Search

Search Results

• 51. [Article] Salmon recovery in the Pacific Northwest : defining what constitutes a wild salmon

  In spite of considerable efforts to restore natural runs of anadromous salmonids in the Pacific Northwest, they remain at risk of extirpation. Along with many other factors influencing the decline, stocking ...

  Citation × Citation Citation Abstract Copy Title: Salmon recovery in the Pacific Northwest : defining what constitutes a wild salmon Author: Courter, Ian I. In spite of considerable efforts to restore natural runs of anadromous salmonids in the Pacific Northwest, they remain at risk of extirpation. Along with many other factors influencing the decline, stocking from hatcheries over the past hundred years is often suggested to be a major cause. The listing of over two dozen runs of salmon under the Endangered Species Act has catalyzed a re-assessment of hatchery effects on naturally spawning salmon. Recent policies have placed a much greater emphasis on restoring runs of wild salmon rather than maintaining runs through stocking from hatchery production. Except at the most superficial level, there is no consensus about how to define "wild." Rather, there is a continuum of definitions for "wild" and each definition supports an implicit policy goal. The precise way in which "wild salmon" is defined potentially has profound policy implications. Ultimately, the choice of definition is a policy decision that incorporates science as one of several factors influencing the decision. A suite of options, often poorly articulated, for defining "wild" are available to policy makers who are selecting recovery goals. To test a subset of the available definitions of wild, I quantified the number of hatchery and naturally spawning salmon for 19 populations of Oregon coastal coho. "Wild" was defined by types 1 through 5 based on the number of hatchery fish released annually and the number of naturally spawning hatchery adults. As currently managed by the Oregon Department of Fish and Wildlife, the Oregon coast has a range of "types" of coho salmon. By clearly and explicitly defining "wild" as steps along a continuum, policy makers and managers can more effectively monitor and achieve specific salmon recovery goals. Title: Salmon recovery in the Pacific Northwest : defining what constitutes a wild salmon Author: Courter, Ian I. In spite of considerable efforts to restore natural runs of anadromous salmonids in the Pacific Northwest, they remain at risk of extirpation. Along with many other factors influencing the decline, stocking from hatcheries over the past hundred years is often suggested to be a major cause. The listing of over two dozen runs of salmon under the Endangered Species Act has catalyzed a re-assessment of hatchery effects on naturally spawning salmon. Recent policies have placed a much greater emphasis on restoring runs of wild salmon rather than maintaining runs through stocking from hatchery production. Except at the most superficial level, there is no consensus about how to define "wild." Rather, there is a continuum of definitions for "wild" and each definition supports an implicit policy goal. The precise way in which "wild salmon" is defined potentially has profound policy implications. Ultimately, the choice of definition is a policy decision that incorporates science as one of several factors influencing the decision. A suite of options, often poorly articulated, for defining "wild" are available to policy makers who are selecting recovery goals. To test a subset of the available definitions of wild, I quantified the number of hatchery and naturally spawning salmon for 19 populations of Oregon coastal coho. "Wild" was defined by types 1 through 5 based on the number of hatchery fish released annually and the number of naturally spawning hatchery adults. As currently managed by the Oregon Department of Fish and Wildlife, the Oregon coast has a range of "types" of coho salmon. By clearly and explicitly defining "wild" as steps along a continuum, policy makers and managers can more effectively monitor and achieve specific salmon recovery goals. Close

• 52. [Article] Spawning chinook salmon (Oncorhynchus tshawytscha) two years in a row : reconditioning for repeated gamete collection

  Spring chinook salmon, Oncorhynchus tshawytscha, in the Snake River Basin are listed as endangered under the Endangered Species Act. The typical life history of spring chinook salmon is semelparous. An ...

