating juvenile salmonids, respectively, and to be estimated with an SE of 0.015 or lower. An innovative virtual/paired-release design was used to estimate dam passage survival, which was defined as survival from the upstream face of a dam to the tailrace mixing zone. A coordinated four-dam study was conducted during the 2012 summer out-migration using 14,026 subyearling Chinook Salmon O. tshawytscha out-migrants with surgically implanted acoustic micro-transmitter tags. The release–recapture design consisted of 9 different release locations and 14 different detection arrays. Each of the four estimates of dam passage survival exceeded BiOp requirements, with values ranging from 0.9414 to 0.9747 (SE = 0.0031–0.0114). The virtual/paired-release design illustrated here has potential applicability wherever dam passage survival of migrant juvenile fish stocks must be estimated.Received November 21, 2013; accepted March 13, 2014
Article
Existing ice and trash sluiceways are commonly used as benign, nonturbine routes for downstream passage of juvenile salmonids at hydropower dams. At The Dalles Dam on the Columbia River, we studied various operational configurations of sluiceway weirs to maximize sluiceway passage of juvenile Pacific salmon Oncorhynchus spp. and steelhead O. mykiss. We applied hydroacoustic methods to compare fish passage rates and sluiceway efficiencies for two weir configurations in each year: three weirs (SL 1; i.e., collectively referring to the three weirs above main turbine unit [MU] 1) versus six weirs (SL 1+18) during 2004; and middle (SL 2+5) versus east (SL 2+19) powerhouse weir locations during 2005. Horizontal distributions at the sluiceway and turbines and the effects of operating turbines beneath open sluiceway gates were also analyzed. Sluiceway passage efficiency relative to the powerhouse (SLY phs) varied between study years, between spring and summer, and between day and night. In 2004, sluiceway passage rates were significantly higher (P = 0.0003) for SL 1+18 than for SL 1 during summer–night but were not significantly different between the two configurations during the other three season–day/night periods. The SLY phs was significantly higher for SL 1+18 than for SL 1. The location comparison during 2005 revealed no significant differences between the SL 2+5 and SL 2+19 configurations, except for summer–day. The experimental findings led to recommendations for long-term operations of The Dalles Dam sluiceway: open six rather than three sluiceway weirs to take advantage of the maximum hydraulic capacity of the sluiceway; open the three weirs above the westernmost operating MU and the three weirs at SL 8, where turbine passage rates are relatively high; operate the MUs below open sluiceway weirs as a standard procedure; operate the sluiceway 24 h/d year-round to maximize its benefits to juvenile salmonids; and use the same weir configuration year-round. These operational concepts are transferable to dams where sluiceway surface flow outlets are used to protect downstream-migrating fishes.Received July 19, 2012; accepted June 26, 2013
Article
An integral part of efforts to recover stocks of Pacific salmon Oncorhynchus spp. and steelhead O. mykiss in Pacific Northwest rivers is to increase passage efficacy and survival of juveniles past hydroelectric dams. As part of this effort, we evaluated the efficacy of a prototype surface bypass structure, the removable spillway weir (RSW), installed in a spillbay at Lower Granite Dam, Washington, on the Snake River during 2002, 2003, 2005, and 2006. Radio-tagged juvenile steelhead were released upstream from the dam and their route of passage through the turbines, juvenile bypass, spillway, or RSW was recorded. The RSW was operated in an on-or-off condition and passed 3–13% of the total discharge at the dam when it was on. Poisson rate models were fit to the passage counts of hatchery- and natural-origin juvenile steelhead to predict the probability of fish passing the dam. Main-effect predictor variables were RSW operation, diel period, day of the year, proportion of flow passed by the spillway, and total discharge at the dam. The combined fish passage through the RSW and spillway was 55–85% during the day and 37–61% during the night. The proportion of steelhead passing through nonturbine routes was <88% when the RSW was off during the day and increased to >95% when the RSW was on during the day. The ratio of the proportion of steelhead passed to the proportion of water passing the RSW was from 6.3:1 to 10.0:1 during the day and from 2.7:1 to 5.2:1 during the night. Steelhead passing through the RSW exited the tailrace about 15 min faster than fish passing through the spillway. Mark–recapture single-release survival estimates for steelhead passing the RSW ranged from 0.95 to 1.00. The RSW appeared to be an effective bypass structure compared with other routes of fish passage at the dam.
