Geology topics

Amy C. Hansen

Publications and source records attributed to Amy C. Hansen.

At least 19 recordsLinked to original sources

USGS2026

Response of juvenile Chinook Salmon to an experimental reservoir operation to facilitate downstream migration

Objectives High-head dams and storage reservoirs impact ecological processes, impeding recovery efforts of Pacific salmon Oncorhynchus spp. in the western United States. These projects can delay migration, increase risks of predation and disease, and induce mortality for juvenile Pacific salmon during downstream passage. To mitigate these negative effects, large-scale changes to dam operations have been proposed as interim measures or alternatives to engineered fish passage solutions. A novel deep drawdown operation of the Lookout Point Project (two dams and reservoirs) in Oregon serves as a case study for learning from a large-scale management experiment. Beginning in July 2024, Lookout Point Reservoir was slowly lowered to attain minimal levels from mid-November to mid-December with the intent of expediting downstream passage through the project for juvenile Chinook Salmon Oncorhynchus tshawytscha . We evaluated the impacts of the months-long operation on two life histories of juvenile Chinook Salmon with different rearing environments and growth rates. Methods Acoustic telemetry was used to monitor juvenile Chinook Salmon in the Lookout Point Project. Environmental data, including water temperature and hydrological conditions, were collected. We fitted a time-integrated migration survival model to these data to estimate the effects of management-influenced covariates and fish length on apparent survival and residence time in each reach of the Lookout Point Project. Results Larger fish had higher survival than smaller fish in each reach of the Lookout Point Project. Apparent survival through each dam of the Lookout Point Project was highest and forebay residence times lowest during the latter part of the drawdown (late November). However, early periods of the drawdown (September) were associated with a transition from a thermally stratified reservoir to a warm isothermal reservoir that negatively impacted reservoir survival. Conclusions The deep drawdown of the Lookout Point Project achieved the management intent to improve downstream passage for juvenile Chinook Salmon at the lowest reservoir elevations but also caused unintended changes in the reservoir rearing environment prior to full drawdown. Further research could resolve remaining uncertainties regarding the overall effectiveness of drawdown operations with respect to the population dynamics of different juvenile life history strategies. Understanding these factors would help optimize future management actions aimed at Pacific salmon recovery above the Lookout Point Project.

Oregon↗

USGS2025

Evaluation of juvenile salmon behavior to inform downstream fish passage development at a high head dam

F ish passage development is a priority at Tieton Dam, on the Tieton River in Washington state, because passage options were not included when the dam was constructed nearly 100 years ago. To inform downstream passage design, we conducted a study to evaluate migration and near-dam behavior of juvenile salmon. The primary goal of the study was to determine how fish approached the dam and to identify areas where they congregated. In its current configuration, water is passed through a deep intake located approximately 548 m upstream of the dam, so there was interest in determining if juvenile salmon spent more time near the intake or at the dam. We found that tagged fish primarily entered the dam forebay offshore and arrived at the dam near the spillway on the left bank of the reservoir. Tagged fish had extended residence times in the forebay and moved repeatedly between the intake and the dam. Using thermal profile data, we inferred that juvenile salmon likely occupied the upper 5 m of the water column during May and June before moving to deeper portions of the water column (10–27 m) during July–September when the reservoir became thermally stratified. We found that a small percentage of tagged fish passed the dam when the reservoir was rapidly drawn down during August–October, but additional research may be needed to fully assess entrainment risk through the intake. These findings suggest that downstream fish passage could be developed at Tieton Dam with a high probability of success, given that most fish survived reservoir passage and spent considerable time near the dam where they would be available to discover and utilize new passage routes.

Washington↗

USGS2024

Outmigration behavior and survival of juvenile Chinook salmon (Oncorhynchus tshawytscha) in response to deep drawdown of the Lookout Point Project, Middle Fork Willamette River, Oregon

An acoustic telemetry study was conducted during August 2023–February 2024 to evaluate outmigration behavior and survival of juvenile Chinook salmon (Oncorhynchus tshawytscha) in the Middle Fork Willamette River, Oregon, during an experimental operation that was designed to facilitate downstream passage through two reservoirs and two dams. The experimental operation consisted of lowering the water surface elevation of Lookout Point Reservoir by nearly 100 feet between August and December 2023, and passing water through regulating outlets at Lookout Point Dam. This operation was intended to reduce residence time for juvenile Chinook salmon in Lookout Point Reservoir so that these fish would enter the free-flowing Willamette River as quickly as possible. During our study, acoustic-tagged juvenile Chinook salmon were released weekly during late August to late October to determine how fish responded to the drawdown. Data collected during the study were analyzed using a temporally stratified multistate mark-recapture model. We found that Lookout Point Reservoir became isothermic during the drawdown and water temperature exceeded 18 degrees Celsius during most of September 2023. This appeared to adversely affect juvenile Chinook salmon because the proportion of tagged fish that were subsequently detected in the forebay of Lookout Point Dam following release at the head of Lookout Point Reservoir during August 30–September 29 ranged from 0.01 to 0.05 for weekly release groups. Detections increased to 0.44–0.52 for fish released later in the year when water temperatures decreased. We found that fish size was a significant predictor of survival as fork length was positively related to survival probability in reservoir and free-flowing river reaches of our study area, but negatively related to survival probability for fish passing Lookout Point Dam. We also found that increased regulating outlet flow at Lookout Point Dam resulted in increased survival probability for juvenile Chinook salmon and water temperature was inversely related to survival. Results from this study suggest that the drawdown failed to create conditions that facilitated downstream passage and survival of juvenile Chinook salmon through the Lookout Point Project. Our analysis provides insights into several key factors that influence survival. This information can be used by resource managers when considering revised operations that may lead to improved outmigration survival in the future.

Oregon↗

USGS2024

Adult green sturgeon (Acipenser medirostris) movements in the Sacramento–San Joaquin River Delta, California, December 2020–January 2023

The U.S. Army Corps of Engineers American River Watershed Common Features project (ACRF) seeks to reduce flood risk for the City of Sacramento, California, and surrounding areas. The project includes levee-remediation measures to address seepage, stability, erosion, and height concerns as well as the widening of the Sacramento Weir and Bypass. The project reach is in the lower extent of the Sacramento River migration corridor for the federally threatened southern Distinct Population Segment of North American green sturgeon ( Acipenser medirostris ). To establish baseline migratory behavior, we examined adult green sturgeon transit through the project area prior to construction. Biologists from the U.S. Army Corps of Engineers collected and tagged 55 adult green sturgeon with acoustic and passive integrated transponders, near Hamilton City, California, at river kilometer 332 of the Sacramento River each fall from 2020 to 2022. To evaluate fish movements, we deployed five acoustic detection sites at river kilometers 101, 90, 76, and 21 on the Sacramento River and in Tule Canal near the Sacramento Bypass at river kilometer 101 of the Sacramento River. The acoustic receivers detected nearly all tagged fish moving downstream through the ARCF study area during the same water year (October 1–September 30) in which they were tagged. Three fish released in October of 2020 arrived at the ARCF study area more than 362 days later in October 2021. The timing of tagged fish movements was associated with increases in river flow and not hour of day. Adult green sturgeon moved downstream from January to August when streamflows exceeded 15,000 cubic feet per second. During water year 2023 and the critically dry water year 2022, fish moved with the first peaks in flow occurring from mid-October to early January. Fish tagged in the critically dry water year 2021 entered the ARCF study area over an extended period from January to October, when flows remained around 10,000 cubic feet per second all year. Fish moved quickly between sites within the ARCF study area and generally spent less than 1 hour at each detection site.

California↗

USGS2023

Survival implications of diversion entrainment for outmigrating juvenile Chinook Salmon (Oncorhynchus tshawytscha) and steelhead (O. mykiss)

Efforts to ameliorate negative effects of diversion dams on aquatic species of concern are important in rivers where water withdrawal supports agricultural economies and are likely to become increasingly important with impending climate change. A multiyear study was conducted to evaluate the survival consequences of diversion dam passage for juvenile Chinook Salmon ( Oncorhynchus tshawytscha ) and steelhead ( O. mykiss ) in the highly managed Yakima River, Washington. Canal entrainment and passage were evaluated at four diversion dams encountered by seaward migrating juvenile salmon and steelhead. Fish pass dams via spillbays or enter canals with downstream fish-screening facilities designed to collect entrained fish and return them to the mainstem river. Percent entrainment into canals was substantial (6–59%) at three of the four diversion dams studied, and entrainment probability was positively associated with the proportion of streamflow diverted into canals. Survival probability estimates for groups of tagged fish that were entrained into canals were lower than survival probability estimates for tagged fish that passed through spillbays on the dams. Absolute differences in survival probabilities between routes ranged from 0.099 to 0.369, demonstrating that canal entrainment reduced survival of outmigrating juvenile Chinook Salmon and steelhead. We also found that entrainment resulted in migration delays, which could further affect survival because fish are increasingly exposed to predation and decreased water quality as water temperature increases throughout the migration season. These results highlight the need to limit entrainment of juvenile salmon and steelhead at diversion dams in rivers where salmon recovery is important.

Washington↗

USGS2022

Passage of adult coho salmon (Oncorhynchus kisutch) over Lake Creek Falls, Oregon, 2019

Across the Pacific Northwest, there are many examples of artificial structures created to allow passage of upstream-migrating salmon over natural barriers. We studied upstream passage across three structures installed in 1989 to allow passage of salmon over Lake Creek Falls, a series of three natural waterfalls at the outlet of Triangle Lake on Lake Creek, in the central Oregon Coast Range (lat 123.57508°; long 44.15735°). To track upstream passage by adult coho salmon ( Oncorhynchus kisutch ), 87 fish were tagged using gastrically implanted radio tags. Tracking was accomplished with a series of stationary receivers installed to detect crossings at each of three structures—over Lake Creek Falls using two upstream Denil-type ladders and a bypass downstream constructed to mimic a natural side channel. Tracking spanned the upstream migration and spawn timing for adult coho salmon in the basin and extended from October 2019 to February 2020. A total of 15 coho salmon (17 percent) were tagged in October, 30 coho salmon (35 percent) were tagged in November, and 42 coho salmon (48 percent) were tagged in December. Later-than-normal precipitation and associated low discharge delayed upstream migrations. Accordingly, most fish arrived late in the season (late November and December) and in sudden flushes with the erratic rain events. Fish that were tagged earlier were more likely to cross all three ladders, with more than 93 percent of fish tagged in October compared to 46.7 and 19.0 percent of November and December fish passing, respectively. The decline in passage rate could be attributed to the overlapping influences of stream discharge and advanced stage of maturation (lower energy reserves) of fish later in the season. Near the end of the study, both fish that crossed and fish obstructed by barriers were observed in tributaries known to be used for spawning by coho salmon. Without a much longer-term study involving many more fish than the current study, more intensive tracking, and coverage of different flow years, firm conclusions are difficult to draw regarding the overall influences of the passage structures on the likelihood of upstream passage by adult coho salmon. However, substantial numbers of fish are capable of crossing during certain conditions. The population-level consequences of the barriers on spawning distribution and the production of coho salmon in the watershed are not clear. Additional empirical study or population modeling could be used to address this question in more detail.

Oregon↗

USGS2022

Juvenile green sturgeon (Acipenser medirostris) movement during autumn and winter in the lower Sacramento River, California, 2016–20

A collaborative acoustic telemetry study was conducted to describe behavior and movement patterns of juvenile green sturgeon ( Acipenser medirostris ) in the lower Sacramento River, California during 2016–19. For the study, juvenile green sturgeon were collected, tagged, and released in the Sacramento River between river kilometer (rkm) 467 and rkm 419 near Red Bluff, California. Telemetry monitoring sites were located between rkm 464 and rkm 1 to detect tagged fish that moved downstream. In this report, we describe movement patterns of juvenile green sturgeon in the lower Sacramento River between rkm 167 and rkm 52. In total, 98 juvenile green sturgeon were tagged and released during the study and 46 of these fish moved downstream and were detected in the lower Sacramento River. Downstream movement appeared to be associated with periods of increasing river flow, and the greatest percentage of tagged fish were detected moving downstream during the first period of increased streamflow each autumn. The number of tagged fish that were detected decreased in lower reaches of the study area, but it’s not clear if this was because fish experienced mortality while moving downstream, stopped moving downstream to rear in study reaches, or their transmitters stopped working due to battery life limitations. We did find that several fish were detected moving upstream between telemetry monitoring sites in the lower reaches of the study area. This study provides new insights into movement patterns and behavior of juvenile green sturgeon in the lower Sacramento River, but additional research will be required to better understand factors such as survival and how fish respond to estuarine conditions.

California↗

USGS2022

Monitoring the movements of juvenile Pacific Lamprey (Entosphenus tridentatus) in the Yakima River, Washington, using acoustic telemetry, 2019–20

Anthropogenic barriers to main-stem and tributary passage are one of the primary threats associated with declining populations of Pacific Lamprey ( Entosphenus tridentatus ) in the Columbia River Basin. Juvenile lamprey are of special interest because their downstream migration to the ocean may be affected by barriers such as dams or water diversions. Telemetry studies that describe the movement and passage of juvenile lamprey have not been possible until the recent development of a micro-transmitter specifically for use in juvenile lamprey and eels. Through a collaborative research approach, we used these prototype transmitters and acoustic monitoring arrays installed for a juvenile salmon ( Oncorhynchus spp.) migration study to evaluate juvenile lamprey movements in the Yakima River (river kilometer 179 to the river mouth) in 2019 and 2020. We tagged and released 152 juvenile lamprey from April 30 to June 5, 2019, and on June 9, 2020. Lamprey were released 6.9 kilometers (km) upstream from Wapato Dam, 1.2 km upstream from Prosser Dam, and into the canal and tailrace at Prosser Dam. Most tagged lamprey did not initiate downstream movements within the 18 days of tag life, as evidenced by our detections of lamprey in the highest numbers at the first monitoring site downstream from their release site, with limited or no detections at sites farther downstream. There was no evidence of missed detections (lamprey detected at a downstream site without corresponding detections upstream). Overall detections of tagged lamprey were low: 27.0 percent in 2019 and 48.0 percent in 2020. River flows were less than the 10-year average during the monitoring period and water temperatures were variable. Lamprey arrived at detections sites predominantly during periods of darkness (85.3–96.6 percent) following daytime releases. Travel rates through the study area ranged from 0.2 to 45.3 kilometers per day, and lamprey generally remained at each detection station for less than about 20 minutes. Groups of lamprey released together generally had similar travel rates with a small number of fish that moved more quickly or slowly than the remainder of the group. In addition to monitoring the migration and behavior of juvenile lamprey, we also assessed some assumptions of survival models (determining downstream drift of purposely killed fish and empirically measuring transmitter operating life) to benefit future evaluations focused on migration survival of juvenile lamprey.

