Snake River Fall Chinook Salmon Research Active
Juvenile Snake River fall Chinook salmon
Snake River fall Chinook salmon were listed as “threatened” under the Endangered Species Act in 1992. At that time, little was known about the spawning, rearing, migration, and life history of this species. This long-term research and monitoring project has produced much of the contemporary knowledge on fall Chinook salmon that has been used by fish managers to implement recovery measures. The population has responded positively to these measures but will likely remain a conservation-reliant species.
Snake River fall Chinook salmon mainly spawn and rear in Hells Canyon on the Snake River and in the Clearwater River basin. They are unique in that they complete the freshwater portion of their life cycle in main-stem habitats unlike other salmonids that use smaller tributaries. Initial work on this project focused on understanding the spawning and rearing requirements of these fish in main-stem habitats as well as identifying important spawning and rearing sites. Because fish must pass eight dams enroute to the ocean as juveniles and as returning adults, much research was later directed at determining appropriate spawning and migration flows. Research increased our understanding of the relationships between downstream movement behavior and water velocity, turbulence, and fish physiology that in turn helped explain life history diversity in this species.
Other research explored the growth differences between fish rearing in riverine and reservoir habitats that shed light on the food web that supports juvenile salmon. Growth is higher in the Snake River than in Lower Granite Reservoir—the first reservoir juvenile fish encounter during their seaward migration—that is due to differences the prey community between the two systems. We documented recent changes to the food webs in lower Snake River reservoirs that included describing the ecology of nonnative Siberian prawns, opossum shrimp, and resurgence of the endemic sand roller. Each of these species influences juvenile fall Chinook salmon either directly or indirectly.
Recent research has focused on estimating the loss of juvenile fall Chinook salmon to smallmouth bass predation in the Snake River. Smallmouth bass are very abundant and are effective predators of juvenile salmon. We showed that bass consumption rate of juvenile fall Chinook salmon has increased 15-fold since the mid-1990s when the last predation study was conducted. This is largely due to increased numbers of juvenile salmon available as prey that has resulted from both increases in natural production and hatchery releases. Interestingly, bass abundance has not changed appreciably through time. Efforts are currently underway to develop a method to distinguish the origin (e.g., hatchery or natural) of juvenile salmon consumed by bass to determine if one prey is more vulnerable than the other.
A list of cooperator publications related to this study can be found here.
Publications associated with this project.
Forecasting survival and passage of migratory juvenile salmonids
Identification of juvenile fall versus spring chinook salmon migrating through the lower Snake River based on body morphology
Physiological development and migratory behavior of subyearling fall chinook salmon in the Columbia River
Migratory behavior and forebay delay of radio-tagged juvenile fall chinook salmon in a lower snake river impoundment
Genetic characterization of naturally spawned Snake River fall-run Chinook salmon
This has been a 28-year partnership between the U.S. Fish and Wildlife Service (project cooperator) and the Bonneville Power Administration (project funder). This long-term partnership has contributed greatly to our increased understanding of Snake River fall Chinook salmon and the peer-reviewed research products we have produced. Other partners include:
- Overview
Snake River fall Chinook salmon were listed as “threatened” under the Endangered Species Act in 1992. At that time, little was known about the spawning, rearing, migration, and life history of this species. This long-term research and monitoring project has produced much of the contemporary knowledge on fall Chinook salmon that has been used by fish managers to implement recovery measures. The population has responded positively to these measures but will likely remain a conservation-reliant species.
Snake River fall Chinook salmon mainly spawn and rear in Hells Canyon on the Snake River and in the Clearwater River basin. They are unique in that they complete the freshwater portion of their life cycle in main-stem habitats unlike other salmonids that use smaller tributaries. Initial work on this project focused on understanding the spawning and rearing requirements of these fish in main-stem habitats as well as identifying important spawning and rearing sites. Because fish must pass eight dams enroute to the ocean as juveniles and as returning adults, much research was later directed at determining appropriate spawning and migration flows. Research increased our understanding of the relationships between downstream movement behavior and water velocity, turbulence, and fish physiology that in turn helped explain life history diversity in this species.
