Search

Search Results

• 231. [Article] Steelhead Escapement Monitoring In the Upper Grande Ronde River - Annual Technical Report 2008

  Abstract -- The Upper Grande Ronde River basin supports a population of summer steelhead O. mykiss that has been defined by segregating it from the other three populations inhabiting the Grande Ronde River ...

  Citation × Citation Citation Abstract Copy Title: Steelhead Escapement Monitoring In the Upper Grande Ronde River - Annual Technical Report 2008 Abstract -- The Upper Grande Ronde River basin supports a population of summer steelhead O. mykiss that has been defined by segregating it from the other three populations inhabiting the Grande Ronde River basin based on topographic, genetic, observational, and other evidence of interactions. Historically, the Grande Ronde River was one of the more significant anadromous fish producing rivers in the Columbia River Basin. Steelhead in the Grande Ronde River basin compose part of the Snake River DPS for summer steelhead and are listed as threatened by the ESA. Despite recovery efforts, these populations remain depressed relative to historic levels. This project will evaluate summer steelhead population abundance for the upper Grande Ronde River summer steelhead population by conducting surveys of redds and spawning activity. These surveys will provide the data needed to estimate adult steelhead escapement, improve our understanding of habitat utilization, and contribute to productivity and survival estimates for this population. We monitored steelhead using a probabilistic sampling approach by incorporating a sample-site selection procedure similar to the Environmental Protection Agency (EPA) environmental monitoring and assessment program (EMAP). We used this EMAP or Generalized Random Tessellation Stratified design (GRTS) approach to select sample sites for status and trend monitoring of steelhead redds within the Upper Grande Ronde River watershed. This steelhead monitoring follows the Oregon Plan for Salmon and Watersheds Monitoring Program approach. ODFW, Eastern Oregon Fish Research (EOFR). Funded by NOAA. Title: Steelhead Escapement Monitoring In the Upper Grande Ronde River - Annual Technical Report 2008 Abstract -- The Upper Grande Ronde River basin supports a population of summer steelhead O. mykiss that has been defined by segregating it from the other three populations inhabiting the Grande Ronde River basin based on topographic, genetic, observational, and other evidence of interactions. Historically, the Grande Ronde River was one of the more significant anadromous fish producing rivers in the Columbia River Basin. Steelhead in the Grande Ronde River basin compose part of the Snake River DPS for summer steelhead and are listed as threatened by the ESA. Despite recovery efforts, these populations remain depressed relative to historic levels. This project will evaluate summer steelhead population abundance for the upper Grande Ronde River summer steelhead population by conducting surveys of redds and spawning activity. These surveys will provide the data needed to estimate adult steelhead escapement, improve our understanding of habitat utilization, and contribute to productivity and survival estimates for this population. We monitored steelhead using a probabilistic sampling approach by incorporating a sample-site selection procedure similar to the Environmental Protection Agency (EPA) environmental monitoring and assessment program (EMAP). We used this EMAP or Generalized Random Tessellation Stratified design (GRTS) approach to select sample sites for status and trend monitoring of steelhead redds within the Upper Grande Ronde River watershed. This steelhead monitoring follows the Oregon Plan for Salmon and Watersheds Monitoring Program approach. ODFW, Eastern Oregon Fish Research (EOFR). Funded by NOAA. Close

• 232. [Article] Steelhead Escapement Monitoring In the Upper Grande Ronde River - Annual Technical Report 2009

  Abstract -- The Upper Grande Ronde River basin supports a population of summer steelhead O. mykiss that has been defined by segregating it from the other three populations inhabiting the Grande Ronde River ...

  Citation × Citation Citation Abstract Copy Title: Steelhead Escapement Monitoring In the Upper Grande Ronde River - Annual Technical Report 2009 Abstract -- The Upper Grande Ronde River basin supports a population of summer steelhead O. mykiss that has been defined by segregating it from the other three populations inhabiting the Grande Ronde River basin based on topographic, genetic, observational, and other evidence of interactions. Historically, the Grande Ronde River was one of the more significant anadromous fish producing rivers in the Columbia River Basin. Steelhead in the Grande Ronde River basin compose part of the Snake River DPS for summer steelhead and are listed as threatened by the ESA. Despite recovery efforts, these populations remain depressed relative to historic levels. This project evaluates summer steelhead population abundance for the upper Grande Ronde River summer steelhead population by conducting surveys of redds and spawning activity. These surveys provide the data needed to estimate adult steelhead escapement, improve our understanding of habitat utilization, and contribute to productivity and survival estimates for this population. We monitored steelhead using a probabilistic sampling approach by incorporating a sample-site selection procedure similar to the Environmental Protection Agency (EPA) environmental monitoring and assessment program (EMAP). We used this EMAP or Generalized Random Tessellation Stratified design (GRTS) approach to select sample sites for status and trend monitoring of steelhead redds within the Upper Grande Ronde River watershed. This steelhead monitoring follows the Oregon Plan for Salmon and Watersheds Monitoring Program approach. ODFW, Eastern Oregon Fish Research (EOFR). Funded by NOAA Title: Steelhead Escapement Monitoring In the Upper Grande Ronde River - Annual Technical Report 2009 Abstract -- The Upper Grande Ronde River basin supports a population of summer steelhead O. mykiss that has been defined by segregating it from the other three populations inhabiting the Grande Ronde River basin based on topographic, genetic, observational, and other evidence of interactions. Historically, the Grande Ronde River was one of the more significant anadromous fish producing rivers in the Columbia River Basin. Steelhead in the Grande Ronde River basin compose part of the Snake River DPS for summer steelhead and are listed as threatened by the ESA. Despite recovery efforts, these populations remain depressed relative to historic levels. This project evaluates summer steelhead population abundance for the upper Grande Ronde River summer steelhead population by conducting surveys of redds and spawning activity. These surveys provide the data needed to estimate adult steelhead escapement, improve our understanding of habitat utilization, and contribute to productivity and survival estimates for this population. We monitored steelhead using a probabilistic sampling approach by incorporating a sample-site selection procedure similar to the Environmental Protection Agency (EPA) environmental monitoring and assessment program (EMAP). We used this EMAP or Generalized Random Tessellation Stratified design (GRTS) approach to select sample sites for status and trend monitoring of steelhead redds within the Upper Grande Ronde River watershed. This steelhead monitoring follows the Oregon Plan for Salmon and Watersheds Monitoring Program approach. ODFW, Eastern Oregon Fish Research (EOFR). Funded by NOAA Close

• 233. [Article] Steelhead Escapement Monitoring In the Upper Grande Ronde River - Annual Technical Report 2010

  Abstract -- The Upper Grande Ronde River basin supports a population of summer steelhead O. mykiss that has been defined by segregating it from the other three populations inhabiting the Grande Ronde River ...

