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• 421. [Article] Use of petroleum oils to prevent spread of stylet-borne viruses by aphids

  The use of petroleum oil prevented, to varying degrees: the transmission of three stylet-borne viruses in three different crops. The use of oils resulted in a marked improvement in the number of lily bulbs ...

  Citation × Citation Citation Abstract Copy Title: Use of petroleum oils to prevent spread of stylet-borne viruses by aphids Author: Ascerno, Mark E. The use of petroleum oil prevented, to varying degrees: the transmission of three stylet-borne viruses in three different crops. The use of oils resulted in a marked improvement in the number of lily bulbs harvested from treated plots as compared to the number of lily bulbs harvested from untreated plots. A random sample of the harvested bulbs forced in the greenhouse showed that substantially more bulbs germinated from treated plots than from untreated plots. Lily virus symptoms were prevented in 13% of the plants in treated plots. All untreated plants were infected. However, this relatively small difference was probably due to the use of too many infector plants. Treated lilies showed more stunting and mottling than did the untreated lilies. The influences of oil sprays on the transmission of bean yellow mosaic virus in beans were studied in 1967 and 1968. Virus symptoms in 1967 were shown to vary significantly with planting dates. The early planting had a greater incidence of plants showing virus symptoms than did the later planting. Oil sprays reduced virus symptoms by 20.9% in the early planting and by 40.7% in the later planting. Oil sprays reduced BYMV symptoms from 10-30% in 1968, depending on the treatment. However, the statistical significance of these treatment effects was questionable. The spread of BYMV in 1968 was strongly correlated with the daily number of aphids trapped at two widely separated trap locations. These correlations were improved when the number of aphids trapped were adjusted for the possible effects of the oil sprays. The implications of the correlations were threefold. First, the direct relationship between virus symptoms and aphid numbers suggested that the timing of sprays to periods of high aphid migrations could improve virus prevention. Second, the prevention of virus spread could be improved by the application of oil during periods when one or more aphid species particularly efficient in virus transmission are migrating. Third, the value of oil could be improved by the maintenance of a highly efficient oil residue for longer periods of time. Oil sprays reduced white -break virus (cucumber mosaic virus) symptoms in gladiolus from 9.5% to 3.1% in the field. However, similar results were not obtained when sample corms from the field plots were forced in the greenhouse. Title: Use of petroleum oils to prevent spread of stylet-borne viruses by aphids Author: Ascerno, Mark E. The use of petroleum oil prevented, to varying degrees: the transmission of three stylet-borne viruses in three different crops. The use of oils resulted in a marked improvement in the number of lily bulbs harvested from treated plots as compared to the number of lily bulbs harvested from untreated plots. A random sample of the harvested bulbs forced in the greenhouse showed that substantially more bulbs germinated from treated plots than from untreated plots. Lily virus symptoms were prevented in 13% of the plants in treated plots. All untreated plants were infected. However, this relatively small difference was probably due to the use of too many infector plants. Treated lilies showed more stunting and mottling than did the untreated lilies. The influences of oil sprays on the transmission of bean yellow mosaic virus in beans were studied in 1967 and 1968. Virus symptoms in 1967 were shown to vary significantly with planting dates. The early planting had a greater incidence of plants showing virus symptoms than did the later planting. Oil sprays reduced virus symptoms by 20.9% in the early planting and by 40.7% in the later planting. Oil sprays reduced BYMV symptoms from 10-30% in 1968, depending on the treatment. However, the statistical significance of these treatment effects was questionable. The spread of BYMV in 1968 was strongly correlated with the daily number of aphids trapped at two widely separated trap locations. These correlations were improved when the number of aphids trapped were adjusted for the possible effects of the oil sprays. The implications of the correlations were threefold. First, the direct relationship between virus symptoms and aphid numbers suggested that the timing of sprays to periods of high aphid migrations could improve virus prevention. Second, the prevention of virus spread could be improved by the application of oil during periods when one or more aphid species particularly efficient in virus transmission are migrating. Third, the value of oil could be improved by the maintenance of a highly efficient oil residue for longer periods of time. Oil sprays reduced white -break virus (cucumber mosaic virus) symptoms in gladiolus from 9.5% to 3.1% in the field. However, similar results were not obtained when sample corms from the field plots were forced in the greenhouse. Close

• 422. [Article] Susceptibility of select salmonids to Myxobolus cerebralis and effects of exposure on anadromous salmonids in Oregon

  Myxobolus cerebralis, a myxozoan parasite of salmonids, is the causative agent of whirling disease. The parasite is considered widespread throughout northeastern Oregon in the Grande Ronde and Imnaha River ...

  Citation × Citation Citation Abstract Copy Title: Susceptibility of select salmonids to Myxobolus cerebralis and effects of exposure on anadromous salmonids in Oregon Author: Sollid, Sarah A. Myxobolus cerebralis, a myxozoan parasite of salmonids, is the causative agent of whirling disease. The parasite is considered widespread throughout northeastern Oregon in the Grande Ronde and Imnaha River basins where threatened and endangered salmonid populations exist. The work presented in this thesis comprises several studies that assess the effects of M. cerebralis on resident and anadromous salmonids in Oregon. Laboratory challenges to determine the susceptibility of indigenous Deschutes River, Oregon, salmonids to M. cerebralis were conducted as part of a study to assess the risk of reintroducing anadromous salmon above a migration barrier on that river. This study was the first to assess the susceptibility of kokanee salmon Oncorhynchus nerka to M. cerebralis, and results contribute to the understanding of salmonid susceptibility as it relates to species and age. Further, this study demonstrates that the indigenous salmonids present in the river are susceptible to infection, but resident rainbow trout Oncorhynchus mykiss would be most at risk should introduction of M. cerebralis occur in this system. The susceptibility of chinook salmon Oncorhynchus tshawytscha to M. cerebralis was assessed following laboratory challenges at different ages to different parasite levels. Results from this study indicate that chinook salmon are more resistant to M. cerebralis infection than susceptible rainbow trout; resistance to disease developed in chinook salmon exposed after 3 weeks of age. Sustained exposures to a low parasite dose were performed to model the conditions chinook salmon would encounter in a natural exposure. Following continuous exposure to low parasite densities, chinook salmon were very resistant to infection and disease. Managed populations of chinook salmon and steelhead Oncorhynchus mykiss juveniles are held in acclimation facilities on their natal streams before release to commence their seaward migration. Rainbow trout fry were held at each of the acclimation facilities to detect the presence of M. cerebralis and to assess the prevalence of exposure during the acclimation period. Results from these exposures indicate that the Wallowa acclimation facility is a high-risk site for parasite exposure of steelhead juveniles. Further, detection was confirmed in several rivers and streams where the presence of M. cerebralis has been suggested. Finally, a preliminary study on the effect of M. cerebralis on survival of steelhead juveniles upon transfer to saltwater was conducted. Results from this study indicate that M. cerebralis exposure and infection may increase mortality among juvenile steelhead during saltwater adaptation. Title: Susceptibility of select salmonids to Myxobolus cerebralis and effects of exposure on anadromous salmonids in Oregon Author: Sollid, Sarah A. Myxobolus cerebralis, a myxozoan parasite of salmonids, is the causative agent of whirling disease. The parasite is considered widespread throughout northeastern Oregon in the Grande Ronde and Imnaha River basins where threatened and endangered salmonid populations exist. The work presented in this thesis comprises several studies that assess the effects of M. cerebralis on resident and anadromous salmonids in Oregon. Laboratory challenges to determine the susceptibility of indigenous Deschutes River, Oregon, salmonids to M. cerebralis were conducted as part of a study to assess the risk of reintroducing anadromous salmon above a migration barrier on that river. This study was the first to assess the susceptibility of kokanee salmon Oncorhynchus nerka to M. cerebralis, and results contribute to the understanding of salmonid susceptibility as it relates to species and age. Further, this study demonstrates that the indigenous salmonids present in the river are susceptible to infection, but resident rainbow trout Oncorhynchus mykiss would be most at risk should introduction of M. cerebralis occur in this system. The susceptibility of chinook salmon Oncorhynchus tshawytscha to M. cerebralis was assessed following laboratory challenges at different ages to different parasite levels. Results from this study indicate that chinook salmon are more resistant to M. cerebralis infection than susceptible rainbow trout; resistance to disease developed in chinook salmon exposed after 3 weeks of age. Sustained exposures to a low parasite dose were performed to model the conditions chinook salmon would encounter in a natural exposure. Following continuous exposure to low parasite densities, chinook salmon were very resistant to infection and disease. Managed populations of chinook salmon and steelhead Oncorhynchus mykiss juveniles are held in acclimation facilities on their natal streams before release to commence their seaward migration. Rainbow trout fry were held at each of the acclimation facilities to detect the presence of M. cerebralis and to assess the prevalence of exposure during the acclimation period. Results from these exposures indicate that the Wallowa acclimation facility is a high-risk site for parasite exposure of steelhead juveniles. Further, detection was confirmed in several rivers and streams where the presence of M. cerebralis has been suggested. Finally, a preliminary study on the effect of M. cerebralis on survival of steelhead juveniles upon transfer to saltwater was conducted. Results from this study indicate that M. cerebralis exposure and infection may increase mortality among juvenile steelhead during saltwater adaptation. Close

• 423. [Article] Spatial and temporal movement patterns of wintering Dunlin (Calidris alpina) and Killdeer (Charadrius vociferus) in the Willamette Valley, Oregon

  Avian movement behavior provides insight on patterns of regional and local fidelity, habitat and resource requirements, the scale at which individuals perceive the landscape, and the relative influence ...

  Citation × Citation Citation Abstract Copy Title: Spatial and temporal movement patterns of wintering Dunlin (Calidris alpina) and Killdeer (Charadrius vociferus) in the Willamette Valley, Oregon Author: Sanzenbacher, Peter M. Avian movement behavior provides insight on patterns of regional and local fidelity, habitat and resource requirements, the scale at which individuals perceive the landscape, and the relative influence of the spatial array of resources. Shorebirds (suborder: Charadrii) are a diverse and mobile group of wetland associated species. Large numbers of shorebirds utilize seasonally flooded wetland habitats in the Willamette Valley of northwest Oregon; however, there is little information on fidelity and movements of birds in the region or at other inland sites. Thus, we quantified winter fidelity and movement patterns of radio-tagged Dunlin (Calidris alpina) and Killdeer (Charadrius vociferus) in the Willamette Valley in 1998-1999 and 1999-2000. Prior to field telemetry, we evaluated use of a leg-loop harness design for attachment of radio-transmitters. Comparisons between captive Western Sandpipers (Calidris mauri) fitted with a harness package and a control group indicated no significant differences in behavior. In addition, observations of wild Killdeer and Dunlin indicated prolonged harness retention and no adverse effects on behavior. Therefore, we determined that the modified harness design was a suitable method for attachment of transmitters to shorebirds. Monitoring of radio-tagged Dunlin and Killdeer indicated interspecific differences in regional fidelity and residency patterns. Dunlin exhibited a high degree of regional fidelity and in most cases remained within the Valley for the duration of the winter. In contrast, Killdeer departed the study area throughout the winter and the population segment monitored was composed of winter residents (63%), winter transients (26%) and year-round resident breeders (11%). Dunlin were highly mobile with frequent movements up to 30 km from roost sites. Among seasons, Dunlin differed significantly in distance traveled, mean distance from capture site, and home range size. All were greatest during late winter. In comparison, the scale of Killdeer movements was much smaller, with no seasonal differences in movements. Results also suggested that resident Killdeer were more sedentary than migrants during the winter months. At a local scale, individuals of both species occurred predominantly in agricultural habitats and exhibited low degrees of fidelity to specific fields, with the exception that Dunlin frequently returned to certain roost sites. On a daily basis, movements of both Dunlin and Killdeer were most pronounced during crepuscular periods. Findings provide insight on the fidelity and winter movements of shorebirds, as well provide insight as to the functional connectivity of shorebird habitats in the Willamette Valley. Title: Spatial and temporal movement patterns of wintering Dunlin (Calidris alpina) and Killdeer (Charadrius vociferus) in the Willamette Valley, Oregon Author: Sanzenbacher, Peter M. Avian movement behavior provides insight on patterns of regional and local fidelity, habitat and resource requirements, the scale at which individuals perceive the landscape, and the relative influence of the spatial array of resources. Shorebirds (suborder: Charadrii) are a diverse and mobile group of wetland associated species. Large numbers of shorebirds utilize seasonally flooded wetland habitats in the Willamette Valley of northwest Oregon; however, there is little information on fidelity and movements of birds in the region or at other inland sites. Thus, we quantified winter fidelity and movement patterns of radio-tagged Dunlin (Calidris alpina) and Killdeer (Charadrius vociferus) in the Willamette Valley in 1998-1999 and 1999-2000. Prior to field telemetry, we evaluated use of a leg-loop harness design for attachment of radio-transmitters. Comparisons between captive Western Sandpipers (Calidris mauri) fitted with a harness package and a control group indicated no significant differences in behavior. In addition, observations of wild Killdeer and Dunlin indicated prolonged harness retention and no adverse effects on behavior. Therefore, we determined that the modified harness design was a suitable method for attachment of transmitters to shorebirds. Monitoring of radio-tagged Dunlin and Killdeer indicated interspecific differences in regional fidelity and residency patterns. Dunlin exhibited a high degree of regional fidelity and in most cases remained within the Valley for the duration of the winter. In contrast, Killdeer departed the study area throughout the winter and the population segment monitored was composed of winter residents (63%), winter transients (26%) and year-round resident breeders (11%). Dunlin were highly mobile with frequent movements up to 30 km from roost sites. Among seasons, Dunlin differed significantly in distance traveled, mean distance from capture site, and home range size. All were greatest during late winter. In comparison, the scale of Killdeer movements was much smaller, with no seasonal differences in movements. Results also suggested that resident Killdeer were more sedentary than migrants during the winter months. At a local scale, individuals of both species occurred predominantly in agricultural habitats and exhibited low degrees of fidelity to specific fields, with the exception that Dunlin frequently returned to certain roost sites. On a daily basis, movements of both Dunlin and Killdeer were most pronounced during crepuscular periods. Findings provide insight on the fidelity and winter movements of shorebirds, as well provide insight as to the functional connectivity of shorebird habitats in the Willamette Valley. Close

• 424. [Article] Determination of marine migratory behavior and its relationship to selected physical traits for least cisco (Coregonus sardinella) of the western Arctic coastal plain, Alaska

  With increased resource development on the western Arctic coastal plain of Alaska (especially within the oil extraction industry) it is important to understand the basic life history attributes of whitefish ...

  Citation × Citation Citation Abstract Copy Title: Determination of marine migratory behavior and its relationship to selected physical traits for least cisco (Coregonus sardinella) of the western Arctic coastal plain, Alaska Author: Seigle, John C. With increased resource development on the western Arctic coastal plain of Alaska (especially within the oil extraction industry) it is important to understand the basic life history attributes of whitefish stocks in the region in order to ensure appropriate management. These fish are a crucial part of subsistence harvests for native Alaskans. Multiple forms of the whitefish least cisco (Coregonus sardinella) have been described based on both appearance and life history traits. Two major forms of least cisco have been mentioned in the literature: a larger normal amphidromous form with fork lengths of approximately 420 mm and a dwarf lake resident form with lengths up to 230 mm. However, there is considerable evidence for additional forms and life history strategies of least cisco. I investigated the relationship between migratory behavior and selected physical traits of least cisco in six lakes and one brackish lagoon in the western Arctic coastal plain of Alaska. I used electron microprobe technology to determine the levels of Sr and Ca in the otoliths of 258 least cisco in order to resolve their marine migratory life history. I also investigated the relationship between migratory behavior and the numbers of gill rakers, lateral line scales, anal rays and dorsal rays as well as condition factor. The vast majority of least cisco captured in these sites were normal in form, yet only ~12% of all samples yielded any sign of sea-run behavior. Evidence for migratory behavior was low even for sites within close proximity to brackish waters. Fish exhibiting marine migratory behavior tended to make their first migrations to sea before age three (mean=2.6 years), although fish in one coastal site (Joeb's) averaged over 5 years of age at first marine visit. There was some evidence of higher condition factors for fish with sea-run migratory experience. There were significant differences in lateral line and dorsal ray numbers among sites but none for anal rays or gill rakers. Variability in all of these characters was high, and fish from coastal sites tended to have greater variability than those from inland sites. Only dorsal rays showed significant differences in meristic traits between sea-run and resident least cisco. These results suggest that least cisco exhibit high variability in physical traits. Also, least cisco appear to be flexible in their use of the marine environment, even within similar forms in the same lake. Some of the most basic life history characteristics of least cisco remain uncertain. With increased resource extraction occurring on the western Arctic coastal plain of Alaska, it is important to continue to investigate these and other life history strategies so as to ensure a sustainable fishery for native inhabitants of the region. Title: Determination of marine migratory behavior and its relationship to selected physical traits for least cisco (Coregonus sardinella) of the western Arctic coastal plain, Alaska Author: Seigle, John C. With increased resource development on the western Arctic coastal plain of Alaska (especially within the oil extraction industry) it is important to understand the basic life history attributes of whitefish stocks in the region in order to ensure appropriate management. These fish are a crucial part of subsistence harvests for native Alaskans. Multiple forms of the whitefish least cisco (Coregonus sardinella) have been described based on both appearance and life history traits. Two major forms of least cisco have been mentioned in the literature: a larger normal amphidromous form with fork lengths of approximately 420 mm and a dwarf lake resident form with lengths up to 230 mm. However, there is considerable evidence for additional forms and life history strategies of least cisco. I investigated the relationship between migratory behavior and selected physical traits of least cisco in six lakes and one brackish lagoon in the western Arctic coastal plain of Alaska. I used electron microprobe technology to determine the levels of Sr and Ca in the otoliths of 258 least cisco in order to resolve their marine migratory life history. I also investigated the relationship between migratory behavior and the numbers of gill rakers, lateral line scales, anal rays and dorsal rays as well as condition factor. The vast majority of least cisco captured in these sites were normal in form, yet only ~12% of all samples yielded any sign of sea-run behavior. Evidence for migratory behavior was low even for sites within close proximity to brackish waters. Fish exhibiting marine migratory behavior tended to make their first migrations to sea before age three (mean=2.6 years), although fish in one coastal site (Joeb's) averaged over 5 years of age at first marine visit. There was some evidence of higher condition factors for fish with sea-run migratory experience. There were significant differences in lateral line and dorsal ray numbers among sites but none for anal rays or gill rakers. Variability in all of these characters was high, and fish from coastal sites tended to have greater variability than those from inland sites. Only dorsal rays showed significant differences in meristic traits between sea-run and resident least cisco. These results suggest that least cisco exhibit high variability in physical traits. Also, least cisco appear to be flexible in their use of the marine environment, even within similar forms in the same lake. Some of the most basic life history characteristics of least cisco remain uncertain. With increased resource extraction occurring on the western Arctic coastal plain of Alaska, it is important to continue to investigate these and other life history strategies so as to ensure a sustainable fishery for native inhabitants of the region. Close

• 425. [Article] Metamorphosis, growth, and settlement of Pacific sanddab (Citharichthys sordidus) to a continental shelf nursery, inferred from otolith microstructure

  Processes of metamorphosis, settlement, and growth were examined in Pacific sanddab using field studies and otolith microstructure. This flatfish transforms at large sizes, has a gradual metamorphosis, ...

  Citation × Citation Citation Abstract Copy Title: Metamorphosis, growth, and settlement of Pacific sanddab (Citharichthys sordidus) to a continental shelf nursery, inferred from otolith microstructure Author: Donohoe, Christopher James Processes of metamorphosis, settlement, and growth were examined in Pacific sanddab using field studies and otolith microstructure. This flatfish transforms at large sizes, has a gradual metamorphosis, and settles to a nursery on the middle continental shelf. Eye migration takes 3 months and "metamorphosis proper" which begins after completion of eye migration (CEM) takes an additional 1-2 months. Larvae at CEM ranged from 30-46 mm SL and were 125-224 d old. Coefficients of variation in length and age at CEM were 0.081 and 0.122, similar to flatfishes that transform at smaller sizes. Accessory primordia (AP) and an opaque region formed in the sagitta 14-49 d before CEM and 2-3 months before the start of the juvenile period. Depth stratified benthic surveys were conducted on the continental shelf and upper slope off central Oregon bimonthly in 1989 and in March 1990-1994. Peak settlement occurred in late fall and winter. Larvae initially landed on the upper slope but continued inshore to the middle shelf, a process that takes ~50-60 d. The nursery is centered at 80-119 m in winter and 50-99 m in summer. Abundance of settling Pacific sanddab on the upper slope in March 1989-1994 was strongly correlated to onshore Ekman transport during the preceding 30 d (r=0.91, P=0.013, n=6). Electron microprobe analysis revealed strong cross-otolith trends in concentrations of Sr, K, and P in Pacific sanddab and Dover sole, but trends were not related to settlement, thermal experience, or otolith and somatic growth. Margin concentrations of Cl and K differed among stations as little as 5-8 km apart, potentially indicating meso-scale patchiness. Patterns also imply long term cohesion of pelagic larvae, a surprising result given the 9 month to 2 year pelagic period of Dover sole. Time series of daily increment widths revealed ontogenetic, seasonal, and individual variation in otolith growth rate. Otolith growth rates were correlated with SST in 1992 and 1994, but were largely determined by timing of settlement. Otolith growth was synchronous among a small portion of each year class. Distinct growth histories acted as natural tags that allowed study of patch dynamics and settlement. Title: Metamorphosis, growth, and settlement of Pacific sanddab (Citharichthys sordidus) to a continental shelf nursery, inferred from otolith microstructure Author: Donohoe, Christopher James Processes of metamorphosis, settlement, and growth were examined in Pacific sanddab using field studies and otolith microstructure. This flatfish transforms at large sizes, has a gradual metamorphosis, and settles to a nursery on the middle continental shelf. Eye migration takes 3 months and "metamorphosis proper" which begins after completion of eye migration (CEM) takes an additional 1-2 months. Larvae at CEM ranged from 30-46 mm SL and were 125-224 d old. Coefficients of variation in length and age at CEM were 0.081 and 0.122, similar to flatfishes that transform at smaller sizes. Accessory primordia (AP) and an opaque region formed in the sagitta 14-49 d before CEM and 2-3 months before the start of the juvenile period. Depth stratified benthic surveys were conducted on the continental shelf and upper slope off central Oregon bimonthly in 1989 and in March 1990-1994. Peak settlement occurred in late fall and winter. Larvae initially landed on the upper slope but continued inshore to the middle shelf, a process that takes ~50-60 d. The nursery is centered at 80-119 m in winter and 50-99 m in summer. Abundance of settling Pacific sanddab on the upper slope in March 1989-1994 was strongly correlated to onshore Ekman transport during the preceding 30 d (r=0.91, P=0.013, n=6). Electron microprobe analysis revealed strong cross-otolith trends in concentrations of Sr, K, and P in Pacific sanddab and Dover sole, but trends were not related to settlement, thermal experience, or otolith and somatic growth. Margin concentrations of Cl and K differed among stations as little as 5-8 km apart, potentially indicating meso-scale patchiness. Patterns also imply long term cohesion of pelagic larvae, a surprising result given the 9 month to 2 year pelagic period of Dover sole. Time series of daily increment widths revealed ontogenetic, seasonal, and individual variation in otolith growth rate. Otolith growth rates were correlated with SST in 1992 and 1994, but were largely determined by timing of settlement. Otolith growth was synchronous among a small portion of each year class. Distinct growth histories acted as natural tags that allowed study of patch dynamics and settlement. Close

• 426. [Article] Evaluation of the environmental conditioning system as a water sensitivity test for asphalt concrete mixtures

  The Environmental Conditioning System (ECS) was designed to evaluate the water sensitivity of asphalt concrete mixtures. The ECS subjects asphalt concrete specimens to a series of conditioning cycles including ...

  Citation × Citation Citation Abstract Copy Title: Evaluation of the environmental conditioning system as a water sensitivity test for asphalt concrete mixtures Author: Allen, Wendy L. The Environmental Conditioning System (ECS) was designed to evaluate the water sensitivity of asphalt concrete mixtures. The ECS subjects asphalt concrete specimens to a series of conditioning cycles including water flow, elevated and/or lowered temperature, and repeated axial loading. The purpose of this research was to: (1) evaluate the ECS test apparatus and procedure, and (2) determine whether the ECS can identify asphalt concrete mixtures that will perform well, or poorly, in the field with regard to water sensitivity. Twelve primary field test sections were identified. For each section, specimens were prepared in the laboratory using the original mix design (or the mix design identified by extraction), and the original aggregates, asphalts, and admixtures. Specimens were tested using two procedures: the ECS and the Oregon State University (OSU) wheel tracker. Field cores were used to evaluate in-situ mixture performance. Nine additional mixtures that have historically experienced water damage were tested in a limited secondary test program. Analyses were performed to determine the mixture properties that were significant in the prediction of mixture performance in the ECS. Mixture type was consistently the most significant predictor of ECS modulus ratio (change in mixture stiffness), degree of visual stripping, and binder migration, which were the performance indicators for water sensitivity evaluated in the ECS. Additional analysis indicated the existence of correlations among the ECS response variables. Significant correlations were found between the coefficient of water permeability and the degree of visual stripping; and between specimen deformation and the degree of visual stripping and binder migration. Mixture performance was compared between the ECS and the OSU wheel tracker and the field. Results indicate that the ECS test procedure can distinguish the relative performance of mixtures, with regard to water sensitivity, and mixture performance in the ECS correlates well with performance in the OSU wheel tracker. No correlation was found between mixture performance in the ECS and mixture performance in the field for the primary test sections. However, the primary field sections are relatively young, and water damage is expected to manifest itself in the future in those pavements identified as water sensitive by the ECS. The ECS predicted failure in the secondary mixtures which were identified as having had poor performance with regard to water sensitivity. Title: Evaluation of the environmental conditioning system as a water sensitivity test for asphalt concrete mixtures Author: Allen, Wendy L. The Environmental Conditioning System (ECS) was designed to evaluate the water sensitivity of asphalt concrete mixtures. The ECS subjects asphalt concrete specimens to a series of conditioning cycles including water flow, elevated and/or lowered temperature, and repeated axial loading. The purpose of this research was to: (1) evaluate the ECS test apparatus and procedure, and (2) determine whether the ECS can identify asphalt concrete mixtures that will perform well, or poorly, in the field with regard to water sensitivity. Twelve primary field test sections were identified. For each section, specimens were prepared in the laboratory using the original mix design (or the mix design identified by extraction), and the original aggregates, asphalts, and admixtures. Specimens were tested using two procedures: the ECS and the Oregon State University (OSU) wheel tracker. Field cores were used to evaluate in-situ mixture performance. Nine additional mixtures that have historically experienced water damage were tested in a limited secondary test program. Analyses were performed to determine the mixture properties that were significant in the prediction of mixture performance in the ECS. Mixture type was consistently the most significant predictor of ECS modulus ratio (change in mixture stiffness), degree of visual stripping, and binder migration, which were the performance indicators for water sensitivity evaluated in the ECS. Additional analysis indicated the existence of correlations among the ECS response variables. Significant correlations were found between the coefficient of water permeability and the degree of visual stripping; and between specimen deformation and the degree of visual stripping and binder migration. Mixture performance was compared between the ECS and the OSU wheel tracker and the field. Results indicate that the ECS test procedure can distinguish the relative performance of mixtures, with regard to water sensitivity, and mixture performance in the ECS correlates well with performance in the OSU wheel tracker. No correlation was found between mixture performance in the ECS and mixture performance in the field for the primary test sections. However, the primary field sections are relatively young, and water damage is expected to manifest itself in the future in those pavements identified as water sensitive by the ECS. The ECS predicted failure in the secondary mixtures which were identified as having had poor performance with regard to water sensitivity. Close

