Snake River Fall Chinook Salmon Research
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.
Distinguishing between natural and hatchery Snake River fall Chinook salmon subyearlings in the field using body morphology
Behavioural thermoregulation by subyearling fall (autumn) Chinook salmon oncorhynchus tshawytscha in a reservoir
Water velocity, turbulence, and migration rate of subyearling fall Chinook salmon in the free-flowing and impounded Snake River
Range expansion of an exotic Siberian prawn to the Lower Snake River
Food habits of Juvenile American Shad and dynamics of zooplankton in the lower Columbia River
As many as 2.4 million adult American shad annually pass John Day Dam, Columbia River to spawn upriver, yet food web interactions of juvenile shad rearing in John Day Reservoir are unexplored. We collected zooplankton and conducted mid-water trawls in McNary (June-July) and John Day reservoirs (August-November) from 1994 through 1996 during the outmigration of subyearling American shad and Chinook
Variables influencing the presence of subyearling fall Chinook salmon in shoreline habitats of the Hanford Reach, Columbia River
Two alternative juvenile life history types for fall Chinook salmon in the Snake River basin
Identification of a genetic marker that discriminates ocean-type and stream-type chinook salmon in the Columbia River basin
Thermal exposure of juvenile fall chinook salmon migrating through a lower Snake River Reservoir
Comparison of subyearling fall chinook salmon's use of riprap revetments and unaltered habitats in Lake Wallula of the Columbia river
Quantifying flow-dependent changes in subyearling fall chinook salmon rearing habitat using two-dimensional spatially explicit modeling
Early life history attributes and run composition of PIT-tagged wild subyearling Chinook salmon recaptured after migrating downstream past Lower Granite Dam
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:
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.
Distinguishing between natural and hatchery Snake River fall Chinook salmon subyearlings in the field using body morphology
Behavioural thermoregulation by subyearling fall (autumn) Chinook salmon oncorhynchus tshawytscha in a reservoir
Water velocity, turbulence, and migration rate of subyearling fall Chinook salmon in the free-flowing and impounded Snake River
Range expansion of an exotic Siberian prawn to the Lower Snake River
Food habits of Juvenile American Shad and dynamics of zooplankton in the lower Columbia River
As many as 2.4 million adult American shad annually pass John Day Dam, Columbia River to spawn upriver, yet food web interactions of juvenile shad rearing in John Day Reservoir are unexplored. We collected zooplankton and conducted mid-water trawls in McNary (June-July) and John Day reservoirs (August-November) from 1994 through 1996 during the outmigration of subyearling American shad and Chinook
Variables influencing the presence of subyearling fall Chinook salmon in shoreline habitats of the Hanford Reach, Columbia River
Two alternative juvenile life history types for fall Chinook salmon in the Snake River basin
Identification of a genetic marker that discriminates ocean-type and stream-type chinook salmon in the Columbia River basin
Thermal exposure of juvenile fall chinook salmon migrating through a lower Snake River Reservoir
Comparison of subyearling fall chinook salmon's use of riprap revetments and unaltered habitats in Lake Wallula of the Columbia river
Quantifying flow-dependent changes in subyearling fall chinook salmon rearing habitat using two-dimensional spatially explicit modeling
Early life history attributes and run composition of PIT-tagged wild subyearling Chinook salmon recaptured after migrating downstream past Lower Granite Dam
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: