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• 41. [Article] Description and prediction of broad-scale spatial variability in expression of anadromy in female Oncorhynchus mykiss in the John Day River, Oregon, USA

  Partial migration is a common migratory behavior where some individuals in a population migrate and others do not. Patterns of partial migration can vary dramatically, especially for species that inhabit ...

  Citation × Citation Citation Abstract Copy Title: Description and prediction of broad-scale spatial variability in expression of anadromy in female Oncorhynchus mykiss in the John Day River, Oregon, USA Author: Mills, Justin S. Partial migration is a common migratory behavior where some individuals in a population migrate and others do not. Patterns of partial migration can vary dramatically, especially for species that inhabit a wide range of environments. I described and predicted spatial variation in marine migration (anadromy) of female Oncorhynchus mykiss (steelhead and rainbow trout) in the John Day River catchment basin, Oregon. This large catchment (20,500 km2), where O. mykiss is known to exhibit partial migration, encompasses a broad range of environmental conditions. I collected 149 juvenile O. mykiss across 72 sites and identified locations used by anadromous females by assigning maternal origin (anadromous versus non-anadromous) to each juvenile. These assignments used comparisons of strontium to calcium ratios in otolith primordia and freshwater growth regions to indicate maternal origin. Individuals within sites were more likely to have the same maternal origin than expected at random (χ2 test, P < 0.001). I used logistic regression to predict probability of anadromy among sites in relation to stream size (as indicated by mean annual runoff). Stream size and maternal origin for single fish collected from 69 sites were used to construct a predictive model. I examined the ability of this model to predict new individuals at 47 of these sites (where a second fish was collected) using a variety of diagnostics, including kappa statistics and receiver operating characteristic curves. The model predicted anadromy in this second set of individuals with a moderate level of accuracy (e.g. 68% correctly predicted with a 0.5 classification threshold). Residuals from the models were not spatially autocorrelated, as indicated by Mantel tests. This result also suggested that remaining variability in the expression of anadromy was due to localized influences, as opposed to broad-scale gradients unrelated to stream size. The importance of stream size implies that occurrence of migratory females was related to environmental variability, but stream size is an indicator of many potential processes, and I was unable to identify a specific likely mechanism. However, I was able to demonstrate 1) that it is possible to predict the probability of anadromy across broad environmental gradients, and 2) the validity of a sampling approach that minimizes the need for sacrificial sampling of individuals. These results are important for the management of O. mykiss because anadromous individuals (steelhead) within the John Day River watershed are listed as a threatened species, and it is difficult to discern steelhead from non-anadromous individuals (rainbow trout). My results provide managers with the first broad-scale description and prediction of locations supporting anadromy, and provide a broad template that can guide future habitat restoration, monitoring, and research to better manage and understand the expression of anadromy in O. mykiss. Title: Description and prediction of broad-scale spatial variability in expression of anadromy in female Oncorhynchus mykiss in the John Day River, Oregon, USA Author: Mills, Justin S. Partial migration is a common migratory behavior where some individuals in a population migrate and others do not. Patterns of partial migration can vary dramatically, especially for species that inhabit a wide range of environments. I described and predicted spatial variation in marine migration (anadromy) of female Oncorhynchus mykiss (steelhead and rainbow trout) in the John Day River catchment basin, Oregon. This large catchment (20,500 km2), where O. mykiss is known to exhibit partial migration, encompasses a broad range of environmental conditions. I collected 149 juvenile O. mykiss across 72 sites and identified locations used by anadromous females by assigning maternal origin (anadromous versus non-anadromous) to each juvenile. These assignments used comparisons of strontium to calcium ratios in otolith primordia and freshwater growth regions to indicate maternal origin. Individuals within sites were more likely to have the same maternal origin than expected at random (χ2 test, P < 0.001). I used logistic regression to predict probability of anadromy among sites in relation to stream size (as indicated by mean annual runoff). Stream size and maternal origin for single fish collected from 69 sites were used to construct a predictive model. I examined the ability of this model to predict new individuals at 47 of these sites (where a second fish was collected) using a variety of diagnostics, including kappa statistics and receiver operating characteristic curves. The model predicted anadromy in this second set of individuals with a moderate level of accuracy (e.g. 68% correctly predicted with a 0.5 classification threshold). Residuals from the models were not spatially autocorrelated, as indicated by Mantel tests. This result also suggested that remaining variability in the expression of anadromy was due to localized influences, as opposed to broad-scale gradients unrelated to stream size. The importance of stream size implies that occurrence of migratory females was related to environmental variability, but stream size is an indicator of many potential processes, and I was unable to identify a specific likely mechanism. However, I was able to demonstrate 1) that it is possible to predict the probability of anadromy across broad environmental gradients, and 2) the validity of a sampling approach that minimizes the need for sacrificial sampling of individuals. These results are important for the management of O. mykiss because anadromous individuals (steelhead) within the John Day River watershed are listed as a threatened species, and it is difficult to discern steelhead from non-anadromous individuals (rainbow trout). My results provide managers with the first broad-scale description and prediction of locations supporting anadromy, and provide a broad template that can guide future habitat restoration, monitoring, and research to better manage and understand the expression of anadromy in O. mykiss. Close

