Search

Search Results

• 1. [Image] Investigation of Two Areas in New York State which may have Potential for Geothermal Energy. Progress Report, May 1, 1976--September 31, 1976

  	Significant results to date include the following: (1) the present Adirondack Mountains Dome is undergoing rapid contemporary vertical doming; the velocity at the center of the dome is 3.7mm/yr, compared ...
  	Citation × Citation Citation Abstract Copy Title: Investigation of Two Areas in New York State which may have Potential for Geothermal Energy. Progress Report, May 1, 1976--September 31, 1976 Author: Isachsen, Y.W. Year: 1976 Significant results to date include the following: (1) the present Adirondack Mountains Dome is undergoing rapid contemporary vertical doming; the velocity at the center of the dome is 3.7mm/yr, compared to 1mm/yr for the Swiss Alps; (2) post-Pleistocene fault offsets measuring from one to eleven millimeters have been found in the Adirondacks, indicating vertical uplift during the past 10,000 years; (3) the Panther Mountain Circular drainage feature is structurally-controlled and shows a 10 to 20 milligal negative Simple Bouguer gravity anomaly such as might be produced by a buried felsic pluton Title: Investigation of Two Areas in New York State which may have Potential for Geothermal Energy. Progress Report, May 1, 1976--September 31, 1976 Author: Isachsen, Y.W. Year: 1976 Significant results to date include the following: (1) the present Adirondack Mountains Dome is undergoing rapid contemporary vertical doming; the velocity at the center of the dome is 3.7mm/yr, compared to 1mm/yr for the Swiss Alps; (2) post-Pleistocene fault offsets measuring from one to eleven millimeters have been found in the Adirondacks, indicating vertical uplift during the past 10,000 years; (3) the Panther Mountain Circular drainage feature is structurally-controlled and shows a 10 to 20 milligal negative Simple Bouguer gravity anomaly such as might be produced by a buried felsic pluton Close

• 2. [Image] Stratigraphy and Alteration, 15 Shallow Thermal Gradient Holes, Roosevelt Hot Springs KGRA and Vicinity, Millard and Beaver Counties, Utah

  	Fifteen shallow thermal gradient drill holes were recently completed by Geothermal Power Corporation (GPCR) in the vicinity of the Roosevelt Hot Springs KGRA. Five holes penetrated Tertiary granitic rocks ...
  	Citation × Citation Citation Abstract Copy Title: Stratigraphy and Alteration, 15 Shallow Thermal Gradient Holes, Roosevelt Hot Springs KGRA and Vicinity, Millard and Beaver Counties, Utah Author: Hulen, J.B. Year: 1978 Fifteen shallow thermal gradient drill holes were recently completed by Geothermal Power Corporation (GPCR) in the vicinity of the Roosevelt Hot Springs KGRA. Five holes penetrated Tertiary granitic rocks and Precambrian gneiss east of the KGRA. Seven holes completed entirely in alluvium near the southwestern corner of the KGRA encountered a near-surface marker horizon of Pleistocene pumice and perlite. Maximum calculated alluvial sedimentation rates since initial deposition of this pumice and perlite range from 1 foot in 12,500 years to 1 foot in 2,300 years. Three holes east of the Mineral Mountains penetrated late Cenozoic basaltic andesite beneath a thin veneer of alluvium. All 15 GPCR drill holes appear to be peripheral to a central zone of anomalously high thermal gradient and low resisitivity delineated by previous investigations. GPCR-8 and -14, however, are characterized by high heat flow and relatively abundant manganese oxide mineralization, which may reflect a favorable hydrologic system controlling thermal fluid flow at depth. These holes thus seem most encouraging for discovery of a deeper high-temperature geothermal resource Title: Stratigraphy and Alteration, 15 Shallow Thermal Gradient Holes, Roosevelt Hot Springs KGRA and Vicinity, Millard and Beaver Counties, Utah Author: Hulen, J.B. Year: 1978 Fifteen shallow thermal gradient drill holes were recently completed by Geothermal Power Corporation (GPCR) in the vicinity of the Roosevelt Hot Springs KGRA. Five holes penetrated Tertiary granitic rocks and Precambrian gneiss east of the KGRA. Seven holes completed entirely in alluvium near the southwestern corner of the KGRA encountered a near-surface marker horizon of Pleistocene pumice and perlite. Maximum calculated alluvial sedimentation rates since initial deposition of this pumice and perlite range from 1 foot in 12,500 years to 1 foot in 2,300 years. Three holes east of the Mineral Mountains penetrated late Cenozoic basaltic andesite beneath a thin veneer of alluvium. All 15 GPCR drill holes appear to be peripheral to a central zone of anomalously high thermal gradient and low resisitivity delineated by previous investigations. GPCR-8 and -14, however, are characterized by high heat flow and relatively abundant manganese oxide mineralization, which may reflect a favorable hydrologic system controlling thermal fluid flow at depth. These holes thus seem most encouraging for discovery of a deeper high-temperature geothermal resource Close

• 3. [Image] A new model for the formation of Crater Lake Caldera, Oregon

  	ill. (some col.), maps ; Thesis (Ph. D.)--Oregon State University, 1972; Includes bibliographical references
  	Citation × Citation Citation Abstract Copy Title: A new model for the formation of Crater Lake Caldera, Oregon Author: Lidstrom, John Walter Year: 1972, 2008 ill. (some col.), maps ; Thesis (Ph. D.)--Oregon State University, 1972; Includes bibliographical references Title: A new model for the formation of Crater Lake Caldera, Oregon Author: Lidstrom, John Walter Year: 1972, 2008 ill. (some col.), maps ; Thesis (Ph. D.)--Oregon State University, 1972; Includes bibliographical references Close

• 4. [Image] The 1980-1982 Geothermal Resource Assessment Program in Washington

  	Since 1978, the Division of Geology and Earth Resources of the Washington Department of Natural Resources has participated in the U.S. Department of Energy's (USDOE) StateCoupled Geothermal Resource Program. ...
  	Citation × Citation Citation Abstract Copy Title: The 1980-1982 Geothermal Resource Assessment Program in Washington Author: Korosec, M. A. Year: 1983 Since 1978, the Division of Geology and Earth Resources of the Washington Department of Natural Resources has participated in the U.S. Department of Energy's (USDOE) StateCoupled Geothermal Resource Program. Federal and state funds have been used to investigate and evaluate the potential for geothermal resources, on both a reconnaissance and area-specific level. Preliminary results and progress reports for the period up through mid-1980 have already been released as a Division Open File Report (Korosec, Schuster, and others, 1981). Preliminary results and progress summaries of work carried out from mid-1980 through the end of 1982 are presented in this report Title: The 1980-1982 Geothermal Resource Assessment Program in Washington Author: Korosec, M. A. Year: 1983 Since 1978, the Division of Geology and Earth Resources of the Washington Department of Natural Resources has participated in the U.S. Department of Energy's (USDOE) StateCoupled Geothermal Resource Program. Federal and state funds have been used to investigate and evaluate the potential for geothermal resources, on both a reconnaissance and area-specific level. Preliminary results and progress reports for the period up through mid-1980 have already been released as a Division Open File Report (Korosec, Schuster, and others, 1981). Preliminary results and progress summaries of work carried out from mid-1980 through the end of 1982 are presented in this report Close

• 5. [Image] Petrographic Analysis and Correlation of Volcanic Rocks in Bostic 1-A Well near Mountain Home, Idaho

  	Detailed examination of volcanic rock cuttings from the Bostic I-A well near Mountain Home, Idaho, provides data that correlate the stratigraphy of the well with the regional stratigraphy of the western ...
  	Citation × Citation Citation Abstract Copy Title: Petrographic Analysis and Correlation of Volcanic Rocks in Bostic 1-A Well near Mountain Home, Idaho Author: Arney, B. H. Year: 1984 Detailed examination of volcanic rock cuttings from the Bostic I-A well near Mountain Home, Idaho, provides data that correlate the stratigraphy of the well with the regional stratigraphy of the western Snake River Plain. The Bostic I-A well penetrates basalt of the Middle Pleistocene Bruneau Formation and underlying sedimentary rocks of the Upper Pliocene Glenns Ferry Formation. Basalt underlying the Glenns Ferry Formation is most likely Banbury Basalt of Middle Pliocene age or Banbury equivalent. A 350-ft interval of felsic volcanics is then intersected above another 600 ft of basalt. The well bottoms in altered felsic volcanics Title: Petrographic Analysis and Correlation of Volcanic Rocks in Bostic 1-A Well near Mountain Home, Idaho Author: Arney, B. H. Year: 1984 Detailed examination of volcanic rock cuttings from the Bostic I-A well near Mountain Home, Idaho, provides data that correlate the stratigraphy of the well with the regional stratigraphy of the western Snake River Plain. The Bostic I-A well penetrates basalt of the Middle Pleistocene Bruneau Formation and underlying sedimentary rocks of the Upper Pliocene Glenns Ferry Formation. Basalt underlying the Glenns Ferry Formation is most likely Banbury Basalt of Middle Pliocene age or Banbury equivalent. A 350-ft interval of felsic volcanics is then intersected above another 600 ft of basalt. The well bottoms in altered felsic volcanics Close

• 6. [Image] Seeking refuge: making space for migratory waterfowl and wetlands along the Pacific Flyway

  	Abstract "Seeking Refuge" examines the history of migratory waterfowl management along the Pacific Flyway, the westernmost of four main migration routes in North America. Drawing on approaches from historical ...
  	Citation × Citation Citation Abstract Copy Title: Seeking refuge: making space for migratory waterfowl and wetlands along the Pacific Flyway Author: Wilson, Robert Michael Year: 2003, 2005, 2004 Abstract "Seeking Refuge" examines the history of migratory waterfowl management along the Pacific Flyway, the westernmost of four main migration routes in North America. Drawing on approaches from historical geography and environmental history, this study shows how wildlife officials developed migratory bird refuges in Oregon and California, where over 60 percent of Pacific Flyway waterfowl winter. During the early-twentieth century, reclamation and river diking eliminated most of the wetlands in the birds' wintering range. Bird enthusiasts such as bird watchers and duck hunters successfully lobbied for the creation of wildlife refuges in a few areas along the flyway. These early refuges failed to protect waterfowl habitat and they were severely degraded by reclamation. In the 1930s and 1940s, the U.S. Fish and Wildlife Service (FWS) and its predecessor, the Bureau of Biological Survey, undertook an ambitious program to resurrect these sanctuaries and to create new ones. Many farmers opposed these refuges out of fear that waterfowl would damage crops. To respond to these concerns and to ensure an adequate food supply for the birds, the FWS raised rice, barley, and other grains. The agency adopted many of the technologies of modern, industrial agriculture including synthetic herbicides and insecticides such as 2, 4-D and DDT. By the 1960s, the refuges had become largely mirrors of the surrounding irrigated farmlands, the main difference being that the FWS raised grain for waterfowl rather than for market. Refuges could not escape the agricultural settings in which they were embedded. As units within the irrigated countryside, Pacific Flyway refuges were often at the mercy of nearby farmers and federal reclamation agencies. Poor water quality and insufficient supplies of water often hampered FWS efforts to manage refuges. In the late-twentieth century, reduced water supply due to diversions to California municipalities and to sustain endangered fish species affected the amount of water reaching refuges. This dissertation has other goals. First, it critiques the anthropocentrism of most historical geography by focusing on how political, cultural, and ecological factors affected wildlife. Second, it contributes to the literature on the state's role in environmental protection by investigating the overlapping, and often contradictory, spaces within which wildlife managers implemented environmental regulations. Title: Seeking refuge: making space for migratory waterfowl and wetlands along the Pacific Flyway Author: Wilson, Robert Michael Year: 2003, 2005, 2004 Abstract "Seeking Refuge" examines the history of migratory waterfowl management along the Pacific Flyway, the westernmost of four main migration routes in North America. Drawing on approaches from historical geography and environmental history, this study shows how wildlife officials developed migratory bird refuges in Oregon and California, where over 60 percent of Pacific Flyway waterfowl winter. During the early-twentieth century, reclamation and river diking eliminated most of the wetlands in the birds' wintering range. Bird enthusiasts such as bird watchers and duck hunters successfully lobbied for the creation of wildlife refuges in a few areas along the flyway. These early refuges failed to protect waterfowl habitat and they were severely degraded by reclamation. In the 1930s and 1940s, the U.S. Fish and Wildlife Service (FWS) and its predecessor, the Bureau of Biological Survey, undertook an ambitious program to resurrect these sanctuaries and to create new ones. Many farmers opposed these refuges out of fear that waterfowl would damage crops. To respond to these concerns and to ensure an adequate food supply for the birds, the FWS raised rice, barley, and other grains. The agency adopted many of the technologies of modern, industrial agriculture including synthetic herbicides and insecticides such as 2, 4-D and DDT. By the 1960s, the refuges had become largely mirrors of the surrounding irrigated farmlands, the main difference being that the FWS raised grain for waterfowl rather than for market. Refuges could not escape the agricultural settings in which they were embedded. As units within the irrigated countryside, Pacific Flyway refuges were often at the mercy of nearby farmers and federal reclamation agencies. Poor water quality and insufficient supplies of water often hampered FWS efforts to manage refuges. In the late-twentieth century, reduced water supply due to diversions to California municipalities and to sustain endangered fish species affected the amount of water reaching refuges. This dissertation has other goals. First, it critiques the anthropocentrism of most historical geography by focusing on how political, cultural, and ecological factors affected wildlife. Second, it contributes to the literature on the state's role in environmental protection by investigating the overlapping, and often contradictory, spaces within which wildlife managers implemented environmental regulations. Close

• 7. [Image] Programmatic environmental assessment for Klamath Basin Ecosystem Restoration Office Projects, 2000-2010