• 427. [Article] Seasonal movement patterns and habitat use of westslope cutthroat trout in two headwater tributary streams of the John Day River

  Radiotelemetry was used to study the seasonal movements and habitat use of adult westslope cutthroat trout Oncorhynchus clarki lewisi in Roberts Creek and Rail Creek, headwater tributaries of the John ...

  Citation × Citation Citation Abstract Copy Title: Seasonal movement patterns and habitat use of westslope cutthroat trout in two headwater tributary streams of the John Day River Author: Starcevich, Steven J. Radiotelemetry was used to study the seasonal movements and habitat use of adult westslope cutthroat trout Oncorhynchus clarki lewisi in Roberts Creek and Rail Creek, headwater tributaries of the John Day River, Oregon, from September 2000 to December 2001. The objectives were to (1) describe adult cutthroat trout life history in headwater streams by comparing seasonal movement patterns, and (2) assess seasonal habitat selection by comparing habitat use to availability. For seasonal comparison, only fish that survived with an active transmitter throughout winter, spring, and summer were used in the analysis. Sample size was 17 (mean fork length, 241mm) on Roberts Creek and 9 (mean fork length, 252 mm) on Rail Creek. In winter and summer, radiotagged fish were relatively sedentary on both Roberts Creek (median home ranges, 35 and 104 m, respectively) and Rail Creek (median home ranges, 104 and 112 m). In spring, 65% of fish in both streams moved over 100 m upstream to spawn; upstream movements were as long as 1,138 m (median, 271 m) on Roberts Creek and as long as 3,771 m (median, 311 m) on Rail Creek. Postspawning movements downstream were common; 82% of fish on Roberts Creek and 57% on Rail Creek showed homing behavior, returning in summer to the same channel unit they inhabited in winter. Fish length was positively correlated to total movement distance in spring on Roberts Creek but not on Rail Creek. Over 86% of the surface area of both creeks consisted of fast-water channel units. Instream large wood created the majority of habitat heterogeneity in both streams and radiotagged cutthroat trout were strongly associated with large wood pools throughout the year. Plunge pools were positively selected throughout the year on both streams. Headwater-resident populations of cutthroat trout are often considered nonmigratory; however, these radiotagged fish showed fluvial migratory behavior. These results demonstrate that habitat heterogeneity and connectivity are important life history requirements for fluvial headwater resident cutthroat trout. Title: Seasonal movement patterns and habitat use of westslope cutthroat trout in two headwater tributary streams of the John Day River Author: Starcevich, Steven J. Radiotelemetry was used to study the seasonal movements and habitat use of adult westslope cutthroat trout Oncorhynchus clarki lewisi in Roberts Creek and Rail Creek, headwater tributaries of the John Day River, Oregon, from September 2000 to December 2001. The objectives were to (1) describe adult cutthroat trout life history in headwater streams by comparing seasonal movement patterns, and (2) assess seasonal habitat selection by comparing habitat use to availability. For seasonal comparison, only fish that survived with an active transmitter throughout winter, spring, and summer were used in the analysis. Sample size was 17 (mean fork length, 241mm) on Roberts Creek and 9 (mean fork length, 252 mm) on Rail Creek. In winter and summer, radiotagged fish were relatively sedentary on both Roberts Creek (median home ranges, 35 and 104 m, respectively) and Rail Creek (median home ranges, 104 and 112 m). In spring, 65% of fish in both streams moved over 100 m upstream to spawn; upstream movements were as long as 1,138 m (median, 271 m) on Roberts Creek and as long as 3,771 m (median, 311 m) on Rail Creek. Postspawning movements downstream were common; 82% of fish on Roberts Creek and 57% on Rail Creek showed homing behavior, returning in summer to the same channel unit they inhabited in winter. Fish length was positively correlated to total movement distance in spring on Roberts Creek but not on Rail Creek. Over 86% of the surface area of both creeks consisted of fast-water channel units. Instream large wood created the majority of habitat heterogeneity in both streams and radiotagged cutthroat trout were strongly associated with large wood pools throughout the year. Plunge pools were positively selected throughout the year on both streams. Headwater-resident populations of cutthroat trout are often considered nonmigratory; however, these radiotagged fish showed fluvial migratory behavior. These results demonstrate that habitat heterogeneity and connectivity are important life history requirements for fluvial headwater resident cutthroat trout. Close

• 428. [Article] Age, chemistry, and tectonic significance of Easter and Sala y Gomez Islands

  Easter Island and Sala y Gomez are part of the Sala y Gomez Ridge, a broad band of high topography and scattered seamounts extending ESE from the East Pacific Rise. It has been proposed that the Sala y ...