  Citation × Citation Citation Abstract Copy Title: Spawning chinook salmon (Oncorhynchus tshawytscha) two years in a row : reconditioning for repeated gamete collection Author: Mayer, Kent Corey Spring chinook salmon, Oncorhynchus tshawytscha, in the Snake River Basin are listed as endangered under the Endangered Species Act. The typical life history of spring chinook salmon is semelparous. An experiment was performed to see if mature male spring chinook salmon parr could be reconditioned after hand-spawning and spawned in successive years. The mature male parr were part of a 1997 and 1998 cohort of captive broodstock from the Grande Ronde River Basin in Oregon. Force-feeding was combined with volitional feeding in an attempt to inhibit senescence and increase survival time after spawning. The viscerosomatic index, fat and protein contents increased with survival time after spawning for both cohorts. There was a significant relationship between percent weight change and survival time for the 1997 cohort (p<0.001). Force-feeding had no effect on survival time after spawning for the 1997 cohort (p=0.074) or the 1998 cohort (p=0.178). Fat content, weight gain and survival time indicated that the reconditioning process was observable in the 1997 cohort at 77 days after spawning and was cyclical, resulting in a physiological response which allowed male chinook salmon to spawn in successive years. Fertilization trials with three reconditioned males yielded a fertilization success rate of 96.9% compared to 95.7% for 4-year old, anadromous male spring chinook salmon (p=0.152), measured as production of eyed-embryos. This experiment provides new knowledge of plasticity in the reproductive biology of male, stream-type, spring chinook salmon. Reconditioning and spawning male chinook salmon parr in successive years could be used to help maximize genetic diversity and aid in the recovery of endangered Oncorhynchus populations. Title: Spawning chinook salmon (Oncorhynchus tshawytscha) two years in a row : reconditioning for repeated gamete collection Author: Mayer, Kent Corey Spring chinook salmon, Oncorhynchus tshawytscha, in the Snake River Basin are listed as endangered under the Endangered Species Act. The typical life history of spring chinook salmon is semelparous. An experiment was performed to see if mature male spring chinook salmon parr could be reconditioned after hand-spawning and spawned in successive years. The mature male parr were part of a 1997 and 1998 cohort of captive broodstock from the Grande Ronde River Basin in Oregon. Force-feeding was combined with volitional feeding in an attempt to inhibit senescence and increase survival time after spawning. The viscerosomatic index, fat and protein contents increased with survival time after spawning for both cohorts. There was a significant relationship between percent weight change and survival time for the 1997 cohort (p<0.001). Force-feeding had no effect on survival time after spawning for the 1997 cohort (p=0.074) or the 1998 cohort (p=0.178). Fat content, weight gain and survival time indicated that the reconditioning process was observable in the 1997 cohort at 77 days after spawning and was cyclical, resulting in a physiological response which allowed male chinook salmon to spawn in successive years. Fertilization trials with three reconditioned males yielded a fertilization success rate of 96.9% compared to 95.7% for 4-year old, anadromous male spring chinook salmon (p=0.152), measured as production of eyed-embryos. This experiment provides new knowledge of plasticity in the reproductive biology of male, stream-type, spring chinook salmon. Reconditioning and spawning male chinook salmon parr in successive years could be used to help maximize genetic diversity and aid in the recovery of endangered Oncorhynchus populations. Close

• 53. [Article] Seasonal and interannual variation in juvenile salmonids and associated fish assemblage in open waters of the lower Columbia River estuary

  This is the publisher’s final pdf. The published article is copyrighted by National Marine Fisheries Service, NOAA, Scientific Publications Office and can be found at: http://fishbull.noaa.gov/. To the ...

  Citation × Citation Citation Abstract Copy Title: Seasonal and interannual variation in juvenile salmonids and associated fish assemblage in open waters of the lower Columbia River estuary Author: Litz, Marisa N. C., Weitkamp, Laurie A., Bentley, Paul J. This is the publisher’s final pdf. The published article is copyrighted by National Marine Fisheries Service, NOAA, Scientific Publications Office and can be found at: http://fishbull.noaa.gov/. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. Title: Seasonal and interannual variation in juvenile salmonids and associated fish assemblage in open waters of the lower Columbia River estuary Author: Litz, Marisa N. C., Weitkamp, Laurie A., Bentley, Paul J. This is the publisher’s final pdf. The published article is copyrighted by National Marine Fisheries Service, NOAA, Scientific Publications Office and can be found at: http://fishbull.noaa.gov/. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. Close

• 54. [Article] Viruses infecting salmonid fishes from Oregon : A. The occurrence and distribution of infectious pancreatic necrosis virus. B. The development of an attenuated strain of infectious hematopoietic necrosis virus (IHNV) for immunization of salmonids

  The occurrence and distribution of fish viruses in Oregon were determined by the examination of anadromous and fresh water salmonids. Infectious pancreatic necrosis virus (IPNV) was isolated and identified ...

