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• 51. [Article] Effects of estuarine circulation patterns and stress on the migratory behavior of juvenile salmonids (Oncorhynchus sp.)

  For the first objective of this thesis, we attempt to understand the role of water flow and directionality in determining steelhead (Oncorhynchus mykiss) and spring/summer and fall Chinook (O. tschawytscha) ...

  Citation × Citation Citation Abstract Copy Title: Effects of estuarine circulation patterns and stress on the migratory behavior of juvenile salmonids (Oncorhynchus sp.) Author: Truelove, Nathan Kobun For the first objective of this thesis, we attempt to understand the role of water flow and directionality in determining steelhead (Oncorhynchus mykiss) and spring/summer and fall Chinook (O. tschawytscha) migration patterns within the Columbia River Estuary and plume by integrating recent advances in biotelemetry and environmental observation and forecasting systems (EOFS). The underlying methodology included analysis of the spatial and temporal movements of juvenile outmigrant salmonids with hydrological data from the CORIE modeling system (http://www.ccalmr.ogi.edu/CORIE). The CORIE modeling system, an EOFS for the Columbia River and nearshore environment, integrates a real-time sensor network, data management system and advanced 3-dimensional numerical models. Numerical simulations of key physical variables (water level, velocities, and directionality) were generated for the precise time and location that individual juvenile salmonids implanted with radio transmitters were present in the Columbia River Estuary. Five general behavioral trends were evident from these simulations: i) passive movement (drifting) during ebb tides, ii) active swimming with the current during ebb tides, iii) active swimming against the current during flood tides, iv) active swimming cross current during flood tides, and v) passive drifting during flood tide. Direction of water flow had a significant effect on fish velocity. All fish types showed a positive relationship between fish velocity and simulated drifter velocity with outgoing water flow. During slack water flow (< 0.25 m/s), this relationship was only observed in barged fall Chinook. With incoming water flow, spring/summer and fall Chinook fish types showed no relationship, whereas steelhead did. Analysis over a three-year period suggested that data from the CORIE modeling system corresponded well with juvenile salmonid migratory behavior and that the model may be a useful tool for evaluating the impact of different hydrological regimes on fish movement. The secondary objective of this thesis evaluated the effects of both acute and chronic crowding stressors on the migratory behavior of hatchery reared juvenile steelhead released into Abernathy Creek, a tributary of the Columbia River Estuary, Washington. The acute stress treatment consisted of surgical implantation of a NanoTag radio transmitter (Lotek Wireless, Canada), followed by 6 hours of crowding immediately prior to release. The chronic stress treatment consisted of surgical implantation of a PIT-tag (Digital Angel Corporation), 36 days of acclimation, followed by 3 weeks of crowding in low water conditions prior to release. Short-term migratory success of steelhead that received the acute stress treatment was determined by radio telemetry. Numbers of migrating fish that received experimental stress treatments and their speed was determined by both mobile radio telemetry and stationary PIT-tag and radio-tag interrogation systems already established on Abernathy Creek. Acute and chronic stress treatments both significantly delayed migration by 2 to 10 days, respectively, compared to controls. Furthermore, the acute stress treatment significantly decreased the both the rate of migration and numbers of juvenile steelhead that successfully migrated out of Abernathy creek. Title: Effects of estuarine circulation patterns and stress on the migratory behavior of juvenile salmonids (Oncorhynchus sp.) Author: Truelove, Nathan Kobun For the first objective of this thesis, we attempt to understand the role of water flow and directionality in determining steelhead (Oncorhynchus mykiss) and spring/summer and fall Chinook (O. tschawytscha) migration patterns within the Columbia River Estuary and plume by integrating recent advances in biotelemetry and environmental observation and forecasting systems (EOFS). The underlying methodology included analysis of the spatial and temporal movements of juvenile outmigrant salmonids with hydrological data from the CORIE modeling system (http://www.ccalmr.ogi.edu/CORIE). The CORIE modeling system, an EOFS for the Columbia River and nearshore environment, integrates a real-time sensor network, data management system and advanced 3-dimensional numerical models. Numerical simulations of key physical variables (water level, velocities, and directionality) were generated for the precise time and location that individual juvenile salmonids implanted with radio transmitters were present in the Columbia River Estuary. Five general behavioral trends were evident from these simulations: i) passive movement (drifting) during ebb tides, ii) active swimming with the current during ebb tides, iii) active swimming against the current during flood tides, iv) active swimming cross current during flood tides, and v) passive drifting during flood tide. Direction of water flow had a significant effect on fish velocity. All fish types showed a positive relationship between fish velocity and simulated drifter velocity with outgoing water flow. During slack water flow (< 0.25 m/s), this relationship was only observed in barged fall Chinook. With incoming water flow, spring/summer and fall Chinook fish types showed no relationship, whereas steelhead did. Analysis over a three-year period suggested that data from the CORIE modeling system corresponded well with juvenile salmonid migratory behavior and that the model may be a useful tool for evaluating the impact of different hydrological regimes on fish movement. The secondary objective of this thesis evaluated the effects of both acute and chronic crowding stressors on the migratory behavior of hatchery reared juvenile steelhead released into Abernathy Creek, a tributary of the Columbia River Estuary, Washington. The acute stress treatment consisted of surgical implantation of a NanoTag radio transmitter (Lotek Wireless, Canada), followed by 6 hours of crowding immediately prior to release. The chronic stress treatment consisted of surgical implantation of a PIT-tag (Digital Angel Corporation), 36 days of acclimation, followed by 3 weeks of crowding in low water conditions prior to release. Short-term migratory success of steelhead that received the acute stress treatment was determined by radio telemetry. Numbers of migrating fish that received experimental stress treatments and their speed was determined by both mobile radio telemetry and stationary PIT-tag and radio-tag interrogation systems already established on Abernathy Creek. Acute and chronic stress treatments both significantly delayed migration by 2 to 10 days, respectively, compared to controls. Furthermore, the acute stress treatment significantly decreased the both the rate of migration and numbers of juvenile steelhead that successfully migrated out of Abernathy creek. Close

• 52. [Article] Extensive Resource Subsidies by Salmon-Supported Bears to Granivores

  In salmon-rich, northern coastal environments brown bears can occur at high densities and exert wide-ranging effects on ecosystem processes. Bear consumption of seasonally available fruit may provide important ...

  Citation × Citation Citation Abstract Copy Title: Extensive Resource Subsidies by Salmon-Supported Bears to Granivores Author: Shakeri, Yasaman N. In salmon-rich, northern coastal environments brown bears can occur at high densities and exert wide-ranging effects on ecosystem processes. Bear consumption of seasonally available fruit may provide important seed dispersal services to plants, and by extension, influence the ecology of seed consumers such as small mammals. In this study, we investigate relationships between bears, fruit, and small mammals in a coastal Alaskan ecosystem in order to understand the extent to which diplochory, two-phase seed dispersal, may influence the community ecology of this system. We collected field data to characterize patterns of bear frugivory and the extent that small mammals consumed and dispersed seeds deposited by bears. Our findings indicate that bears are an important initial dispersal agent for 12 species of fruit. Bear-deposited seed piles were intensively utilized and dispersed by several different small mammal species, primarily northwestern deer mice (Peromyscus keeni) and red backed voles (Myodes rutilus). In addition to serving as secondary seed dispersers, small mammals likely incurred significant nutritional benefits from bear deposited seeds. Our results illustrate the important direct role that bears play in seed dispersal and indirectly on the community ecology of small mammals. We further highlight the prevalence of a two-phase mammalian seed dispersal mechanism by quantifying visitation rates and the energetic subsidies described in north coastal temperate rainforest ecosystems. Due to the presence of salmon, high density coastal bear populations play an important role in structuring the community ecology of temperate rainforest ecosystem. Title: Extensive Resource Subsidies by Salmon-Supported Bears to Granivores Author: Shakeri, Yasaman N. In salmon-rich, northern coastal environments brown bears can occur at high densities and exert wide-ranging effects on ecosystem processes. Bear consumption of seasonally available fruit may provide important seed dispersal services to plants, and by extension, influence the ecology of seed consumers such as small mammals. In this study, we investigate relationships between bears, fruit, and small mammals in a coastal Alaskan ecosystem in order to understand the extent to which diplochory, two-phase seed dispersal, may influence the community ecology of this system. We collected field data to characterize patterns of bear frugivory and the extent that small mammals consumed and dispersed seeds deposited by bears. Our findings indicate that bears are an important initial dispersal agent for 12 species of fruit. Bear-deposited seed piles were intensively utilized and dispersed by several different small mammal species, primarily northwestern deer mice (Peromyscus keeni) and red backed voles (Myodes rutilus). In addition to serving as secondary seed dispersers, small mammals likely incurred significant nutritional benefits from bear deposited seeds. Our results illustrate the important direct role that bears play in seed dispersal and indirectly on the community ecology of small mammals. We further highlight the prevalence of a two-phase mammalian seed dispersal mechanism by quantifying visitation rates and the energetic subsidies described in north coastal temperate rainforest ecosystems. Due to the presence of salmon, high density coastal bear populations play an important role in structuring the community ecology of temperate rainforest ecosystem. Close

• 53. [Article] Beyond dichotomous life histories in partially migrating populations: cessation of anadromy in a long-lived fish

  This is the publisher’s final pdf. The published article is copyrighted by Ecological Society of America and can be found at: http://www.esajournals.org/loi/ecol

  Citation × Citation Citation Abstract Copy Title: Beyond dichotomous life histories in partially migrating populations: cessation of anadromy in a long-lived fish Author: Miller, Jessica A., Bond, Morgan H. This is the publisher’s final pdf. The published article is copyrighted by Ecological Society of America and can be found at: http://www.esajournals.org/loi/ecol Title: Beyond dichotomous life histories in partially migrating populations: cessation of anadromy in a long-lived fish Author: Miller, Jessica A., Bond, Morgan H. This is the publisher’s final pdf. The published article is copyrighted by Ecological Society of America and can be found at: http://www.esajournals.org/loi/ecol Close

• 54. [Article] Coastal cutthroat trout : life in the watershed

  Citation × Citation Citation Abstract Copy Title: Coastal cutthroat trout : life in the watershed Author: Fitzpatrick, Martin S., Oregon State University. Sea Grant College Program Title: Coastal cutthroat trout : life in the watershed Author: Fitzpatrick, Martin S., Oregon State University. Sea Grant College Program Close

• 55. [Article] Coastal steelhead trout : life in the watershed

  Citation × Citation Citation Abstract Copy Title: Coastal steelhead trout : life in the watershed Author: Fitzpatrick, Martin S., Oregon State University. Sea Grant College Program Title: Coastal steelhead trout : life in the watershed Author: Fitzpatrick, Martin S., Oregon State University. Sea Grant College Program Close

• 56. [Article] Bioenergetics-based predator-prey relationships between piscivorous birds and juvenile salmonids in the Columbia River estuary

  This dissertation focuses on the predator-prey relationship between two species of avian predators, Caspian terns (Hydroprogne caspia) and double-crested cormorants (Phalacrocorax auritus), and one of ...