• 42. [Article] 2012 Metolius Basin bull trout redd counts

  Abstract -- Bull trout are indigenous to the Metolius River basin; however, they were managed as a nuisance species due to their interactions with anadromous sportfish for several decades. In 1960, nuisance ...

  Citation × Citation Citation Abstract Copy Title: 2012 Metolius Basin bull trout redd counts Abstract -- Bull trout are indigenous to the Metolius River basin; however, they were managed as a nuisance species due to their interactions with anadromous sportfish for several decades. In 1960, nuisance management of bull trout ended and protection of bull trout began in 1983 with mandatory catch and release regulations throughout the Metolius River basin. In 1986, the Department initiated annual redd counts for bull trout throughout the basin to document the species status. Redd surveys showed low spawning numbers, and the Department responded by closing all tributaries downstream of Lake Creek to fishing in 1994. A Threatened listing of Columbia River bull trout under the Endangered Species Act in 1998 followed the fishery closure (Fies et al. 1996 and Lohr et al. ####). Bull trout redd counts continue in the basin in accordance with the goals of the Native Fish Conservation Policy. Title: 2012 Metolius Basin bull trout redd counts Abstract -- Bull trout are indigenous to the Metolius River basin; however, they were managed as a nuisance species due to their interactions with anadromous sportfish for several decades. In 1960, nuisance management of bull trout ended and protection of bull trout began in 1983 with mandatory catch and release regulations throughout the Metolius River basin. In 1986, the Department initiated annual redd counts for bull trout throughout the basin to document the species status. Redd surveys showed low spawning numbers, and the Department responded by closing all tributaries downstream of Lake Creek to fishing in 1994. A Threatened listing of Columbia River bull trout under the Endangered Species Act in 1998 followed the fishery closure (Fies et al. 1996 and Lohr et al. ####). Bull trout redd counts continue in the basin in accordance with the goals of the Native Fish Conservation Policy. Close

• 43. [Article] 2011 Metolius River subbasin bull trout redd counts

  Abstract -- Bull trout are indigenous to the Metolius River basin; however, they were managed as a nuisance species due to their interactions with anadromous sportfish for several decades. In 1960, nuisance ...

  Citation × Citation Citation Abstract Copy Title: 2011 Metolius River subbasin bull trout redd counts Abstract -- Bull trout are indigenous to the Metolius River basin; however, they were managed as a nuisance species due to their interactions with anadromous sportfish for several decades. In 1960, nuisance management of bull trout ended and protection of bull trout began in 1983 with mandatory catch and release regulations throughout the Metolius River basin. In 1986, the Department initiated annual redd counts for bull trout throughout the basin to document the species status. Redd surveys showed low spawning numbers, and the Department responded by closing all tributaries downstream of Lake Creek to fishing in 1994. A Threatened listing of Columbia River bull trout under the Endangered Species Act in 1998 followed the fishery closure (Fies et al. 1996 and Lohr et al. ####). Bull trout redd counts continue in the basin in accordance with the goals of the Native Fish Conservation Policy. Title: 2011 Metolius River subbasin bull trout redd counts Abstract -- Bull trout are indigenous to the Metolius River basin; however, they were managed as a nuisance species due to their interactions with anadromous sportfish for several decades. In 1960, nuisance management of bull trout ended and protection of bull trout began in 1983 with mandatory catch and release regulations throughout the Metolius River basin. In 1986, the Department initiated annual redd counts for bull trout throughout the basin to document the species status. Redd surveys showed low spawning numbers, and the Department responded by closing all tributaries downstream of Lake Creek to fishing in 1994. A Threatened listing of Columbia River bull trout under the Endangered Species Act in 1998 followed the fishery closure (Fies et al. 1996 and Lohr et al. ####). Bull trout redd counts continue in the basin in accordance with the goals of the Native Fish Conservation Policy. Close