  Citation × Citation Citation Abstract Copy Title: Viruses infecting salmonid fishes from Oregon : A. The occurrence and distribution of infectious pancreatic necrosis virus. B. The development of an attenuated strain of infectious hematopoietic necrosis virus (IHNV) for immunization of salmonids Author: Tebbit, Guy Lee The occurrence and distribution of fish viruses in Oregon were determined by the examination of anadromous and fresh water salmonids. Infectious pancreatic necrosis virus (IPNV) was isolated and identified from asymptomatic adult coho (Oncorhynchus kisutch) and chinook (0. tshawytscha) salmon returning to the Columbia River system. Infectious pancreatic necrosis virus was also identified as the causative agent of severe losses of eastern brook trout juveniles (Salvelinus fontinalis) at the Fall River trout hatchery in central Oregon. This was the first documented IPNV epizootic in fish from Oregon. A high incidence of IPNV was detected in eastern brook trout populations from central Oregon indicating that this virus poses a threat to the rearing of that species in Oregon. An attenuated strain of infectious hematopoietic necrosis virus (IHNV) was developed for use as a water-borne vaccine for the control of IHNV disease. This water-brone vaccine is easily administered as an immunizing agent by direct addition to the water containing fish. The attenuated IHNV water-borne vaccine strain was determined to be one hundred three times less virulent than the wild type strain from which it was derived. This vaccine was proven to be efficacious against high levels of both water route and injected challenges of virulent wild type virus in kokanee (0. nerka) and sockeye salmon (0. nerka). Other parameters for the development of an effective vaccine preparation were also tested. An optimal exposure period to the immunizing virus of 48 hours was determined as were the minimum immunizing dose for sockeye and chinook salmon. The attenuated IHNV water-borne vaccine produced immunity with a duration of at least 110 days and was shown to provide protection to sockeye salmon challenged with four isolates of virulent IHNV from different geographic locations. Another method of immunization, vacuum infiltration, was tested using a second strain of attenuated IHNV as an immunizing agent. Even though this method of immunization was effective in eliciting a protective immune response in chinook and kokanee salmon, it did not produce the level of protection provided by the attenuated IHNV water-borne vaccine. Title: Viruses infecting salmonid fishes from Oregon : A. The occurrence and distribution of infectious pancreatic necrosis virus. B. The development of an attenuated strain of infectious hematopoietic necrosis virus (IHNV) for immunization of salmonids Author: Tebbit, Guy Lee The occurrence and distribution of fish viruses in Oregon were determined by the examination of anadromous and fresh water salmonids. Infectious pancreatic necrosis virus (IPNV) was isolated and identified from asymptomatic adult coho (Oncorhynchus kisutch) and chinook (0. tshawytscha) salmon returning to the Columbia River system. Infectious pancreatic necrosis virus was also identified as the causative agent of severe losses of eastern brook trout juveniles (Salvelinus fontinalis) at the Fall River trout hatchery in central Oregon. This was the first documented IPNV epizootic in fish from Oregon. A high incidence of IPNV was detected in eastern brook trout populations from central Oregon indicating that this virus poses a threat to the rearing of that species in Oregon. An attenuated strain of infectious hematopoietic necrosis virus (IHNV) was developed for use as a water-borne vaccine for the control of IHNV disease. This water-brone vaccine is easily administered as an immunizing agent by direct addition to the water containing fish. The attenuated IHNV water-borne vaccine strain was determined to be one hundred three times less virulent than the wild type strain from which it was derived. This vaccine was proven to be efficacious against high levels of both water route and injected challenges of virulent wild type virus in kokanee (0. nerka) and sockeye salmon (0. nerka). Other parameters for the development of an effective vaccine preparation were also tested. An optimal exposure period to the immunizing virus of 48 hours was determined as were the minimum immunizing dose for sockeye and chinook salmon. The attenuated IHNV water-borne vaccine produced immunity with a duration of at least 110 days and was shown to provide protection to sockeye salmon challenged with four isolates of virulent IHNV from different geographic locations. Another method of immunization, vacuum infiltration, was tested using a second strain of attenuated IHNV as an immunizing agent. Even though this method of immunization was effective in eliciting a protective immune response in chinook and kokanee salmon, it did not produce the level of protection provided by the attenuated IHNV water-borne vaccine. Close

• 55. [Article] Systematics, variation, distribution, and biology of lampreys of the genus Lampetra in Oregon

  Based on the number of velar tentacles and the form of longitudinal lingual laminae found in Lampetra (Entosphenus) t. tridentata and its closely related forms, the taxon Entosphenus should not be considered ...

  Citation × Citation Citation Abstract Copy Title: Systematics, variation, distribution, and biology of lampreys of the genus Lampetra in Oregon Author: Kan, Ting Tien Based on the number of velar tentacles and the form of longitudinal lingual laminae found in Lampetra (Entosphenus) t. tridentata and its closely related forms, the taxon Entosphenus should not be considered as a genus as commonly adopted, but, along with the taxa Lethenteron and Lampetra, should be regarded as a subgenus of the genus Lampetra. The genus Lampetra is distinct for various reasons, including particularly the character that no cusps are present in the area distal to the lateral circumorals. Six nominal species, belonging to the subgenera Entosphenus and Lampetra, have been known to occur in four of the seven major drainage systems of Oregon. The anadromous L. (E.) t.tridentata, is widespread in the Columbia River and Coastal drainage systems, occurring in most streams with access to the ocean regardless of distance to the ocean, as long as suitable spawning grounds and ammocoete habitats are present. Morphometrics and dentitional features vary little over its geographical range. The number of trunk myomeres and the adult body size vary appreciably so that two categories of regional forms, coastal and inland, may be recognized. The coastal forms are generally smaller and have fewer trunk myomeres compared to those of the larger inland forms. The spawning migration begins from the late spring to late summer for the coastal forms but may occur much earlier for the inland forms. The adult body size appears to be positively correlated with absolute fecundity, but is negatively correlated with relative fecundity. Duration of the larval period is from four to six years. Metamorphosis usually takes place in the fall. Macrophthalmia are known to enter the ocean over a long period, those descending coastal streams enter salt water in the late fall and early winter, whereas the peak of emigration from inland streams is in the early spring. Duration of its marine parasitic phase appears to be from 20 to 40 months. The small landlocked L. (E.) t. kawiaga n. subsp., found only in the Klamath and Goose Lake drainage systems in southern Oregon and northern California, differs from t. tridentata in body size and various meristic and morphometric characters. Its lacustrine parasitic phase is about 12 months long. L. (E.) lethophaga, the nonparasitic derivative of tridentata, occurs in the Klamath and probably also the Goose Lake drainage system. It is characterized by an extension of the larval phase and by a greatly reduced post-larval period. The presumably extinct L. (E. ) minima, a parasitic derivative of tridentata, found formerly only in Miller Lake, Oregon, possessed a number of characters that were concomitants of dwarfism, the distinctive feature of the species. Relationships and evolution among the subgenus Entosphenus were discussed. Distributional records of L. ayresii and L. richardsoni of the subgenus Lampetra in Oregon were given. Evidence indicates that a complex of clinal races, including L. pacifica Vladykov, 1973, may exist in the latter species. Title: Systematics, variation, distribution, and biology of lampreys of the genus Lampetra in Oregon Author: Kan, Ting Tien Based on the number of velar tentacles and the form of longitudinal lingual laminae found in Lampetra (Entosphenus) t. tridentata and its closely related forms, the taxon Entosphenus should not be considered as a genus as commonly adopted, but, along with the taxa Lethenteron and Lampetra, should be regarded as a subgenus of the genus Lampetra. The genus Lampetra is distinct for various reasons, including particularly the character that no cusps are present in the area distal to the lateral circumorals. Six nominal species, belonging to the subgenera Entosphenus and Lampetra, have been known to occur in four of the seven major drainage systems of Oregon. The anadromous L. (E.) t.tridentata, is widespread in the Columbia River and Coastal drainage systems, occurring in most streams with access to the ocean regardless of distance to the ocean, as long as suitable spawning grounds and ammocoete habitats are present. Morphometrics and dentitional features vary little over its geographical range. The number of trunk myomeres and the adult body size vary appreciably so that two categories of regional forms, coastal and inland, may be recognized. The coastal forms are generally smaller and have fewer trunk myomeres compared to those of the larger inland forms. The spawning migration begins from the late spring to late summer for the coastal forms but may occur much earlier for the inland forms. The adult body size appears to be positively correlated with absolute fecundity, but is negatively correlated with relative fecundity. Duration of the larval period is from four to six years. Metamorphosis usually takes place in the fall. Macrophthalmia are known to enter the ocean over a long period, those descending coastal streams enter salt water in the late fall and early winter, whereas the peak of emigration from inland streams is in the early spring. Duration of its marine parasitic phase appears to be from 20 to 40 months. The small landlocked L. (E.) t. kawiaga n. subsp., found only in the Klamath and Goose Lake drainage systems in southern Oregon and northern California, differs from t. tridentata in body size and various meristic and morphometric characters. Its lacustrine parasitic phase is about 12 months long. L. (E.) lethophaga, the nonparasitic derivative of tridentata, occurs in the Klamath and probably also the Goose Lake drainage system. It is characterized by an extension of the larval phase and by a greatly reduced post-larval period. The presumably extinct L. (E. ) minima, a parasitic derivative of tridentata, found formerly only in Miller Lake, Oregon, possessed a number of characters that were concomitants of dwarfism, the distinctive feature of the species. Relationships and evolution among the subgenus Entosphenus were discussed. Distributional records of L. ayresii and L. richardsoni of the subgenus Lampetra in Oregon were given. Evidence indicates that a complex of clinal races, including L. pacifica Vladykov, 1973, may exist in the latter species. Close

• 56. [Article] Potential for dispersal of the non-native parasite Myxobolus cerebralis : qualitative risk assessments for the state of Alaska and the Willamette River Basin, Oregon

  First introduced to the USA in 1958, Myxobolus cerebralis, the parasite responsible for whirling disease in salmonids, has since spread across the country causing severe declines in wild trout populations ...

  Citation × Citation Citation Abstract Copy Title: Potential for dispersal of the non-native parasite Myxobolus cerebralis : qualitative risk assessments for the state of Alaska and the Willamette River Basin, Oregon Author: Arsan, E. Leyla First introduced to the USA in 1958, Myxobolus cerebralis, the parasite responsible for whirling disease in salmonids, has since spread across the country causing severe declines in wild trout populations in the intermountain west. Recent development of risk assessment models used to assess the likelihood and consequences of exotic parasite introduction, have strengthened the process of science-based decision-making in aquatic animal health. In the case of M. cerebralis, it is necessary to use a risk assessment model with two unique segments that clearly address the distinct life stages and respective hosts of the parasite separately. The studies described examine the probability of M. cerebralis introduction and establishment for two regions: the state of Alaska, and the Willamette River basin, Oregon. The Alaska risk assessment was based on the assumption that the parasite did not already occur in the state. However, in the process of validating this assumption, we documented the first polymerase chain reaction (PCR) detection of the parasite in the state. The pathogen was identified in hatchery rainbow trout (Oncorhynchus mykiss) from the Anchorage area. Although this is the first detection of the parasite in Alaska, clinical whirling disease has never been documented in the state. To qualitatively assess the risk of further spread of M. cerebralis in Alaska, four potential routes of dissemination were examined: movement of fish by humans, natural dispersal (via migratory birds and stray anadromous salmon), recreational activities, and commercial seafood processing. This research indicates the most likely pathway for M. cerebralis transport in Alaska is human movement of fish. In the Willamette River basin, Oregon, introduction of M. cerebralis has already occurred, though establishment appears limited to a single private hatchery. Introduction in this region was considered the most likely to occur as a result of human movements of fish. Straying anadromous salmonids were also assessed and were present in higher numbers than predicted. However, they were not infected with the parasite, and thus the probability for introduction by this route is low. The probability of introduction of the parasite varies throughout the Willamette River basin. Areas with the highest probability for M. cerebralis introduction were identified as the Clackamas and Santiam River subbasins. The Clackamas River has already experienced an introduction of the parasite, has the largest concentration of hatcheries (state, federal, and private), has a popular sport fishery, and is the closest major tributary to the enormous piscivorous bird-populations in the Columbia River estuary. The Santiam subbasin has a popular sport fishery, received the highest number of stray fish in the Willamette River basin, and has the second largest concentration of hatcheries in the Willamette River basin. Unique from introduction, establishment of the parasite is dependent upon several environmental and biological factors including: water temperatures, spatial/temporal overlap of hosts, and the distribution and genetic composition of the parasite’s invertebrate host, Tubifex tubifex. The distribution, genetic composition and susceptibility of T. tubifex, were considered the most important factor in the ability of M. cerebralis to establish in both systems. Surveys of oligochaete populations were conducted in both study regions. In Alaska, T. tubifex was not detected from the southeast region and the apparent lack of appropriate tubificid hosts may prevent establishment in that part of the state. However, 4 lineages (I, III, IV, and VI) of the species were identified from southcentral Alaska. Lineage IV has not been previously been described in North America and its susceptibility to M. cerebralis was unknown. When lineage IV T. tubifex and 3 mixed-lineage (I, III, IV and VI) groups were exposed to M. cerebralis, only lineage III became infected under our experimental conditions. Thus, if the parasite were dispersed, conditions are appropriate for establishment and propagation of the parasite life cycle in southcentral Alaska, although detrimental effects on fish populations may be reduced as a result of the presence of non-susceptible lineages of T. tubifex. The probability of further establishment in this area is greatest in Ship Creek, where the abundance of susceptible T. tubifex, the presence of susceptible rainbow trout (Oncorhynchus mykiss), and the proximity to the known area of infection make conditions particularly appropriate. Similar to findings in Alaska, the Willamette River basin, Oregon also supports populations of susceptible T. tubifex. If the pathogen were introduced, probability of establishment is high in certain areas of the basin as all conditions are appropriate for propagation of the parasite life cycle. Tributaries to the mainstem Willamette River have the highest probability of establishment as these areas have the greatest numbers of susceptible T. tubifex. However, the abundance of resistant strains of T. tubifex could mitigate the effects of M. cerebralis if introduced. Management recommendations to reduce the likelihood of parasite dissemination are similar for Oregon and Alaska since human movement of fish and angler activities were considered the most likely routes of introduction for both regions. Based on this research, steps should also be taken to limit human movement of fish, whether by restricting carcass planting for stream enrichment in Oregon, or by prohibiting use of fish heads as bait in southcentral Alaska. The states should also allot resources to angler education and awareness of the effects of angler activity and recreation on dispersal of M. cerebralis. This could be done using a combination of brochures and signage at boat ramps describing how to prevent spread of aquatic