Search

Search Results

• 291. [Article] Abundance, Life History, and Distribution of Bull Trout in the Hood River Basin: A Summary of Findings from 2006 to 2009 Information Reports number 2010-01

  Abstract -- Bull trout have been adversely affected by many land, water, and fisheries management activities throughout the range of the species. Degraded and fragmented habitat and negative interactions with ...

  Citation × Citation Citation Abstract Copy Title: Abundance, Life History, and Distribution of Bull Trout in the Hood River Basin: A Summary of Findings from 2006 to 2009 Information Reports number 2010-01 Abstract -- Bull trout have been adversely affected by many land, water, and fisheries management activities throughout the range of the species. Degraded and fragmented habitat and negative interactions with nonnative fishes have led to a decline in bull trout distribution and abundance, several local extirpations, and a federal listing in 1998 as a threatened species under the Endangered Species Act (USFWS 2002). Distribution and abundance of bull trout also have declined in Oregon, and most management units in the state are considered to be threatened by conservation risks (ODFW 2005). One of these at-risk management units exists in the Hood River basin (ODFW 2005). Bull trout in Hood River basin currently are thought to exist as two independent reproductive units (USFWS 2002), known as local populations (Rieman and McIntyre 1995). The Clear Branch local population was isolated from the rest of the basin by the construction of Clear Branch Dam in 1968. This dam provides limited downstream fish passage during periods of spill and no voluntary upstream passage. Bull trout in this population inhabit Laurance Lake reservoir and the tributaries Pinnacle Creek and upper Clear Branch, which flow into the reservoir. The Hood River local population is distributed in the mainstem Hood River, Middle Fork Hood River (Middle Fork), and a few Middle Fork tributaries. Fluvial migrants from Hood River basin also forage and winter in the Columbia River (Pribyl et al. 1996, Buchanan et al. 1997). Bull trout have been observed in the East and West Fork basins of the Hood River, but these sightings have been rare. Presently, there is little evidence to suggest local populations exist in these tributary basins (USFWS 2002, Reagan and Olsen 2008). The status of both local populations is extremely precarious. Threats that put the Clear Branch population at risk of extirpation include low abundance, negative interactions with illegally introduced smallmouth bass, isolation from upstream migration and immigration, and diminished spawning and rearing habitat (USFW 1998). The Hood River population also appears to be small and is affected by passage barriers, unscreened irrigation diversions, impaired water quality, and periodic debris flows during glacial outbursts (USFWS 1998). As mandated by their federally designated threatened status, recovery plans were drafted by the US Fish and Wildlife Service (USFWS) for each distinct population segment, including for Hood River bull trout in 2002. This draft plan listed four goals for recovery in this basin: 1) establish at least one more local population in addition to the two existing populations, 2) increase the estimated adult population in the basin to at least 500 individuals, 3) achieve a stable or increasing trend at the population recovery level for at least two generations (=10 years), and 4) improve habitat connectivity by addressing problems with passage and screening at diversions and seasonal water quality barriers (USFWS 2002). The recovery plan also sets out research and monitoring needs critical to the recovery of these populations. Needed are accurate adult abundance estimates; a standardized monitoring program; more life history information for each local population, including how Hood River bull trout use of the Columbia River and the effects of potential passage obstructions on movement; and more information on the threat posed to the Clear Branch population by the illegal introduction of smallmouth bass in Lake Laurance reservoir. The Oregon Department of Fish and Wildlife (ODFW), with the help of the USDA Forest Service (USFS), initiated a four-year study in 2006 seeking to address these needs by synthesizing available data and conducting further studies to improve our understanding of the abundance, life history, and potential limiting factors of bull trout in the Hood River recovery unit. This report describes our findings, summarizes previous studies in the context of new information, and recommends a standardized monitoring protocol and future research. Our specific study objectives were as follows: 1. Assess adult abundance of the Clear Branch local population and develop a monitoring protocol to track abundance trends that is statistically reliable, cost-effective, and that minimizes potential adverse effects on this small isolated population. 2. Describe the juvenile and adult life history patterns of the Clear Branch local population. 3. Assess the potential impact of smallmouth bass on bull trout in Laurance Lake reservoir. 4. Determine current distribution of bull trout reproduction and early rearing in potential bull trout streams in the Hood River basin. 5. Describe the migratory life history of Hood River bull trout and assess the potential impacts of Coe Diversion and two new falls on the Middle Fork Hood River (scoured by the November 2006 glacial outburst) on bull trout migrations. Title: Abundance, Life History, and Distribution of Bull Trout in the Hood River Basin: A Summary of Findings from 2006 to 2009 Information Reports number 2010-01 Abstract -- Bull trout have been adversely affected by many land, water, and fisheries management activities throughout the range of the species. Degraded and fragmented habitat and negative interactions with nonnative fishes have led to a decline in bull trout distribution and abundance, several local extirpations, and a federal listing in 1998 as a threatened species under the Endangered Species Act (USFWS 2002). Distribution and abundance of bull trout also have declined in Oregon, and most management units in the state are considered to be threatened by conservation risks (ODFW 2005). One of these at-risk management units exists in the Hood River basin (ODFW 2005). Bull trout in Hood River basin currently are thought to exist as two independent reproductive units (USFWS 2002), known as local populations (Rieman and McIntyre 1995). The Clear Branch local population was isolated from the rest of the basin by the construction of Clear Branch Dam in 1968. This dam provides limited downstream fish passage during periods of spill and no voluntary upstream passage. Bull trout in this population inhabit Laurance Lake reservoir and the tributaries Pinnacle Creek and upper Clear Branch, which flow into the reservoir. The Hood River local population is distributed in the mainstem Hood River, Middle Fork Hood River (Middle Fork), and a few Middle Fork tributaries. Fluvial migrants from Hood River basin also forage and winter in the Columbia River (Pribyl et al. 1996, Buchanan et al. 1997). Bull trout have been observed in the East and West Fork basins of the Hood River, but these sightings have been rare. Presently, there is little evidence to suggest local populations exist in these tributary basins (USFWS 2002, Reagan and Olsen 2008). The status of both local populations is extremely precarious. Threats that put the Clear Branch population at risk of extirpation include low abundance, negative interactions with illegally introduced smallmouth bass, isolation from upstream migration and immigration, and diminished spawning and rearing habitat (USFW 1998). The Hood River population also appears to be small and is affected by passage barriers, unscreened irrigation diversions, impaired water quality, and periodic debris flows during glacial outbursts (USFWS 1998). As mandated by their federally designated threatened status, recovery plans were drafted by the US Fish and Wildlife Service (USFWS) for each distinct population segment, including for Hood River bull trout in 2002. This draft plan listed four goals for recovery in this basin: 1) establish at least one more local population in addition to the two existing populations, 2) increase the estimated adult population in the basin to at least 500 individuals, 3) achieve a stable or increasing trend at the population recovery level for at least two generations (=10 years), and 4) improve habitat connectivity by addressing problems with passage and screening at diversions and seasonal water quality barriers (USFWS 2002). The recovery plan also sets out research and monitoring needs critical to the recovery of these populations. Needed are accurate adult abundance estimates; a standardized monitoring program; more life history information for each local population, including how Hood River bull trout use of the Columbia River and the effects of potential passage obstructions on movement; and more information on the threat posed to the Clear Branch population by the illegal introduction of smallmouth bass in Lake Laurance reservoir. The Oregon Department of Fish and Wildlife (ODFW), with the help of the USDA Forest Service (USFS), initiated a four-year study in 2006 seeking to address these needs by synthesizing available data and conducting further studies to improve our understanding of the abundance, life history, and potential limiting factors of bull trout in the Hood River recovery unit. This report describes our findings, summarizes previous studies in the context of new information, and recommends a standardized monitoring protocol and future research. Our specific study objectives were as follows: 1. Assess adult abundance of the Clear Branch local population and develop a monitoring protocol to track abundance trends that is statistically reliable, cost-effective, and that minimizes potential adverse effects on this small isolated population. 2. Describe the juvenile and adult life history patterns of the Clear Branch local population. 3. Assess the potential impact of smallmouth bass on bull trout in Laurance Lake reservoir. 4. Determine current distribution of bull trout reproduction and early rearing in potential bull trout streams in the Hood River basin. 5. Describe the migratory life history of Hood River bull trout and assess the potential impacts of Coe Diversion and two new falls on the Middle Fork Hood River (scoured by the November 2006 glacial outburst) on bull trout migrations. Close

• 292. [Article] 2008 Amphibian Distribution Surveys in Wadeable Streams and Ponds in Western and Southeast Oregon, Information Reports Number 2010-05

  Abstract -- The ODFW Oregon Conservation Strategy identified monitoring needs for 17 amphibian species native to the state of Oregon that are designated as “Strategy species”, or Species of Greatest Conservation ...

  Citation × Citation Citation Abstract Copy Title: 2008 Amphibian Distribution Surveys in Wadeable Streams and Ponds in Western and Southeast Oregon, Information Reports Number 2010-05 Abstract -- The ODFW Oregon Conservation Strategy identified monitoring needs for 17 amphibian species native to the state of Oregon that are designated as “Strategy species”, or Species of Greatest Conservation Need (per USFWS requirements for State Wildlife Action Plans). The distribution of many species of amphibians in western Oregon is sparsely documented (Oregon Conservation Strategy, page 27). Although a broad-scale survey for amphibian presence would provide important baseline information about amphibian species composition and distribution, most studies have focused on limited areas. The majority of Oregon’s amphibians rely on aquatic habitats at some point of their life, either for breeding and juvenile development or to inhabit as adults. Most aquatic amphibians breed from late winter to early summer, and adults frequently remain in or near their breeding sites into the summer. Most tadpoles and juvenile amphibians are also active in and occupy aquatic habitats during the summer. Ongoing aquatic habitat and fish surveys are opportunities to observe species and life stages (breeding adults, tadpoles and juveniles) that occupy aquatic or riparian habitats during the summer. One cost-effective approach is to combine amphibian surveys with existing aquatic habitat and fish surveys such as those conducted as part of the Oregon Plan for Salmon and Watersheds (OCSRI 1997). The Oregon Plan has been in place since 1997 and the monitoring component provides a survey framework for streams in the lower Columbia River and Oregon coast drainages. The sampling framework is also compatible with implementation of the aquatic components of the Conservation Strategy, as demonstrated by this study. This study describes the presence of amphibians in and along wadeable streams in coast and lower Columbia River drainages of Oregon, ponds and sloughs in the Willamette Valley, and selected streams in the Great Basin of southeast and central Oregon. As a component of monitoring under the Oregon Plan, the Aquatic Inventories Project (AIP) conducts aquatic habitat surveys at randomly selected and spatially balanced sites across all 1st through 4th order streams in coastal and lower Columbia River drainages. The purpose of the habitat surveys is to describe stream morphology, instream physical habitat, and riparian vegetation. Because the surveyors were already observing features within and alongside the stream channel, they were able to record observations of amphibians. The amphibian component was consistent with the survey protocol used by the US Geological Survey’s Amphibian Research and Monitoring Initiative (http://armi.usgs.gov/). The advantage of coupling an amphibian component with the OR Plan aquatic surveys was that it not only was an efficient use of resources, but more importantly, provided information using a statistically rigorous survey design across a broad geographic area. The Native Fish Investigations Project began a six year study in 2007 to document the distribution and abundance of redband trout in the Great Basin region of Eastern Oregon. The site selection procedure is comparable to the statistical standards as the Oregon Plan survey design. Amphibian data are also collected during three other survey projects, and although the site selection procedure does not conform to the same statistical standards as the Oregon Plan survey design, the projects offer a number of opportunities to collect amphibian occurrence information over a wide variety of habitats. The amphibian observations from these three projects are also included in this report. The three projects are as follows: • AIP conducts aquatic habitat surveys on selected streams throughout the state. • AIP conducts aquatic habitat surveys at stream habitat restoration projects in Western Oregon. • Native Fish Project conducts surveys of pond and slough sites for Oregon chub in the Willamette Valley. Due to the success of the 2006 and 2007 field studies, we continued our research during the summer of 2008 to improve our knowledge of distribution and community structure of amphibians. The summer 2008 surveys took place in 9 of Oregon’s 10 ecoregions (Figure 1) (Thorson et al. 2003). Ecoregions provide a framework for discussing amphibian distribution across the state because they are relatively large areas defined by distinctive geographic and ecological (flora and fauna) characteristics. The goals of our 2008 work were to: • Increase the consistency, efficiency and ability of habitat crews in identifying amphibians through improved training. • Increase knowledge of distribution, community structure, and habitat associations of amphibians in streams in: o Western Oregon coastal and lower Columbia drainages. o Ponds, sloughs and other off-channel aquatic habitats in the Willamette Valley. o Great Basin of eastern Oregon and selected streams in central Oregon. • Combine the 2008 observations with the 2006-07 results. Title: 2008 Amphibian Distribution Surveys in Wadeable Streams and Ponds in Western and Southeast Oregon, Information Reports Number 2010-05 Abstract -- The ODFW Oregon Conservation Strategy identified monitoring needs for 17 amphibian species native to the state of Oregon that are designated as “Strategy species”, or Species of Greatest Conservation Need (per USFWS requirements for State Wildlife Action Plans). The distribution of many species of amphibians in western Oregon is sparsely documented (Oregon Conservation Strategy, page 27). Although a broad-scale survey for amphibian presence would provide important baseline information about amphibian species composition and distribution, most studies have focused on limited areas. The majority of Oregon’s amphibians rely on aquatic habitats at some point of their life, either for breeding and juvenile development or to inhabit as adults. Most aquatic amphibians breed from late winter to early summer, and adults frequently remain in or near their breeding sites into the summer. Most tadpoles and juvenile amphibians are also active in and occupy aquatic habitats during the summer. Ongoing aquatic habitat and fish surveys are opportunities to observe species and life stages (breeding adults, tadpoles and juveniles) that occupy aquatic or riparian habitats during the summer. One cost-effective approach is to combine amphibian surveys with existing aquatic habitat and fish surveys such as those conducted as part of the Oregon Plan for Salmon and Watersheds (OCSRI 1997). The Oregon Plan has been in place since 1997 and the monitoring component provides a survey framework for streams in the lower Columbia River and Oregon coast drainages. The sampling framework is also compatible with implementation of the aquatic components of the Conservation Strategy, as demonstrated by this study. This study describes the presence of amphibians in and along wadeable streams in coast and lower Columbia River drainages of Oregon, ponds and sloughs in the Willamette Valley, and selected streams in the Great Basin of southeast and central Oregon. As a component of monitoring under the Oregon Plan, the Aquatic Inventories Project (AIP) conducts aquatic habitat surveys at randomly selected and spatially balanced sites across all 1st through 4th order streams in coastal and lower Columbia River drainages. The purpose of the habitat surveys is to describe stream morphology, instream physical habitat, and riparian vegetation. Because the surveyors were already observing features within and alongside the stream channel, they were able to record observations of amphibians. The amphibian component was consistent with the survey protocol used by the US Geological Survey’s Amphibian Research and Monitoring Initiative (http://armi.usgs.gov/). The advantage of coupling an amphibian component with the OR Plan aquatic surveys was that it not only was an efficient use of resources, but more importantly, provided information using a statistically rigorous survey design across a broad geographic area. The Native Fish Investigations Project began a six year study in 2007 to document the distribution and abundance of redband trout in the Great Basin region of Eastern Oregon. The site selection procedure is comparable to the statistical standards as the Oregon Plan survey design. Amphibian data are also collected during three other survey projects, and although the site selection procedure does not conform to the same statistical standards as the Oregon Plan survey design, the projects offer a number of opportunities to collect amphibian occurrence information over a wide variety of habitats. The amphibian observations from these three projects are also included in this report. The three projects are as follows: • AIP conducts aquatic habitat surveys on selected streams throughout the state. • AIP conducts aquatic habitat surveys at stream habitat restoration projects in Western Oregon. • Native Fish Project conducts surveys of pond and slough sites for Oregon chub in the Willamette Valley. Due to the success of the 2006 and 2007 field studies, we continued our research during the summer of 2008 to improve our knowledge of distribution and community structure of amphibians. The summer 2008 surveys took place in 9 of Oregon’s 10 ecoregions (Figure 1) (Thorson et al. 2003). Ecoregions provide a framework for discussing amphibian distribution across the state because they are relatively large areas defined by distinctive geographic and ecological (flora and fauna) characteristics. The goals of our 2008 work were to: • Increase the consistency, efficiency and ability of habitat crews in identifying amphibians through improved training. • Increase knowledge of distribution, community structure, and habitat associations of amphibians in streams in: o Western Oregon coastal and lower Columbia drainages. o Ponds, sloughs and other off-channel aquatic habitats in the Willamette Valley. o Great Basin of eastern Oregon and selected streams in central Oregon. • Combine the 2008 observations with the 2006-07 results. Close

• 293. [Article] Amphibian Distribution in Wadeable Streams and Ponds in Western and Southeast Oregon, 2009-2010 Progress Reports 2011

  Abstract -- The ODFW Oregon Conservation Strategy identified monitoring needs for 17 amphibian species native to the state of Oregon that are designated as “Strategy Species”, or “Species of Greatest Conservation ...

  Citation × Citation Citation Abstract Copy Title: Amphibian Distribution in Wadeable Streams and Ponds in Western and Southeast Oregon, 2009-2010 Progress Reports 2011 Abstract -- The ODFW Oregon Conservation Strategy identified monitoring needs for 17 amphibian species native to the state of Oregon that are designated as “Strategy Species”, or “Species of Greatest Conservation Need” (per USFWS requirements for State Wildlife Action Plans). The distribution of many species of amphibians in western Oregon is sparsely documented (Oregon Conservation Strategy, page 27). Although a broad-scale survey for amphibian presence would provide important baseline information about amphibian species composition and distribution, most studies have focused on limited areas. The majority of Oregon’s amphibians rely on aquatic habitats at some point of their life, either for breeding and juvenile development or to inhabit as adults. Most aquatic amphibians breed from late winter to early summer, and adults frequently remain in or near their breeding sites into the summer. Most tadpoles and juvenile amphibians are also active in and occupy aquatic habitats during the summer. Ongoing aquatic habitat and fish surveys are opportunities to observe species and life stages (breeding adults, tadpoles and juveniles) that occupy aquatic or riparian habitats during the summer. One cost-effective approach is to combine amphibian surveys with existing aquatic habitat and fish surveys such as those conducted as part of the Oregon Plan for Salmon and Watersheds (OCSRI 1997). The Oregon Plan has been in place since 1997 and the monitoring component provides a survey framework for streams in the lower Columbia River and Oregon coast drainages. The sampling framework is also compatible with implementation of the aquatic components of the Conservation Strategy, as demonstrated by this study. This study describes the presence of amphibians in and along wadeable streams in coast and lower Columbia River drainages of Oregon, ponds and sloughs in the Willamette Valley, and selected streams in the Great Basin of southeast and central Oregon. As a component of monitoring under the Oregon Plan, the Aquatic Inventories Project (AIP) conducts aquatic habitat surveys at randomly selected and spatially balanced sites across all 1st through 4th order streams in coastal and lower Columbia River drainages. The purpose of the habitat surveys is to describe stream morphology, instream physical habitat, and riparian vegetation. Because the surveyors were already observing features within and alongside the stream channel, they were able to record observations of amphibians. The advantage of coupling an amphibian component with the OR Plan aquatic surveys was that it not only was an efficient use of resources, but more importantly, provided information using a statistically rigorous survey design across a broad geographic area. The Native Fish Investigations Project began a six year study in 2007 to document the distribution and abundance of redband trout in the Great Basin region of Eastern Oregon. The site selection procedure is comparable to the statistical standards as the Oregon Plan survey design. Amphibian data are also collected during three other survey projects, and although the site selection procedure does not conform to the same statistical standards as the Oregon Plan survey design, the projects offer a number of opportunities to collect amphibian occurrence information over a wide variety of habitats. The amphibian observations from these three projects are also included in this report. The three projects are as follows: AIP conducts aquatic habitat surveys on selected streams throughout the state. AIP conducts aquatic habitat surveys at stream habitat restoration projects in Western Oregon. Native Fish Project conducts surveys of pond and slough sites for Oregon chub in the Willamette Valley. Due to the success of the 2007 and 2008 field studies, we continued our research during the summer of 2009 and 2010 to improve our knowledge of distribution and community structure of amphibians. The summer 2009 and 2010 surveys took place in 9 of Oregon’s 10 ecoregions (Figure 1) (Thorson et al. 2003). Ecoregions provide a framework for discussing amphibian distribution across the state because they are relatively large areas defined by distinctive geographic and ecological (flora and fauna) characteristics. The goals of our 2009-2010 work were to: Increase the consistency, efficiency and ability of habitat crews in identifying amphibians through improved training. Increase knowledge of distribution, community structure, and habitat associations of amphibians in streams in: Western Oregon coastal and lower Columbia drainages. Ponds, sloughs and other off-channel aquatic habitats in the Willamette Valley. Great Basin of eastern Oregon and selected streams in central Oregon. Combine the 2009-2010 observations with the 2007-2008 results. Title: Amphibian Distribution in Wadeable Streams and Ponds in Western and Southeast Oregon, 2009-2010 Progress Reports 2011 Abstract -- The ODFW Oregon Conservation Strategy identified monitoring needs for 17 amphibian species native to the state of Oregon that are designated as “Strategy Species”, or “Species of Greatest Conservation Need” (per USFWS requirements for State Wildlife Action Plans). The distribution of many species of amphibians in western Oregon is sparsely documented (Oregon Conservation Strategy, page 27). Although a broad-scale survey for amphibian presence would provide important baseline information about amphibian species composition and distribution, most studies have focused on limited areas. The majority of Oregon’s amphibians rely on aquatic habitats at some point of their life, either for breeding and juvenile development or to inhabit as adults. Most aquatic amphibians breed from late winter to early summer, and adults frequently remain in or near their breeding sites into the summer. Most tadpoles and juvenile amphibians are also active in and occupy aquatic habitats during the summer. Ongoing aquatic habitat and fish surveys are opportunities to observe species and life stages (breeding adults, tadpoles and juveniles) that occupy aquatic or riparian habitats during the summer. One cost-effective approach is to combine amphibian surveys with existing aquatic habitat and fish surveys such as those conducted as part of the Oregon Plan for Salmon and Watersheds (OCSRI 1997). The Oregon Plan has been in place since 1997 and the monitoring component provides a survey framework for streams in the lower Columbia River and Oregon coast drainages. The sampling framework is also compatible with implementation of the aquatic components of the Conservation Strategy, as demonstrated by this study. This study describes the presence of amphibians in and along wadeable streams in coast and lower Columbia River drainages of Oregon, ponds and sloughs in the Willamette Valley, and selected streams in the Great Basin of southeast and central Oregon. As a component of monitoring under the Oregon Plan, the Aquatic Inventories Project (AIP) conducts aquatic habitat surveys at randomly selected and spatially balanced sites across all 1st through 4th order streams in coastal and lower Columbia River drainages. The purpose of the habitat surveys is to describe stream morphology, instream physical habitat, and riparian vegetation. Because the surveyors were already observing features within and alongside the stream channel, they were able to record observations of amphibians. The advantage of coupling an amphibian component with the OR Plan aquatic surveys was that it not only was an efficient use of resources, but more importantly, provided information using a statistically rigorous survey design across a broad geographic area. The Native Fish Investigations Project began a six year study in 2007 to document the distribution and abundance of redband trout in the Great Basin region of Eastern Oregon. The site selection procedure is comparable to the statistical standards as the Oregon Plan survey design. Amphibian data are also collected during three other survey projects, and although the site selection procedure does not conform to the same statistical standards as the Oregon Plan survey design, the projects offer a number of opportunities to collect amphibian occurrence information over a wide variety of habitats. The amphibian observations from these three projects are also included in this report. The three projects are as follows: AIP conducts aquatic habitat surveys on selected streams throughout the state. AIP conducts aquatic habitat surveys at stream habitat restoration projects in Western Oregon. Native Fish Project conducts surveys of pond and slough sites for Oregon chub in the Willamette Valley. Due to the success of the 2007 and 2008 field studies, we continued our research during the summer of 2009 and 2010 to improve our knowledge of distribution and community structure of amphibians. The summer 2009 and 2010 surveys took place in 9 of Oregon’s 10 ecoregions (Figure 1) (Thorson et al. 2003). Ecoregions provide a framework for discussing amphibian distribution across the state because they are relatively large areas defined by distinctive geographic and ecological (flora and fauna) characteristics. The goals of our 2009-2010 work were to: Increase the consistency, efficiency and ability of habitat crews in identifying amphibians through improved training. Increase knowledge of distribution, community structure, and habitat associations of amphibians in streams in: Western Oregon coastal and lower Columbia drainages. Ponds, sloughs and other off-channel aquatic habitats in the Willamette Valley. Great Basin of eastern Oregon and selected streams in central Oregon. Combine the 2009-2010 observations with the 2007-2008 results. Close

• 294. [Article] Downstream rearing of juvenile Chinook salmon abundance, distribution and growth in the Upper Mainstem of the John Day River

  Abstract -- Juvenile spring Chinook (Oncorhynchus tshawytscha) emerge from the gravel in the late winter or early spring, and most follow a life history pattern known as Natal Reach Rearing (NRR) in which ...

  Citation × Citation Citation Abstract Copy Title: Downstream rearing of juvenile Chinook salmon abundance, distribution and growth in the Upper Mainstem of the John Day River Abstract -- Juvenile spring Chinook (Oncorhynchus tshawytscha) emerge from the gravel in the late winter or early spring, and most follow a life history pattern known as Natal Reach Rearing (NRR) in which juvenile fish remain in the stream reaches where they were spawned until their second spring of life when they start migrating towards the ocean (Healey 1991). However, in Columbia River tributaries, some juveniles have been observed following a Downstream Rearing (DSR) life history, in which they start moving downstream during their first spring towards other nursery habitats or perhaps ocean rearing (Copeland & Venditti 2009; Schroeder et al. 2016). Rearing in different habitats during their first year gives fish with these two life histories access to diverse food resources and, it is hypothesized that, this leads to different survival and growth advantages for these two groups. Differences in growth are of interest in efforts to conserve this threatened species because size is positively correlated to survival for salmon across multiple stages of their life cycle (Groot & Margolis 1991; Healey 1991; Quinn & Peterson 1996; Roni et al. 2012) Chinook salmon in the upper John Day River, Oregon, exhibit both NRR and DSR life history patterns. Fish following the DSR life history pattern are larger than NRR fish late in the spring, possibly due to factors such as higher fish density, lower stream productivity, and colder water temperatures in their natal reach than in the downstream reaches. However, this size advantage may be lost due to adverse summer conditions. Hot summer days combined with the withdrawal of water for agriculture lead to stream water temperatures well above lethal thresholds for salmon in many downstream reaches. DSR fish have been observed in tributaries of the mainstem John Day River, however their growth and survival during summer is unknown. Title: Downstream rearing of juvenile Chinook salmon abundance, distribution and growth in the Upper Mainstem of the John Day River Abstract -- Juvenile spring Chinook (Oncorhynchus tshawytscha) emerge from the gravel in the late winter or early spring, and most follow a life history pattern known as Natal Reach Rearing (NRR) in which juvenile fish remain in the stream reaches where they were spawned until their second spring of life when they start migrating towards the ocean (Healey 1991). However, in Columbia River tributaries, some juveniles have been observed following a Downstream Rearing (DSR) life history, in which they start moving downstream during their first spring towards other nursery habitats or perhaps ocean rearing (Copeland & Venditti 2009; Schroeder et al. 2016). Rearing in different habitats during their first year gives fish with these two life histories access to diverse food resources and, it is hypothesized that, this leads to different survival and growth advantages for these two groups. Differences in growth are of interest in efforts to conserve this threatened species because size is positively correlated to survival for salmon across multiple stages of their life cycle (Groot & Margolis 1991; Healey 1991; Quinn & Peterson 1996; Roni et al. 2012) Chinook salmon in the upper John Day River, Oregon, exhibit both NRR and DSR life history patterns. Fish following the DSR life history pattern are larger than NRR fish late in the spring, possibly due to factors such as higher fish density, lower stream productivity, and colder water temperatures in their natal reach than in the downstream reaches. However, this size advantage may be lost due to adverse summer conditions. Hot summer days combined with the withdrawal of water for agriculture lead to stream water temperatures well above lethal thresholds for salmon in many downstream reaches. DSR fish have been observed in tributaries of the mainstem John Day River, however their growth and survival during summer is unknown. Close