  	Programmatic Environmental Assessment Summary This Environmental Assessment (EA) provides compliance with the National Environmental Policy Act (NEPA) for restoration actions undertaken by the US Fish ...
  	Citation × Citation Citation Abstract Copy Title: Programmatic environmental assessment for Klamath Basin Ecosystem Restoration Office Projects, 2000-2010 Author: U.S. Fish and Wildlife Service. Klamath Basin Ecosystem Restoration Office. Year: 2000, 2005, 2004 Programmatic Environmental Assessment Summary This Environmental Assessment (EA) provides compliance with the National Environmental Policy Act (NEPA) for restoration actions undertaken by the US Fish & Wildlife Service's Klamath Basin Ecosystem Restoration Office (ERO) in Klamath Falls, Oregon. These restoration activities are needed due to the large-scale loss of wetland and riparian habitat and degraded water quality. The purpose of these restoration efforts is the improvement of conditions of the watershed with specific regard to habitat and water quality, resulting in, among other benefits, improved conditions for the endangered fish species (bull trout and Lost River and shortnose sucker) populations of the basin. The geographic scope of this EA is defined as the upper Klamath River basin, including the entire watershed from Irongate Dam upstream to the headwaters. This EA is intended to provide NEPA compliance for restoration projects conducted between the years 2000 and 2010. The ERO was established in 1993 to sponsor and assist with a variety of restoration activities in the Klamath Basin. The ERO funds and provides technical assistance to restoration projects involving private landholders, concerned groups, and other state, federal, and tribal agencies. Four alternatives are presented in this EA. The proposed alternative (Alternative 1) consists of a comprehensive program of ecosystem restoration, promoting projects in both riparian areas and in upland habitats. This would continue the current program in effect since 1994. NEPA compliance would primarily be carried out via a single, programmatic document saving time and funds. The Fish & Wildlife Service proposes to fund and administer the following projects types: Riparian Projects: (fencing for livestock management; native plant establishment & diversification; non-native plant removal/control; erosion control; contour re-establishment; impoundment removal; wildlife habitat improvements) Wetland Projects: (fencing; wetland restoration and enhancement; wildlife habitat improvements) Upland or Road Projects: (road abandonment, decommissioning, & obliteration; road drainage improvements and storm proofing, re-establishment of historic contours; silvicultural treatments; native plant establishment/diversification; non-native plant removal/control; fencing; landslide treatments; culvert/stream crossing upgrades; erosion control; wildlife habitat improvements). In-stream Projects: (habitat complexity and diversity improvements; hydrologic regime improvements; coarse woody debris supplementation; natural or artificial barrier removal, modification &/or creation; fish screens installation). Alternative 2 would concentrate restoration efforts only on riparian, instream, and wetland areas. Road projects would be conducted only within the riparian corridor, as defined. NEPA compliance would also be conducted programmatically. Alternative 3 would cease all restoration activities conducted and funded by the ERO in the Klamath Basin. This alternative would serve as a benchmark against which the effects of the restoration alternatives discussed above can be compared. Alternative 4, the "No Action" alternative, would continue current management policies with regard to NEPA compliance, providing compliance on a project by project basis requiring independent analysis for each project. The affected environment of the region is described in detail. The environment has been changed significantly since the 1890's due to logging, agriculture and urban development. An extensive system of dams, canals, and drainage structures has resulted in the conversion of approximately 80% of pre-settlement wetlands to agricultural uses. Riparian corridors have been similarly impacted, and upland forests regions have been affected by logging, road construction and other factors. These changes have contributed to problems with the water quality in the region, contributing to the listing of several fish species as threatened or endangered; loss of habitat has affected a large number of other species as well. The environmental effects of each alternative is analyzed. Some short term negative impacts could occur as a result of the projects authorized by both Alternative 1 and Alternative 2, but these would be strongly offset by the expected beneficial results to water quality and habitat conditions. Alternative 1 would be expected to have a greater overall effect on the environment than Alternative 2, since many of the underlying factors with which restoration efforts are concerned originate in upland conditions (i.e. sedimentation and hydrologic functionality). Alternative 3 would result in conditions remaining much as they are currently, although other programs and organizations are making efforts at restoration activities. The environmental impacts of individual projects anticipated under Alternative 4 would be generally the same as for similar projects under Alternative 1. The primary difference between the two alternatives would be the higher efficiency and improved cumulative analysis resulting from a programmatic approach as proposed in Alternative 1. Public participation in the NEPA process has been, and will continue to be, solicited and welcomed. Compliance with state and federal laws and regulations such as the Clean Water Act, National Historic Preservation Act, and the Endangered Species Act, as well as guidelines for contaminant surveys, will be carried out as detailed. While these projects are expected to play an important role in the restoration of the region, none of these alternatives are expected to have a significant impact when compared with the loss of wetland, riparian and upland habitats over the past century, impacts which do occur would be of a cumulatively beneficial nature. Other restoration efforts are being carried out in the area by other governmental and private groups, and it is expected that these combined efforts will achieve important beneficial results for the ecosystem. Title: Programmatic environmental assessment for Klamath Basin Ecosystem Restoration Office Projects, 2000-2010 Author: U.S. Fish and Wildlife Service. Klamath Basin Ecosystem Restoration Office. Year: 2000, 2005, 2004 Programmatic Environmental Assessment Summary This Environmental Assessment (EA) provides compliance with the National Environmental Policy Act (NEPA) for restoration actions undertaken by the US Fish & Wildlife Service's Klamath Basin Ecosystem Restoration Office (ERO) in Klamath Falls, Oregon. These restoration activities are needed due to the large-scale loss of wetland and riparian habitat and degraded water quality. The purpose of these restoration efforts is the improvement of conditions of the watershed with specific regard to habitat and water quality, resulting in, among other benefits, improved conditions for the endangered fish species (bull trout and Lost River and shortnose sucker) populations of the basin. The geographic scope of this EA is defined as the upper Klamath River basin, including the entire watershed from Irongate Dam upstream to the headwaters. This EA is intended to provide NEPA compliance for restoration projects conducted between the years 2000 and 2010. The ERO was established in 1993 to sponsor and assist with a variety of restoration activities in the Klamath Basin. The ERO funds and provides technical assistance to restoration projects involving private landholders, concerned groups, and other state, federal, and tribal agencies. Four alternatives are presented in this EA. The proposed alternative (Alternative 1) consists of a comprehensive program of ecosystem restoration, promoting projects in both riparian areas and in upland habitats. This would continue the current program in effect since 1994. NEPA compliance would primarily be carried out via a single, programmatic document saving time and funds. The Fish & Wildlife Service proposes to fund and administer the following projects types: Riparian Projects: (fencing for livestock management; native plant establishment & diversification; non-native plant removal/control; erosion control; contour re-establishment; impoundment removal; wildlife habitat improvements) Wetland Projects: (fencing; wetland restoration and enhancement; wildlife habitat improvements) Upland or Road Projects: (road abandonment, decommissioning, & obliteration; road drainage improvements and storm proofing, re-establishment of historic contours; silvicultural treatments; native plant establishment/diversification; non-native plant removal/control; fencing; landslide treatments; culvert/stream crossing upgrades; erosion control; wildlife habitat improvements). In-stream Projects: (habitat complexity and diversity improvements; hydrologic regime improvements; coarse woody debris supplementation; natural or artificial barrier removal, modification &/or creation; fish screens installation). Alternative 2 would concentrate restoration efforts only on riparian, instream, and wetland areas. Road projects would be conducted only within the riparian corridor, as defined. NEPA compliance would also be conducted programmatically. Alternative 3 would cease all restoration activities conducted and funded by the ERO in the Klamath Basin. This alternative would serve as a benchmark against which the effects of the restoration alternatives discussed above can be compared. Alternative 4, the "No Action" alternative, would continue current management policies with regard to NEPA compliance, providing compliance on a project by project basis requiring independent analysis for each project. The affected environment of the region is described in detail. The environment has been changed significantly since the 1890's due to logging, agriculture and urban development. An extensive system of dams, canals, and drainage structures has resulted in the conversion of approximately 80% of pre-settlement wetlands to agricultural uses. Riparian corridors have been similarly impacted, and upland forests regions have been affected by logging, road construction and other factors. These changes have contributed to problems with the water quality in the region, contributing to the listing of several fish species as threatened or endangered; loss of habitat has affected a large number of other species as well. The environmental effects of each alternative is analyzed. Some short term negative impacts could occur as a result of the projects authorized by both Alternative 1 and Alternative 2, but these would be strongly offset by the expected beneficial results to water quality and habitat conditions. Alternative 1 would be expected to have a greater overall effect on the environment than Alternative 2, since many of the underlying factors with which restoration efforts are concerned originate in upland conditions (i.e. sedimentation and hydrologic functionality). Alternative 3 would result in conditions remaining much as they are currently, although other programs and organizations are making efforts at restoration activities. The environmental impacts of individual projects anticipated under Alternative 4 would be generally the same as for similar projects under Alternative 1. The primary difference between the two alternatives would be the higher efficiency and improved cumulative analysis resulting from a programmatic approach as proposed in Alternative 1. Public participation in the NEPA process has been, and will continue to be, solicited and welcomed. Compliance with state and federal laws and regulations such as the Clean Water Act, National Historic Preservation Act, and the Endangered Species Act, as well as guidelines for contaminant surveys, will be carried out as detailed. While these projects are expected to play an important role in the restoration of the region, none of these alternatives are expected to have a significant impact when compared with the loss of wetland, riparian and upland habitats over the past century, impacts which do occur would be of a cumulatively beneficial nature. Other restoration efforts are being carried out in the area by other governmental and private groups, and it is expected that these combined efforts will achieve important beneficial results for the ecosystem. Close

• 8. [Image] Draft upper Williamson River Watershed assessment

  	"Prepared for Klamath Basin Ecosystem Foundation, and the Upper Williamson River Catchment Group, in cooperation with the Upper Klamath Basin Working Group, and the Klamath Watershed Council."
  	Citation × Citation Citation Abstract Copy Title: Draft upper Williamson River Watershed assessment Author: David Evans and Associates, Inc. Year: 2004, 2005 "Prepared for Klamath Basin Ecosystem Foundation, and the Upper Williamson River Catchment Group, in cooperation with the Upper Klamath Basin Working Group, and the Klamath Watershed Council." Title: Draft upper Williamson River Watershed assessment Author: David Evans and Associates, Inc. Year: 2004, 2005 "Prepared for Klamath Basin Ecosystem Foundation, and the Upper Williamson River Catchment Group, in cooperation with the Upper Klamath Basin Working Group, and the Klamath Watershed Council." Close

• 9. [Image] Ground water hydrology of four proposed project areas in the Klamath Basin, Oregon

  	"OF-01-01"
  	Citation × Citation Citation Abstract Copy Title: Ground water hydrology of four proposed project areas in the Klamath Basin, Oregon Author: Oregon. Water Resources Dept Year: 2001, 2005 "OF-01-01" Title: Ground water hydrology of four proposed project areas in the Klamath Basin, Oregon Author: Oregon. Water Resources Dept Year: 2001, 2005 "OF-01-01" Close

• 10. [Image] Distribution and biology of suckers in Lower Klamath reservoirs : 1999 final report