Other research explored the growth differences between fish rearing in riverine and reservoir habitats that shed light on the food web that supports juvenile salmon. Growth is higher in the Snake River than in Lower Granite Reservoir—the first reservoir juvenile fish encounter during their seaward migration—that is due to differences the prey community between the two systems. We documented recent changes to the food webs in lower Snake River reservoirs that included describing the ecology of nonnative Siberian prawns, opossum shrimp, and resurgence of the endemic sand roller. Each of these species influences juvenile fall Chinook salmon either directly or indirectly.
Recent research has focused on estimating the loss of juvenile fall Chinook salmon to smallmouth bass predation in the Snake River. Smallmouth bass are very abundant and are effective predators of juvenile salmon. We showed that bass consumption rate of juvenile fall Chinook salmon has increased 15-fold since the mid-1990s when the last predation study was conducted. This is largely due to increased numbers of juvenile salmon available as prey that has resulted from both increases in natural production and hatchery releases. Interestingly, bass abundance has not changed appreciably through time. Efforts are currently underway to develop a method to distinguish the origin (e.g., hatchery or natural) of juvenile salmon consumed by bass to determine if one prey is more vulnerable than the other.
A list of cooperator publications related to this study can be found here.
- Publications
Publications associated with this project.
Filter Total Items: 29Forecasting survival and passage of migratory juvenile salmonids
We developed methods to forecast survival and cumulative percent passage for subyearling chinook salmon Oncorhynchus tshawytscha at a dam to help managers effectively time the release of reservoir water to mitigate for passage delays and reduced survival. We tagged Snake River subyearling chinook salmon upstream of a dam from 1993 to 1998 and determined when a subsample of the tagged fish passed tAuthorsWilliam P. Connor, R. Kirk Steinhorst, Howard L. BurgeIdentification of juvenile fall versus spring chinook salmon migrating through the lower Snake River based on body morphology
We tested the use of body morphology to distinguish among subyearling fall-run, subyearling spring-run, and yearling spring-run smolts of chinook salmon Oncorhynchus tshawytscha at two lower Snake River dams during the summer emigration. Based on principal-components analysis, subyearling fall-run chinook salmon had smaller heads and eyes, deeper bodies, and shorter caudal peduncles than yearlingAuthorsK.F. Tiffan, D.W. Rondorf, R.D. Garland, P.A. VerheyPhysiological development and migratory behavior of subyearling fall chinook salmon in the Columbia River
We describe the migratory behavior and physiological development of subyearling fall chinook salmon Oncorhynchus tshawytscha migrating through John Day Reservoir on the Columbia River, Washington and Oregon. Fish were freeze-branded and coded-wire-tagged at McNary Dam, Oregon, from 1991 to 1994, to determine travel time to John Day Dam and subsequent adult contribution. Stepwise multiple regressioAuthorsK.F. Tiffan, D.W. Rondorf, P.G. WagnerMigratory behavior and forebay delay of radio-tagged juvenile fall chinook salmon in a lower snake river impoundment
During July and August 1995-1997, we used radiotelemetry to estimate the migration rate of 405 juvenile fall chinook salmon Oncorhynchus tshawytscha (mean fork length, 138-144 mm) through Little Goose Reservoir. Migration rates decreased significantly as fish approached the dam. Median migration rates in 1995 were 26.0 km/d through the 45.9-km reach immediately below Lower Granite Dam, 14.9 km/d tAuthorsD.A. Venditti, D.W. Rondorf, J.M. KrautGenetic characterization of naturally spawned Snake River fall-run Chinook salmon
We sampled juvenile Snake River chinook salmon Oncorhynchus tshawytscha to genetically characterize the endangered Snake River fall-run population. Juveniles from fall and spring–summer lineages coexisted in our sampling areas but were differentiated by large allozyme allele frequency differences. We sorted juveniles by multilocus genotypes into putative fall and spring lineage subsamples and deteAuthorsA.R. Marshall, H.L. Blankenship, W.P. Connor - Partners
This has been a 28-year partnership between the U.S. Fish and Wildlife Service (project cooperator) and the Bonneville Power Administration (project funder). This long-term partnership has contributed greatly to our increased understanding of Snake River fall Chinook salmon and the peer-reviewed research products we have produced. Other partners include: