David R. Geist

Physicochemical Characteristics of the Hyporheic Zone Affect Redd Site Selection by Chum Salmon and Fall Chinook Salmon in the Columbia River

Abstract Chum salmon Oncorhynchus keta and fall chinook salmon O. tshawytscha spawned at separate locations in a side channel near Ives Island, Washington, in the Columbia River downstream of Bonneville Dam. We hypothesized that measurements of water depth, substrate size, and water velocity would not sufficiently explain the separation in spawning areas and began a 2-year investigation of physicochemical characteristics of the hyporheic zone. We found that chum salmon spawned in upwelling water that was significantly warmer than the surrounding river water. In contrast, fall chinook salmon constructed redds at downwelling sites, where there was no difference in temperature between the river and its bed. An understanding of the specific factors affecting chum salmon and fall chinook salmon redd site selection at Ives Island will be useful to resource managers attempting to maximize available salmonid spawning habitat within the constraints imposed by other water resource needs.

Impacts of the Columbia River Hydroelectric System on Main-Stem Habitats of Fall Chinook Salmon

Abstract Salmonid habitats in main-stem reaches of the Columbia and Snake rivers have changed dramatically during the past 60 years because of hydroelectric development and operation. Only about 13% and 58% of riverine habitats in the Columbia and Snake rivers, respectively, remain. Most riverine habitat is found in the upper Snake River; however, it is upstream of Hells Canyon Dam and not accessible to anadromous salmonids. We determined that approximately 661 and 805 km of the Columbia and Snake rivers, respectively, were once used by fall chinook salmon Oncorhynchus tshawytscha for spawning. Fall chinook salmon currently use only about 85 km of the main-stem Columbia River and 163 km of the main-stem Snake River for spawning. We used a geomorphic model to identify three river reaches downstream of present migration barriers with high potential for restoration of riverine processes: the Columbia River upstream of John Day Dam, the Columbia-Snake-Yakima River confluence, and the lower Snake River upstrea...

Comparison of mainstem spawning habitats for two populations of fall chinook salmon in the Columbia River basin

Extensive hydroelectric development in the Columbia River system has eliminated most mainstem riverine habitat available for spawning by fall chinook salmon (Oncorhynchus tshawytscha). The two remaining populations, Hanford Reach, Columbia River and Hells Canyon Reach, Snake River, are separated geographically and their status is markedly different. Annual escapements to Hanford Reach have averaged approximately 80 000 adults, while the Snake River run size has declined to <1500 adults over the past 10 years. We compared their spawning habitat characteristics over a range of measurement scales, as a means to identify strategies for rebuilding the weak Snake River population. Physical habitat characteristics of redds were similar for both study areas. Redd locations were correlated with channel characteristics, such as braiding and sinuosity. Several differences between the two spawning areas were identified at the watershed scale: the Hells Canyon Reach had a much steeper longitudinal gradient, was largely confined by bedrock, and had a more variable flow regime. These features are controlling variables that operate at the reach-scale to limit the availability and size of substrate and other conditions that influence egg deposition and incubation survival. Geomorphological characteristics of the two study sites are sufficiently different to indicate that the production potential of the Hells Canyon Reach population is markedly lower than that of the Hanford Reach population. Copyright

The Use of Electromyogram Telemetry to Estimate Energy Expenditure of Adult Fall Chinook Salmon

Abstract Excess energy expenditure during the upstream migration of adult fall chinook salmon Oncorhynchus tshawytscha may reduce spawning success or lead to increased prespawning mortality. Recent advances in biotelemetry make it possible to assess the energetic costs of upstream migration. Our objectives were to evaluate the use of physiological telemetry to estimate the energy expended by adult fall chinook salmon at different swimming velocities and to compare these data to those associated with other species of salmonids. An electromyogram (EMG) telemetry system was used to obtain, transmit, and record an integrated EMG pulse signal that represented the time between muscle contractions. The EMG telemetry system provides a means to evaluate the effects of structural or operational changes in the hydropower system on energy expenditure and reproductive success of upstream migrant adult salmon. Seven adult salmon (71.5 to 106 cm fork length [FL]) were tagged and exercised in a respirometer at 15 and 20°...

Use of electromyogram telemetry to assess swimming activity of adult spring Chinook salmon migrating past a Columbia river dam

Abstract Electromyogram (EMG) radiotelemetry was used to estimate the swim speeds of spring Chinook salmon Oncorhynchus tshawytscha migrating upstream past a Columbia River dam. Electrodes from EMG transmitters were surgically implanted in the red muscle of fish captured at Bonneville Dam, and output from the tags was calibrated to defined swim speeds for each fish in a tunnel respirometer. The fish were then released below Bonneville Dam and radio-tracked as they migrated through the tailraces, fishways, and forebays of the dam. On average, swim speed was significantly higher when tagged salmon were moving through tailraces than when they were moving through other parts of the dam. Specifically, swim speeds for fish in tailraces (106.4 cm/s) were 23% higher than those of fish in fishways (84.9 cm/s) and 32% higher than those of fish in forebays (80.2 cm/s). Swim speeds were higher in fishways during the day than during the night, but there were no diel differences in swim speeds in tailraces and forebays...

