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• 191. [Article] Abundance, Productivity, and Life History of Fifteenmile Creek Steelhead; Annual Report 2016

  Abstract -- The Fifteenmile Creek watershed in North Central Oregon hosts a native population of steelhead (Oncorhynchus mykiss) that is without influence of previous hatchery augmentation. The Fifteenmile ...

  Citation × Citation Citation Abstract Copy Title: Abundance, Productivity, and Life History of Fifteenmile Creek Steelhead; Annual Report 2016 Abstract -- The Fifteenmile Creek watershed in North Central Oregon hosts a native population of steelhead (Oncorhynchus mykiss) that is without influence of previous hatchery augmentation. The Fifteenmile Creek steelhead are a subpopulation within the Distinct Population Segment (DPS) of the Middle Columbia River steelhead and was listed as ‘threatened’ by the National Marine Fisheries Service (NMFS) first on March 25, 1999 and relisted as a DPS on January 5, 2006. Subsequently, a conservation and recovery management plan was developed for the Middle Columbia River steelhead DPS within Oregon state borders. The goal of the plan is to recover Middle Columbia River steelhead to a level that would allow the removal of threatened status, in addition to providing a long-term goal to recover the population sufficiently to provide sustainable fisheries and other ecological, cultural, social and economic benefits for future generations. The DPS-level recovery plan sets specific recovery goals for the areas within the DPS, which designates Fifteenmile Creek explicitly. The Fifteenmile Creek steelhead population is considered the most inland winter race of steelhead in the Columbia River Basin, as designated by NOAA fisheries. However review of this designation may be necessary at the next Federal Columbia River Power System (FCRPS) Biological Opinion (BiOp) status-review because the run-timing of adult steelhead passing Bonneville Dam has been inconsistent with known winter-run steelhead in the area. The population was identified as “must have viable” status by the Interior Columbia Technical Recovery Team (ICTRT), and reaching viable status is essential for achieving DPS delisting. The ICTRT, Recovery Plan, and the Federal Columbia River Power System (FCRPS-BiOp) have all identified this population as high priority for improving precision and accuracy of abundance, productivity, diversity, and spatial structure information. Title: Abundance, Productivity, and Life History of Fifteenmile Creek Steelhead; Annual Report 2016 Abstract -- The Fifteenmile Creek watershed in North Central Oregon hosts a native population of steelhead (Oncorhynchus mykiss) that is without influence of previous hatchery augmentation. The Fifteenmile Creek steelhead are a subpopulation within the Distinct Population Segment (DPS) of the Middle Columbia River steelhead and was listed as ‘threatened’ by the National Marine Fisheries Service (NMFS) first on March 25, 1999 and relisted as a DPS on January 5, 2006. Subsequently, a conservation and recovery management plan was developed for the Middle Columbia River steelhead DPS within Oregon state borders. The goal of the plan is to recover Middle Columbia River steelhead to a level that would allow the removal of threatened status, in addition to providing a long-term goal to recover the population sufficiently to provide sustainable fisheries and other ecological, cultural, social and economic benefits for future generations. The DPS-level recovery plan sets specific recovery goals for the areas within the DPS, which designates Fifteenmile Creek explicitly. The Fifteenmile Creek steelhead population is considered the most inland winter race of steelhead in the Columbia River Basin, as designated by NOAA fisheries. However review of this designation may be necessary at the next Federal Columbia River Power System (FCRPS) Biological Opinion (BiOp) status-review because the run-timing of adult steelhead passing Bonneville Dam has been inconsistent with known winter-run steelhead in the area. The population was identified as “must have viable” status by the Interior Columbia Technical Recovery Team (ICTRT), and reaching viable status is essential for achieving DPS delisting. The ICTRT, Recovery Plan, and the Federal Columbia River Power System (FCRPS-BiOp) have all identified this population as high priority for improving precision and accuracy of abundance, productivity, diversity, and spatial structure information. Close

• 192. [Article] Klamath Mountains Province Steelhead Project, 1999 Annual Report Report Number: OPSW-ODFW-2002-09

  Abstract -- The steelhead supplement to the Oregon Plan for Salmon and Watersheds (OSPW) is intended to maintain wild steelhead populations in Oregon at sustainable and productive levels that provide substantial ...

  Citation × Citation Citation Abstract Copy Title: Klamath Mountains Province Steelhead Project, 1999 Annual Report Report Number: OPSW-ODFW-2002-09 Abstract -- The steelhead supplement to the Oregon Plan for Salmon and Watersheds (OSPW) is intended to maintain wild steelhead populations in Oregon at sustainable and productive levels that provide substantial environmental, cultural, and economic benefits. The OSPW attempts to better define “sustainable and productive” by committing the Oregon Department of Fish and Wildlife (ODFW) to establish “Population Health Goals” for each Evolutionary Significant Unit (ESU) of wild steelhead within the state. In addition, section ODFW IB1S of the plan calls for ODFW to assess adult escapement and juvenile production of wild steelhead in each ESU. The National Marine Fisheries Service identified seven ESUs for steelhead in Oregon and concluded that steelhead produced in coastal basins between Cape Blanco in southern Oregon and the Klamath River Basin in northern California constitutes one ESU. This area closely corresponds to the geologic boundaries of the Klamath Mountains Province (KMP). Steelhead in the KMP differ from those in adjoining areas because of distinctive life history and genetic characteristics (Busby et al. 1994). Primary differences in life history parameters have been identified for wild KMP steelhead. Summer steelhead and winter steelhead differ in time of return as adults, tendency to return to fresh water on a false spawning migration (the “half-pounder” run), age at ocean entry, growth rate and migration patterns of juveniles in fresh water (ODFW 1990a; ODFW 1994). As a result of these differences, separate health goals seem warranted for summer and winter steelhead populations. Winter steelhead inhabit streams throughout the KMP, while summer steelhead are found only in a portion of the Rogue River Basin. However, the distribution of summer and winter steelhead overlap in major areas of the Rogue River Basin (Everest 1973) and as juveniles of the respective races cannot be differentiated, some population health goals will have to apply to both races. The status of wild steelhead in the Klamath Mountains Province ESU is not readily apparent. Busby et al. (1994) concluded that the steelhead in this ESU “is not now at risk of extinction, but if present trends continue, it is likely to become so in the foreseeable future”. In contrast, Chilcote (1998) concluded that almost all steelhead populations in the Oregon portion of the ESU “are relatively healthy and certainly do not warrant listing as threatened under the ESA”. Uncertainty as to the status of the resource, coupled with the comprehensive conservation plan developed by Oregon and the termination of wild fish harvest in all streams except the Rogue River, lead the National Marine Fisheries Service to defer a listing of KMP steelhead under the Endangered Species Act. However, KMP steelhead remained a candidate species during 1999. The goal of this project is to develop and implement assessment methods to determine the status of wild steelhead in the Oregon portion of the KMP. Project objectives include (1) develop population health goals and allied monitoring methods and (2) determine resource status in relation to health goals. Attainment of all of the population health goals will likely indicate that the populations of wild steelhead in the KMP are healthy and may allow managers to restore harvest opportunities for wild fish. Conversely, failure to attain any of the population health goals will likely indicate that the populations are depressed and would likely lead to actions designed to minimize fishing mortality. However, in most years it is likely that some goals will be attained while some will not be attained. Under that scenario, and depending on which goals are attained, selective fisheries, like the current one for wild winter steelhead in the Rogue River, remain as viable options for