• 44. [Article] 2010 Metolius Basin bull trout redds

  Abstract -- Bull trout are indigenous to the Metolius River basin; however, they were managed as a nuisance species due to their interactions with anadromous sportfish for several decades. In 1960, nuisance ...

  Citation × Citation Citation Abstract Copy Title: 2010 Metolius Basin bull trout redds Abstract -- Bull trout are indigenous to the Metolius River basin; however, they were managed as a nuisance species due to their interactions with anadromous sportfish for several decades. In 1960, nuisance management of bull trout ended and protection of bull trout began in 1983 with mandatory catch and release regulations throughout the Metolius River basin. In 1986, the Department initiated annual redd counts for bull trout throughout the basin to document the species status. Redd surveys showed low spawning numbers, and the Department responded by closing all tributaries downstream of Lake Creek to fishing in 1994. A Threatened listing of Columbia River bull trout under the Endangered Species Act in 1998 followed the fishery closure (Fies et al. 1996 and Lohr et al. ####). Bull trout redd counts continue in the basin in accordance with the goals of the Native Fish Conservation Policy. Title: 2010 Metolius Basin bull trout redds Abstract -- Bull trout are indigenous to the Metolius River basin; however, they were managed as a nuisance species due to their interactions with anadromous sportfish for several decades. In 1960, nuisance management of bull trout ended and protection of bull trout began in 1983 with mandatory catch and release regulations throughout the Metolius River basin. In 1986, the Department initiated annual redd counts for bull trout throughout the basin to document the species status. Redd surveys showed low spawning numbers, and the Department responded by closing all tributaries downstream of Lake Creek to fishing in 1994. A Threatened listing of Columbia River bull trout under the Endangered Species Act in 1998 followed the fishery closure (Fies et al. 1996 and Lohr et al. ####). Bull trout redd counts continue in the basin in accordance with the goals of the Native Fish Conservation Policy. Close

• 45. [Article] Predicted Redistribution of Ceratomyxa shasta Genotypes with Salmonid Passage in the Deschutes River, Oregon

  This is the publisher’s final pdf. The published article is copyrighted by Taylor & Francis and can be found at: http://www.tandf.co.uk/journals/.

  Citation × Citation Citation Abstract Copy Title: Predicted Redistribution of Ceratomyxa shasta Genotypes with Salmonid Passage in the Deschutes River, Oregon Author: Bartholomew, Jerri L., Stinson, Matthew E. T. This is the publisher’s final pdf. The published article is copyrighted by Taylor & Francis and can be found at: http://www.tandf.co.uk/journals/. Title: Predicted Redistribution of Ceratomyxa shasta Genotypes with Salmonid Passage in the Deschutes River, Oregon Author: Bartholomew, Jerri L., Stinson, Matthew E. T. This is the publisher’s final pdf. The published article is copyrighted by Taylor & Francis and can be found at: http://www.tandf.co.uk/journals/. Close

• 46. [Article] A study of Myxobolus cerebralis in the Lostine River, Oregon : epizootiology, distribution and implications for resident and anadromous salmonids

  Myxobolus cerebralis, a myxozoan parasite that infects almost all species of wild and cultured salmonids, was first identified in northeastern Oregon in the Lostine River in 1986. Fish that are heavily ...

  Citation × Citation Citation Abstract Copy Title: A study of Myxobolus cerebralis in the Lostine River, Oregon : epizootiology, distribution and implications for resident and anadromous salmonids Author: Sandell, Todd A. Myxobolus cerebralis, a myxozoan parasite that infects almost all species of wild and cultured salmonids, was first identified in northeastern Oregon in the Lostine River in 1986. Fish that are heavily infected with M. cerebralis develop whirling disease, which was determined to be the cause of catastrophic declines in rainbow trout populations in Montana and Colorado in 1996. There have been no reports of severe salmonid population declines attributed to whirling disease in Oregon, although many populations are at levels that warrant protective listing under the Endangered Species Act. This study was undertaken to I) establish the distribution and seasonal prevalence of M. cerebralis infection in the Lostine River, 2) investigate the epizootiological factors influencing the occurrence of whirling disease in this river, 3) determine the potential impact of the parasite on chinook salmon, and 4) evaluate the suitability of a non-lethal tissue sampling protocol for the detection of M. cerebralis in juvenile and adult salmonids for use in monitoring the effects and distribution of the parasite in protected salmonid populations. Results of this study indicate that the parasite is present throughout the main stem of the Lostine River during all seasons, and that rainbow and anadromous steelhead trout fry emerging in the lower river are most likely to become infected and develop whirling disease. Chinook salmon were shown to be relatively resistant to M. cerebralis at low levels of exposure, but this effect was less evident when the parasite exposure increased. The non-lethal sampling protocol was successful in detecting M. cerebralis in juvenile salmonids but not in adults, where it is most needed. The information gathered during these studies was then correlated with the life histories of resident and anadromous salmonids in the Lostine River to determine the potential impact of M. cerebralis On salmonid populations in this region. Title: A study of Myxobolus cerebralis in the Lostine River, Oregon : epizootiology, distribution and implications for resident and anadromous salmonids Author: Sandell, Todd A. Myxobolus cerebralis, a myxozoan parasite that infects almost all species of wild and cultured salmonids, was first identified in northeastern Oregon in the Lostine River in 1986. Fish that are heavily infected with M. cerebralis develop whirling disease, which was determined to be the cause of catastrophic declines in rainbow trout populations in Montana and Colorado in 1996. There have been no reports of severe salmonid population declines attributed to whirling disease in Oregon, although many populations are at levels that warrant protective listing under the Endangered Species Act. This study was undertaken to I) establish the distribution and seasonal prevalence of M. cerebralis infection in the Lostine River, 2) investigate the epizootiological factors influencing the occurrence of whirling disease in this river, 3) determine the potential impact of the parasite on chinook salmon, and 4) evaluate the suitability of a non-lethal tissue sampling protocol for the detection of M. cerebralis in juvenile and adult salmonids for use in monitoring the effects and distribution of the parasite in protected salmonid populations. Results of this study indicate that the parasite is present throughout the main stem of the Lostine River during all seasons, and that rainbow and anadromous steelhead trout fry emerging in the lower river are most likely to become infected and develop whirling disease. Chinook salmon were shown to be relatively resistant to M. cerebralis at low levels of exposure, but this effect was less evident when the parasite exposure increased. The non-lethal sampling protocol was successful in detecting M. cerebralis in juvenile salmonids but not in adults, where it is most needed. The information gathered during these studies was then correlated with the life histories of resident and anadromous salmonids in the Lostine River to determine the potential impact of M. cerebralis On salmonid populations in this region. Close

• 47. [Article] The present state of the Columbia River salmon resources

  Reprinted from Proceedings of the Sixth Pacific Science Congress, University of California Press, Berkeley, California, 1941.

  Citation × Citation Citation Abstract Copy Title: The present state of the Columbia River salmon resources Author: Oregon. Fish Commission. Research Dept., Rich, Willis H. (Willis Horton), 1885-1972 Reprinted from Proceedings of the Sixth Pacific Science Congress, University of California Press, Berkeley, California, 1941. Title: The present state of the Columbia River salmon resources Author: Oregon. Fish Commission. Research Dept., Rich, Willis H. (Willis Horton), 1885-1972 Reprinted from Proceedings of the Sixth Pacific Science Congress, University of California Press, Berkeley, California, 1941. Close

• 48. [Article] The salmon runs of the Columbia River in 1938

  Exceptional data are available for the study of the salmon runs of the Columbia River in 1938. Detailed figures on catch were supplied by Oregon and Washington in such form that they could readily be combined ...

  Citation × Citation Citation Abstract Copy Title: The salmon runs of the Columbia River in 1938 Author: Oregon. Fish Commission, Rich, Willis H. (Willis Horton), 1885-1972 Exceptional data are available for the study of the salmon runs of the Columbia River in 1938. Detailed figures on catch were supplied by Oregon and Washington in such form that they could readily be combined with the counts at Bonneville Dam to provide a basis for estimating the escapement. Tables show the catch of each species for each week in each of six zones, and the counts at Bonneville and Rock Island dams. The general course of the run of each species is shown. The numbers of fish bound for the spawning grounds above Rock Island Dam are estimated as follows: Chinook salmon entering Columbia River before May 1, 4 percent; during May, 6 percent; June and July, 15 percent; and August to December, 1 percent. Blueback salmon entering the river during the above periods, 40 percent. Steelhead trout entering the river during June to September, 1 percent; during the rest of the year, 10 percent. Fishing intensities are shown by escapement to catch ratios. Percentages of chinook salmon escapement are less than 15 during May; 17 during June and July; and 33 during the remainder of the year. The June and July runs are now greatly depleted, and an important part of these runs spawns above Rock Island Dam. The blueback salmon escapement is about 20 percent, and of steelhead trout about 33 percent. Weekly and seasonal closed periods are shown to be almost entirely ineffective for increasing the spawning escapement. Exploitation is further increased by the intensive troll fishery conducted from Monterey Bay to southeastern Alaska. Chinook salmon are also subjected to a sport fishery of considerable importance. Main runs of salmon to the Columbia River are practically unprotected and are fished with destructive intensity. Title: The salmon runs of the Columbia River in 1938 Author: Oregon. Fish Commission, Rich, Willis H. (Willis Horton), 1885-1972 Exceptional data are available for the study of the salmon runs of the Columbia River in 1938. Detailed figures on catch were supplied by Oregon and Washington in such form that they could readily be combined with the counts at Bonneville Dam to provide a basis for estimating the escapement. Tables show the catch of each species for each week in each of six zones, and the counts at Bonneville and Rock Island dams. The general course of the run of each species is shown. The numbers of fish bound for the spawning grounds above Rock Island Dam are estimated as follows: Chinook salmon entering Columbia River before May 1, 4 percent; during May, 6 percent; June and July, 15 percent; and August to December, 1 percent. Blueback salmon entering the river during the above periods, 40 percent. Steelhead trout entering the river during June to September, 1 percent; during the rest of the year, 10 percent. Fishing intensities are shown by escapement to catch ratios. Percentages of chinook salmon escapement are less than 15 during May; 17 during June and July; and 33 during the remainder of the year. The June and July runs are now greatly depleted, and an important part of these runs spawns above Rock Island Dam. The blueback salmon escapement is about 20 percent, and of steelhead trout about 33 percent. Weekly and seasonal closed periods are shown to be almost entirely ineffective for increasing the spawning escapement. Exploitation is further increased by the intensive troll fishery conducted from Monterey Bay to southeastern Alaska. Chinook salmon are also subjected to a sport fishery of considerable importance. Main runs of salmon to the Columbia River are practically unprotected and are fished with destructive intensity. Close

• 49. [Article] Abundance, distribution, and migratory behavior of coastal cutthroat trout in two lower Columbia River tributaries

  Abstract -- Coastal cutthroat trout (Oncorhynchus clarki clarki) exhibit multiple life history types characterized by diverse migratory strategies, including anadromous, potomodromous, and freshwater resident ...