  Citation × Citation Citation Abstract Copy Title: Steelhead Escapement Monitoring In the Upper Grande Ronde River - Annual Technical Report 2010 Abstract -- The Upper Grande Ronde River basin supports a population of summer steelhead O. mykiss that has been defined by segregating it from the other three populations inhabiting the Grande Ronde River basin based on topographic, genetic, observational, and other evidence of interactions. Historically, the Grande Ronde River was one of the more significant anadromous fish producing rivers in the Columbia River Basin. Steelhead in the Grande Ronde River basin compose part of the Snake River DPS for summer steelhead and are listed as threatened by the ESA. Despite recovery efforts, these populations remain depressed relative to historic levels. This project will evaluate summer steelhead population abundance for the upper Grande Ronde River summer steelhead population by conducting surveys of redds and spawning activity. These surveys will provide the data needed to estimate adult steelhead escapement, improve our understanding of habitat utilization, and contribute to productivity and survival estimates for this population. We monitored steelhead using a probabilistic sampling approach by incorporating a sample-site selection procedure similar to the Environmental Protection Agency (EPA) environmental monitoring and assessment program (EMAP). We used this EMAP or Generalized Random Tessellation Stratified design (GRTS) approach to select sample sites for status and trend monitoring of steelhead redds within the Upper Grande Ronde River watershed. This steelhead monitoring follows the Oregon Plan for Salmon and Watersheds Monitoring Program approach. ODFW, Eastern Oregon Fish Research (EOFR). Funded by NOAA Title: Steelhead Escapement Monitoring In the Upper Grande Ronde River - Annual Technical Report 2010 Abstract -- The Upper Grande Ronde River basin supports a population of summer steelhead O. mykiss that has been defined by segregating it from the other three populations inhabiting the Grande Ronde River basin based on topographic, genetic, observational, and other evidence of interactions. Historically, the Grande Ronde River was one of the more significant anadromous fish producing rivers in the Columbia River Basin. Steelhead in the Grande Ronde River basin compose part of the Snake River DPS for summer steelhead and are listed as threatened by the ESA. Despite recovery efforts, these populations remain depressed relative to historic levels. This project will evaluate summer steelhead population abundance for the upper Grande Ronde River summer steelhead population by conducting surveys of redds and spawning activity. These surveys will provide the data needed to estimate adult steelhead escapement, improve our understanding of habitat utilization, and contribute to productivity and survival estimates for this population. We monitored steelhead using a probabilistic sampling approach by incorporating a sample-site selection procedure similar to the Environmental Protection Agency (EPA) environmental monitoring and assessment program (EMAP). We used this EMAP or Generalized Random Tessellation Stratified design (GRTS) approach to select sample sites for status and trend monitoring of steelhead redds within the Upper Grande Ronde River watershed. This steelhead monitoring follows the Oregon Plan for Salmon and Watersheds Monitoring Program approach. ODFW, Eastern Oregon Fish Research (EOFR). Funded by NOAA Close

• 234. [Article] Steelhead Escapement Monitoring In the Upper Grande Ronde River - Annual Technical Report 2011

  Abstract -- The UGRR basin supports a population of summer steelhead that has been segregated from three other populations in the entire Grande Ronde River basin based on topographic, genetic, observational, ...

  Citation × Citation Citation Abstract Copy Title: Steelhead Escapement Monitoring In the Upper Grande Ronde River - Annual Technical Report 2011 Abstract -- The UGRR basin supports a population of summer steelhead that has been segregated from three other populations in the entire Grande Ronde River basin based on topographic, genetic, observational, and other evidence of interactions. Historically, the Grande Ronde River was one of the more significant anadromous fish producing rivers in the Columbia River Basin. Summer steelhead in the Grande Ronde River basin compose part of the Snake River Distinct Population Segment (DPS) and are listed as threatened under the Endangered Species Act (62 FR 43937; August 18,1997). Despite recovery efforts, these populations remain depressed relative to historic levels. This project annually evaluates summer steelhead population abundance for the UGRR by conducting surveys of redds and spawning activity. These surveys provide the data needed to estimate adult steelhead escapement, improve our understanding of habitat utilization, and contribute to productivity and survival estimates for this population. Steelhead were monitored using a probabilistic sampling approach that incorporates a sample-site selection procedure created for the Environmental Protection Agency’s environmental monitoring and assessment program (EMAP). We used this EMAP design to select sample sites for status and trend monitoring of steelhead redds within the UGRR watershed. This method allowed us to sample spatially balanced survey sites distributed within the basin, and followed the Oregon Plan for Salmon and Watersheds Monitoring Program approach (Stevens 2002). ODFW- Eastern Oregon Fish Research (EOFR). BPA contract # IGC 51891 Title: Steelhead Escapement Monitoring In the Upper Grande Ronde River - Annual Technical Report 2011 Abstract -- The UGRR basin supports a population of summer steelhead that has been segregated from three other populations in the entire Grande Ronde River basin based on topographic, genetic, observational, and other evidence of interactions. Historically, the Grande Ronde River was one of the more significant anadromous fish producing rivers in the Columbia River Basin. Summer steelhead in the Grande Ronde River basin compose part of the Snake River Distinct Population Segment (DPS) and are listed as threatened under the Endangered Species Act (62 FR 43937; August 18,1997). Despite recovery efforts, these populations remain depressed relative to historic levels. This project annually evaluates summer steelhead population abundance for the UGRR by conducting surveys of redds and spawning activity. These surveys provide the data needed to estimate adult steelhead escapement, improve our understanding of habitat utilization, and contribute to productivity and survival estimates for this population. Steelhead were monitored using a probabilistic sampling approach that incorporates a sample-site selection procedure created for the Environmental Protection Agency’s environmental monitoring and assessment program (EMAP). We used this EMAP design to select sample sites for status and trend monitoring of steelhead redds within the UGRR watershed. This method allowed us to sample spatially balanced survey sites distributed within the basin, and followed the Oregon Plan for Salmon and Watersheds Monitoring Program approach (Stevens 2002). ODFW- Eastern Oregon Fish Research (EOFR). BPA contract # IGC 51891 Close

• 235. [Article] Status and Distribution of Native Fishes in the Goose Lake Basin Information Reports number 2008-02

  Abstract -- This study describes the current distribution of the nine native fish species in the Oregon portion of the Goose Lake basin (Lake County): Goose Lake redband trout Oncorhynchus mykiss ssp., ...