• 295. [Article] Effectiveness Monitoring Report for the Western Oregon Stream Restoration Program, 1999-2008 Report Number: OPSW-ODFW-2010-6

  Abstract -- State and federal agencies have invested millions of dollars to restore streams and watersheds in the Pacific Northwest over the past two decades. In Oregon alone, over 500 million dollars ...

  Citation × Citation Citation Abstract Copy Title: Effectiveness Monitoring Report for the Western Oregon Stream Restoration Program, 1999-2008 Report Number: OPSW-ODFW-2010-6 Abstract -- State and federal agencies have invested millions of dollars to restore streams and watersheds in the Pacific Northwest over the past two decades. In Oregon alone, over 500 million dollars has been spent on completed projects from 1995 to 2007 (Oregon Watershed Enhancement Board 2009). Restoration practitioners have distributed the investment among watershed scale activities such as road repair, dam removal, and upland management, and stream scale activities such as passage, instream complexity, and riparian plantings. The Western Oregon Stream Restoration Program (WOSRP) was established to work in cooperation with private and corporate landowners to restore stream habitat for juvenile and adult salmonids. In addition to the WOSRP, the Oregon Watershed Enhancement Board (OWEB) funds restoration projects with local watershed councils, who commonly partner with state and federal agencies. Eight WOSRP restoration biologists in Tillamook, Newport, Charleston, Gold Beach, Roseburg, Clackamas, and Salem select sites and implement projects consistent with the criteria described in Thom et al (2001). A monitoring component is integrated in the program, with surveys coordinated and reported by a biologist in Corvallis. The goal of the monitoring program is to assess the long term effectiveness of instream restoration projects implemented by WOSRP, and to evaluate progress towards salmon conservation and recovery goals in Oregon’s coastal basins. The WOSRP restoration sites are distributed throughout the Willamette, Lower Columbia, and coastal drainage's. Restoration treatments added large wood and/or boulders, improved fish passage, planted trees in riparian areas, or were a combination of the three. Large wood was placed in complex jams at intervals throughout the stream to increase stream roughness and complexity. Boulders were sometimes used in conjunction with wood jams to provide stability to the structures, and prevent large wood from moving downstream and posing a hazard to culverts and bridges. Bedrock dominated streams were often treated with boulders to collect gravel and cobble, intended to aggrade the streambed. In the future, large wood may be added to these streams. Fish passage projects opened previously inaccessible habitat to juvenile and/or adult salmonids while riparian plantings and fencing were designed to improve riparian vegetation and bank structure. The project length varied from site to site. Fish passage sites were quite short, but provided access to kilometers of fish habitat, and large wood sites were up to several kilometers in length. Large wood and boulder placement projects have become commonplace in the Pacific Northwest to restore complex stream habitat for juvenile coho and other salmonids (Katz et al. 2007, Roni et al. 2008). Detailed assessments have been published for individual projects or experiments (e.g. Moore and Gregory, 1988, Nickelson et al. 1992, Cederholm et al.1997). More extensive evaluations have used a post treatment design (Hicks et al 1991, Roni and Quinn 2001), but none have used a pre- and post treatment design. In this paper we evaluate habitat changes at 103 restoration projects in western Oregon from pre-treatment to one year post treatment to 6 years following treatment. Projects commonly treated 0.5 – 1 km of stream, but some extended up to 6 km. The projects we evaluated in this paper were treated with large logs, usually arranged in jams, and were not cabled or driven into banks or bottom. As of 2008, the OWEB and WOSRP projects have treated approximately 750 km of stream with large wood (Figure 1), 120 km with boulders, and over 4,000 km of stream have been made accessible by replacing and/or removing culverts. Each year, OWEB receives 210 grant applications for restoration projects. These projects generally adhere to a similar selection process and design, so the results of this study can be expected to apply more broadly within the Pacific Northwest. Roni et al (2008), in a synthesis paper, summarized many of the potential physical benefits of restoration; these include pool depth and frequency, habitat complexity, woody debris, and sediment retention and quality of spawning gravel. Some projects in deeply incised channels have reduced the incision and increased bed elevation. Evaluations of biological responses have been confounded by natural variability of populations, duration of study, or length of stream examined. For example, determination of success based on spawning ground counts is problematic because of variation in ocean survival. However, longer duration and watershed scale studies have shown positive responses of juvenile and adult salmon (Johnson et al 2005). Burnett et al. (2008) conducted a systematic review of peer-reviewed articles to examine the effects of large wood placement on salmonid abundance, growth, or survival, or on overall stream habitat complexity. Few publications were both relevant and met the rigorous standards outlined in their review. Although the review supported short term improvements in habitat complexity, the relationship to salmonid productivity was less definitive. Notable exceptions included Johnson et al. (2005) cited above, and Solazzi et al. (2000). An alternative approach to directly assessing biological response is to model potential changes in abundance or productivity. The Habitat Limiting Factors Model (Reeves et al. 1989, Nickelson et al.1992a, Nickelson 1998) was developed to quantify the carrying capacity of coastal streams for juvenile coho during the summer and winter. Use of this model is appropriate because most of the instream restoration projects in western Oregon were intended to improve habitat for juvenile coho. In this paper, we evaluated the physical response directly, and quantified the potential response of juvenile coho salmon by application of the Habitat Limiting Factors Model. Project effectiveness monitoring requires linking the restoration treatment to improved physical conditions for and biological response of salmon (Katz et al. 2007) and defining desired outcomes (Rumps et al. 2007). Because the WOSRP projects were designed to improve ecological and hydrologic stream function specifically for salmonids, we evaluated 1) retention of wood structures, 2) natural recruitment of additional wood, 3) increase in pool number, area, and depth, 4) retention of gravels and sorting of finer substrates, and 5) increase in channel complexity – secondary channels and off-channel habitats. Biological evaluation was based on estimates of the potential carrying capacity for juvenile coho during the overwinter life stage. The primary objectives of this evaluation are to test for these changes one year following treatment and 6 years following treatment. Secondarily, we evaluated the response of the projects by geographic location and position along the stream network. Previous WOSRP monitoring reports (e.g. Jacobsen and Jones 2003, Jacobsen et al. 2007) have focused on conditions one year following treatment, with relatively few sites assessed 2-3 years following restoration. Since 2003, the restoration projects have increased in complexity – more and larger pieces and jams, and treated more kilometers of stream length per site. The WOSRP program has provided a unique opportunity to evaluate the effects of restoration projects over longer times and broader geographic scales than previously feasible. We have been surveying the restoration sites in both summer and winter to monitor changes in stream habitat and evaluate the success of treatments, such as the placement of wood and/or boulders and fish passage. Surveys are logistically easier to manage in the summer, but surveys conducted during the winter provide a more timely and accurate assessment of over-winter rearing potential for juvenile coho. Because we have paired surveys, we are able to assess the added value of revisits across seasons. We test the hypothesis that habitat characteristics