nuisance species. Title: Potential for dispersal of the non-native parasite Myxobolus cerebralis : qualitative risk assessments for the state of Alaska and the Willamette River Basin, Oregon Author: Arsan, E. Leyla First introduced to the USA in 1958, Myxobolus cerebralis, the parasite responsible for whirling disease in salmonids, has since spread across the country causing severe declines in wild trout populations in the intermountain west. Recent development of risk assessment models used to assess the likelihood and consequences of exotic parasite introduction, have strengthened the process of science-based decision-making in aquatic animal health. In the case of M. cerebralis, it is necessary to use a risk assessment model with two unique segments that clearly address the distinct life stages and respective hosts of the parasite separately. The studies described examine the probability of M. cerebralis introduction and establishment for two regions: the state of Alaska, and the Willamette River basin, Oregon. The Alaska risk assessment was based on the assumption that the parasite did not already occur in the state. However, in the process of validating this assumption, we documented the first polymerase chain reaction (PCR) detection of the parasite in the state. The pathogen was identified in hatchery rainbow trout (Oncorhynchus mykiss) from the Anchorage area. Although this is the first detection of the parasite in Alaska, clinical whirling disease has never been documented in the state. To qualitatively assess the risk of further spread of M. cerebralis in Alaska, four potential routes of dissemination were examined: movement of fish by humans, natural dispersal (via migratory birds and stray anadromous salmon), recreational activities, and commercial seafood processing. This research indicates the most likely pathway for M. cerebralis transport in Alaska is human movement of fish. In the Willamette River basin, Oregon, introduction of M. cerebralis has already occurred, though establishment appears limited to a single private hatchery. Introduction in this region was considered the most likely to occur as a result of human movements of fish. Straying anadromous salmonids were also assessed and were present in higher numbers than predicted. However, they were not infected with the parasite, and thus the probability for introduction by this route is low. The probability of introduction of the parasite varies throughout the Willamette River basin. Areas with the highest probability for M. cerebralis introduction were identified as the Clackamas and Santiam River subbasins. The Clackamas River has already experienced an introduction of the parasite, has the largest concentration of hatcheries (state, federal, and private), has a popular sport fishery, and is the closest major tributary to the enormous piscivorous bird-populations in the Columbia River estuary. The Santiam subbasin has a popular sport fishery, received the highest number of stray fish in the Willamette River basin, and has the second largest concentration of hatcheries in the Willamette River basin. Unique from introduction, establishment of the parasite is dependent upon several environmental and biological factors including: water temperatures, spatial/temporal overlap of hosts, and the distribution and genetic composition of the parasite’s invertebrate host, Tubifex tubifex. The distribution, genetic composition and susceptibility of T. tubifex, were considered the most important factor in the ability of M. cerebralis to establish in both systems. Surveys of oligochaete populations were conducted in both study regions. In Alaska, T. tubifex was not detected from the southeast region and the apparent lack of appropriate tubificid hosts may prevent establishment in that part of the state. However, 4 lineages (I, III, IV, and VI) of the species were identified from southcentral Alaska. Lineage IV has not been previously been described in North America and its susceptibility to M. cerebralis was unknown. When lineage IV T. tubifex and 3 mixed-lineage (I, III, IV and VI) groups were exposed to M. cerebralis, only lineage III became infected under our experimental conditions. Thus, if the parasite were dispersed, conditions are appropriate for establishment and propagation of the parasite life cycle in southcentral Alaska, although detrimental effects on fish populations may be reduced as a result of the presence of non-susceptible lineages of T. tubifex. The probability of further establishment in this area is greatest in Ship Creek, where the abundance of susceptible T. tubifex, the presence of susceptible rainbow trout (Oncorhynchus mykiss), and the proximity to the known area of infection make conditions particularly appropriate. Similar to findings in Alaska, the Willamette River basin, Oregon also supports populations of susceptible T. tubifex. If the pathogen were introduced, probability of establishment is high in certain areas of the basin as all conditions are appropriate for propagation of the parasite life cycle. Tributaries to the mainstem Willamette River have the highest probability of establishment as these areas have the greatest numbers of susceptible T. tubifex. However, the abundance of resistant strains of T. tubifex could mitigate the effects of M. cerebralis if introduced. Management recommendations to reduce the likelihood of parasite dissemination are similar for Oregon and Alaska since human movement of fish and angler activities were considered the most likely routes of introduction for both regions. Based on this research, steps should also be taken to limit human movement of fish, whether by restricting carcass planting for stream enrichment in Oregon, or by prohibiting use of fish heads as bait in southcentral Alaska. The states should also allot resources to angler education and awareness of the effects of angler activity and recreation on dispersal of M. cerebralis. This could be done using a combination of brochures and signage at boat ramps describing how to prevent spread of aquatic nuisance species. Close