fishery managers. Title: Klamath Mountains Province Steelhead Project, 1999 Annual Report Report Number: OPSW-ODFW-2002-09 Abstract -- The steelhead supplement to the Oregon Plan for Salmon and Watersheds (OSPW) is intended to maintain wild steelhead populations in Oregon at sustainable and productive levels that provide substantial environmental, cultural, and economic benefits. The OSPW attempts to better define “sustainable and productive” by committing the Oregon Department of Fish and Wildlife (ODFW) to establish “Population Health Goals” for each Evolutionary Significant Unit (ESU) of wild steelhead within the state. In addition, section ODFW IB1S of the plan calls for ODFW to assess adult escapement and juvenile production of wild steelhead in each ESU. The National Marine Fisheries Service identified seven ESUs for steelhead in Oregon and concluded that steelhead produced in coastal basins between Cape Blanco in southern Oregon and the Klamath River Basin in northern California constitutes one ESU. This area closely corresponds to the geologic boundaries of the Klamath Mountains Province (KMP). Steelhead in the KMP differ from those in adjoining areas because of distinctive life history and genetic characteristics (Busby et al. 1994). Primary differences in life history parameters have been identified for wild KMP steelhead. Summer steelhead and winter steelhead differ in time of return as adults, tendency to return to fresh water on a false spawning migration (the “half-pounder” run), age at ocean entry, growth rate and migration patterns of juveniles in fresh water (ODFW 1990a; ODFW 1994). As a result of these differences, separate health goals seem warranted for summer and winter steelhead populations. Winter steelhead inhabit streams throughout the KMP, while summer steelhead are found only in a portion of the Rogue River Basin. However, the distribution of summer and winter steelhead overlap in major areas of the Rogue River Basin (Everest 1973) and as juveniles of the respective races cannot be differentiated, some population health goals will have to apply to both races. The status of wild steelhead in the Klamath Mountains Province ESU is not readily apparent. Busby et al. (1994) concluded that the steelhead in this ESU “is not now at risk of extinction, but if present trends continue, it is likely to become so in the foreseeable future”. In contrast, Chilcote (1998) concluded that almost all steelhead populations in the Oregon portion of the ESU “are relatively healthy and certainly do not warrant listing as threatened under the ESA”. Uncertainty as to the status of the resource, coupled with the comprehensive conservation plan developed by Oregon and the termination of wild fish harvest in all streams except the Rogue River, lead the National Marine Fisheries Service to defer a listing of KMP steelhead under the Endangered Species Act. However, KMP steelhead remained a candidate species during 1999. The goal of this project is to develop and implement assessment methods to determine the status of wild steelhead in the Oregon portion of the KMP. Project objectives include (1) develop population health goals and allied monitoring methods and (2) determine resource status in relation to health goals. Attainment of all of the population health goals will likely indicate that the populations of wild steelhead in the KMP are healthy and may allow managers to restore harvest opportunities for wild fish. Conversely, failure to attain any of the population health goals will likely indicate that the populations are depressed and would likely lead to actions designed to minimize fishing mortality. However, in most years it is likely that some goals will be attained while some will not be attained. Under that scenario, and depending on which goals are attained, selective fisheries, like the current one for wild winter steelhead in the Rogue River, remain as viable options for fishery managers. Close