  Citation × Citation Citation Abstract Copy Title: Bioenergetics-based predator-prey relationships between piscivorous birds and juvenile salmonids in the Columbia River estuary Author: Lyons, Donald E. This dissertation focuses on the predator-prey relationship between two species of avian predators, Caspian terns (Hydroprogne caspia) and double-crested cormorants (Phalacrocorax auritus), and one of their important prey types, juvenile salmonids (Oncorhynchus spp.), in the Columbia River estuary of Oregon and Washington states during the period 1998 – 2007. I used a data-rich bioenergetics framework to estimate juvenile salmonid consumption by these two avian predators, assessed impacts to at-risk salmonid populations by estimating salmonid mortality rates due to avian predation, and estimated potential demographic benefits to salmonids if avian predation were reduced. The managed relocation of the Caspian tern colony from Rice Island to East Sand Island, lower in the Columbia River estuary, reduced tern predation on salmonids from over 11 million smolts consumed annually to 4 – 7 million, but those benefits accrued primarily to sub-yearling Chinook salmon (O. tshawytscha). Combined consumption of juvenile salmonids by Caspian terns and double-crested cormorants in the Columbia River estuary was ca. 7 – 15 million smolts per year during 2006-2007, causing an 8 – 17% mortality rate among smolts migrating through the estuary, with higher mortality rates for steelhead (O. mykiss) and coho salmon (O. kisutch). Under a potential management scenario to reduce avian predation by both species, improvements in the average annual population growth rate (λ) of salmonids ranged from 0.4% for sub-yearling Chinook to 3.1% for coho. These improvements are generally less than what is possible from altered hydropower system operation within the Columbia Basin for salmonid populations that are more severely affected by dams. For a few salmonid populations, reduced avian predation might contribute to stabilizing the population (λ = 1), but would need to be part of a broader recovery strategy to ensure population growth and recovery (λ > 1). Climate was an important factor modulating Caspian tern predation on salmonids, with greater consumption of smolts occurring in years of cooler ocean conditions and higher Columbia River flows. Climate did not contribute to variation in consumption of salmonids by cormorants, perhaps due to the larger effect of growth in the size of the cormorant colony during the study period. Due to current trends in colony size (terns: stable, cormorants: increasing) and the planned dispersal of a portion of the tern population, cormorant predation will likely be a more significant mortality factor for Columbia Basin salmonids in the future than will tern predation. A critical unknown factor remains; that is the degree to which reductions in avian predation on salmonids might be compensated for by other salmonid mortality factors. Title: Bioenergetics-based predator-prey relationships between piscivorous birds and juvenile salmonids in the Columbia River estuary Author: Lyons, Donald E. This dissertation focuses on the predator-prey relationship between two species of avian predators, Caspian terns (Hydroprogne caspia) and double-crested cormorants (Phalacrocorax auritus), and one of their important prey types, juvenile salmonids (Oncorhynchus spp.), in the Columbia River estuary of Oregon and Washington states during the period 1998 – 2007. I used a data-rich bioenergetics framework to estimate juvenile salmonid consumption by these two avian predators, assessed impacts to at-risk salmonid populations by estimating salmonid mortality rates due to avian predation, and estimated potential demographic benefits to salmonids if avian predation were reduced. The managed relocation of the Caspian tern colony from Rice Island to East Sand Island, lower in the Columbia River estuary, reduced tern predation on salmonids from over 11 million smolts consumed annually to 4 – 7 million, but those benefits accrued primarily to sub-yearling Chinook salmon (O. tshawytscha). Combined consumption of juvenile salmonids by Caspian terns and double-crested cormorants in the Columbia River estuary was ca. 7 – 15 million smolts per year during 2006-2007, causing an 8 – 17% mortality rate among smolts migrating through the estuary, with higher mortality rates for steelhead (O. mykiss) and coho salmon (O. kisutch). Under a potential management scenario to reduce avian predation by both species, improvements in the average annual population growth rate (λ) of salmonids ranged from 0.4% for sub-yearling Chinook to 3.1% for coho. These improvements are generally less than what is possible from altered hydropower system operation within the Columbia Basin for salmonid populations that are more severely affected by dams. For a few salmonid populations, reduced avian predation might contribute to stabilizing the population (λ = 1), but would need to be part of a broader recovery strategy to ensure population growth and recovery (λ > 1). Climate was an important factor modulating Caspian tern predation on salmonids, with greater consumption of smolts occurring in years of cooler ocean conditions and higher Columbia River flows. Climate did not contribute to variation in consumption of salmonids by cormorants, perhaps due to the larger effect of growth in the size of the cormorant colony during the study period. Due to current trends in colony size (terns: stable, cormorants: increasing) and the planned dispersal of a portion of the tern population, cormorant predation will likely be a more significant mortality factor for Columbia Basin salmonids in the future than will tern predation. A critical unknown factor remains; that is the degree to which reductions in avian predation on salmonids might be compensated for by other salmonid mortality factors. Close

• 57. [Article] Rearing in a distorted magnetic field disrupts the ‘map sense’ of juvenile steelhead trout

  To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by the author(s) ...

  Citation × Citation Citation Abstract Copy Title: Rearing in a distorted magnetic field disrupts the ‘map sense’ of juvenile steelhead trout Author: Meinke, Amanda M., Putman, Nathan F., Noakes, David L. G. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by the author(s) and published by the Royal Society. The published article can be found at: http://rsbl.royalsocietypublishing.org/. Title: Rearing in a distorted magnetic field disrupts the ‘map sense’ of juvenile steelhead trout Author: Meinke, Amanda M., Putman, Nathan F., Noakes, David L. G. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by the author(s) and published by the Royal Society. The published article can be found at: http://rsbl.royalsocietypublishing.org/. Close

• 58. [Article] Effective size of a wild salmonid population is greatly reduced by hatchery supplementation

  This is the publisher’s final pdf. The published article is copyrighted by Macmillan Publishers Limited and the Nature Publishing Group and can be found at: http://www.nature.com/hdy/index.html. To the ...

  Citation × Citation Citation Abstract Copy Title: Effective size of a wild salmonid population is greatly reduced by hatchery supplementation Author: Blouin, M. S., French, R. A., Marine, M. L., Christie, M. R., Waples, R. S. This is the publisher’s final pdf. The published article is copyrighted by Macmillan Publishers Limited and the Nature Publishing Group and can be found at: http://www.nature.com/hdy/index.html. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. Title: Effective size of a wild salmonid population is greatly reduced by hatchery supplementation Author: Blouin, M. S., French, R. A., Marine, M. L., Christie, M. R., Waples, R. S. This is the publisher’s final pdf. The published article is copyrighted by Macmillan Publishers Limited and the Nature Publishing Group and can be found at: http://www.nature.com/hdy/index.html. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. Close