  Citation × Citation Citation Abstract Copy Title: Abundance, distribution, and migratory behavior of coastal cutthroat trout in two lower Columbia River tributaries Abstract -- Coastal cutthroat trout (Oncorhynchus clarki clarki) exhibit multiple life history types characterized by diverse migratory strategies, including anadromous, potomodromous, and freshwater resident forms. The factors contributing to life history variation within populations are not well understood, but probably are not strictly genetic (e.g. Johnson et al, in review). Variation in migration tendency within cutthroat populations may result from phenotype plasticity, influenced by density, frequency, or condition dependent processes (Hendry et al. 2004). For example, an individual cutthroat’s choice to migrate at a given time or age may be a response to environmental conditions mediated by a genetically determined reaction norm (Hutchings 2004). This report summarizes a study undertaken to describe the expression of migratory behavior within coastal cutthroat trout populations, the relationship among migratory and non-migratory individuals, and the implications of life history diversity for management of cutthroat trout in tributaries of the lower Columbia River. The relationship between resident and migratory populations (or resident and migratory individuals within populations) is of central importance for management of coastal cutthroat trout. In the lower Columbia River and southwest Washington State a proposed rule to list anadromous cutthroat as threatened under the federal Endangered Species Act (ESA) was withdrawn after the US Fish and Wildlife Service (USFWS) decided during its review process to include resident and anadromous forms in the same Distinct Population Segment (DPS). Debate over proposed ESA listing highlighted a general lack of knowledge about coastal cutthroat trout life history, relationships between resident and migratory forms, and estuarine habitat use in the lower Columbia River. In 2009, the decision not to list the DPS as threatened was remanded to the USFWS on the grounds that the Service had not adequately considered whether marine and estuarine habitats formed a significant portion of the range of the DPS (USFWS 2009). We evaluated the distribution and abundance of coastal cutthroat trout in Big Creek and Bear Creek, two tributaries that join the Columbia River estuary from the south (Oregon) side roughly 30 kilometers from the ocean, and monitored the migratory behavior of cutthroat that emigrated from these streams and entered the Columbia River estuary. Big Creek is an interesting system because a fish weir and diversion dam at an ODFW hatchery, established in 1941 and refurbished in 1957, prevent cutthroat trout from passing upstream, isolating the cutthroat spawning population above the hatchery. Despite this barrier to upstream migration, offspring of resident cutthroat in the upper watershed continue to “smolt” and migrate downstream past the barrier. We were interested in the fate of these fish and their contribution to the adult population. Bear Creek, on the other hand, has always had full access for anadromous cutthroat through much of its drainage. These two systems permit a comparison of life history characteristics, migration, and survival of coastal cutthroat rearing in streams above and below migration barriers, and provide study sites in Oregon to compliment research by USFWS of coastal cutthroat migration behavior in tributaries entering the estuary from the north side of the Columbia River (USFWS 2008; and see Hudson et al. 2008; Johnson 2008; Zydlewski et al. 2008). A major objective of our work in Big Creek and Bear Creek was to increase understanding of coastal cutthroat trout biology and the relationship between resident and migratory cutthroat in lower Columbia tributaries. Additionally, we sought to document habitat use in the Columbia River estuary by migrant cutthroat. Our specific objectives were to: • Estimate abundance of coastal cutthroat trout in Big Creek (above hatchery barrier) and Bear Creek (above and below a large dam) • Quantify the proportions of the cutthroat populations that are migratory, identify which individuals migrate and describe the timing of migration • Describe habitats used by anadromous migrants and characterize migration behavior within the Columbia River estuary • Measure estuarine/marine survival of anadromous individuals and document return to natal streams Title: Abundance, distribution, and migratory behavior of coastal cutthroat trout in two lower Columbia River tributaries Abstract -- Coastal cutthroat trout (Oncorhynchus clarki clarki) exhibit multiple life history types characterized by diverse migratory strategies, including anadromous, potomodromous, and freshwater resident forms. The factors contributing to life history variation within populations are not well understood, but probably are not strictly genetic (e.g. Johnson et al, in review). Variation in migration tendency within cutthroat populations may result from phenotype plasticity, influenced by density, frequency, or condition dependent processes (Hendry et al. 2004). For example, an individual cutthroat’s choice to migrate at a given time or age may be a response to environmental conditions mediated by a genetically determined reaction norm (Hutchings 2004). This report summarizes a study undertaken to describe the expression of migratory behavior within coastal cutthroat trout populations, the relationship among migratory and non-migratory individuals, and the implications of life history diversity for management of cutthroat trout in tributaries of the lower Columbia River. The relationship between resident and migratory populations (or resident and migratory individuals within populations) is of central importance for management of coastal cutthroat trout. In the lower Columbia River and southwest Washington State a proposed rule to list anadromous cutthroat as threatened under the federal Endangered Species Act (ESA) was withdrawn after the US Fish and Wildlife Service (USFWS) decided during its review process to include resident and anadromous forms in the same Distinct Population Segment (DPS). Debate over proposed ESA listing highlighted a general lack of knowledge about coastal cutthroat trout life history, relationships between resident and migratory forms, and estuarine habitat use in the lower Columbia River. In 2009, the decision not to list the DPS as threatened was remanded to the USFWS on the grounds that the Service had not adequately considered whether marine and estuarine habitats formed a significant portion of the range of the DPS (USFWS 2009). We evaluated the distribution and abundance of coastal cutthroat trout in Big Creek and Bear Creek, two tributaries that join the Columbia River estuary from the south (Oregon) side roughly 30 kilometers from the ocean, and monitored the migratory behavior of cutthroat that emigrated from these streams and entered the Columbia River estuary. Big Creek is an interesting system because a fish weir and diversion dam at an ODFW hatchery, established in 1941 and refurbished in 1957, prevent cutthroat trout from passing upstream, isolating the cutthroat spawning population above the hatchery. Despite this barrier to upstream migration, offspring of resident cutthroat in the upper watershed continue to “smolt” and migrate downstream past the barrier. We were interested in the fate of these fish and their contribution to the adult population. Bear Creek, on the other hand, has always had full access for anadromous cutthroat through much of its drainage. These two systems permit a comparison of life history characteristics, migration, and survival of coastal cutthroat rearing in streams above and below migration barriers, and provide study sites in Oregon to compliment research by USFWS of coastal cutthroat migration behavior in tributaries entering the estuary from the north side of the Columbia River (USFWS 2008; and see Hudson et al. 2008; Johnson 2008; Zydlewski et al. 2008). A major objective of our work in Big Creek and Bear Creek was to increase understanding of coastal cutthroat trout biology and the relationship between resident and migratory cutthroat in lower Columbia tributaries. Additionally, we sought to document habitat use in the Columbia River estuary by migrant cutthroat. Our specific objectives were to: • Estimate abundance of coastal cutthroat trout in Big Creek (above hatchery barrier) and Bear Creek (above and below a large dam) • Quantify the proportions of the cutthroat populations that are migratory, identify which individuals migrate and describe the timing of migration • Describe habitats used by anadromous migrants and characterize migration behavior within the Columbia River estuary • Measure estuarine/marine survival of anadromous individuals and document return to natal streams Close