• 193. [Article] Klamath Mountains Province Steelhead Project, 2000-01 Annual Report Report Number: OPSW-ODFW-2003-08

  Abstract -- The steelhead supplement to the Oregon Plan for Salmon and Watersheds (OSPW) is intended to maintain wild steelhead populations in Oregon at sustainable and productive levels that provide substantial ...

  Citation × Citation Citation Abstract Copy Title: Klamath Mountains Province Steelhead Project, 2000-01 Annual Report Report Number: OPSW-ODFW-2003-08 Abstract -- The steelhead supplement to the Oregon Plan for Salmon and Watersheds (OSPW) is intended to maintain wild steelhead populations in Oregon at sustainable and productive levels that provide substantial environmental, cultural, and economic benefits. The OSPW attempts to better define "sustainable and productive" by committing the Oregon Department of Fish and Wildlife (ODFW) to establish "Population Health Goals" for each Evolutionary Significant Unit (ESU) of wild steelhead within the state. In addition, section ODFW IB1S of the plan calls for ODFW to assess adult escapement and juvenile production of wild steelhead in each ESU. The National Marine Fisheries Service identified seven ESUs for steelhead in Oregon and concluded that steelhead produced in coastal basins between Cape Blanco in southern Oregon and the Klamath River Basin in northern California constitutes one ESU. This area closely corresponds to the geologic boundaries of the Klamath Mountains Province (KMP). Steelhead in the KMP differ from those in adjoining areas because of distinctive life history and genetic characteristics (Busby et al. 1994). Primary differences in life history parameters have been identified for wild KMP steelhead. Summer steelhead and winter steelhead differ in time of return as adults, tendency to return to fresh water on a false spawning migration (the "half-pounder" run), age at ocean entry, growth rate and migration patterns of juveniles in fresh water (ODFW 1990; ODFW 1994). As a result of these differences, separate health goals seem warranted for summer and winter steelhead populations. Winter steelhead inhabit streams throughout the KMP, while summer steelhead are found only in a portion of the Rogue River Basin. However, the distribution of summer and winter steelhead overlap in major areas of the Rogue River Basin (Everest 1973) and as juveniles of the respective races cannot be differentiated, some population health goals will have to apply to both races. The status of wild steelhead in the Klamath Mountains Province ESU is not readily apparent. Busby et al. (1994) concluded that the steelhead in this ESU “is not now at risk of extinction, but if present trends continue, it is likely to become so in the foreseeable future”. In contrast, Chilcote (1998) concluded that almost all steelhead populations in the Oregon portion of the ESU "are relatively healthy and certainly do not warrant listing as threatened under the ESA". Uncertainty as to the status of the resource, coupled with the comprehensive conservation plan developed by Oregon and the termination of wild fish harvest in all streams except the Rogue River, lead the National Marine Fisheries Service to defer a listing of KMP steelhead under the Endangered Species Act. However, KMP steelhead remained a candidate species during 2000. The goal of this project is to develop and implement assessment methods to determine the status of wild steelhead in the Oregon portion of the KMP. Project objectives include (1) develop population health goals and allied monitoring methods and (2) determine resource status in relation to health goals. Directed sampling began in 1999 and the findings from 1999 were reported by Satterthwaite (2002a). Title: Klamath Mountains Province Steelhead Project, 2000-01 Annual Report Report Number: OPSW-ODFW-2003-08 Abstract -- The steelhead supplement to the Oregon Plan for Salmon and Watersheds (OSPW) is intended to maintain wild steelhead populations in Oregon at sustainable and productive levels that provide substantial environmental, cultural, and economic benefits. The OSPW attempts to better define "sustainable and productive" by committing the Oregon Department of Fish and Wildlife (ODFW) to establish "Population Health Goals" for each Evolutionary Significant Unit (ESU) of wild steelhead within the state. In addition, section ODFW IB1S of the plan calls for ODFW to assess adult escapement and juvenile production of wild steelhead in each ESU. The National Marine Fisheries Service identified seven ESUs for steelhead in Oregon and concluded that steelhead produced in coastal basins between Cape Blanco in southern Oregon and the Klamath River Basin in northern California constitutes one ESU. This area closely corresponds to the geologic boundaries of the Klamath Mountains Province (KMP). Steelhead in the KMP differ from those in adjoining areas because of distinctive life history and genetic characteristics (Busby et al. 1994). Primary differences in life history parameters have been identified for wild KMP steelhead. Summer steelhead and winter steelhead differ in time of return as adults, tendency to return to fresh water on a false spawning migration (the "half-pounder" run), age at ocean entry, growth rate and migration patterns of juveniles in fresh water (ODFW 1990; ODFW 1994). As a result of these differences, separate health goals seem warranted for summer and winter steelhead populations. Winter steelhead inhabit streams throughout the KMP, while summer steelhead are found only in a portion of the Rogue River Basin. However, the distribution of summer and winter steelhead overlap in major areas of the Rogue River Basin (Everest 1973) and as juveniles of the respective races cannot be differentiated, some population health goals will have to apply to both races. The status of wild steelhead in the Klamath Mountains Province ESU is not readily apparent. Busby et al. (1994) concluded that the steelhead in this ESU “is not now at risk of extinction, but if present trends continue, it is likely to become so in the foreseeable future”. In contrast, Chilcote (1998) concluded that almost all steelhead populations in the Oregon portion of the ESU "are relatively healthy and certainly do not warrant listing as threatened under the ESA". Uncertainty as to the status of the resource, coupled with the comprehensive conservation plan developed by Oregon and the termination of wild fish harvest in all streams except the Rogue River, lead the National Marine Fisheries Service to defer a listing of KMP steelhead under the Endangered Species Act. However, KMP steelhead remained a candidate species during 2000. The goal of this project is to develop and implement assessment methods to determine the status of wild steelhead in the Oregon portion of the KMP. Project objectives include (1) develop population health goals and allied monitoring methods and (2) determine resource status in relation to health goals. Directed sampling began in 1999 and the findings from 1999 were reported by Satterthwaite (2002a). Close

• 194. [Article] Klamath Mountains Province Steelhead Project, 2001-02 Annual Report Report Number: OPSW-ODFW-2004-08

  Abstract -- The steelhead supplement to the Oregon Plan for Salmon and Watersheds (OSPW) is intended to maintain wild steelhead populations in Oregon at sustainable and productive levels that provide substantial ...

  Citation × Citation Citation Abstract Copy Title: Klamath Mountains Province Steelhead Project, 2001-02 Annual Report Report Number: OPSW-ODFW-2004-08 Abstract -- The steelhead supplement to the Oregon Plan for Salmon and Watersheds (OSPW) is intended to maintain wild steelhead populations in Oregon at sustainable and productive levels that provide substantial environmental, cultural, and economic benefits. The OSPW attempts to better define "sustainable and productive" by committing the Oregon Department of Fish and Wildlife (ODFW) to establish "Population Health Goals" for each Evolutionary Significant Unit (ESU) of wild steelhead within the state. In addition, section ODFW IB1S of the plan calls for ODFW to assess adult escapement and juvenile production of wild steelhead in each ESU. The National Marine Fisheries Service identified seven ESUs for steelhead in Oregon and concluded that steelhead produced in coastal basins between Cape Blanco in southern Oregon and the Klamath River Basin in northern California constitutes one ESU. This area closely corresponds to the geologic boundaries of the Klamath Mountains Province (KMP). Steelhead in the KMP differ from those in adjoining areas because of distinctive life history and genetic characteristics (Busby et al. 1994). Primary differences in life history parameters have been identified for wild KMP steelhead. Summer steelhead and winter steelhead differ in time of return as adults, tendency to return to fresh water on a false spawning migration (the "half-pounder" run), age at ocean entry, growth rate and migration patterns of juveniles in fresh water (ODFW 1990; ODFW 1994). As a result of these differences, separate health goals seem warranted for summer and winter steelhead populations. Winter steelhead inhabit streams throughout the KMP, while summer steelhead are found only in a portion of the Rogue River Basin. However, the distribution of summer and winter steelhead overlap in major areas of the Rogue River Basin (Everest 1973) and, as juveniles of the respective races cannot be differentiated, some population health goals have to apply to both races. The status of wild steelhead in the Klamath Mountains Province ESU is not readily apparent from historic sources of information. Uncertainty about resource status, coupled with a comprehensive conservation plan developed by Oregon and the termination of wild fish harvest in almost all KMP streams, lead the National Marine Fisheries Service (NMFS), in 1998, to defer a listing of KMP steelhead under the Endangered Species Act. On 30 March, 2001, NMFS announced that, after a review of new information, that an Endangered Species Act listing was not warranted for KMP steelhead. In 2002, ODFW adopted new methods to monitor steelhead populations on the Oregon coast. Allied with the decision, ODFW decided to terminate the KMP steelhead project. Consequently, this report presents findings from the third, and final, year of the project. The goal of the project was to develop and implement assessment methods to determine the status of wild steelhead in the Oregon portion of the KMP. Project objectives included (1) develop population health goals and allied monitoring methods and (2) determine resource status in relation to health goals Satterthwaite (2002a). Directed sampling began in 1999 and findings from the first two years of the project were reported by Satterthwaite (2002b) and Satterthwaite (2003). Title: Klamath Mountains Province Steelhead Project, 2001-02 Annual Report Report Number: OPSW-ODFW-2004-08 Abstract -- The steelhead supplement to the Oregon Plan for Salmon and Watersheds (OSPW) is intended to maintain wild steelhead populations in Oregon at sustainable and productive levels that provide substantial environmental, cultural, and economic benefits. The OSPW attempts to better define "sustainable and productive" by committing the Oregon Department of Fish and Wildlife (ODFW) to establish "Population Health Goals" for each Evolutionary Significant Unit (ESU) of wild steelhead within the state. In addition, section ODFW IB1S of the plan calls for ODFW to assess adult escapement and juvenile production of wild steelhead in each ESU. The National Marine Fisheries Service identified seven ESUs for steelhead in Oregon and concluded that steelhead produced in coastal basins between Cape Blanco in southern Oregon and the Klamath River Basin in northern California constitutes one ESU. This area closely corresponds to the geologic boundaries of the Klamath Mountains Province (KMP). Steelhead in the KMP differ from those in adjoining areas because of distinctive life history and genetic characteristics (Busby et al. 1994). Primary differences in life history parameters have been identified for wild KMP steelhead. Summer steelhead and winter steelhead differ in time of return as adults, tendency to return to fresh water on a false spawning migration (the "half-pounder" run), age at ocean entry, growth rate and migration patterns of juveniles in fresh water (ODFW 1990; ODFW 1994). As a result of these differences, separate health goals seem warranted for summer and winter steelhead populations. Winter steelhead inhabit streams throughout the KMP, while summer steelhead are found only in a portion of the Rogue River Basin. However, the distribution of summer and winter steelhead overlap in major areas of the Rogue River Basin (Everest 1973) and, as juveniles of the respective races cannot be differentiated, some population health goals have to apply to both races. The status of wild steelhead in the Klamath Mountains Province ESU is not readily apparent from historic sources of information. Uncertainty about resource status, coupled with a comprehensive conservation plan developed by Oregon and the termination of wild fish harvest in almost all KMP streams, lead the National Marine Fisheries Service (NMFS), in 1998, to defer a listing of KMP steelhead under the Endangered Species Act. On 30 March, 2001, NMFS announced that, after a review of new information, that an Endangered Species Act listing was not warranted for KMP steelhead. In 2002, ODFW adopted new methods to monitor steelhead populations on the Oregon coast. Allied with the decision, ODFW decided to terminate the KMP steelhead project. Consequently, this report presents findings from the third, and final, year of the project. The goal of the project was to develop and implement assessment methods to determine the status of wild steelhead in the Oregon portion of the KMP. Project objectives included (1) develop population health goals and allied monitoring methods and (2) determine resource status in relation to health goals Satterthwaite (2002a). Directed sampling began in 1999 and findings from the first two years of the project were reported by Satterthwaite (2002b) and Satterthwaite (2003). Close

