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• 21. [Image] The Endangered Species Act : a primer

  	Report for Congress; "Updated March 31, 2005."
  	Citation × Citation Citation Abstract Copy Title: The Endangered Species Act : a primer Author: Baldwin, Pamela; Buck, Eugene H.; Corn, M. Lynne (Mary Lynne), 1946- Year: 2005 Report for Congress; "Updated March 31, 2005." Title: The Endangered Species Act : a primer Author: Baldwin, Pamela; Buck, Eugene H.; Corn, M. Lynne (Mary Lynne), 1946- Year: 2005 Report for Congress; "Updated March 31, 2005." Close

• 22. [Image] Integrated scientific assessment for ecosystem management in the interior Columbia Basin and portions of the Klamath and Great Basins

  	Abstract Quigley, Thomas M.; Haynes, Richard W.; Graham, Russell T., tech. eds. 1996. Integrated scientific assessment for ecosystem management in the interior Columbia basin and portions of the Klamath ...
  	Citation × Citation Citation Abstract Copy Title: Integrated scientific assessment for ecosystem management in the interior Columbia Basin and portions of the Klamath and Great Basins Year: 1996, 2005, 2000 Abstract Quigley, Thomas M.; Haynes, Richard W.; Graham, Russell T., tech. eds. 1996. Integrated scientific assessment for ecosystem management in the interior Columbia basin and portions of the Klamath and Great Basins. Gen. Tech. Rep. PNW-GTR-382. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 303 p. (Quigley, Thomas M., tech. ed. The Interior Columbia Basin Ecosystem Management Project: Scientific Assessment.) The Integrated Scientific Assessment for Ecosystem Management for the Interior Columbia Basin links landscape, aquatic, terrestrial, social, and economic characterizations to describe biophysical and social systems. Integration was achieved through a framework built around six goals for ecosystem management and three different views of the future. These goals are: maintain evolutionary and ecological processes; manage for multiple ecological domains and evolutionary timeframes; maintain viable populations of native and desired non-native species; encourage social and economic resiliency; manage for places with definable values; and, manage to maintain a variety of ecosystem goods, services, and conditions that society wants. Ratings of relative ecological integrity and socioeconomic resiliency were used to make broad statements about ecosystem conditions in the Basin. Currently in the Basin high integrity and resiliency are found on 16 and 20 percent of the area, respectively. Low integrity and resiliency are found on 60 and 68 percent of the area. Different approaches to management can alter the risks to the assets of people living in the Basin and to the ecosystem itself. Continuation of current management leads to increasing risks while management approaches focusing on reserves or restoration result in trends that mostly stabilize or reduce risks. Even where ecological integrity is projected to improve with the application of active management, population increases and the pressures of expanding demands on resources may cause increasing trends in risk. Keywords: Ecosystem assessment, management and goals; ecological integrity; socio-economic resiliency; risk management Title: Integrated scientific assessment for ecosystem management in the interior Columbia Basin and portions of the Klamath and Great Basins Year: 1996, 2005, 2000 Abstract Quigley, Thomas M.; Haynes, Richard W.; Graham, Russell T., tech. eds. 1996. Integrated scientific assessment for ecosystem management in the interior Columbia basin and portions of the Klamath and Great Basins. Gen. Tech. Rep. PNW-GTR-382. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 303 p. (Quigley, Thomas M., tech. ed. The Interior Columbia Basin Ecosystem Management Project: Scientific Assessment.) The Integrated Scientific Assessment for Ecosystem Management for the Interior Columbia Basin links landscape, aquatic, terrestrial, social, and economic characterizations to describe biophysical and social systems. Integration was achieved through a framework built around six goals for ecosystem management and three different views of the future. These goals are: maintain evolutionary and ecological processes; manage for multiple ecological domains and evolutionary timeframes; maintain viable populations of native and desired non-native species; encourage social and economic resiliency; manage for places with definable values; and, manage to maintain a variety of ecosystem goods, services, and conditions that society wants. Ratings of relative ecological integrity and socioeconomic resiliency were used to make broad statements about ecosystem conditions in the Basin. Currently in the Basin high integrity and resiliency are found on 16 and 20 percent of the area, respectively. Low integrity and resiliency are found on 60 and 68 percent of the area. Different approaches to management can alter the risks to the assets of people living in the Basin and to the ecosystem itself. Continuation of current management leads to increasing risks while management approaches focusing on reserves or restoration result in trends that mostly stabilize or reduce risks. Even where ecological integrity is projected to improve with the application of active management, population increases and the pressures of expanding demands on resources may cause increasing trends in risk. Keywords: Ecosystem assessment, management and goals; ecological integrity; socio-economic resiliency; risk management Close

• 23. [Image] Defining and evaluating recovery of OCN coho salmon stocks : implications for rebuilding stocks under the Oregon Plan : summary of a workshop organized by the Independent Multidisciplinary Science Team, August 4-5, 1999

  	"December 10, 1999."
  	Citation × Citation Citation Abstract Copy Title: Defining and evaluating recovery of OCN coho salmon stocks : implications for rebuilding stocks under the Oregon Plan : summary of a workshop organized by the Independent Multidisciplinary Science Team, August 4-5, 1999 Author: Independent Multidisciplinary Science Team (Or.) Year: 1999, 2005 "December 10, 1999." Title: Defining and evaluating recovery of OCN coho salmon stocks : implications for rebuilding stocks under the Oregon Plan : summary of a workshop organized by the Independent Multidisciplinary Science Team, August 4-5, 1999 Author: Independent Multidisciplinary Science Team (Or.) Year: 1999, 2005 "December 10, 1999." Close

• 24. [Image] A framework for ecosystem management in the interior Columbia Basin and portions of the Klamath and Great Basins

  	Haynes, Richard W.; Graham, Russell T.; Quigley, Thomas M., tech. eds. 1996. A framework for ecosystem management in the Interior Columbia Basin including portions of the Klamath and Great Basins. Gen. ...
  	Citation × Citation Citation Abstract Copy Title: A framework for ecosystem management in the interior Columbia Basin and portions of the Klamath and Great Basins Year: 1996, 2005 Haynes, Richard W.; Graham, Russell T.; Quigley, Thomas M., tech. eds. 1996. A framework for ecosystem management in the Interior Columbia Basin including portions of the Klamath and Great Basins. Gen. Tech. Rep. PNW-GTR-374. Portland, OR; U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 66 p. A framework for ecosystem management is proposed. This framework assumes the purpose of ecosystem management is to maintain the integrity of ecosystems over time and space. It is based on four ecosystem principles: ecosystems are dynamic, can be viewed as hierarchies with temporal and spatial dimensions, have limits, and are relatively unpredictable. This approach recognizes that people are part of ecosystems and that stewardship must be able to resolve tough challenges including how to meet multiple demands with finite resources. The framework describes a general planning model for ecosystem management that has four iterative steps: monitoring, assessment, decision-making, and implementation. Since ecosystems cross jurisdictional lines, the implementation of the framework depends on partnerships among land managers, the scientific community, and stakeholders. It proposes that decision-making be based on information provided by the best available science and the most appropriate technologies for land management. Keywords: Ecosystem assessment, ecosystem principles, ecosystem management, planning models, management goals, risk analysis. Title: A framework for ecosystem management in the interior Columbia Basin and portions of the Klamath and Great Basins Year: 1996, 2005 Haynes, Richard W.; Graham, Russell T.; Quigley, Thomas M., tech. eds. 1996. A framework for ecosystem management in the Interior Columbia Basin including portions of the Klamath and Great Basins. Gen. Tech. Rep. PNW-GTR-374. Portland, OR; U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 66 p. A framework for ecosystem management is proposed. This framework assumes the purpose of ecosystem management is to maintain the integrity of ecosystems over time and space. It is based on four ecosystem principles: ecosystems are dynamic, can be viewed as hierarchies with temporal and spatial dimensions, have limits, and are relatively unpredictable. This approach recognizes that people are part of ecosystems and that stewardship must be able to resolve tough challenges including how to meet multiple demands with finite resources. The framework describes a general planning model for ecosystem management that has four iterative steps: monitoring, assessment, decision-making, and implementation. Since ecosystems cross jurisdictional lines, the implementation of the framework depends on partnerships among land managers, the scientific community, and stakeholders. It proposes that decision-making be based on information provided by the best available science and the most appropriate technologies for land management. Keywords: Ecosystem assessment, ecosystem principles, ecosystem management, planning models, management goals, risk analysis. Close