Article
Snake River stream-type Chinook salmon Oncorhynchus tshawytscha exhibited substantial delayed mortality despite recent improvements in oceanic and climatic conditions. These salmon declined sharply with the completion of the Columbia River hydrosystem in addition to other anthropogenic impacts and changes in oceanic conditions. Previous analytical approaches have compared management options for halting the population decline. The predicted benefits of these options on salmon recovery hinged on whether the source of the mortality that takes place in the estuary and during early ocean residence is related to earlier hydrosystem experience during downstream migration (i.e., delayed hydrosystem mortality). We analyzed the spatial and temporal patterns of mortality for Chinook salmon populations to determine whether delayed mortality for the Snake River populations decreased during the recent period of favorable oceanic and climatic conditions. We found that Snake River stream-type Chinook salmon populations continued to exhibit survival patterns similar to those of their downriver counterparts but survived only one-fourth to one-third as well. The hypothesis that delayed mortality decreased and became negligible with more favorable oceanic conditions appears inconsistent with the patterns we observed for the common year effect and our estimates of delayed mortality of in-river migrants. A plausible explanation for this persistent pattern of delayed mortality for Snake River populations is that it is related to the construction and operation of the hydrosystem.
Article
The juvenile salmon acoustic telemetry system (JSATS) is a nonproprietary technology developed by the U.S. Army Corps of Engineers, Portland District for detecting and tracking small fish. The JSATS consists of acoustic microtransmitters; autonomous, cabled, or portable receivers with hydrophones; and data management and processing applications. Each microtransmitter, surgically implanted in fish, transmits a unique 31?bit binary code encoded using BPSK at 416.7 kHz. Cabled systems are deployed at dams and used to determine passage?route and near?dam behavior for fish. Each cabled system is synchronized to a universal GPSclock and waveforms are saved to the computer before being decoded. Valid detections are separated from spurious detections using filtering processes requiring a minimum of six messages with a pulse interval matching that expected from properly functioning tags within a fixed period. Time?of?arrival information for valid detections on four hydrophones is used to solve for the 3?D position of tagged fish. For the cabled system at John Day Dam, the range for 3?D tracking is more than 100 m upstream of the dam face where hydrophones are deployed. Cabled systems have been successfully deployed on several major dams to acquire information for salmon protection and to develop more fish?friendly hydroelectric facilities. [This study was funded by the U.S. Army Corps of Engineers, Portland District.]
Article
Studies of fish guidance with submersible traveling screens (STS) were conducted at the Bonneville Dam second powerhouse, Columbia River, during the 1983-1989 seaward migrations of yearling (age-1) and subyearling (age-0) salmonids Oncorhynchus spp. In 1983, the initial measurements of fish guidance levels were less than 25% for yearling and subyearling chinook O. tshawytscha and coho O. kisutch salmon and approximately 33% for steelhead O. mykiss, compared with expected levels greater than 70% for all species. Modifications based upon hydraulic models and field research were made to the trashracks, STSs, and face of the powerhouse. With these modifications, yearling chinook and coho salmon guidance levels greater than 75% were sometimes attained, but maximum steelhead guidance was less than 70%. Guidance of subyearling chinook salmon during the spring migration was as high as 60% but during the summer migration remained below 30%. Even with major modifications to the second powerhouse, fish guidance was lower than levels obtained at many other hydroelectric projects on the Columbia River.