  	Abstract The objectives of this two-year study (1998-1999) were to document distribution, abundance, age class structure, recruitment success, and habitat use by all life history stages of shortnose and ...
  	Citation × Citation Citation Abstract Copy Title: Distribution and biology of suckers in Lower Klamath reservoirs : 1999 final report Author: Desjardins, Marc; Markle, Douglas F. Year: 2000, 2005 Abstract The objectives of this two-year study (1998-1999) were to document distribution, abundance, age class structure, recruitment success, and habitat use by all life history stages of shortnose and Lost River suckers in three lower Klamath River hydroelectric reservoirs (J. C. Boyle, Copco, and Iron Gate). Lost River sucker catches were sporadic (only 3 adult individuals total) and the focus of our analyses, therefore, shifted to shortnose suckers. Adult and larval suckers were found in all reservoirs both years. All life history stages (larvae, juveniles and adults) were found in J. C. Boyle during both years and in Copco in 1999. Juvenile suckers were not found in Copco in 1998. The number of adult shortnose suckers was highest in Copco reservoir (n=165), followed by J.C. Boyle (n=50) and Iron Gate (n=22). Larger and older individuals dominated Copco and Iron Gate reservoirs and little size structure was detected. J. C. Boyle tended to have smaller adult shortnose suckers and many size classes were present. Unidentifiable larval suckers were most abundant in Copco reservoir where historic spawning of shortnose suckers has been documented. Larval suckers in Copco and Iron Gate reservoirs were most abundant in mid to late June before quickly disappearing from catches. J. C. Boyle larval suckers peaked in mid July, attained larger sizes, and were caught later in the season. It appeared that recruitment of young-of-the-year suckers only occurred in J. C. Boyle with downstream reservoirs recruiting older individuals, perhaps those that had earlier recruited to J. C. Boyle. Tagging studies could clarify adult recruitment dynamics and an additional study of juvenile recruitment would be needed to confirm these patterns. Predation pressure may be somewhat reduced in J. C. Boyle in comparison to the other reservoirs as its fish community was dominated by native fishes while communities in Copco and Iron Gate reservoirs were dominated by exotic predators. J. C. Boyle also possessed proportionally more littoral habitat, which suggests it may provide a more stable environment for young fishes. However, our sampling was inadequate to demonstrate such relationships due to high variance in larval and juvenile catches and potentially confounding habitat variables. One such variable was water level fluctuations, which could interact with habitat and resource availability in complex ways. For example, water level fluctuations, presumed to have a negative impact, were greatest in J. C. Boyle. Extrapolation from the literature suggests it should have had the poorest habitat for larval and juvenile suckers, but our results indicated J. C. Boyle had the most young suckers. Additional study of the relationships between water level fluctuations, habitat availability, the exotic fish community, and juvenile sucker recruitment would be needed to better understand early life history ecology of endangered lake suckers in these systems. Title: Distribution and biology of suckers in Lower Klamath reservoirs : 1999 final report Author: Desjardins, Marc; Markle, Douglas F. Year: 2000, 2005 Abstract The objectives of this two-year study (1998-1999) were to document distribution, abundance, age class structure, recruitment success, and habitat use by all life history stages of shortnose and Lost River suckers in three lower Klamath River hydroelectric reservoirs (J. C. Boyle, Copco, and Iron Gate). Lost River sucker catches were sporadic (only 3 adult individuals total) and the focus of our analyses, therefore, shifted to shortnose suckers. Adult and larval suckers were found in all reservoirs both years. All life history stages (larvae, juveniles and adults) were found in J. C. Boyle during both years and in Copco in 1999. Juvenile suckers were not found in Copco in 1998. The number of adult shortnose suckers was highest in Copco reservoir (n=165), followed by J.C. Boyle (n=50) and Iron Gate (n=22). Larger and older individuals dominated Copco and Iron Gate reservoirs and little size structure was detected. J. C. Boyle tended to have smaller adult shortnose suckers and many size classes were present. Unidentifiable larval suckers were most abundant in Copco reservoir where historic spawning of shortnose suckers has been documented. Larval suckers in Copco and Iron Gate reservoirs were most abundant in mid to late June before quickly disappearing from catches. J. C. Boyle larval suckers peaked in mid July, attained larger sizes, and were caught later in the season. It appeared that recruitment of young-of-the-year suckers only occurred in J. C. Boyle with downstream reservoirs recruiting older individuals, perhaps those that had earlier recruited to J. C. Boyle. Tagging studies could clarify adult recruitment dynamics and an additional study of juvenile recruitment would be needed to confirm these patterns. Predation pressure may be somewhat reduced in J. C. Boyle in comparison to the other reservoirs as its fish community was dominated by native fishes while communities in Copco and Iron Gate reservoirs were dominated by exotic predators. J. C. Boyle also possessed proportionally more littoral habitat, which suggests it may provide a more stable environment for young fishes. However, our sampling was inadequate to demonstrate such relationships due to high variance in larval and juvenile catches and potentially confounding habitat variables. One such variable was water level fluctuations, which could interact with habitat and resource availability in complex ways. For example, water level fluctuations, presumed to have a negative impact, were greatest in J. C. Boyle. Extrapolation from the literature suggests it should have had the poorest habitat for larval and juvenile suckers, but our results indicated J. C. Boyle had the most young suckers. Additional study of the relationships between water level fluctuations, habitat availability, the exotic fish community, and juvenile sucker recruitment would be needed to better understand early life history ecology of endangered lake suckers in these systems. Close