at the restoration sites do not change from summer to winter. The findings permit us to modify the survey program if the information is duplicative, and use the resources in another fashion. Title: Effectiveness Monitoring Report for the Western Oregon Stream Restoration Program, 1999-2008 Report Number: OPSW-ODFW-2010-6 Abstract -- State and federal agencies have invested millions of dollars to restore streams and watersheds in the Pacific Northwest over the past two decades. In Oregon alone, over 500 million dollars has been spent on completed projects from 1995 to 2007 (Oregon Watershed Enhancement Board 2009). Restoration practitioners have distributed the investment among watershed scale activities such as road repair, dam removal, and upland management, and stream scale activities such as passage, instream complexity, and riparian plantings. The Western Oregon Stream Restoration Program (WOSRP) was established to work in cooperation with private and corporate landowners to restore stream habitat for juvenile and adult salmonids. In addition to the WOSRP, the Oregon Watershed Enhancement Board (OWEB) funds restoration projects with local watershed councils, who commonly partner with state and federal agencies. Eight WOSRP restoration biologists in Tillamook, Newport, Charleston, Gold Beach, Roseburg, Clackamas, and Salem select sites and implement projects consistent with the criteria described in Thom et al (2001). A monitoring component is integrated in the program, with surveys coordinated and reported by a biologist in Corvallis. The goal of the monitoring program is to assess the long term effectiveness of instream restoration projects implemented by WOSRP, and to evaluate progress towards salmon conservation and recovery goals in Oregon’s coastal basins. The WOSRP restoration sites are distributed throughout the Willamette, Lower Columbia, and coastal drainage's. Restoration treatments added large wood and/or boulders, improved fish passage, planted trees in riparian areas, or were a combination of the three. Large wood was placed in complex jams at intervals throughout the stream to increase stream roughness and complexity. Boulders were sometimes used in conjunction with wood jams to provide stability to the structures, and prevent large wood from moving downstream and posing a hazard to culverts and bridges. Bedrock dominated streams were often treated with boulders to collect gravel and cobble, intended to aggrade the streambed. In the future, large wood may be added to these streams. Fish passage projects opened previously inaccessible habitat to juvenile and/or adult salmonids while riparian plantings and fencing were designed to improve riparian vegetation and bank structure. The project length varied from site to site. Fish passage sites were quite short, but provided access to kilometers of fish habitat, and large wood sites were up to several kilometers in length. Large wood and boulder placement projects have become commonplace in the Pacific Northwest to restore complex stream habitat for juvenile coho and other salmonids (Katz et al. 2007, Roni et al. 2008). Detailed assessments have been published for individual projects or experiments (e.g. Moore and Gregory, 1988, Nickelson et al. 1992, Cederholm et al.1997). More extensive evaluations have used a post treatment design (Hicks et al 1991, Roni and Quinn 2001), but none have used a pre- and post treatment design. In this paper we evaluate habitat changes at 103 restoration projects in western Oregon from pre-treatment to one year post treatment to 6 years following treatment. Projects commonly treated 0.5 – 1 km of stream, but some extended up to 6 km. The projects we evaluated in this paper were treated with large logs, usually arranged in jams, and were not cabled or driven into banks or bottom. As of 2008, the OWEB and WOSRP projects have treated approximately 750 km of stream with large wood (Figure 1), 120 km with boulders, and over 4,000 km of stream have been made accessible by replacing and/or removing culverts. Each year, OWEB receives 210 grant applications for restoration projects. These projects generally adhere to a similar selection process and design, so the results of this study can be expected to apply more broadly within the Pacific Northwest. Roni et al (2008), in a synthesis paper, summarized many of the potential physical benefits of restoration; these include pool depth and frequency, habitat complexity, woody debris, and sediment retention and quality of spawning gravel. Some projects in deeply incised channels have reduced the incision and increased bed elevation. Evaluations of biological responses have been confounded by natural variability of populations, duration of study, or length of stream examined. For example, determination of success based on spawning ground counts is problematic because of variation in ocean survival. However, longer duration and watershed scale studies have shown positive responses of juvenile and adult salmon (Johnson et al 2005). Burnett et al. (2008) conducted a systematic review of peer-reviewed articles to examine the effects of large wood placement on salmonid abundance, growth, or survival, or on overall stream habitat complexity. Few publications were both relevant and met the rigorous standards outlined in their review. Although the review supported short term improvements in habitat complexity, the relationship to salmonid productivity was less definitive. Notable exceptions included Johnson et al. (2005) cited above, and Solazzi et al. (2000). An alternative approach to directly assessing biological response is to model potential changes in abundance or productivity. The Habitat Limiting Factors Model (Reeves et al. 1989, Nickelson et al.1992a, Nickelson 1998) was developed to quantify the carrying capacity of coastal streams for juvenile coho during the summer and winter. Use of this model is appropriate because most of the instream restoration projects in western Oregon were intended to improve habitat for juvenile coho. In this paper, we evaluated the physical response directly, and quantified the potential response of juvenile coho salmon by application of the Habitat Limiting Factors Model. Project effectiveness monitoring requires linking the restoration treatment to improved physical conditions for and biological response of salmon (Katz et al. 2007) and defining desired outcomes (Rumps et al. 2007). Because the WOSRP projects were designed to improve ecological and hydrologic stream function specifically for salmonids, we evaluated 1) retention of wood structures, 2) natural recruitment of additional wood, 3) increase in pool number, area, and depth, 4) retention of gravels and sorting of finer substrates, and 5) increase in channel complexity – secondary channels and off-channel habitats. Biological evaluation was based on estimates of the potential carrying capacity for juvenile coho during the overwinter life stage. The primary objectives of this evaluation are to test for these changes one year following treatment and 6 years following treatment. Secondarily, we evaluated the response of the projects by geographic location and position along the stream network. Previous WOSRP monitoring reports (e.g. Jacobsen and Jones 2003, Jacobsen et al. 2007) have focused on conditions one year following treatment, with relatively few sites assessed 2-3 years following restoration. Since 2003, the restoration projects have increased in complexity – more and larger pieces and jams, and treated more kilometers of stream length per site. The WOSRP program has provided a unique opportunity to evaluate the effects of restoration projects over longer times and broader geographic scales than previously feasible. We have been surveying the restoration sites in both summer and winter to monitor changes in stream habitat and evaluate the success of treatments, such as the placement of wood and/or boulders and fish passage. Surveys are logistically easier to manage in the summer, but surveys conducted during the winter provide a more timely and accurate assessment of over-winter rearing potential for juvenile coho. Because we have paired surveys, we are able to assess the added value of revisits across seasons. We test the hypothesis that habitat characteristics at the restoration sites do not change from summer to winter. The findings permit us to modify the survey program if the information is duplicative, and use the resources in another fashion. Close