Article
A new and improved system for diverting, bypassing, and collecting juvenile salmon, Oncorhynchus sp., and steelhead trout, Salmo gairdneri, at Lower Granite Dam on the lower Snake River is described. Major changes from previous systems of this type include a special fish screen slot for placement of the improved traveling screen, an open gallery bypass system for routing fish around the turbines, and a collection and holding area totally supplied by gravity-flow. The system is currently being evaluated by the National Marine Fisheries Service under contract to the U.S. Army Corps of Engineers.
Article
We analyzed five years of route-specific fish-passage data acquired by fixed-aspect hydroacoustic sampling of juvenile salmonids passing downstream through Bonneville Dam. High passage effectiveness of surface-flow outlets relative to the spillway and turbines suggests that juvenile salmonids are preferentially selecting surface outlets over adjacent turbines. Seasonal estimates showed that median combined effectiveness of surface-flow outlets (7.8) was 7.1 times higher than that of the spillway (1.1) and 9.8 times higher than that of turbines (0.8). Islands prevent the spillway from attracting fish from either powerhouse, something that may occur at other projects. Regressions indicated that percent flow passing a specific route explained from 50 to 97% of fish-passage variation, and relations were useful for evaluating fish-passage alternatives. Fitted curves for surface-passage routes, including the sluiceway at Powerhouse 1 (B1) and Powerhouse 2 (B2) were much steeper at low percent low (2-15%) than were curves for the spillway or turbines. Regressions indicate that increasing surface-flow percentages of B1 flow from 1% to 10% could increase B1 sluiceway-passage efficiency from 40% to 83%. Increasing B2 flow to the B2 sluiceway from 4% to 15% could increase fish passage from 31% to 62%. Without spill, about 50% of fish passed by non-turbine routes.
Article
Conventional hatcheries, supplementation, and habitat protection are management activities located on a production continuum. At one end of the continuum is the conventional hatchery which attempts to separate artificially propagated fish from naturally reproducing populations. On the other end of the continuum is natural production. Supplementation which attempts to increase natural production through the use of artificial propagation lies somewhere between natural production and conventional hatcheries on the continuum. The use of artificial propagation in the recovery of listed species is controversial. Guidance on the use of artificial propagation in the recovery of listed species comes from three sources: The Endangered Species Act (ESA), US Fish and Wildlife Service (USFWS) policies and National Marine Fisheries Service (NMFS) guidelines.
Article
A surface flow bypass provides a route in the upper water column for naturally, surface-oriented juvenile salmonids to safely migrate through a hydroelectric dam. Surface flow bypasses were recommended in several regional salmon recovery plans as a means to increase passage survival of juvenile salmonids at Columbia and Snake River dams. A prototype surface flow bypass, called the SBC, was retrofit on Lower Granite Dam and evaluated from 1996 to 2000 using biotelemetry and hydroacoustic techniques. In terms of passage efficiency, the best SBC configurations were a surface skimmer (99 m3/s [3,500 cfs], three entrances 5 m wide, 5 m deep and one entrance 5 m wide, 15 m deep) and a single chute (99 m3/s, one entrance 5 m wide, 8.5 m deep). They each passed 62 ? 3% (95% confidence interval) of the total juvenile fish population that entered the section of the dam with the SBC entrances (Turbine Units 4-5). Smooth entrance shape and concentrated surface flow characteristics of these configurations are worth pursuing in designs for future surface flow bypasses. In addition, a guidance wall in the Lower Granite Dam forebay diverted the following percentages of juvenile salmonids away from Turbine Units 1-3 toward other passage routes, including the SBC: run-at-large 79 ? 18%; hatchery steelhead 86%; wild steelhead 65%; and yearling chinook salmon 66%. When used in combination with spill or turbine intake screens, a surface flow bypass with a guidance wall can produce a high level (> 90% of total project passage) of non-turbine passage and provide operational flexibility to fisheries managers and dam operators responsible for enhancing juvenile salmonid survival.