  Citation × Citation Citation Abstract Copy Title: Age, chemistry, and tectonic significance of Easter and Sala y Gomez Islands Author: Clark, James Gregory, 1948- Easter Island and Sala y Gomez are part of the Sala y Gomez Ridge, a broad band of high topography and scattered seamounts extending ESE from the East Pacific Rise. It has been proposed that the Sala y Gomez Ridge results from the movement of the Nazca Plate over a fixed melting spot in the mantle. To test this hypothesis volcanic rocks from Easter Island and Sala y Gomez were analyzed for their K-Ar ages and major element abundances. Subaerial Easter Island was constructed in three distinct episodes, occurring at 2.5 m.y., 0.9 m.y., and 0.4 m.y. ago. The youngest rocks on the island are the Roiho olivine basalts, and are probably less than 50,000 years old. Eruptive activity on Sala y Gomez was essentially contemporaneous with the early volcanism on Easter Island. No migration of volcanism with time is apparent along the Sala y Gomez Ridge, thus a major criterion of the melting spot hypothesis is not fulfilled. Volcanic rocks from Easter Island constitute a tholeiitic differentiation series; they are chemically similar to those from other islands situated near mid-ocean rise crests. The wide compositional spectrum is most likely the result of fractional crystallization from a basaltic parent liquid, though the data is ambiguous for the highly silicic differentiates. The youngest basalts possess more alkaline affinities which are probably not related to fractional crystallization from the earlier basalts. The alkaline nature of these rocks may be the result of a downward migration of the fusion zone with time, as the island moved eastward over a progressively thickening lithosphere. Volcanic rocks from Sala y Gomez belong to an alkali olivine basalt series. The fundamental chemical differences between the Easter Island and Sala y Gomez suites suggest that the two islands were not derived from a common source, as predicted by the melting spot hypothesis. The evidence does not support a melting spot origin for Easter Island, Sala y Gomez, and the Sala y Gomez Ridge. An alternative model involving diapiric intrusion and decompression melting of asthenosphere material along a major fracture in the Nazca Plate provides a better explanation for the data. Synchronous volcanism along the eastern extension of the Easter Island transform fault has given rise to the islands and seamounts on the Sala y Gomez Ridge. Title: Age, chemistry, and tectonic significance of Easter and Sala y Gomez Islands Author: Clark, James Gregory, 1948- Easter Island and Sala y Gomez are part of the Sala y Gomez Ridge, a broad band of high topography and scattered seamounts extending ESE from the East Pacific Rise. It has been proposed that the Sala y Gomez Ridge results from the movement of the Nazca Plate over a fixed melting spot in the mantle. To test this hypothesis volcanic rocks from Easter Island and Sala y Gomez were analyzed for their K-Ar ages and major element abundances. Subaerial Easter Island was constructed in three distinct episodes, occurring at 2.5 m.y., 0.9 m.y., and 0.4 m.y. ago. The youngest rocks on the island are the Roiho olivine basalts, and are probably less than 50,000 years old. Eruptive activity on Sala y Gomez was essentially contemporaneous with the early volcanism on Easter Island. No migration of volcanism with time is apparent along the Sala y Gomez Ridge, thus a major criterion of the melting spot hypothesis is not fulfilled. Volcanic rocks from Easter Island constitute a tholeiitic differentiation series; they are chemically similar to those from other islands situated near mid-ocean rise crests. The wide compositional spectrum is most likely the result of fractional crystallization from a basaltic parent liquid, though the data is ambiguous for the highly silicic differentiates. The youngest basalts possess more alkaline affinities which are probably not related to fractional crystallization from the earlier basalts. The alkaline nature of these rocks may be the result of a downward migration of the fusion zone with time, as the island moved eastward over a progressively thickening lithosphere. Volcanic rocks from Sala y Gomez belong to an alkali olivine basalt series. The fundamental chemical differences between the Easter Island and Sala y Gomez suites suggest that the two islands were not derived from a common source, as predicted by the melting spot hypothesis. The evidence does not support a melting spot origin for Easter Island, Sala y Gomez, and the Sala y Gomez Ridge. An alternative model involving diapiric intrusion and decompression melting of asthenosphere material along a major fracture in the Nazca Plate provides a better explanation for the data. Synchronous volcanism along the eastern extension of the Easter Island transform fault has given rise to the islands and seamounts on the Sala y Gomez Ridge. Close

• 429. [Article] Bioenergetics and behavior of the krill Euphausia pacifica in the California Current System off the Oregon coast

  Euphausia pacifica, the North Pacific krill, is a key grazer in the California Current System and an important prey item for consumers such as salmon, seabirds, and whales. As a crucial link between phytoplankton ...