  Citation × Citation Citation Abstract Copy Title: Status and Distribution of Native Fishes in the Goose Lake Basin Information Reports number 2008-02 Abstract -- This study describes the current distribution of the nine native fish species in the Oregon portion of the Goose Lake basin (Lake County): Goose Lake redband trout Oncorhynchus mykiss ssp., Goose Lake lamprey Entosphenus sp., Goose Lake tui chub Siphateles bicolor thalassinus, Goose Lake sucker Catostomus occidentalis lacusanserinus, Modoc sucker Catostomus microps, Pit-Klamath brook lamprey Entosphenus lethophagus, speckled dace Rhinichthys osculus, Pit roach Lavinia symmetricus mitrulus, and Pit sculpin Cottus pitensis. The Goose Lake basin is an endorheic, or topographically closed basin located in south central Oregon and northeastern California. The basin is within the usually closed northeastern extremity of the adjoining Sacramento River basin, astride the Oregon-California boundary. Although most of the lake lies in California, most of its valley and nearly two-thirds of the total drainage area (~722 sq. mi.) are in Oregon. The largest streams in the basin are Drews, Cottonwood, and Thomas Creeks. Annual precipitation averages about 36 cm per year (Phillips and van Denburgh 1971). Goose Lake overflowed briefly into the North Fork Pit River in 1868 and 1881, but storage and diversion of irrigation water has substantially reduced the inflow and future overflow is unlikely (USGS 1971). The lakebed was dry in the summers of 1926, 1929- 1934, and 1992. About half the basin is forestland, 20% is hay fields and pastureland, and 16% is shrub and rangeland. Currently, almost 35% of the inflow is diverted for irrigation (OWRD 1989). The Goose Lake basin is home to four endemic fish taxa: the Goose Lake redband trout, lamprey, sucker, and tui chub. Endemic fishes of the Goose Lake basin split their life histories between Goose Lake and its tributaries, as opposed to the five native but non-endemic species that primarily occupy stream habitats. Pit roach and all endemic fishes except Goose Lake tui chub are listed as a “species of concern” by the USFWS, a designation that implies there is concern about species viability, but not enough information is known to initiate a listing review for threatened or endangered status. The Modoc sucker was listed as a federally endangered species in 1985 (USFWS 1985). No formal recovery plan was required due to an existing “Action Plan for the Recovery of the Modoc Sucker” (USFWS 1984). Most of the recovery actions outlined in the action plan were either completed or are no longer relevant (Stewart Reid, Western Fishes, personal communication). However, actions 26 and 27 pertaining to range expansion remain incomplete. Action 26 suggests reclassification to threatened upon establishment of safe populations (for 3-5 years) throughout the Rush and Turner Creek watersheds in the Pit River basin. Action 27 suggests delisting upon establishing safe populations in two other historic streams. At the time of listing, the historic range of Modoc sucker was thought to have included only two small tributaries of the Pit River in Modoc and Lassen Counties, Ash and Turner Creeks (USFWS 1985). Therefore, a major recovery goal was to expand the species’ range with additional populations (USFWS 1984). In 2001, reexamination of historical documents and museum specimens established that Modoc suckers had also historically occupied Thomas Creek in the Goose Lake basin. Field collections in 2001, with subsequent morphological and genetic analysis, confirmed that the population was still present in Thomas Creek (Stewart Reid, Western Fishes, personal communication); however, the broader range of Modoc sucker in the Goose Lake watershed was not known. In 1995, the Goose Lake Fishes Working Group drafted a conservation plan for “prelisting” recovery of all native fish in response to severe drought and habitat degradation (GLFWG 1995). The Aquatic Inventories Project of the Oregon Department of Fish and Wildlife (ODFW) conducted habitat and fish distribution surveys (1991-1995) to obtain baseline information to help inform recovery efforts (ODFW, unpublished data). Since then, field work to monitor the distribution and abundance of Goose Lake fishes has been limited and sporadic, targeting only Goose Lake redband trout and Modoc sucker (Dambacher 2001; Reid 2007). No comprehensive follow up work has been conducted to evaluate fish response to climatic conditions, habitat restoration projects, and continued irrigation activities. ODFW recently drafted a status review of native fish of Oregon (ODFW 2005). Except for redband trout, Goose Lake fishes were not included in the status review due to a lack of new information since the previous status review in 1995 (Kostow et al. 1995). Further, the review of Goose Lake redband trout was limited by a lack of long-term data series. The first objective of this study was to document the current distribution of native fishes in Oregon’s portion of the Goose Lake basin and assess changes in distribution that may have occurred since the last surveys were conducted 12 years ago. The second objective was to provide new information about the distribution of Modoc suckers within the basin. The third objective was to determine relative abundance and age-class diversity of native fishes at randomly selected sample sites. All objectives were addressed throughout the potential riverine distribution of fish in the Oregon portion of the Goose Lake basin. Information gathered in this study is critical to effective conservation and management of each species and its habitat. In addition, this report describes the distribution and relative abundance of nonnative fishes (fathead minnow (Pimephales promelas), brown bullhead (Ameiurus nebulosus), white crappie (Pomoxis annularis), yellow perch (Perca flavescens), pumpkinseed (Lepomis gibbosus), and brook trout (Salvelinus fontinalis)) in the basin. Unlike prior efforts, this study used a statisticallybased design to select sample points with the aim of achieving a representative sample across the Oregon portion of the Goose Lake watershed. Additionally, a wide array of fish sampling gear was employed to maximize our ability to capture all fish species present across the diversity of habitat types encountered. Title: Status and Distribution of Native Fishes in the Goose Lake Basin Information Reports number 2008-02 Abstract -- This study describes the current distribution of the nine native fish species in the Oregon portion of the Goose Lake basin (Lake County): Goose Lake redband trout Oncorhynchus mykiss ssp., Goose Lake lamprey Entosphenus sp., Goose Lake tui chub Siphateles bicolor thalassinus, Goose Lake sucker Catostomus occidentalis lacusanserinus, Modoc sucker Catostomus microps, Pit-Klamath brook lamprey Entosphenus lethophagus, speckled dace Rhinichthys osculus, Pit roach Lavinia symmetricus mitrulus, and Pit sculpin Cottus pitensis. The Goose Lake basin is an endorheic, or topographically closed basin located in south central Oregon and northeastern California. The basin is within the usually closed northeastern extremity of the adjoining Sacramento River basin, astride the Oregon-California boundary. Although most of the lake lies in California, most of its valley and nearly two-thirds of the total drainage area (~722 sq. mi.) are in Oregon. The largest streams in the basin are Drews, Cottonwood, and Thomas Creeks. Annual precipitation averages about 36 cm per year (Phillips and van Denburgh 1971). Goose Lake overflowed briefly into the North Fork Pit River in 1868 and 1881, but storage and diversion of irrigation water has substantially reduced the inflow and future overflow is unlikely (USGS 1971). The lakebed was dry in the summers of 1926, 1929- 1934, and 1992. About half the basin is forestland, 20% is hay fields and pastureland, and 16% is shrub and rangeland. Currently, almost 35% of the inflow is diverted for irrigation (OWRD 1989). The Goose Lake basin is home to four endemic fish taxa: the Goose Lake redband trout, lamprey, sucker, and tui chub. Endemic fishes of the Goose Lake basin split their life histories between Goose Lake and its tributaries, as opposed to the five native but non-endemic species that primarily occupy stream habitats. Pit roach and all endemic fishes except Goose Lake tui chub are listed as a “species of concern” by the USFWS, a designation that implies there is concern about species viability, but not enough information is known to initiate a listing review for threatened or endangered status. The Modoc sucker was listed as a federally endangered species in 1985 (USFWS 1985). No formal recovery plan was required due to an existing “Action Plan for the Recovery of the Modoc Sucker” (USFWS 1984). Most of the recovery actions outlined in the action plan were either completed or are no longer relevant (Stewart Reid, Western Fishes, personal communication). However, actions 26 and 27 pertaining to range expansion remain incomplete. Action 26 suggests reclassification to threatened upon establishment of safe populations (for 3-5 years) throughout the Rush and Turner Creek watersheds in the Pit River basin. Action 27 suggests delisting upon establishing safe populations in two other historic streams. At the time of listing, the historic range of Modoc sucker was thought to have included only two small tributaries of the Pit River in Modoc and Lassen Counties, Ash and Turner Creeks (USFWS 1985). Therefore, a major recovery goal was to expand the species’ range with additional populations (USFWS 1984). In 2001, reexamination of historical documents and museum specimens established that Modoc suckers had also historically occupied Thomas Creek in the Goose Lake basin. Field collections in 2001, with subsequent morphological and genetic analysis, confirmed that the population was still present in Thomas Creek (Stewart Reid, Western Fishes, personal communication); however, the broader range of Modoc sucker in the Goose Lake watershed was not known. In 1995, the Goose Lake Fishes Working Group drafted a conservation plan for “prelisting” recovery of all native fish in response to severe drought and habitat degradation (GLFWG 1995). The Aquatic Inventories Project of the Oregon Department of Fish and Wildlife (ODFW) conducted habitat and fish distribution surveys (1991-1995) to obtain baseline information to help inform recovery efforts (ODFW, unpublished data). Since then, field work to monitor the distribution and abundance of Goose Lake fishes has been limited and sporadic, targeting only Goose Lake redband trout and Modoc sucker (Dambacher 2001; Reid 2007). No comprehensive follow up work has been conducted to evaluate fish response to climatic conditions, habitat restoration projects, and continued irrigation activities. ODFW recently drafted a status review of native fish of Oregon (ODFW 2005). Except for redband trout, Goose Lake fishes were not included in the status review due to a lack of new information since the previous status review in 1995 (Kostow et al. 1995). Further, the review of Goose Lake redband trout was limited by a lack of long-term data series. The first objective of this study was to document the current distribution of native fishes in Oregon’s portion of the Goose Lake basin and assess changes in distribution that may have occurred since the last surveys were conducted 12 years ago. The second objective was to provide new information about the distribution of Modoc suckers within the basin. The third objective was to determine relative abundance and age-class diversity of native fishes at randomly selected sample sites. All objectives were addressed throughout the potential riverine distribution of fish in the Oregon portion of the Goose Lake basin. Information gathered in this study is critical to effective conservation and management of each species and its habitat. In addition, this report describes the distribution and relative abundance of nonnative fishes (fathead minnow (Pimephales promelas), brown bullhead (Ameiurus nebulosus), white crappie (Pomoxis annularis), yellow perch (Perca flavescens), pumpkinseed (Lepomis gibbosus), and brook trout (Salvelinus fontinalis)) in the basin. Unlike prior efforts, this study used a statisticallybased design to select sample points with the aim of achieving a representative sample across the Oregon portion of the Goose Lake watershed. Additionally, a wide array of fish sampling gear was employed to maximize our ability to capture all fish species present across the diversity of habitat types encountered. Close

• 236. [Article] 2011 Warner Sucker Investigations (Honey Creek) Progress Reports 2011

  Abstract -- The Warner sucker (Catostomus warnerensis) is endemic to the Warner Valley, an endorheic subbasin of the Great Basin in southeastern Oregon and northwestern Nevada. Historically, this species ...

  Citation × Citation Citation Abstract Copy Title: 2011 Warner Sucker Investigations (Honey Creek) Progress Reports 2011 Abstract -- The Warner sucker (Catostomus warnerensis) is endemic to the Warner Valley, an endorheic subbasin of the Great Basin in southeastern Oregon and northwestern Nevada. Historically, this species was abundant and its range included three permanent lakes (Hart, Crump, and Pelican), several ephemeral lakes, a network of sloughs and diversion canals, and three major tributary drainages (Honey, Deep, and Twentymile Creeks) (U.S. Fish and Wildlife Service 1985). Warner sucker abundance and distribution has declined over the past century and it was federally listed as threatened in 1985 due to habitat fragmentation and threats posed by the proliferation of piscivorous non-native game fishes (U.S. Fish and Wildlife Service 1985). The Warner sucker inhabits the lakes and low gradient stream reaches of the Warner Valley. The Warner sucker metapopulation is comprised of both lake and stream life history morphs. The lake suckers are lacustrine adfluvial or potamodromous fish that normally spawn in the streams. However, upstream migration may be blocked by low stream flows during low water years or by irrigation diversion dams. When this happens, spawning may occur in nearshore areas of the lakes (White et al. 1990). Large lake-dwelling populations of introduced fishes likely reduce recruitment by preying on young suckers (U.S. Fish and Wildlife Service 1998). The stream suckers inhabit and spawn in Honey, Deep, and Twentymile Creeks. The Recovery Plan for the Threatened and Rare Native Fishes of the Warner Basin and Alkali Subbasin (U.S. Fish and Wildlife Service 1998) sets recovery criteria for delisting the species. These criteria require that: 1) a self-sustaining metapopulation is distributed throughout the Twentymile, Honey, and Deep Creek (below the falls) drainages, and in Pelican, Crump, and Hart Lakes, 2) passage is restored within and among the Twentymile, Honey, and Deep Creek (below the falls) drainages so that the individual populations of Warner suckers can function as a metapopulation, and 3) no threats exist that would likely threaten the survival of the species over a significant portion of its range. To inform progress towards the first criteria, our objectives in 2011 were: 1) obtain a population estimate for suckers in the Honey Creek drainage and describe their current distribution and 2) describe the association between the distribution of suckers and habitat variables in Honey Creek. In addition, we obtained a population estimate of suckers at the Summer Lake Wildlife Management Area (WMA), where a self-sustaining population became established after a fish salvage from Hart Lake in 1991 when the lakes desiccated. Title: 2011 Warner Sucker Investigations (Honey Creek) Progress Reports 2011 Abstract -- The Warner sucker (Catostomus warnerensis) is endemic to the Warner Valley, an endorheic subbasin of the Great Basin in southeastern Oregon and northwestern Nevada. Historically, this species was abundant and its range included three permanent lakes (Hart, Crump, and Pelican), several ephemeral lakes, a network of sloughs and diversion canals, and three major tributary drainages (Honey, Deep, and Twentymile Creeks) (U.S. Fish and Wildlife Service 1985). Warner sucker abundance and distribution has declined over the past century and it was federally listed as threatened in 1985 due to habitat fragmentation and threats posed by the proliferation of piscivorous non-native game fishes (U.S. Fish and Wildlife Service 1985). The Warner sucker inhabits the lakes and low gradient stream reaches of the Warner Valley. The Warner sucker metapopulation is comprised of both lake and stream life history morphs. The lake suckers are lacustrine adfluvial or potamodromous fish that normally spawn in the streams. However, upstream migration may be blocked by low stream flows during low water years or by irrigation diversion dams. When this happens, spawning may occur in nearshore areas of the lakes (White et al. 1990). Large lake-dwelling populations of introduced fishes likely reduce recruitment by preying on young suckers (U.S. Fish and Wildlife Service 1998). The stream suckers inhabit and spawn in Honey, Deep, and Twentymile Creeks. The Recovery Plan for the Threatened and Rare Native Fishes of the Warner Basin and Alkali Subbasin (U.S. Fish and Wildlife Service 1998) sets recovery criteria for delisting the species. These criteria require that: 1) a self-sustaining metapopulation is distributed throughout the Twentymile, Honey, and Deep Creek (below the falls) drainages, and in Pelican, Crump, and Hart Lakes, 2) passage is restored within and among the Twentymile, Honey, and Deep Creek (below the falls) drainages so that the individual populations of Warner suckers can function as a metapopulation, and 3) no threats exist that would likely threaten the survival of the species over a significant portion of its range. To inform progress towards the first criteria, our objectives in 2011 were: 1) obtain a population estimate for suckers in the Honey Creek drainage and describe their current distribution and 2) describe the association between the distribution of suckers and habitat variables in Honey Creek. In addition, we obtained a population estimate of suckers at the Summer Lake Wildlife Management Area (WMA), where a self-sustaining population became established after a fish salvage from Hart Lake in 1991 when the lakes desiccated. Close

• 237. [Article] Warner Sucker Investigations (2009)

  Abstract -- The Warner sucker (Catostomus warnerensis) is endemic to the Warner Valley, an endorheic subbasin of the Great Basin in southeastern Oregon and northwestern Nevada. Historically, this species ...

  Citation × Citation Citation Abstract Copy Title: Warner Sucker Investigations (2009) Abstract -- The Warner sucker (Catostomus warnerensis) is endemic to the Warner Valley, an endorheic subbasin of the Great Basin in southeastern Oregon and northwestern Nevada. Historically, this species was abundant and its range included three permanent lakes (Hart, Crump, and Pelican), several ephemeral lakes, a network of sloughs and diversion canals, and three major tributary drainages (Honey, Deep, and Twentymile Creeks) (U.S. Fish and Wildlife Service 1985). Warner sucker abundance and distribution has declined over the past century and it was federally listed as threatened in 1985 due to habitat fragmentation and threats posed by the proliferation of piscivorous non-native game fishes (U.S. Fish and Wildlife Service 1985). The Warner sucker inhabits the lakes and low gradient stream reaches of the Warner Valley. The Warner sucker metapopulation is comprised of both lake and stream life history morphs. The lake suckers are lacustrine adfluvial or potamodromous fish that normally spawn in the streams. However, upstream migration may be blocked by low stream flows during low water years or by irrigation diversion dams. When this happens, spawning may occur in nearshore areas of the lakes (White et al. 1990). Large lake-dwelling populations of introduced fishes likely reduce recruitment by preying on young suckers (U.S. Fish and Wildlife Service 1998). The stream suckers inhabit and spawn in Honey, Deep, and Twentymile Creeks. The Recovery Plan for the Threatened and Rare Native Fishes of the Warner Basin and Alkali Subbasin (U.S. Fish and Wildlife Service 1998) sets recovery criteria for delisting the species. These criteria require that: 1) a self-sustaining metapopulation is distributed throughout the Twentymile, Honey, and Deep Creek (below the falls) drainages, and in Pelican, Crump, and Hart Lakes, 2) passage is restored within and among the Twentymile, Honey, and Deep Creek (below the falls) drainages so that the individual populations of Warner suckers can function as a metapopulation, and 3) no threats exist that would likely threaten the survival of the species over a significant portion of its range. Objectives of our 2009 investigations included: 1) obtain a mark-recapture population estimate for suckers in the Twentymile Creek drainage and describe their current distribution, 2) describe associations between the distribution of suckers and habitat variables in Twentymile Creek, 3) evaluate a non-lethal ageing technique, 4) track radiotagged lake suckers (tagged in 2008) in Hart and Crump Lakes to assess spring movement patterns, 5) track spring spawning movements of lake suckers across a PIT-tag antenna installed at the mouth of Honey Creek, 6) test the feasibility of trapping larval suckers near the mouth of Honey Creek using larval drift nets and light traps to describe the relative abundance and timing of larval sucker movements, and 7) obtain a mark-recapture population estimate of suckers at the Summer Lake Wildlife Management Area (WMA), where a self-sustaining population became established after a fish salvage from Hart Lake during the 1991 drought. Title: Warner Sucker Investigations (2009) Abstract -- The Warner sucker (Catostomus warnerensis) is endemic to the Warner Valley, an endorheic subbasin of the Great Basin in southeastern Oregon and northwestern Nevada. Historically, this species was abundant and its range included three permanent lakes (Hart, Crump, and Pelican), several ephemeral lakes, a network of sloughs and diversion canals, and three major tributary drainages (Honey, Deep, and Twentymile Creeks) (U.S. Fish and Wildlife Service 1985). Warner sucker abundance and distribution has declined over the past century and it was federally listed as threatened in 1985 due to habitat fragmentation and threats posed by the proliferation of piscivorous non-native game fishes (U.S. Fish and Wildlife Service 1985). The Warner sucker inhabits the lakes and low gradient stream reaches of the Warner Valley. The Warner sucker metapopulation is comprised of both lake and stream life history morphs. The lake suckers are lacustrine adfluvial or potamodromous fish that normally spawn in the streams. However, upstream migration may be blocked by low stream flows during low water years or by irrigation diversion dams. When this happens, spawning may occur in nearshore areas of the lakes (White et al. 1990). Large lake-dwelling populations of introduced fishes likely reduce recruitment by preying on young suckers (U.S. Fish and Wildlife Service 1998). The stream suckers inhabit and spawn in Honey, Deep, and Twentymile Creeks. The Recovery Plan for the Threatened and Rare Native Fishes of the Warner Basin and Alkali Subbasin (U.S. Fish and Wildlife Service 1998) sets recovery criteria for delisting the species. These criteria require that: 1) a self-sustaining metapopulation is distributed throughout the Twentymile, Honey, and Deep Creek (below the falls) drainages, and in Pelican, Crump, and Hart Lakes, 2) passage is restored within and among the Twentymile, Honey, and Deep Creek (below the falls) drainages so that the individual populations of Warner suckers can function as a metapopulation, and 3) no threats exist that would likely threaten the survival of the species over a significant portion of its range. Objectives of our 2009 investigations included: 1) obtain a mark-recapture population estimate for suckers in the Twentymile Creek drainage and describe their current distribution, 2) describe associations between the distribution of suckers and habitat variables in Twentymile Creek, 3) evaluate a non-lethal ageing technique, 4) track radiotagged lake suckers (tagged in 2008) in Hart and Crump Lakes to assess spring movement patterns, 5) track spring spawning movements of lake suckers across a PIT-tag antenna installed at the mouth of Honey Creek, 6) test the feasibility of trapping larval suckers near the mouth of Honey Creek using larval drift nets and light traps to describe the relative abundance and timing of larval sucker movements, and 7) obtain a mark-recapture population estimate of suckers at the Summer Lake Wildlife Management Area (WMA), where a self-sustaining population became established after a fish salvage from Hart Lake during the 1991 drought. Close

• 238. [Article] Willamette BiOp - Genetic Stock Identification and Relative Natural Production of Willamette River Steelhead

  Abstract -- We used genotypic data from 15 microsatellite loci to characterize the stock structure of Oncorhynchus mykiss in the upper Willamette River basin. We then used two analytical approaches, implemented ...

  Citation × Citation Citation Abstract Copy Title: Willamette BiOp - Genetic Stock Identification and Relative Natural Production of Willamette River Steelhead Abstract -- We used genotypic data from 15 microsatellite loci to characterize the stock structure of Oncorhynchus mykiss in the upper Willamette River basin. We then used two analytical approaches, implemented in the programs ONCOR and STRUCTURE, to assign (presumably) natural-origin, unmarked fish to their most likely reporting group or hybrid class. We investigated sibling relationships among unknown samples with the program ML RELATE. In the upper Willamette River, O. mykiss genetic structure can be characterized by four principal groups: summer steelhead of Skamania stock ancestry, eastern tributaries winter steelhead, western tributaries winter steelhead and resident rainbow trout. We found that about 10% of unmarked juvenile O. mykiss sampled at Willamette Falls in 2009-2011 were summer steelhead and that an additional 10% of samples were summer x winter steelhead hybrids. Most O. mykiss sampled from the McKenzie River were either summer steelhead or summer x winter steelhead hybrids. Natural production of pure summer steelhead appeared to be very low in the North and South Santiam rivers, though summer steelhead hybrids represented 11.1% and 14.8% of samples. Results from ML RELATE analyses appeared unreliable and inconclusive, and may have been limited by low genetic diversity among summer steelhead samples. We provide several recommendations to better understand and reduce potentially negative interactions between hatchery summer steelhead and native upper Willamette River O. mykiss populations. These include reductions in adult steelhead on natural spawning grounds, improved reproductive isolation between hatchery and native populations and additional research to evaluate genetic integrity within and among O. mykiss populations. Title: Willamette BiOp - Genetic Stock Identification and Relative Natural Production of Willamette River Steelhead Abstract -- We used genotypic data from 15 microsatellite loci to characterize the stock structure of Oncorhynchus mykiss in the upper Willamette River basin. We then used two analytical approaches, implemented in the programs ONCOR and STRUCTURE, to assign (presumably) natural-origin, unmarked fish to their most likely reporting group or hybrid class. We investigated sibling relationships among unknown samples with the program ML RELATE. In the upper Willamette River, O. mykiss genetic structure can be characterized by four principal groups: summer steelhead of Skamania stock ancestry, eastern tributaries winter steelhead, western tributaries winter steelhead and resident rainbow trout. We found that about 10% of unmarked juvenile O. mykiss sampled at Willamette Falls in 2009-2011 were summer steelhead and that an additional 10% of samples were summer x winter steelhead hybrids. Most O. mykiss sampled from the McKenzie River were either summer steelhead or summer x winter steelhead hybrids. Natural production of pure summer steelhead appeared to be very low in the North and South Santiam rivers, though summer steelhead hybrids represented 11.1% and 14.8% of samples. Results from ML RELATE analyses appeared unreliable and inconclusive, and may have been limited by low genetic diversity among summer steelhead samples. We provide several recommendations to better understand and reduce potentially negative interactions between hatchery summer steelhead and native upper Willamette River O. mykiss populations. These include reductions in adult steelhead on natural spawning grounds, improved reproductive isolation between hatchery and native populations and additional research to evaluate genetic integrity within and among O. mykiss populations. Close

• 239. [Article] Warner Valley Fish Investigations- Warner Suckers Progress Reports 2008

  Abstract -- The Warner sucker (Catostomus warnerensis) is endemic to the Warner Valley, an endorheic subbasin of the Great Basin in southeastern Oregon and northwestern Nevada. This species was historically ...

  Citation × Citation Citation Abstract Copy Title: Warner Valley Fish Investigations- Warner Suckers Progress Reports 2008 Abstract -- The Warner sucker (Catostomus warnerensis) is endemic to the Warner Valley, an endorheic subbasin of the Great Basin in southeastern Oregon and northwestern Nevada. This species was historically abundant and its historical range includes three permanent lakes (Hart, Crump, and Pelican), several ephemeral lakes, a network of sloughs and diversion canals, and three major tributary drainages (Honey, Deep, and Twentymile Creeks). Warner sucker abundance and distribution has declined over the past century and it was federally listed as threatened in 1985 due to habitat fragmentation and threats posed by the proliferation of piscivorous non-native game fishes (U.S. Fish and Wildlife Service 1985). The Warner Valley is a northeast-southwest trending endorheic basin which extends approximately 90 km (Figure 1). The elevation of the valley floor is approximately 1,370 m and the basin is bound by fault block escarpments, the Warner Rim on the west and Hart Mountain and Poker Jim Ridge on the east. The Warner basin was formed during the middle Tertiary and late Quaternary geologic periods as a result of volcanic and tectonic activity (Baldwin 1976). Abundant precipitation during the Pleistocene Epoch resulted in the formation of Pluvial Lake Warner (Hubbs and Miller 1948). At its maximum extent approximately 11,000 years ago, the lake reached approximately 100 m in depth and 1,300 km2 in area (Snyder et al. 1964, Weide 1975). In 2008, precipitation and snow pack were near average and Hart and Crump Lakes never filled completely. In 2007, Crump Lake water levels were very low with less than a quarter of the surface area wetted during the winter. Both lakes have been watered continuously since 1993. The Warner sucker inhabits the lakes and low gradient stream reaches of the Warner Valley. Two life history forms are present that comprise the metapopulation of Warner suckers: lake and stream morphs. The lake suckers are lacustrine adfluvial or potamodromous fish which normally spawn in the streams. However, upstream migration may be blocked by low stream flows during dry water years or by irrigation diversion dams and spawning may occur in nearshore areas of the lakes (White et al. 1990). The stream suckers inhabit and spawn in the three major tributary drainages (Honey, Deep, and Twentymile Creeks). Large lake-dwelling populations of introduced fishes in the lakes likely reduce sucker recruitment by predation on young suckers (U.S. Fish and Wildlife Service 1998). The Recovery Plan for the Threatened and Rare Native Fishes of the Warner Basin and Alkali Subbasin (U.S. Fish and Wildlife Service 1998) sets recovery criteria for delisting the species. These criteria require that (1) a self-sustaining metapopulation is distributed throughout the Twentymile, Honey, and Deep Creek (below the falls) drainages, and in Pelican, Crump, and Hart Lakes, (2) passage is restored within and among the Twentymile, Honey, and Deep Creek (below the falls) drainages so that the individual populations of Warner suckers can function as a metapopulation, and (3) no threats exist that would likely threaten the survival of the species over a significant portion of its range. In 2008, we conducted investigations in Hart and Crump Lakes to quantify the abundance and distribution of Warner suckers, to search for evidence of recent recruitment, and to estimate sucker abundance relative to nonnative fish abundance. In addition we investigated growth and movement patterns. We used Passive Integrated Transponder (PIT) tagged suckers to determine growth rates and movements, tracked radio-tagged suckers to document seasonal spawning migrations, fished a screw trap in Twelvemile Creek to monitor downstream movements, and operated a trap at the Dyke diversion dam on Twentymile Creek to monitor upstream movements. Title: Warner Valley Fish Investigations- Warner Suckers Progress Reports 2008 Abstract -- The Warner sucker (Catostomus warnerensis) is endemic to the Warner Valley, an endorheic subbasin of the Great Basin in southeastern Oregon and northwestern Nevada. This species was historically abundant and its historical range includes three permanent lakes (Hart, Crump, and Pelican), several ephemeral lakes, a network of sloughs and diversion canals, and three major tributary drainages (Honey, Deep, and Twentymile Creeks). Warner sucker abundance and distribution has declined over the past century and it was federally listed as threatened in 1985 due to habitat fragmentation and threats posed by the proliferation of piscivorous non-native game fishes (U.S. Fish and Wildlife Service 1985). The Warner Valley is a northeast-southwest trending endorheic basin which extends approximately 90 km (Figure 1). The elevation of the valley floor is approximately 1,370 m and the basin is bound by fault block escarpments, the Warner Rim on the west and Hart Mountain and Poker Jim Ridge on the east. The Warner basin was formed during the middle Tertiary and late Quaternary geologic periods as a result of volcanic and tectonic activity (Baldwin 1976). Abundant precipitation during the Pleistocene Epoch resulted in the formation of Pluvial Lake Warner (Hubbs and Miller 1948). At its maximum extent approximately 11,000 years ago, the lake reached approximately 100 m in depth and 1,300 km2 in area (Snyder et al. 1964, Weide 1975). In 2008, precipitation and snow pack were near average and Hart and Crump Lakes never filled completely. In 2007, Crump Lake water levels were very low with less than a quarter of the surface area wetted during the winter. Both lakes have been watered continuously since 1993. The Warner sucker inhabits the lakes and low gradient stream reaches of the Warner Valley. Two life history forms are present that comprise the metapopulation of Warner suckers: lake and stream morphs. The lake suckers are lacustrine adfluvial or potamodromous fish which normally spawn in the streams. However, upstream migration may be blocked by low stream flows during dry water years or by irrigation diversion dams and spawning may occur in nearshore areas of the lakes (White et al. 1990). The stream suckers inhabit and spawn in the three major tributary drainages (Honey, Deep, and Twentymile Creeks). Large lake-dwelling populations of introduced fishes in the lakes likely reduce sucker recruitment by predation on young suckers (U.S. Fish and Wildlife Service 1998). The Recovery Plan for the Threatened and Rare Native Fishes of the Warner Basin and Alkali Subbasin (U.S. Fish and Wildlife Service 1998) sets recovery criteria for delisting the species. These criteria require that (1) a self-sustaining metapopulation is distributed throughout the Twentymile, Honey, and Deep Creek (below the falls) drainages, and in Pelican, Crump, and Hart Lakes, (2) passage is restored within and among the Twentymile, Honey, and Deep Creek (below the falls) drainages so that the individual populations of Warner suckers can function as a metapopulation, and (3) no threats exist that would likely threaten the survival of the species over a significant portion of its range. In 2008, we conducted investigations in Hart and Crump Lakes to quantify the abundance and distribution of Warner suckers, to search for evidence of recent recruitment, and to estimate sucker abundance relative to nonnative fish abundance. In addition we investigated growth and movement patterns. We used Passive Integrated Transponder (PIT) tagged suckers to determine growth rates and movements, tracked radio-tagged suckers to document seasonal spawning migrations, fished a screw trap in Twelvemile Creek to monitor downstream movements, and operated a trap at the Dyke diversion dam on Twentymile Creek to monitor upstream movements. Close

• 240. [Article] Status, Distribution, and Life History Investigations of Warner Suckers, 2006-2010 Information Reports number 2011-02

  Abstract -- The Warner sucker Catostomus warnerensis is endemic to the Warner Valley, a subbasin of the Great Basin in southeastern Oregon and northwestern Nevada. This species was historically abundant ...

  Citation × Citation Citation Abstract Copy Title: Status, Distribution, and Life History Investigations of Warner Suckers, 2006-2010 Information Reports number 2011-02 Abstract -- The Warner sucker Catostomus warnerensis is endemic to the Warner Valley, a subbasin of the Great Basin in southeastern Oregon and northwestern Nevada. This species was historically abundant (Snyder 1908) and its historical range includes three permanent lakes (Hart, Crump, and Pelican), several ephemeral lakes, a network of sloughs and diversion canals, and three major tributary drainages (Honey, Deep, and Twentymile creeks). Warner sucker abundance and distribution has declined over the past century and it was federally listed as threatened in 1985 due to habitat fragmentation and threats posed by the proliferation of piscivorous non-native game fishes (U.S. Fish and Wildlife Service 1985). The Warner Valley is a northeast-southwest trending endorheic basin that extends approximately 90 km (Figure 1). The elevation of the valley floor is approximately 1,370 m and the basin is bound by fault block escarpments, the Warner Rim on the west and Hart Mountain and Poker Jim Ridge on the east. The Warner basin was formed during the middle Tertiary and late Quaternary geologic periods as a result of volcanic and tectonic activity (Baldwin 1974). Abundant precipitation during the Pleistocene Epoch resulted in the formation of Pluvial Lake Warner (Hubbs and Miller 1948). At its maximum extent approximately 11,000 years ago, the lake reached approximately 100 m in depth and 1,300 km2 in area (Snyder et al. 1964; Weide 1975). The Warner sucker inhabits the lakes and low gradient stream reaches of the Warner Valley. The metapopulation of Warner suckers is comprised of two life history forms: lake and stream morphs. The lake suckers display a lacustrine-adfluvial pattern in which they spend most of the year in the lake and spawn in the streams. However, when upstream migration is hindered by low stream flows during drought years or by irrigation diversion dams, lake suckers may spawn in nearshore areas of the lakes (White et al. 1990). Large lake-dwelling populations of introduced fishes in the lakes likely reduce sucker recruitment by predation on young suckers (U.S. Fish and Wildlife Service 1998). Periodic lake desiccation also threatens the lake suckers. The stream suckers display a fluvial life-history pattern and spawn in the three major tributary drainages (Honey, Deep, and Twentymile Creeks). Threats specific to the stream form include water withdrawals for irrigation and impacts from grazing. Stream suckers recolonized the lakes after past drying events (mid-1930’s and early-1990’s). The Recovery Plan for the Threatened and Rare Native Fishes of the Warner Basin and Alkali Subbasin (U.S. Fish and Wildlife Service 1998) sets three recovery criteria for delisting the species. These criteria require that: (1) a self-sustaining metapopulation is distributed throughout the drainages of Twentymile Creek, Honey Creek, and below the falls on Deep Creek, and in Pelican, Crump, and Hart Lakes; (2) passage is restored within and among these drainages so that individual populations of Warner suckers can function as a metapopulation; and (3) no threats exist that would likely threaten the survival of the species over a significant portion of its range. The Oregon Department of Fish and Wildlife’s (ODFW’s) Native Fish Investigations Project conducted investigations from 2006 through 2010 to describe the conservation (recovery) status of Warner suckers. The objectives of our investigations were to: 1) describe the current distribution of suckers in the Warner subbasin, 2) estimate their abundance in the lakes and streams, 3) collect life history information, and 4) describe the primary factors that currently limit the sucker’s ability to maintain a functioning metapopulation, including connectivity/fragmentation of habitats and factors affecting successful recruitment in the lake and stream environments. Previous similar studies were conducted in 1990, 1991, 1994, 1995, 1996, 1997, and 2001 (White et al. 1990; White et al. 1991; Allen et al. 1994; Allen et al. 1995; Allen et al. 1996; Bosse et al. 1997; Hartzell et al. 2001). We addressed these objectives by implementing the following tasks: 1) conducting surveys in Hart and Crump Lakes to describe the distribution and quantify the abundance of Warner suckers, search for evidence of recent recruitment, estimate sucker abundance relative to nonnative fish abundance, and describe certain life history characteristics, 2) tagging suckers with Passive Integrated Transponder (PIT) tags in the lakes and tributaries to estimate growth rates and describe seasonal movements, 3) radio tracking suckers in the lakes and tributaries to describe seasonal movements, 4) fishing screw traps in Warner basin tributaries to monitor downstream movements, 5) operating a trap at a fish ladder on a Warner tributary to assess upstream passage success, 6) conducting surveys in Warner basin tributaries to describe the current distribution of stream resident populations of Warner suckers and to quantify their abundance, 7) describing associations between the distribution of suckers and habitat variables in Twentymile Creek, 8) trapping larval suckers in the tributaries to describe the relative abundance and timing of larval movements, 9) describing life history parameters including growth rates, length frequency distributions, length at maturity, and weight-length relationships, 10) evaluating a nonlethal ageing technique, 11) describing the distribution and abundance of the Warner suckers at Summer Lake Wildlife Management area, where a self-sustaining population became established after fish salvage from Hart Lake during the 1992 drought, and 12) collecting tissue samples for future genetic analyses. This report compiles the results of this work, synthesizes and interprets findings relative to the conservation status of the species, and recommends future studies. Title: Status, Distribution, and Life History Investigations of Warner Suckers, 2006-2010 Information Reports number 2011-02 Abstract -- The Warner sucker Catostomus warnerensis is endemic to the Warner Valley, a subbasin of the Great Basin in southeastern Oregon and northwestern Nevada. This species was historically abundant (Snyder 1908) and its historical range includes three permanent lakes (Hart, Crump, and Pelican), several ephemeral lakes, a network of sloughs and diversion canals, and three major tributary drainages (Honey, Deep, and Twentymile creeks). Warner sucker abundance and distribution has declined over the past century and it was federally listed as threatened in 1985 due to habitat fragmentation and threats posed by the proliferation of piscivorous non-native game fishes (U.S. Fish and Wildlife Service 1985). The Warner Valley is a northeast-southwest trending endorheic basin that extends approximately 90 km (Figure 1). The elevation of the valley floor is approximately 1,370 m and the basin is bound by fault block escarpments, the Warner Rim on the west and Hart Mountain and Poker Jim Ridge on the east. The Warner basin was formed during the middle Tertiary and late Quaternary geologic periods as a result of volcanic and tectonic activity (Baldwin 1974). Abundant precipitation during the Pleistocene Epoch resulted in the formation of Pluvial Lake Warner (Hubbs and Miller 1948). At its maximum extent approximately 11,000 years ago, the lake reached approximately 100 m in depth and 1,300 km2 in area (Snyder et al. 1964; Weide 1975). The Warner sucker inhabits the lakes and low gradient stream reaches of the Warner Valley. The metapopulation of Warner suckers is comprised of two life history forms: lake and stream morphs. The lake suckers display a lacustrine-adfluvial pattern in which they spend most of the year in the lake and spawn in the streams. However, when upstream migration is hindered by low stream flows during drought years or by irrigation diversion dams, lake suckers may spawn in nearshore areas of the lakes (White et al. 1990). Large lake-dwelling populations of introduced fishes in the lakes likely reduce sucker recruitment by predation on young suckers (U.S. Fish and Wildlife Service 1998). Periodic lake desiccation also threatens the lake suckers. The stream suckers display a fluvial life-history pattern and spawn in the three major tributary drainages (Honey, Deep, and Twentymile Creeks). Threats specific to the stream form include water withdrawals for irrigation and impacts from grazing. Stream suckers recolonized the lakes after past drying events (mid-1930’s and early-1990’s). The Recovery Plan for the Threatened and Rare Native Fishes of the Warner Basin and Alkali Subbasin (U.S. Fish and Wildlife Service 1998) sets three recovery criteria for delisting the species. These criteria require that: (1) a self-sustaining metapopulation is distributed throughout the drainages of Twentymile Creek, Honey Creek, and below the falls on Deep Creek, and in Pelican, Crump, and Hart Lakes; (2) passage is restored within and among these drainages so that individual populations of Warner suckers can function as a metapopulation; and (3) no threats exist that would likely threaten the survival of the species over a significant portion of its range. The Oregon Department of Fish and Wildlife’s (ODFW’s) Native Fish Investigations Project conducted investigations from 2006 through 2010 to describe the conservation (recovery) status of Warner suckers. The objectives of our investigations were to: 1) describe the current distribution of suckers in the Warner subbasin, 2) estimate their abundance in the lakes and streams, 3) collect life history information, and 4) describe the primary factors that currently limit the sucker’s ability to maintain a functioning metapopulation, including connectivity/fragmentation of habitats and factors affecting successful recruitment in the lake and stream environments. Previous similar studies were conducted in 1990, 1991, 1994, 1995, 1996, 1997, and 2001 (White et al. 1990; White et al. 1991; Allen et al. 1994; Allen et al. 1995; Allen et al. 1996; Bosse et al. 1997; Hartzell et al. 2001). We addressed these objectives by implementing the following tasks: 1) conducting surveys in Hart and Crump Lakes to describe the distribution and quantify the abundance of Warner suckers, search for evidence of recent recruitment, estimate sucker abundance relative to nonnative fish abundance, and describe certain life history characteristics, 2) tagging suckers with Passive Integrated Transponder (PIT) tags in the lakes and tributaries to estimate growth rates and describe seasonal movements, 3) radio tracking suckers in the lakes and tributaries to describe seasonal movements, 4) fishing screw traps in Warner basin tributaries to monitor downstream movements, 5) operating a trap at a fish ladder on a Warner tributary to assess upstream passage success, 6) conducting surveys in Warner basin tributaries to describe the current distribution of stream resident populations of Warner suckers and to quantify their abundance, 7) describing associations between the distribution of suckers and habitat variables in Twentymile Creek, 8) trapping larval suckers in the tributaries to describe the relative abundance and timing of larval movements, 9) describing life history parameters including growth rates, length frequency distributions, length at maturity, and weight-length relationships, 10) evaluating a nonlethal ageing technique, 11) describing the distribution and abundance of the Warner suckers at Summer Lake Wildlife Management area, where a self-sustaining population became established after fish salvage from Hart Lake during the 1992 drought, and 12) collecting tissue samples for future genetic analyses. This report compiles the results of this work, synthesizes and interprets findings relative to the conservation status of the species, and recommends future studies. Close