Washington↗

USGS2021

Behavior and survival of hatchery rainbow trout (Oncorhynchus mykiss) in the upper Cowlitz River Basin, Washington, 2013 and 2017

A two-year study (2013 and 2017) was conducted to determine if annual releases of hatchery rainbow trout (resident Oncorhynchus mykiss ) in the upper Cowlitz River Basin, Washington adversely affected anadromous fish in the basin. Rainbow trout tagged with radio transmitters were monitored after release to describe movement patterns, entrainment rates at Cowlitz Falls Dam, and survival. Additionally, trout that were radio-tagged in 2017 were monitored during spring 2018 to determine if any moved upstream and entered tributaries where winter steelhead (anadromous Oncorhynchus mykiss ) spawning occurs. A total of 580 hatchery rainbow trout (122 in 2013 and 458 in 2017) were radio-tagged and released at three release sites: (1) Cowlitz Falls Campground on Cowlitz River Arm of Lake Scanewa river kilometer (rkm) 155, (2) Cispus River Arm of Lake Scanewa rkm 1, and (3) Day Use Park on Cowlitz River Arm of Lake Scanewa rkm 146. Most radio-tagged trout (70 percent) remained within 6.4 rkm of the release site but some fish moved at least 25.7 rkm from the release site. The predominant movement direction was downstream. More than twice as many fish released at Cowlitz Falls Campground in 2017 (compared to the other two release sites) remained in the Cowlitz River, where potential overlap with steelhead occurs. A total of 28.3 percent of the study fish were entrained at Cowlitz Falls Dam. Apparent survival (time until movement ceased) for most tagged trout was fewer than 100 days from release in both years and no fish were detected moving during the spring following their release. In summary, hatchery rainbow trout released upstream from Cowlitz Falls Dam seem to remain primarily in Lake Scanewa or entrained at Cowlitz Falls Dam with few fish surviving to winter months. We found no evidence of hatchery trout interacting with steelhead in spawning tributaries during spring months. These results suggest that trout stocking in the upper Cowlitz River Basin poses minimal threat to anadromous fish in the basin.

Washington↗

USGS2021

Evaluation of movement and survival of juvenile steelhead (Oncorhynchus mykiss) and coho salmon (Oncorhynchus kisutch) in the Klickitat River, Washington, 2018–2019

A 2-year telemetry study was conducted April–July in 2018 and 2019 to evaluate migration behavior and survival of juvenile steelhead ( Oncorhynchus mykiss ) and coho salmon ( O. kisutch ) in the Klickitat River, Washington. A total of 612 natural-origin steelhead, collected in a smolt trap on the Klickitat River, were tagged, released, and monitored as they outmigrated through the lower 17 kilometers (km) of the Klickitat River, and in the 52 km reach between the mouth of the Klickitat River and Bonneville Dam. The primary goal of the steelhead study was to estimate survival through the Klickitat River delta, the 2 km reach located at the confluence of the Klickitat and Columbia rivers. A total of 400 hatchery-origin coho salmon were tagged and released at the Klickitat Hatchery and monitored during migration through the lower 68 km of the Klickitat River and in the Columbia River to Bonneville Dam. The primary goals of the coho salmon study were (1) to estimate survival through the Klickitat River delta and (2) to determine residence time in the Klickitat River to assess potential for interactions with rearing natural-origin fish. Many tagged steelhead and coho salmon moved quickly downstream and left the Klickitat River shortly after release. Median elapsed time from release to Klickitat River exit ranged from 1.4 to 1.5 days for steelhead, and from 5.1 to 12.9 days for coho salmon during the two-year study. Ten percent of the tagged coho salmon in 2018 remained in the Klickitat River for 21.9–29.2 days before entering the Columbia River. In 2019, ten percent of the tagged coho salmon remained in the Klickitat River for 36.0–45.5 days before entering the Columbia River. This suggests that some hatchery fish spend considerable time in the river after hatchery release. Migration rates were consistently slow for both species in the Klickitat River delta compared to upstream reaches of the free-flowing Klickitat River and downstream reaches of the Columbia River. Similarly, reach-specific survival was highest in free-flowing reaches of the Klickitat River and lowest near the Klickitat River delta. Cumulative survival from release to sites located downstream of the Klickitat River delta were 0.78 for juvenile steelhead in both 2018 and 2019, and 0.57 and 0.61 for juvenile coho salmon in 2018 and 2019. Standardized survival estimates (survival per 100 river kilometers) were 0.243 in 2018 and 0.302 in 2019 for steelhead, and 0.100 in 2018 and 0.153 in 2019 for coho salmon. These estimates of standardized survival are low compared to similar estimates from other rivers in Washington, Oregon, Idaho, and California. This study provided new information about survival and residence time of juvenile steelhead and coho salmon in the Klickitat River. Additional studies would be helpful to understand factors affecting outmigration survival and overlap between hatchery-origin and natural-original juvenile steelhead and coho salmon in the system.

Washington↗

USGS2021

Evaluation of factors affecting migration success of adult sockeye salmon (Oncorhynchus nerka) in the Yakima River, Washington, 2020

A study was conducted during June–October 2020 to evaluate factors affecting the migration success of adult sockeye salmon ( Oncorhynchus nerka ) in the Yakima River, Washington. A total of 144 adult sockeye salmon were tagged and released during the study. Most fish (112 fish) were collected, tagged with passive integrated transponder (PIT), and released at the mouth of the Yakima River. The remaining fish were tagged with a radio transmitter and PIT tag: 13 fish were collected, tagged, and released at Prosser Dam; 13 fish were collected and tagged at Prosser Dam, transported downstream, and released at the mouth of the Yakima River; and 6 fish were collected, tagged, and released at the mouth of the Yakima River. Radio-tagged fish released at Prosser Dam initially moved upstream and spread out in the river reach between Prosser and Sunnyside Dams, but all fish stopped moving and several transmitters were recovered. Detection records and temperature data from recovered transmitters were the basis for inferring that avian predators consumed at least 6 of the 13 fish. Fifteen of the 19 radio-tagged sockeye salmon released at the mouth of the Yakima River moved upstream in the Columbia River and were detected at Johnson Island in the Hanford Reach, or at Priest Rapids Dam. Two of these fish, tagged on August 7, eventually moved back downstream and entered the Yakima River when water temperatures in the lower Yakima River were 16–18 degrees Celsius (°C). One fish moved upstream to Sunnyside Dam where its tag was later recovered. The other fish moved farther upstream and was detected at Prosser Dam, but eventually moved downstream and its tag was recovered near Benton City, Washington. None of the recovered tags were found near a carcass. More than one-half of the sockeye salmon that were collected, tagged, and released at the mouth of the Yakima River were subsequently detected, and the greatest proportion of fish from groups released during June, July, and August entered the Yakima River. This finding suggests that adult sockeye salmon are present at the mouth of the Yakima River throughout the summer. Detection records for tagged fish at monitoring sites located near cool water inputs in the lower Yakima River suggest that sockeye salmon do not spend a substantial amount of time at these locations. Fish count data at Prosser Dam fish ladders showed that sockeye salmon had a bi-modal pattern of upstream migration with peaks in late June/early July and September when water temperature in the lower Yakima River was 20 °C or less. Sixty-one percent of PIT-tagged sockeye salmon detected at Prosser Dam were eventually collected at the adult fish trapping facility at Roza Dam where fish are collected and transported upstream to Cle Elum Reservoir. These data, in conjunction with results from other studies, suggest that a substantial proportion of Yakima River sockeye salmon fail to arrive at Roza Dam. Additional research will be required to better understand factors affecting Yakima River sockeye salmon.

Washington↗

USGS2020

Behavior and movement of adult winter steelhead ( Oncorhynchus mykiss ) in the upper Cowlitz River Basin, Washington, 2017–18

Executive Summary A 2-year radiotelemetry study was completed to monitor the movements of adult winter steelhead ( Oncorhynchus mykiss ) in the upper Cowlitz River Basin. A reintroduction program was established to restore healthy and harvestable populations of steelhead because volitional access to the area was blocked in the 1960s after construction of dams in the lower river. A trap-and-haul program is used to move adult steelhead and salmon ( Oncorhynchus spp.) upstream, around the dams and large reservoirs, and release them in the upper basin to spawn naturally. Fish are released into Lake Scanewa, the uppermost reservoir in the system, and into the Cowlitz and Cispus Rivers. The goal of this study was to describe the behavior, movement, and tributary use of adult steelhead in the upper Cowlitz River Basin to assist in evaluating the trap-and-haul program and reintroduction program. We were specifically interested in learning more about the locations where steelhead spawn. Individual fish were assigned one of four fates, based on their location during the spawning period: Cowlitz River, Cispus River, Lake Scanewa, or fallback below the dam that impounds the reservoir. A total of 215 steelhead were tagged for the 2017–18 study. Of these, 5 fish regurgitated their transmitters before or shortly after release, so 210 tagged fish were used for analyses, including 121 fish (57.6 percent) released into the Cispus River and 89 fish (42.4 percent) released into Lake Scanewa. The Cowlitz River release site was not evaluated. Hatchery-origin (HOR) and natural-origin (NOR) steelhead were included in the study. Within the first 10 days after release, most steelhead had moved at least 2 river kilometers away from their release site. Fish released into Lake Scanewa, however, moved from their release site significantly sooner than fish released into the Cispus River, regardless of origin or sex. Most radio-tagged steelhead (93–100 percent) made no more than one trip between the reservoir and one of the rivers prior to spawning. Steelhead were predominantly assigned fates in the river closest to where they were released, but origin also played a role. Steelhead released into the Cispus River were assigned Cispus River fates more than 80 percent of the time, including both origins and both years. About 13 percent of NOR fish had fates in the Cowlitz River, but the proportion was lower for HOR fish (0–2 percent). Fallback was the least common fate for Cispus-released steelhead (three HOR fish in 2017), followed by the reservoir fate, ranging from 5 to 9 percent in 2017, and zero in 2018. The steelhead released into Lake Scanewa were almost exclusively NOR fish, which had primarily Cowlitz River fates (55–57 percent). We released only six HOR steelhead into Lake Scanewa, and they all had Cowlitz River fates. The reservoir fate was uncommon for both release sites, and it was consistently lower in 2018 compared to 2017. Flow conditions were higher in 2017, which may have affected steelhead movement patterns or timing. The three HOR steelhead released in the Cispus River in 2017 were the only fish that fell back over Cowlitz Falls Dam, which represented 1.4 percent of the total study fish, 5.7 percent of the Cispus-released fish in 2017, and 9.4 percent of the Cispus-released HOR fish in 2017. About 62 percent of the steelhead released in Lake Scanewa spawned in the Cowlitz River, with the remaining 38 percent in the Cispus River. Within the Cowlitz River, close to one-half (about 47 percent) of the fish spawned in the upper reach, and about 16 percent spawned in the lower reach. Steelhead released into Lake Scanewa that spawned in the Cispus River were minimal in reach 5 (4 percent) and distributed in approximately equal proportions in the middle (reach 6; 16 percent) and upper (reach 7; 18 percent) reaches. Steelhead released into the Cispus River spawned almost exclusively in the Cispus River (94 percent). The upper Cispus River reach (reach 7) was used by more fish (72 percent) than the middle Cispus reach (reach 6; 16 percent). Taken together, the upper Cowlitz River reach (reach 4) and upper Cispus River reach (reach 7) accounted for more than 71 percent of the spawning locations for radio-tagged steelhead. When the middle Cispus River reach (reach 6) is included with the upper reaches, they account for 87 percent of our described spawning sites. We described 12 tributaries in the Cowlitz River and 8 tributaries in the Cispus River where steelhead spawned. After spawning, about 53–63 percent of steelhead moved downstream as kelts, either being collected at Cowlitz Falls Dam or being detected downstream from the dam. More fish were collected from both release sites in 2018 compared to 2017. Across release sites and years, more NOR fish and females moved downstream as kelts. This study added to the understanding of the behavior and movement of adult steelhead in the upper Cowlitz River Basin, supporting the findings of previous studies in the basin and describing spawning sites in the system’s two main rivers and their tributaries. Future research efforts in this system may use additional telemetry studies, genetic analyses, and spawning ground surveys to provide further insights into the progress of the reintroduction effort.

Washington↗

USGS2020

Evaluation of water temperature effects on adult sockeye salmon (Oncorhynchus nerka) behavior in the Yakima River, Washington, 2019

A study was conducted in the lower Yakima River, Washington, during June–October 2019 to evaluate water temperature effects on adult sockeye salmon ( Oncorhynchus nerka ) behavior. A total of 60 sockeye salmon adults were tagged with radio transmitters and monitored during the study. Fourteen of the fish were collected and tagged at Prosser Dam in late June and the remainder were collected and tagged at the mouth of the Yakima River in late July. Water temperature exceeded 20 degrees Celsius (°C), conditions shown to block upstream migration of adult sockeye salmon in other river systems, from June 9, 2019 to September 15, 2019. These elevated temperatures seemed to affect the behavior of tagged fish during this study. Fish that were collected and tagged at Prosser Dam left the Yakima River within days of release and tagged fish that were collected and released at the mouth of the Yakima River failed to enter and move upstream until mid-September when water temperature decreased to less than (<) 20 °C. Monitoring sites were located adjacent to several known areas of cool-water inputs that may provide thermal refuge for fish in the lower Yakima River to determine if tagged fish spent time in these areas. Although several tagged fish moved repeatedly past these sites, most fish spent <30 minutes at any given site, indicating that fish were actively migrating past the sites rather than holding near cool-water inputs. A single tagged fish moved upstream to Roza Dam and was collected for upstream transport to Cle Elum Reservoir during our study. Additional research in subsequent years likely will be required to better understand how water temperature affects adult sockeye salmon in the lower Yakima River.

Washington↗

USGS2019

Using the STARS Model to evaluate the effects of two proposed projects for the long-term operation of State Water Project Incidental Take Permit Application and CEQA compliance