• 57. [Article] Distribution and characteristics of an isolated population of coastal cutthroat trout (Oncorhynchus clarki) in streams of Triangle Lake Basin, Oregon

  This research focused on features of a genetically isolated population of cutthroat trout (Oncorhynchus clarki) in the Triangle Lake basin of coastal Oregon. A falls at the outlet of Triangle Lake has ...

  Citation × Citation Citation Abstract Copy Title: Distribution and characteristics of an isolated population of coastal cutthroat trout (Oncorhynchus clarki) in streams of Triangle Lake Basin, Oregon Author: Hurley, Steven M. This research focused on features of a genetically isolated population of cutthroat trout (Oncorhynchus clarki) in the Triangle Lake basin of coastal Oregon. A falls at the outlet of Triangle Lake has blocked upstream migration of trout and anadromous salmonids into the basin. Cutthroat trout were found throughout the six study streams of the Triangle Lake basin in association with other native fishes and introduced warmwater fishes. Warmwater species (e.g. Centrarchidae) were restricted largely to the lakes of Triangle Lake basin, and did not comprise a significant part of the stream fish fauna. Salmonids and cottids dominated the upper forested reaches of the basin, whereas nonsalmonids dominated the lower reaches. The middle reaches contained a transitional fish community between the upper and lower reaches. Reach type was a major factor influencing cutthroat trout density and size distribution. Areal densities of cutthroat trout were highest in the upper reaches and lowest in the lower reaches with the exception of 0+ cutthroat trout, which occurred at similar densities in all reaches. The highest frequency of 1+ cutthroat trout occurred in the middle reaches, whereas the highest frequency of 0+ cutthroat occurred in the lower reaches. Within reaches, channel unit type influenced the density and age structure of cutthroat trout. Pools and rapids had the highest densities of cutthroat trout, whereas riffles, glides, and cascades had lower densities. Larger trout were found primarily in pools and rapids. Planted steelhead fry (Oncorhynchus mykiss) were found in two streams, Congdon Creek and Lake Creek. Although most steelhead fry leave the basin as smolts, some steelhead appear to become resident and may hybridize with native cutthroat trout. Cutthroat trout spawning was observed from late December 1987 through late May 1988. Differences in the time and place of spawning may serve to genetically isolate two populations of cutthroat trout in Triangle Lake basin. One population may be lake dwelling as adults and spawn lower in the basin in late spring. The other population may be stream dwelling and spawn in the winter during higher flows, which allows them to spawn in the upper reaches of the basin. Title: Distribution and characteristics of an isolated population of coastal cutthroat trout (Oncorhynchus clarki) in streams of Triangle Lake Basin, Oregon Author: Hurley, Steven M. This research focused on features of a genetically isolated population of cutthroat trout (Oncorhynchus clarki) in the Triangle Lake basin of coastal Oregon. A falls at the outlet of Triangle Lake has blocked upstream migration of trout and anadromous salmonids into the basin. Cutthroat trout were found throughout the six study streams of the Triangle Lake basin in association with other native fishes and introduced warmwater fishes. Warmwater species (e.g. Centrarchidae) were restricted largely to the lakes of Triangle Lake basin, and did not comprise a significant part of the stream fish fauna. Salmonids and cottids dominated the upper forested reaches of the basin, whereas nonsalmonids dominated the lower reaches. The middle reaches contained a transitional fish community between the upper and lower reaches. Reach type was a major factor influencing cutthroat trout density and size distribution. Areal densities of cutthroat trout were highest in the upper reaches and lowest in the lower reaches with the exception of 0+ cutthroat trout, which occurred at similar densities in all reaches. The highest frequency of 1+ cutthroat trout occurred in the middle reaches, whereas the highest frequency of 0+ cutthroat occurred in the lower reaches. Within reaches, channel unit type influenced the density and age structure of cutthroat trout. Pools and rapids had the highest densities of cutthroat trout, whereas riffles, glides, and cascades had lower densities. Larger trout were found primarily in pools and rapids. Planted steelhead fry (Oncorhynchus mykiss) were found in two streams, Congdon Creek and Lake Creek. Although most steelhead fry leave the basin as smolts, some steelhead appear to become resident and may hybridize with native cutthroat trout. Cutthroat trout spawning was observed from late December 1987 through late May 1988. Differences in the time and place of spawning may serve to genetically isolate two populations of cutthroat trout in Triangle Lake basin. One population may be lake dwelling as adults and spawn lower in the basin in late spring. The other population may be stream dwelling and spawn in the winter during higher flows, which allows them to spawn in the upper reaches of the basin. Close

• 58. [Article] Bull Trout (Salvelinus confluentus) population and habitat surveys in the McKenzie and Middle Fork Willamette Basins, 2000

  DOE/BP-00004093-1

  Citation × Citation Citation Abstract Copy Title: Bull Trout (Salvelinus confluentus) population and habitat surveys in the McKenzie and Middle Fork Willamette Basins, 2000 Author: Taylor, Greg DOE/BP-00004093-1 Title: Bull Trout (Salvelinus confluentus) population and habitat surveys in the McKenzie and Middle Fork Willamette Basins, 2000 Author: Taylor, Greg DOE/BP-00004093-1 Close

• 59. [Article] Breeding and foraging ecology of Caspian terns nesting on artificial islands in the Upper Klamath Basin, California

  Availability of suitable nesting habitat that is free of nest predators and provides access to adequate prey resources within commuting distance is a major factor limiting seabird populations. Caspian ...