Article
We reviewed research conducted by the U.S. National Marine Fisheries Service from 1968 through 1989 on the benefits of using trucks and barges to transport migrating juvenile Chinook salmon Onchorhynchus tsawytscha from the Snake River around dams and reservoirs in the lower Snake and Columbia rivers. Early results from studies that used trucks indicated that Chinook salmon benefited from transportation: therefore, transportation was adopted as a management strategy by the late 1970s. Our review shows that large-scale transportation by truck was unlikely to benefit survival of juvenile Chinook salmon. Our results from reviewing more recent studies indicate that the use of barges to transport juvenile Chinook salmon may result in improved survival. Benefits may be lower than previously reported because results may have been biased by experimental design: however, even after we adjusted for those potential violations, results from four of six studies on the use of barges indicated that survival of transported fish was higher than survival of fish left to migrate in-river. Because the improved survival from barging may not be enough to ensure recovery of endangered stocks of Chinook salmon, we recommend that management of Snake River Chinook salmon not rely heavily on any one management technique.
Article
The hypotheses that fish survival probabilities may be lower (1) at less than peak operating turbine efficiency; (2) at deeper entrainment depth; and (3) with the deployment of extended-length intake guidance screens, are not supported by results on yearling chinook salmon smolts (Oncorhynchus tshawytscha) at Lower Granite Dam, Snake River, Washington. Estimated 96 h survival probabilities for the six test conditions ranged from 0.937 to 0.972, with the highest survival at turbine operating towards the lower end of its efficiency. A blanket recommendation to operate all Kaplan type turbines within ± 1 percent of their peak efficiency appears too restrictive. Cavitation mode survival (0.946) was comparable to that at peak operating efficiency mode (0.937), as was the survival between upper (0.947) and mid depths (0.937). Survival differed only slightly among three turbine intake bays at the same depth (0.937 to 0.954), most likely due to differential flow distribution. Extended-length intake fish guidance screens did not reduce survival. However, the sources of injury somewhat differed with depth; probable pressure and shear-related injuries were common on fish entrained at mid-depth, and mechanically-induced injuries were common at upper depth. Operating conditions that reduce turbulence within the turbine environment may enhance fish survival; however, controlled experiments that integrate turbine flow physics and geometry and the path entrained fish traverse are needed to develop specific guidance to further enhance fish passage survival.
Potential impact of Renibacterium salmoninarum on adult returns of Snake River spring/summer Chinook Salmon
  • J G Williams
Williams, J. G. 2001. Potential impact of Renibacterium salmoninarum on adult returns of Snake River spring/summer Chinook Salmon. Bulletin of National Research Institute of Aquaculture 5(Supplement):55-59.
Trade-offs for efficiently passing juvenile salmonids through Bonneville Dam on the lower Columbia River. Pages 325–347 in Balancing fisheries management and water uses for impounded river systems
  • G R Ploskey
  • M A Weiland
  • J Kim
Ploskey, G. R., M. A. Weiland, and J. Kim. 2008. Trade-offs for efficiently passing juvenile salmonids through Bonneville Dam on the lower Columbia River. Pages 325–347 in M. S. Allen, S. Sammons, and M. J. Maceina, editors. Balancing fisheries management and water uses for impounded river systems. American Fisheries Society, Symposium 62, Bethesda, Maryland.
Genetic conservation of salmonid fishes: proceedings of a NATO Advanced Study Institute
  • Thorgaard
Thorgaard, editors. Genetic conservation of salmonid fishes: proceedings of a NATO Advanced Study Institute. Plenum Press, New York.
The use of supplementation to aid in natural stock restoration. Pages 269-293 in
  • M L Cuenco
  • W H Backman
  • P R Mundy
Cuenco, M. L., W. H. Backman, and P. R. Mundy. 1993. The use of supplementation to aid in natural stock restoration. Pages 269-293 in J. G. Cloud and G. H. Thorgaard, editors. Genetic conservation of salmonid fishes: proceedings of a NATO Advanced Study Institute. Plenum Press, New York.