• 195. [Article] Willamette BiOp - Genetic Stock Identification and Relative Natural Production of Willamette River Steelhead

  Abstract -- We used genotypic data from 15 microsatellite loci to characterize the stock structure of Oncorhynchus mykiss in the upper Willamette River basin. We then used two analytical approaches, implemented ...

  Citation × Citation Citation Abstract Copy Title: Willamette BiOp - Genetic Stock Identification and Relative Natural Production of Willamette River Steelhead Abstract -- We used genotypic data from 15 microsatellite loci to characterize the stock structure of Oncorhynchus mykiss in the upper Willamette River basin. We then used two analytical approaches, implemented in the programs ONCOR and STRUCTURE, to assign (presumably) natural-origin, unmarked fish to their most likely reporting group or hybrid class. We investigated sibling relationships among unknown samples with the program ML RELATE. In the upper Willamette River, O. mykiss genetic structure can be characterized by four principal groups: summer steelhead of Skamania stock ancestry, eastern tributaries winter steelhead, western tributaries winter steelhead and resident rainbow trout. We found that about 10% of unmarked juvenile O. mykiss sampled at Willamette Falls in 2009-2011 were summer steelhead and that an additional 10% of samples were summer x winter steelhead hybrids. Most O. mykiss sampled from the McKenzie River were either summer steelhead or summer x winter steelhead hybrids. Natural production of pure summer steelhead appeared to be very low in the North and South Santiam rivers, though summer steelhead hybrids represented 11.1% and 14.8% of samples. Results from ML RELATE analyses appeared unreliable and inconclusive, and may have been limited by low genetic diversity among summer steelhead samples. We provide several recommendations to better understand and reduce potentially negative interactions between hatchery summer steelhead and native upper Willamette River O. mykiss populations. These include reductions in adult steelhead on natural spawning grounds, improved reproductive isolation between hatchery and native populations and additional research to evaluate genetic integrity within and among O. mykiss populations. Title: Willamette BiOp - Genetic Stock Identification and Relative Natural Production of Willamette River Steelhead Abstract -- We used genotypic data from 15 microsatellite loci to characterize the stock structure of Oncorhynchus mykiss in the upper Willamette River basin. We then used two analytical approaches, implemented in the programs ONCOR and STRUCTURE, to assign (presumably) natural-origin, unmarked fish to their most likely reporting group or hybrid class. We investigated sibling relationships among unknown samples with the program ML RELATE. In the upper Willamette River, O. mykiss genetic structure can be characterized by four principal groups: summer steelhead of Skamania stock ancestry, eastern tributaries winter steelhead, western tributaries winter steelhead and resident rainbow trout. We found that about 10% of unmarked juvenile O. mykiss sampled at Willamette Falls in 2009-2011 were summer steelhead and that an additional 10% of samples were summer x winter steelhead hybrids. Most O. mykiss sampled from the McKenzie River were either summer steelhead or summer x winter steelhead hybrids. Natural production of pure summer steelhead appeared to be very low in the North and South Santiam rivers, though summer steelhead hybrids represented 11.1% and 14.8% of samples. Results from ML RELATE analyses appeared unreliable and inconclusive, and may have been limited by low genetic diversity among summer steelhead samples. We provide several recommendations to better understand and reduce potentially negative interactions between hatchery summer steelhead and native upper Willamette River O. mykiss populations. These include reductions in adult steelhead on natural spawning grounds, improved reproductive isolation between hatchery and native populations and additional research to evaluate genetic integrity within and among O. mykiss populations. Close