  Citation × Citation Citation Abstract Copy Title: Breeding and foraging ecology of Caspian terns nesting on artificial islands in the Upper Klamath Basin, California Author: Patterson, Allison (Allison Glider) Availability of suitable nesting habitat that is free of nest predators and provides access to adequate prey resources within commuting distance is a major factor limiting seabird populations. Caspian terns (Hydroprogne caspia) in western North America have shifted their breeding habitat from naturally occurring habitats in interior wetlands, lakes, and rivers to primarily human-created habitats in coastal bays and estuaries. This shift has brought Caspian terns into conflict with fisheries of conservation concern, in particular anadromous salmonids. Prior to the 2010 breeding season, three artificial islands were built in the Klamath Basin National Wildlife Refuge (NWR) Complex as alternative nesting habitat for Caspian terns currently nesting at the world's largest colony for the species, near the mouth of the Columbia River, Oregon. I investigated the efficacy of habitat creation (island building) and social attraction (decoys and recorded vocalizations) for establishing new breeding colonies in the Upper Klamath Basin, California. In 2010, approximately 258 pairs of Caspian terns attempted to nest on the new islands and raised an average of 0.65 fledglings/breeding pair; in 2011, 222 pairs attempted to nest and raised an average of 0.11 fledglings/breeding pair. Competition with California and ring-billed gulls (Larus californicus and L. delawarensis) for nesting space, gull predation on Caspian tern eggs and chicks, low water levels, and depredation by great horned owls (Bubo virginianus) were the primary factors limiting colony development and productivity, especially in 2011. The immediate response by Caspian terns to habitat creation and social attraction in the Upper Klamath Basin demonstrates that these can be effective restoration techniques to establish new breeding colonies where nesting habitat is a major limiting factor; however, continued management of other limiting factors (e.g., control of on-colony predators and competitors) will likely be necessary to promote the development of established, self-sustaining breeding colonies on these artificial islands. Efforts to conserve and restore seabird colonies can be compromised by low prey availability within foraging distance of the breeding colony. I used GPS telemetry to study the fine-scale foraging behavior of Caspian terns nesting at two newly established colonies and cluster analysis to discriminate behavioral states based on movement characteristics. Terns breeding at the Sheepy Lake colony spent less time at the colony (52% of the day) than terns breeding at the Tule Lake colony (74%). Caspian terns breeding at Sheepy Lake foraged more extensively than terns breeding at Tule Lake; the foraging trips of Sheepy Lake terns lasted longer (median = 186 min) and were longer-distance (27 km) compared to those of Tule Lake terns (55 min and 6 km, respectively). Between-colony differences in foraging behavior corresponded to 5% lower average body mass of breeding adults and significantly lower size-adjusted body mass of chicks at the Sheepy Lake colony compared to the Tule Lake colony. Proximity to high-quality foraging areas influenced the foraging behavior and parental care of breeding Caspian terns, which in turn had effects on nesting success. The successful use of GPS telemetry to study the fine-scale foraging behavior of Caspian terns represents a significant advance in our ability to investigate the foraging ecology of this species and other moderate-sized seabirds. Title: Breeding and foraging ecology of Caspian terns nesting on artificial islands in the Upper Klamath Basin, California Author: Patterson, Allison (Allison Glider) Availability of suitable nesting habitat that is free of nest predators and provides access to adequate prey resources within commuting distance is a major factor limiting seabird populations. Caspian terns (Hydroprogne caspia) in western North America have shifted their breeding habitat from naturally occurring habitats in interior wetlands, lakes, and rivers to primarily human-created habitats in coastal bays and estuaries. This shift has brought Caspian terns into conflict with fisheries of conservation concern, in particular anadromous salmonids. Prior to the 2010 breeding season, three artificial islands were built in the Klamath Basin National Wildlife Refuge (NWR) Complex as alternative nesting habitat for Caspian terns currently nesting at the world's largest colony for the species, near the mouth of the Columbia River, Oregon. I investigated the efficacy of habitat creation (island building) and social attraction (decoys and recorded vocalizations) for establishing new breeding colonies in the Upper Klamath Basin, California. In 2010, approximately 258 pairs of Caspian terns attempted to nest on the new islands and raised an average of 0.65 fledglings/breeding pair; in 2011, 222 pairs attempted to nest and raised an average of 0.11 fledglings/breeding pair. Competition with California and ring-billed gulls (Larus californicus and L. delawarensis) for nesting space, gull predation on Caspian tern eggs and chicks, low water levels, and depredation by great horned owls (Bubo virginianus) were the primary factors limiting colony development and productivity, especially in 2011. The immediate response by Caspian terns to habitat creation and social attraction in the Upper Klamath Basin demonstrates that these can be effective restoration techniques to establish new breeding colonies where nesting habitat is a major limiting factor; however, continued management of other limiting factors (e.g., control of on-colony predators and competitors) will likely be necessary to promote the development of established, self-sustaining breeding colonies on these artificial islands. Efforts to conserve and restore seabird colonies can be compromised by low prey availability within foraging distance of the breeding colony. I used GPS telemetry to study the fine-scale foraging behavior of Caspian terns nesting at two newly established colonies and cluster analysis to discriminate behavioral states based on movement characteristics. Terns breeding at the Sheepy Lake colony spent less time at the colony (52% of the day) than terns breeding at the Tule Lake colony (74%). Caspian terns breeding at Sheepy Lake foraged more extensively than terns breeding at Tule Lake; the foraging trips of Sheepy Lake terns lasted longer (median = 186 min) and were longer-distance (27 km) compared to those of Tule Lake terns (55 min and 6 km, respectively). Between-colony differences in foraging behavior corresponded to 5% lower average body mass of breeding adults and significantly lower size-adjusted body mass of chicks at the Sheepy Lake colony compared to the Tule Lake colony. Proximity to high-quality foraging areas influenced the foraging behavior and parental care of breeding Caspian terns, which in turn had effects on nesting success. The successful use of GPS telemetry to study the fine-scale foraging behavior of Caspian terns represents a significant advance in our ability to investigate the foraging ecology of this species and other moderate-sized seabirds. Close