Modeling the oxygen consumption rates in Pacific salmon and steelhead: An assessment of current models and practices

Abstract Bioenergetic models of fish have been used to study a large number of processes. Like most models, bioenergetic models require the estimation of numerous parameters. As a consequence, they have often relied on parameters borrowed from other species or values extrapolated from other life stages or size-classes. The magnitude of the biases associated with these practices remains largely unknown. The objective of this study was to determine whether or not metabolic rates could be extrapolated between closely related species and life stages. We focused on Pacific salmon Oncorhynchus spp. and steelhead O. mykiss, as the metabolic rates of these species have been well documented. Our analyses showed that models derived from closely related species did not accurately predict the metabolic rates of salmon, indicating that the practice of “species borrowing” should be avoided in assessing fish metabolic rates. Our work also showed that allometric equations of metabolic rates were not stable when measured ...

Practical Application of Electromyogram Radiotelemetry: The Suitability of Applying Laboratory-Acquired Calibration Data to Field Data

Abstract One of the practical problems with quantifying the amount of energy used by fish implanted with electromyogram (EMG) radio transmitters is that the signals emitted by the transmitters provide only a relative index of activity unless they are calibrated to the swimming speed of the fish. Ideally, calibration would be conducted for each fish before it is released, but this is often not possible. Consequently, calibration curves derived from more than one fish are used to interpret EMG signals from individuals that have not been calibrated. We tested the validity of this approach by comparing EMG data within three groups of three wild juvenile white sturgeon Acipenser transmontanus implanted with the same EMG radio transmitter. We also tested an additional six fish that were implanted with separate EMG transmitters. Within each group, a single EMG radio transmitter usually did not produce similar results in different fish. Grouping EMG signals among fish produced less accurate results than having in...

Effects of Intraperitoneal Transmitters on the Social Interaction of Rainbow Trout

Abstract Recent reductions in the size of intraperitoneal transmitters have allowed detailed research of the movement and habitat use of small (<300-mm) salmonids. Because these aspects of behavior are, in part, socially determined, study methods that influence dominance contests or agonism may bias results. We studied the effect of transmitters on social interaction of rainbow trout Oncorhynchus mykiss. Dominant fish with dummy transmitters retained their rank and showed no significant differences from control fish in amounts of agonism and interaction time with subdominant fish.

Influence of River Level on Temperature and Hydraulic Gradients in Chum and Fall Chinook Salmon Spawning Areas Downstream of Bonneville Dam, Columbia River

Abstract Chum salmon Oncorhynchus keta and fall Chinook salmon O. tshawytscha segregate spatially during spawning in the Ives Island side channel of the lower Columbia River downstream from Bonneville Dam. Previous research during one spawning season (2000) suggested that these species selected spawning habitats based on differences in hyporheic temperature and vertical hydraulic gradient (VHG). In this study we confirmed the spatial segregation of spawning based on hyporheic characteristics over 4 years (2001–2004) and examined the effects of load-following operations (power generation to meet short-term electrical demand) at Bonneville Dam on hyporheic function and characteristics. We found that during the study period hyporheic temperature and VHG in chum salmon spawning areas were highly variable during periods of load-following operation, when river levels fluctuated. In contrast, hyporheic water temperature and VHG within chum salmon spawning areas fluctuated less when river levels were not changing...

Unique Allacustrine Migration Patterns of a Bull Trout Population in the Pend Oreille River Drainage, Idaho

Abstract We captured and radio-tagged six adult bull trout Salvelinus confluentus in a spawning tributary of the East River basin, Idaho. These fish were tracked for a year to determine the type of migration they endured to reach their overwintering and spawning locations. Our tracking efforts revealed that the fish made complex postspawning migrations downstream and then upstream either towards or into Lake Pend Oreille. To reach the lake, bull trout migrated at least 12 km out of the East River basin into the Priest River, traveled 34 km down the Priest River into the Pend Oreille River, and then turned upstream and migrated 36 km to Lake Pend Oreille. Three of the six bull trout returned to the East River basin during the subsequent spring. These movement patterns are uniquely complex and extensive for outlet-spawning or allacustrine bull trout. This work illustrates the type of allacustrine migrations bull trout can have and suggests the need for new approaches for accomplishing bull trout population ...