The California Department of Water Resources (DWR) requested analysis of juvenile Chinook salmon survival in the Sacramento-San Joaquin River Delta (henceforth identified as “the Delta”) as part of an effects analysis that will be included in an Incidental Take Permit (ITP) Application. This application is in compliance with the California Endangered Species Act (CESA) and Environmental Impact Report (EIR), which is itself in compliance with California Environmental Quality Act (CEQA). DWR is seeking an ITP and preparing CEQA compliance documentation for long-term operation of the State Water Project (SWP). DWR requested assistance from the U.S. Geological Survey to aid in determining the effect of two proposed projects on juvenile Chinook salmon ( Oncorhynchus tshawytscha ) populations migrating through the Delta. Therefore, in this report we analyzed an 82-year time series of simulated river flows and Delta Cross Channel (DCC) gate operations under three scenarios constructed for the ITP: the proposed project (PP), the second proposed project (PP2b) and the existing (EX) scenarios. To evaluate the proposed projects (PP and PP2b), we used the STARS model (Survival, Travel time, And Routing Simulation model), a stochastic, individual-based simulation model designed to predict survival of a cohort of fish that experience variable daily river flows during migration through the Delta. The STARS model uses parameter estimates from a Bayesian mark-recapture model that jointly estimates travel time and survival in eight discrete reaches of the Delta and migration routing at two key river junctions. By applying the STARS model to the three 82-year scenarios, we found that both proposed projects had negative effects on survival, travel time, and routing in November but slightly positive effects in October, December, and May, and in June for only the PP. In November, there was a high probability that survival for PP and PP2b were less than EX and that travel time and routing to the Interior Delta for PP and PP2b were greater than for EX. We found that the magnitude of the difference in survival between scenarios was large in some years. For example, survival under both the PP and PP2b scenarios were 10 percent lower than EX in 25 percent of the water years in November. During this period, inflow to the Delta tended to be lower under the PP and PP2b scenarios, and the DCC gate was open more frequently under the PP and PP2b scenarios relative to the EX scenario. Lower inflow reduces survival, and more frequent operation of the DCC gate 1) increases the proportion of fish entering the Interior Delta, where survival is low, and thus 2) reduces survival in the Sacramento River in reaches downstream of the DCC. In contrast, during October, December, May (both PP and PP2b), and June (PP only), survival was slightly higher, travel times were lower, and routing to the Interior Delta was lower under the PP and PP2b relative to the EX scenario in the same time period, although the magnitude of the increase was relatively small in most years (less than two percent). This difference between scenarios was driven by higher river flows in some years under the PP and PP2b relative to the EX scenario. Overall, the differences in survival, travel time, and routing distance between the three operational scenarios were primarily driven by the timing and magnitude of the annual high river flows.

California↗

USGS2019

Movement and apparent survival of acoustically tagged juvenile late-fall run chinook salmon released upstream of Shasta Reservoir, California

Stakeholder interests have spurred the reintroduction of the critically endangered populations of Chinook Salmon to tributaries upstream of Shasta Dam, in northern California. We released two groups of acoustically tagged, juvenile hatchery, late-fall Chinook Salmon to determine how juvenile salmon would distribute and survive. We measured travel times to Shasta Dam, and the number of fish that moved between locations within Shasta Reservoir. We used mark-recapture methods to determine detection and apparent survival probabilities of the tagged fish as they traveled through five reaches of the Sacramento River from the McCloud River to San Francisco Bay (~590 km) over the two 3-month observation periods. After our first (February) release of 262 tagged fish, 182 fish (70%) were detected at least once at the dam, 41 (16%) were detected at least once downstream of Shasta Dam, and 3 (1%) traveled as far as San Francisco Bay. After the second (November) release of 355 tagged fish, only 4 (1%) were detected at Shasta Dam. No fish were detected below Shasta Dam, so we could not estimate survival for this second release group. The first release of fish was fortuitously exposed to exceptionally high river flows and dam discharges, which may have contributed to the more distant downstream migration and detection of these fish — though other factors such as season, diploid versus triploid, and fish maturation and size may have also contributed to release differences. The reported fish travel times as well as detection and survival rates are the first estimates of juvenile salmon emigration from locations above Shasta Dam in more than 70 years. This information should help inform resource managers about how best to assess juvenile winter-run Chinook Salmon and assist in their reintroduction to watersheds upstream of Shasta Dam.

California↗

USGS2019

Juvenile Chinook salmon (Oncorhynchus tshawytscha) survival in Lookout Point Reservoir, Oregon, 2018