• 50. [Article] Coastal Chinook Salmon Management Plan Summary Mailing, 1991

  Abstract -- The Coastal Chinook Salmon Management Plan is the fourth in a series of individual species plans concerning management of anadromous salmonid populations in Oregon. This plan focuses on actions ...

  Citation × Citation Citation Abstract Copy Title: Coastal Chinook Salmon Management Plan Summary Mailing, 1991 Abstract -- The Coastal Chinook Salmon Management Plan is the fourth in a series of individual species plans concerning management of anadromous salmonid populations in Oregon. This plan focuses on actions the Oregon Department of Fish and Wildlife will take regarding chinook salmon populations produced in Oregon Coastal watersheds from the Necanicum River in the north to the Winchuck River at the Oregon-California border. Management of chinook salmon in the Columbia River Basin - which is guided by a cooperative agreement with Washington, the Columbia River Treaty Indian Tribes, and the Federal Government - is not included in this document. Title: Coastal Chinook Salmon Management Plan Summary Mailing, 1991 Abstract -- The Coastal Chinook Salmon Management Plan is the fourth in a series of individual species plans concerning management of anadromous salmonid populations in Oregon. This plan focuses on actions the Oregon Department of Fish and Wildlife will take regarding chinook salmon populations produced in Oregon Coastal watersheds from the Necanicum River in the north to the Winchuck River at the Oregon-California border. Management of chinook salmon in the Columbia River Basin - which is guided by a cooperative agreement with Washington, the Columbia River Treaty Indian Tribes, and the Federal Government - is not included in this document. Close