  Citation × Citation Citation Abstract Copy Title: Bioenergetics and behavior of the krill Euphausia pacifica in the California Current System off the Oregon coast Author: Lindsey, Brie J. Euphausia pacifica, the North Pacific krill, is a key grazer in the California Current System and an important prey item for consumers such as salmon, seabirds, and whales. As a crucial link between phytoplankton and higher trophic levels, it is essential to understand both the behavior and bioenergetics of this species in the context of its physical environment in order to anticipate distributions in time and space. The second chapter of this dissertation explores an hypothesis of differential transport of larval stages at the Oregon coast with an analysis of previously-collected and staged samples of E. pacifica. A metric was proposed to quantify the fraction of migrating late larval stages in net tows and how it was anticipated to vary with upwelling on an event-length time scale, due to differential cross-shelf transport. While the data from one year were consistent with the hypothesized relationship, the other years in the analysis did not conform to expectations. Results suggest there may be other confounding factors operating in the Oregon upwelling zone that prevent the direct observation of differential transport of larvae with field samples. The third chapter discusses egg transport between the Oregon coast shelf break and the inner shelf region. Modeling of egg trajectories demonstrated that females spawning at or beyond the shelf break are unlikely to be the primary source of eggs found at an inner shelf station. Years with strongly positive (warm) Pacific Decadal Oscillation index values are not likely to be years with large fluxes of E. pacifica eggs to the nearshore region if they originate at the shelf break or seaward, as a result of increased egg development rate. Finally, the fourth chapter introduces an individual based model (IBM) of E. pacifica bioenergetics and explores the potential for the species to maintain its position in a region off Oregon, as well as the assumption that repeated sampling in the region is resampling the same E. pacifica population over a period of months. Optimistic (i.e. no mortality) trajectories of individuals modeled off Oregon suggest that cohort analyses of juvenile and adult E. pacifica in the region may not always violate the assumption of resampling a single population, especially if samples are taken during the fall or krill are caught in mesoscale features such as eddies. In these special cases, cohort analysis may be useful for estimating in situ growth rates, which might not be expected for a region as dynamic as the Northern California Current. There are still significant gaps in our understanding of fundamental biological processes for E. pacifica, such as how it responds to an ocean environment with generally insufficient food, whether overwintering metabolism is greatly reduced, how consumption rates by larval stages change when multiple food types are available, what mechanisms cause the variability in larval stage diel-vertical migration, and what the impact of different qualities of food might have on egg characteristics such as buoyancy. Addressing these unknowns and how well E. pacifica copes under non-ideal conditions will facilitate a fuller understanding of the dynamics of this species. Title: Bioenergetics and behavior of the krill Euphausia pacifica in the California Current System off the Oregon coast Author: Lindsey, Brie J. Euphausia pacifica, the North Pacific krill, is a key grazer in the California Current System and an important prey item for consumers such as salmon, seabirds, and whales. As a crucial link between phytoplankton and higher trophic levels, it is essential to understand both the behavior and bioenergetics of this species in the context of its physical environment in order to anticipate distributions in time and space. The second chapter of this dissertation explores an hypothesis of differential transport of larval stages at the Oregon coast with an analysis of previously-collected and staged samples of E. pacifica. A metric was proposed to quantify the fraction of migrating late larval stages in net tows and how it was anticipated to vary with upwelling on an event-length time scale, due to differential cross-shelf transport. While the data from one year were consistent with the hypothesized relationship, the other years in the analysis did not conform to expectations. Results suggest there may be other confounding factors operating in the Oregon upwelling zone that prevent the direct observation of differential transport of larvae with field samples. The third chapter discusses egg transport between the Oregon coast shelf break and the inner shelf region. Modeling of egg trajectories demonstrated that females spawning at or beyond the shelf break are unlikely to be the primary source of eggs found at an inner shelf station. Years with strongly positive (warm) Pacific Decadal Oscillation index values are not likely to be years with large fluxes of E. pacifica eggs to the nearshore region if they originate at the shelf break or seaward, as a result of increased egg development rate. Finally, the fourth chapter introduces an individual based model (IBM) of E. pacifica bioenergetics and explores the potential for the species to maintain its position in a region off Oregon, as well as the assumption that repeated sampling in the region is resampling the same E. pacifica population over a period of months. Optimistic (i.e. no mortality) trajectories of individuals modeled off Oregon suggest that cohort analyses of juvenile and adult E. pacifica in the region may not always violate the assumption of resampling a single population, especially if samples are taken during the fall or krill are caught in mesoscale features such as eddies. In these special cases, cohort analysis may be useful for estimating in situ growth rates, which might not be expected for a region as dynamic as the Northern California Current. There are still significant gaps in our understanding of fundamental biological processes for E. pacifica, such as how it responds to an ocean environment with generally insufficient food, whether overwintering metabolism is greatly reduced, how consumption rates by larval stages change when multiple food types are available, what mechanisms cause the variability in larval stage diel-vertical migration, and what the impact of different qualities of food might have on egg characteristics such as buoyancy. Addressing these unknowns and how well E. pacifica copes under non-ideal conditions will facilitate a fuller understanding of the dynamics of this species. Close

• 430. [Article] Avian Predation on Juvenile Salmonids: Spatial and Temporal Analysis Based on Acoustic and Passive Integrated Transponder Tags

  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 article is copyrighted by the American Fisheries ...

  Citation × Citation Citation Abstract Copy Title: Avian Predation on Juvenile Salmonids: Spatial and Temporal Analysis Based on Acoustic and Passive Integrated Transponder Tags Author: Evans, Allen F., Cramer, Bradley, Roby, Daniel D., Turecek, Aaron, Sullivan, Leah, Dotson, Curtis, Weiland, Mark, Collis, Ken, Payton, Quinn, Skalski, John, Loschl, Peter J. 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 article is copyrighted by the American Fisheries Society and published by Taylor & Francis. It can be found at: http://www.tandfonline.com/doi/full/10.1080/00028487.2016.1150881 Title: Avian Predation on Juvenile Salmonids: Spatial and Temporal Analysis Based on Acoustic and Passive Integrated Transponder Tags Author: Evans, Allen F., Cramer, Bradley, Roby, Daniel D., Turecek, Aaron, Sullivan, Leah, Dotson, Curtis, Weiland, Mark, Collis, Ken, Payton, Quinn, Skalski, John, Loschl, Peter J. 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 article is copyrighted by the American Fisheries Society and published by Taylor & Francis. It can be found at: http://www.tandfonline.com/doi/full/10.1080/00028487.2016.1150881 Close