• 25. [Image] Review of the hatchery measures in the Oregon plan for salmon and watersheds. Part I, Consistency of the Oregon plan with recommendations from recent scientific review panels

  	"December 10, 1998."
  	Citation × Citation Citation Abstract Copy Title: Review of the hatchery measures in the Oregon plan for salmon and watersheds. Part I, Consistency of the Oregon plan with recommendations from recent scientific review panels Author: Independent Multidisciplinary Science Team (Or.) Year: 1998, 2005 "December 10, 1998." Title: Review of the hatchery measures in the Oregon plan for salmon and watersheds. Part I, Consistency of the Oregon plan with recommendations from recent scientific review panels Author: Independent Multidisciplinary Science Team (Or.) Year: 1998, 2005 "December 10, 1998." Close

• 26. [Image] The Klamath Indians of southwestern Oregon : Part I - Grammar

  	Part of the first volume of Gatschet's monumental two-volume study of Klamath culture and language. Includes 3 sections. The first is a 97-page 'Ethnographic Sketch' that covers geography, topography, ...
  	Citation × Citation Citation Abstract Copy Title: The Klamath Indians of southwestern Oregon : Part I - Grammar Author: Gatschet, Albert S. (Albert Samuel), 1832-1907 Year: 1890, 2005 Part of the first volume of Gatschet's monumental two-volume study of Klamath culture and language. Includes 3 sections. The first is a 97-page 'Ethnographic Sketch' that covers geography, topography, camping places, tribal names/subdivisions, physical characteristics, linguistic affinities, history, demographic statistics, and religion. The next major part of the volume is 'Texts of the Klamath Language, with Explanatory Notes,' which includes direct transcription of Klamath informants' family stories, myths, oral history (including the Modoc War and Rogue River raids), religion, and songs, with English translations. The 500-page 'Grammar of the Klamath Language' concludes the volume and is a comprehensive linguistic analysis of the Klamath language. Gatschet, an American ethnologist, born in Switzerland, was trained as a linguist in the universities of Bern and Berlin. He was a pioneer in the scientific study of Native American languages, an ethnologist of the U.S. Geological Survey, and, beginning in 1879 a member of the newly organized Bureau of American Ethnology ; At head of title: Department of the interior. U.S. Geographical and geological survey of the Rocky Mountain region. J. W. Powell, in charge Title: The Klamath Indians of southwestern Oregon : Part I - Grammar Author: Gatschet, Albert S. (Albert Samuel), 1832-1907 Year: 1890, 2005 Part of the first volume of Gatschet's monumental two-volume study of Klamath culture and language. Includes 3 sections. The first is a 97-page 'Ethnographic Sketch' that covers geography, topography, camping places, tribal names/subdivisions, physical characteristics, linguistic affinities, history, demographic statistics, and religion. The next major part of the volume is 'Texts of the Klamath Language, with Explanatory Notes,' which includes direct transcription of Klamath informants' family stories, myths, oral history (including the Modoc War and Rogue River raids), religion, and songs, with English translations. The 500-page 'Grammar of the Klamath Language' concludes the volume and is a comprehensive linguistic analysis of the Klamath language. Gatschet, an American ethnologist, born in Switzerland, was trained as a linguist in the universities of Bern and Berlin. He was a pioneer in the scientific study of Native American languages, an ethnologist of the U.S. Geological Survey, and, beginning in 1879 a member of the newly organized Bureau of American Ethnology ; At head of title: Department of the interior. U.S. Geographical and geological survey of the Rocky Mountain region. J. W. Powell, in charge Close

• 27. [Image] The Klamath Indians of southwestern Oregon : Part I - Letter of transmittal, Ethnographic sketch, Texts

  	Part of the first volume of Gatschet's monumental two-volume study of Klamath culture and language. Includes 3 sections. The first is a 97-page 'Ethnographic Sketch' that covers geography, topography, ...
  	Citation × Citation Citation Abstract Copy Title: The Klamath Indians of southwestern Oregon : Part I - Letter of transmittal, Ethnographic sketch, Texts Author: Gatschet, Albert S. (Albert Samuel), 1832-1907 Year: 1890, 2005 Part of the first volume of Gatschet's monumental two-volume study of Klamath culture and language. Includes 3 sections. The first is a 97-page 'Ethnographic Sketch' that covers geography, topography, camping places, tribal names/subdivisions, physical characteristics, linguistic affinities, history, demographic statistics, and religion. The next major part of the volume is 'Texts of the Klamath Language, with Explanatory Notes,' which includes direct transcription of Klamath informants' family stories, myths, oral history (including the Modoc War and Rogue River raids), religion, and songs, with English translations. The 500-page 'Grammar of the Klamath Language' concludes the volume and is a comprehensive linguistic analysis of the Klamath language. Gatschet, an American ethnologist, born in Switzerland, was trained as a linguist in the universities of Bern and Berlin. He was a pioneer in the scientific study of Native American languages, an ethnologist of the U.S. Geological Survey, and, beginning in 1879 a member of the newly organized Bureau of American Ethnology ; At head of title: Department of the interior. U.S. Geographical and geological survey of the Rocky Mountain region. J. W. Powell, in charge Title: The Klamath Indians of southwestern Oregon : Part I - Letter of transmittal, Ethnographic sketch, Texts Author: Gatschet, Albert S. (Albert Samuel), 1832-1907 Year: 1890, 2005 Part of the first volume of Gatschet's monumental two-volume study of Klamath culture and language. Includes 3 sections. The first is a 97-page 'Ethnographic Sketch' that covers geography, topography, camping places, tribal names/subdivisions, physical characteristics, linguistic affinities, history, demographic statistics, and religion. The next major part of the volume is 'Texts of the Klamath Language, with Explanatory Notes,' which includes direct transcription of Klamath informants' family stories, myths, oral history (including the Modoc War and Rogue River raids), religion, and songs, with English translations. The 500-page 'Grammar of the Klamath Language' concludes the volume and is a comprehensive linguistic analysis of the Klamath language. Gatschet, an American ethnologist, born in Switzerland, was trained as a linguist in the universities of Bern and Berlin. He was a pioneer in the scientific study of Native American languages, an ethnologist of the U.S. Geological Survey, and, beginning in 1879 a member of the newly organized Bureau of American Ethnology ; At head of title: Department of the interior. U.S. Geographical and geological survey of the Rocky Mountain region. J. W. Powell, in charge Close

• 28. [Image] Natural history and ecology of larval Lost River suckers and larval shortnose suckers in the Williamson River-Upper Klamath Lake System

  	We monitored larval Lost River and shortnose suckers from natal beds in the Williamson and Sprague rivers to nursery grounds in Upper Klamath Lake. Downstream movements occurred at night, in the middle ...
  	Citation × Citation Citation Abstract Copy Title: Natural history and ecology of larval Lost River suckers and larval shortnose suckers in the Williamson River-Upper Klamath Lake System Author: Cooperman, Michael S. Year: 2004, 2005 We monitored larval Lost River and shortnose suckers from natal beds in the Williamson and Sprague rivers to nursery grounds in Upper Klamath Lake. Downstream movements occurred at night, in the middle of the channel, and on the falling limb of the hydrograph. Ages, sizes, and developmental stages of larvae from spawning beds and the river mouth were similar, while larvae collected contemporaneously from the lake tended to be larger and better fed. Our results indicate in-river rearing was rare, that a rapid outmigration to the lake was favorable for larval survival, and that modification of the lower Williamson River does not appear to have prohibited rapid entry or preclude access to Upper Klamath Lake. Within the Williamson River and Upper Klamath Lake, emergent macrophytes supported significantly higher abundance, larger mean sizes, and better fed larvae than submerged macrophytes, woody vegetation, or open water areas. Analysis of seven years of larval sucker production and survival corroborated the habitat analysis by identifying a positive relationship with emergent macrophyte availability as well as a positive relationship with air temperature and a negative relationship with high wind. These findings illustrate the importance of fast growth, appropriate habitat and calm hydrological conditions for larvae, and are highly consistent with other larval fish studies. Title: Natural history and ecology of larval Lost River suckers and larval shortnose suckers in the Williamson River-Upper Klamath Lake System Author: Cooperman, Michael S. Year: 2004, 2005 We monitored larval Lost River and shortnose suckers from natal beds in the Williamson and Sprague rivers to nursery grounds in Upper Klamath Lake. Downstream movements occurred at night, in the middle of the channel, and on the falling limb of the hydrograph. Ages, sizes, and developmental stages of larvae from spawning beds and the river mouth were similar, while larvae collected contemporaneously from the lake tended to be larger and better fed. Our results indicate in-river rearing was rare, that a rapid outmigration to the lake was favorable for larval survival, and that modification of the lower Williamson River does not appear to have prohibited rapid entry or preclude access to Upper Klamath Lake. Within the Williamson River and Upper Klamath Lake, emergent macrophytes supported significantly higher abundance, larger mean sizes, and better fed larvae than submerged macrophytes, woody vegetation, or open water areas. Analysis of seven years of larval sucker production and survival corroborated the habitat analysis by identifying a positive relationship with emergent macrophyte availability as well as a positive relationship with air temperature and a negative relationship with high wind. These findings illustrate the importance of fast growth, appropriate habitat and calm hydrological conditions for larvae, and are highly consistent with other larval fish studies. Close

• 29. [Image] Historical landscape overview of the upper Klamath River Canyon of Oregon and California

  	"Submitted to Klamath Falls Resource Area, Bureau of Land Management, Lakeview District, Klamath Falls, Oregon." ; "Contract no.: HAP032021."; Includes bibliographical references (p. 178-200)
  	Citation × Citation Citation Abstract Copy Title: Historical landscape overview of the upper Klamath River Canyon of Oregon and California Author: Beckham, Stephen Dow Year: 2006, 2008, 2007 "Submitted to Klamath Falls Resource Area, Bureau of Land Management, Lakeview District, Klamath Falls, Oregon." ; "Contract no.: HAP032021."; Includes bibliographical references (p. 178-200) Title: Historical landscape overview of the upper Klamath River Canyon of Oregon and California Author: Beckham, Stephen Dow Year: 2006, 2008, 2007 "Submitted to Klamath Falls Resource Area, Bureau of Land Management, Lakeview District, Klamath Falls, Oregon." ; "Contract no.: HAP032021."; Includes bibliographical references (p. 178-200) Close

• 30. [Image] Reproductive biology and demographics of endangered Lost River and shortnose suckers in Upper Klamath Lake, Oregon

  	We analyzed the reproductive biology and demographics of the Lost River sucker Deltistes luxatus and shortnose sucker Chasmistes brevirostris, two endangered species endemic to the upper Klamath Basin ...
  	Citation × Citation Citation Abstract Copy Title: Reproductive biology and demographics of endangered Lost River and shortnose suckers in Upper Klamath Lake, Oregon Author: Perkins, David L.; Scoppettone, Gary; Buettner, Mark Year: 2000, 2005 We analyzed the reproductive biology and demographics of the Lost River sucker Deltistes luxatus and shortnose sucker Chasmistes brevirostris, two endangered species endemic to the upper Klamath Basin of Oregon and California, from 1984-1997. Lost River suckers had distinct river and lake shoreline spawning stocks, and individuals of both species commonly spawned in consecutive years. In the Williamson River and lower Sprague River, spawning migration by both species occurred mainly during a 5-week period that started within the first three weeks of April and peaked between mid April and early May, although a separate, earlier (mid March) run of Lost River suckers may also spawn in the upper Sprague River. Migration of both species was several times higher at dawn (0500-0730 h) and evening (1800-2200 h) than other times of the day. Peak migrations almost always corresponded to peaks in water temperature, usually at 10-15°C. Lost River suckers were captured at springs along the east shore of the lake from late February through mid May, with peak spawning usually in mid March to mid April. Shortnose suckers were generally captured at the springs from late March through late May, but the time of peak spawning was not determined. Size and age at maturity was determined by recruitment from a strong year class (1991). Male Lost River suckers began recruitment into the adult population at age 4+ (375-475 mm). Substantial recruitment of females did not begin until age 7+ (510-560 mm). Male and female shortnose suckers began recruitment at age 4+, with the majority offish recruited by age 5+. Males recruited at 270-370 mm; females recruited at 325-425 mm. Fecundity estimates were quite variable ranging from 44,000-236,000 eggs per female Lost River sucker and 18,000-72,000 eggs per female shortnose sucker. In 1984 and 1985, the spawning populations of both species were dominated by large, old individuals, with little indication of recent adult recruitment. In the next 13 years, only one strong year class (1991) recruited into the spawning populations of both species. This year class temporarily boosted population numbers, but annual fish kills from 1995 to 1997 eliminated most adults of both species. Associated with poor water quality caused by the proliferation and decay of blue-green algae Aphanizomenonflos-aquae, these fish kills raise concern that alterations to the lake ecosystem over the past several decades have Perkins et al. Lost River and shortnose suckers 5 increased the magnitude and frequency of poor water quality. As a result, mortality rates of all life stages may have increased, thereby disrupting the species' life history pattern and potentially decreasing long-term population viability. Introduction The Lost River sucker Deltistes luxatus and shortnose sucker Chasmistes brevirostris are large, long-lived suckers endemic to the upper Klamath Basin of Oregon and California. Both species are typically lake dwelling but migrate to tributaries or shoreline springs to spawn (Moyle 1976, Scoppettone and Vinyard 1991). Once extremely abundant (Cope 1884, Gilbert 1898), both species have experienced severe population declines and were federally listed as endangered in 1988 (USFWS 1988). Much of the original habitat of these suckers has been destroyed or altered by conversion of lake areas to agriculture, dams, instream flow diversions, and water quality problems associated with timber harvest, loss of riparian vegetation, livestock grazing, and agricultural practices (USFWS 1988). Knowledge of the life history of Lost River and shortnose suckers is fundamental to recovery of these species. The objective of this report was to present the results of studies conducted from 1987-1998 on the reproductive biology and demographics of Lost River and shortnose suckers, and to compare these results with earlier unpublished data. Study Sites Studies were conducted on Upper Klamath Lake and the lower Williamson-Sprague river system (Figure 1). These waters form the upper portion of the Klamath River Basin in south-central Oregon and represent most remaining native habitat of Lost River and shortnose suckers. Upper Klamath Lake is a remnant of pluvial Lake Modoc that included eight major basins and encompassed 2,839 km2 (Dicken 1980). Today, Upper Klamath Lake serves as a storage reservoir that provides water for agricultural irrigation, waterfowl refuges, instream flow requirements of anadromous fish, and hydroelectric power generation. At full capacity, the lake covers approximately 360 km2 and has an average depth of 2.4 m. Most deeper water (3-12 m) is restricted to narrow trenches along the western shore. Lake elevation is controlled at the outlet by Link River Title: Reproductive biology and demographics of endangered Lost River and shortnose suckers in Upper Klamath Lake, Oregon Author: Perkins, David L.; Scoppettone, Gary; Buettner, Mark Year: 2000, 2005 We analyzed the reproductive biology and demographics of the Lost River sucker Deltistes luxatus and shortnose sucker Chasmistes brevirostris, two endangered species endemic to the upper Klamath Basin of Oregon and California, from 1984-1997. Lost River suckers had distinct river and lake shoreline spawning stocks, and individuals of both species commonly spawned in consecutive years. In the Williamson River and lower Sprague River, spawning migration by both species occurred mainly during a 5-week period that started within the first three weeks of April and peaked between mid April and early May, although a separate, earlier (mid March) run of Lost River suckers may also spawn in the upper Sprague River. Migration of both species was several times higher at dawn (0500-0730 h) and evening (1800-2200 h) than other times of the day. Peak migrations almost always corresponded to peaks in water temperature, usually at 10-15°C. Lost River suckers were captured at springs along the east shore of the lake from late February through mid May, with peak spawning usually in mid March to mid April. Shortnose suckers were generally captured at the springs from late March through late May, but the time of peak spawning was not determined. Size and age at maturity was determined by recruitment from a strong year class (1991). Male Lost River suckers began recruitment into the adult population at age 4+ (375-475 mm). Substantial recruitment of females did not begin until age 7+ (510-560 mm). Male and female shortnose suckers began recruitment at age 4+, with the majority offish recruited by age 5+. Males recruited at 270-370 mm; females recruited at 325-425 mm. Fecundity estimates were quite variable ranging from 44,000-236,000 eggs per female Lost River sucker and 18,000-72,000 eggs per female shortnose sucker. In 1984 and 1985, the spawning populations of both species were dominated by large, old individuals, with little indication of recent adult recruitment. In the next 13 years, only one strong year class (1991) recruited into the spawning populations of both species. This year class temporarily boosted population numbers, but annual fish kills from 1995 to 1997 eliminated most adults of both species. Associated with poor water quality caused by the proliferation and decay of blue-green algae Aphanizomenonflos-aquae, these fish kills raise concern that alterations to the lake ecosystem over the past several decades have Perkins et al. Lost River and shortnose suckers 5 increased the magnitude and frequency of poor water quality. As a result, mortality rates of all life stages may have increased, thereby disrupting the species' life history pattern and potentially decreasing long-term population viability. Introduction The Lost River sucker Deltistes luxatus and shortnose sucker Chasmistes brevirostris are large, long-lived suckers endemic to the upper Klamath Basin of Oregon and California. Both species are typically lake dwelling but migrate to tributaries or shoreline springs to spawn (Moyle 1976, Scoppettone and Vinyard 1991). Once extremely abundant (Cope 1884, Gilbert 1898), both species have experienced severe population declines and were federally listed as endangered in 1988 (USFWS 1988). Much of the original habitat of these suckers has been destroyed or altered by conversion of lake areas to agriculture, dams, instream flow diversions, and water quality problems associated with timber harvest, loss of riparian vegetation, livestock grazing, and agricultural practices (USFWS 1988). Knowledge of the life history of Lost River and shortnose suckers is fundamental to recovery of these species. The objective of this report was to present the results of studies conducted from 1987-1998 on the reproductive biology and demographics of Lost River and shortnose suckers, and to compare these results with earlier unpublished data. Study Sites Studies were conducted on Upper Klamath Lake and the lower Williamson-Sprague river system (Figure 1). These waters form the upper portion of the Klamath River Basin in south-central Oregon and represent most remaining native habitat of Lost River and shortnose suckers. Upper Klamath Lake is a remnant of pluvial Lake Modoc that included eight major basins and encompassed 2,839 km2 (Dicken 1980). Today, Upper Klamath Lake serves as a storage reservoir that provides water for agricultural irrigation, waterfowl refuges, instream flow requirements of anadromous fish, and hydroelectric power generation. At full capacity, the lake covers approximately 360 km2 and has an average depth of 2.4 m. Most deeper water (3-12 m) is restricted to narrow trenches along the western shore. Lake elevation is controlled at the outlet by Link River Close