A field study was conducted to estimate survival of juvenile Chinook salmon ( Oncorhynchus tshawytscha ) in Lookout Point Reservoir, Oregon, during 2018. The study consisted of releasing three groups of genetically-marked fish into the reservoir, and sampling them monthly. Juveniles were released during April 10–13 (116,708 fish), May 15–18 (31,911 fish), and June 19–20 (11,758 fish). Reservoir sampling began in May and occurred monthly through October, consisting of 5-day events where juvenile Chinook salmon were collected using electrofishing, shoreline traps, and gill nets. Data were analyzed using a staggered release-recovery model and a parentage-based tagging (PBT) N-mixture model. The staggered release-recovery model provided survival estimates from three periods: mid-April to mid-May (SSRRM1); mid-May to mid-June (SSRRM2); and mid-April to mid-June (SSRRM12). Multiple estimates of survival were possible for each period using different combinations of recovery data from the three groups of fish that were released. Survival probability estimates for SSRRM1 ranged from 0.98520 to 0.98954; estimates for SSRRM2 ranged from 0.09338 to 0.62142; and the estimate for cumulative survival from mid-April to mid-June (SSRRM12) were 0.75211. We suspect that issues with release groups in May ( R 2 ) and June ( R 3 ) led to biased survival results using the staggered release-recovery model. The PBT N-mixture model provided survival estimates from six periods: mid-April to mid-May (SNMIX1); mid-May to mid-June (SNMIX2), mid-June to mid-July (SNMIX3), mid-July to mid-August (SNMIX4), mid-August to mid-September (SNMIX5); and mid-September to mid-October (SNMIX6). Survival estimates from the PBT N-mixture model were lowest for SNMIX6 (0.41620) and highest for SNMIX1 (0.79587). These results differed from those in 2017 when monthly survival increased across months. This suggests that one or more factors could have affected juvenile Chinook salmon survival in Lookout Point Reservoir. One possible factor could be copepods (which were highly prevalent on juvenile Chinook salmon during summer 2018), but environmental factors such as reserveroir elevation, discharge at Lookout Point Dam, and fish distributions within the reservoir differed between study years. Two PBT N-mixture models provided cumulative survival estimates from mid-April to mid-October. Estimates from the two models were 0.061 and 0.039, which suggests that survival of subyearling Chinook salmon in Lookout Point Reservoir was very low in 2018. Additional research is recommended to better understand inter-annual variability of subyearling Chinook salmon in the reservoir and to gain insights into factors that affect their survival.

Oregon↗

USGS2019

Movements of juvenile Pacific Lamprey (Entosphenus tridentatus) in the Yakima and Columbia Rivers, Washington, 2018—A pilot study using acoustic telemetry

Telemetry has been an invaluable tool to improve our understanding of adult Pacific Lamprey ( Entosphenus tridentatus ) movements and to guide management approaches to protect and restore this species of concern. Juvenile and larval lamprey, however, are much smaller than adults, and have not been monitored with telemetry because available transmitters have traditionally been too large. With funding from the U.S. Department of Energy and the U.S. Army Corps of Engineers, the Pacific Northwest National Laboratory developed a prototype micro-transmitter of appropriate size for use in small fish such as juvenile lampreys and eels. Through a collaborative research approach, we used these prototype transmitters to do a pilot level evaluation of juvenile lamprey (macrophthalmia) movements in the Yakima and Columbia Rivers in 2018. Our project monitored tagged lamprey using acoustic monitoring arrays installed and maintained for juvenile salmon ( Oncorhynchus spp.) migration studies done by our partners. The study was done in the lower Yakima River, Washington, from river mile 111 to the river mouth, and in the Columbia River, from the Yakima River mouth to Camas, Washington, downstream of Bonneville Dam. We released four groups of tagged lamprey from May 9 to 15, 2018. Two groups were released at the upper site (located at the State Route 24 bridge, about 4.5 river miles upstream of Wapato Dam), and two groups were released at the lower site (about 1.7 miles upstream of the Yakima River mouth). We detected 95.6 percent of the tagged lamprey, with more individuals detected in the Columbia River than in the Yakima River. Lamprey arrived at Bonneville Dam in an average of 8.0–9.6 days from the upper site (300 river miles) and in an average of 6.5 days from the lower site (193 river miles). Lamprey moved through the study area at an average rate of 30–35 miles per day and generally remained at each detection site for less than about 20 minutes. Most lamprey (63 percent) arrived at detection sites during periods of darkness, but some travel occurred during daylight and transitional light periods.

Washington↗

USGS2019

Adult sockeye salmon (Oncorhynchus nerka) behavior and movement from Roza Dam to Cle Elum Dam, Washington, 2018

An evaluation was conducted to describe adult sockeye salmon ( Oncorhynchus nerka ) upstream movement patterns from Roza Dam to Cle Elum Dam in the Yakima Basin, Washington. Sockeye salmon adults that arrive at Roza Dam are currently trapped and transported upstream of Cle Elum Dam because upstream fish-passage facilities are not currently in place at the dam. However, these facilities are being designed, so resource managers wanted to confirm that sockeye salmon could successfully move upstream through the Roza Dam-to-Cle Elum Dam reach. A total of 20 adult sockeye salmon were collected, tagged with a radio transmitter, and released at Roza Dam during July 2018. These fish were monitored using a series of fixed monitoring sites and mobile tracking for 2 months. All tagged sockeye salmon successfully moved upstream and were detected in the tailrace of Cle Elum Dam. Median elapsed time from release at Roza Dam to first detection at Cle Elum Dam was 17 days (d) and ranged from 7 to 30 d. We examined migration delay at the Town Ditch diversion dam by comparing elapsed time of detection at that site to elapsed time of detection at other sites in the study area. We found that median elapsed time at the Town Ditch site (19.7 hours) was substantially higher than median elapsed time at other sites (1.7 hours or less). This suggests that tagged sockeye salmon were delayed at the diversion dam. However, most tagged fish (75 percent) arrived at Cle Elum Dam within 20 d of release, and all fish arrived within 30 d, which suggests that delay at the diversion dam may be of little consequence. Our results suggest that adult sockeye salmon can readily migrate upstream from Roza Dam to Cle Elum Dam.

Washington↗