• 296. [Article] Hood River Bull Trout Abundance, Life History, and Habitat Connectivity, 2007 Progress Reports 2007

  Abstract -- Hood River bull trout are thought to exist as two independent reproductive units (USFWS 2004), known as local populations (Rieman and McIntyre 1995). The Clear Branch local population is isolated ...

  Citation × Citation Citation Abstract Copy Title: Hood River Bull Trout Abundance, Life History, and Habitat Connectivity, 2007 Progress Reports 2007 Abstract -- Hood River bull trout are thought to exist as two independent reproductive units (USFWS 2004), known as local populations (Rieman and McIntyre 1995). The Clear Branch local population is isolated above Clear Branch Dam, which provides limited downstream fish passage during infrequent and sporadic periods of spill and no upstream passage. Bull trout in this population inhabit Laurance Lake Reservoir and tributaries upstream of Clear Branch Dam. The Hood River local population occurs in the mainstem Hood River and Middle Fork Hood River downstream of the Clear Branch Dam and a small number of adult bull trout migrate each year into the Hood River from the Columbia River (Figure 1). The status of both populations is extremely precarious. The Clear Branch population is at risk of a random extinction event due to low numbers, negative interactions with non-native smallmouth bass, isolation and limited spawning habitat (USFWS, 1998). The Hood River population also appears to be small and is threatened by passage barriers, unscreened irrigation systems, impaired water quality and periodic siltation of spawning substrate by glacial outbursts. Clear Branch bull trout spawn in Clear Branch and Pinnacle Creek. After rearing in these two natal streams for an unknown time period, most are believed to migrate downstream to Laurance Lake Reservoir. Clear Branch bull trout have been documented passing over the dam spillway during high water events (Pribyl et al. 1996) and may provide a recruitment source for the Hood River local population. Adult bull trout tagged at Powerdale Dam have been observed at Coe Branch irrigation diversion and in a trap at the base of Clear Branch dam. These fish may have been attempting to reach spawning areas located upstream of the dam. However, the success of bull trout migrating downstream via the spillway or the possibility of successfully navigating through the diversion network has never been determined. Depending on the water year, the Middle Fork Irrigation District (MFID) may not spill at all, or the timing of the spill may not coincide with the timing of downstream migration, which is currently unknown (East Fork Hood River and Middle Fork Hood River Watershed analysis). Smallmouth bass were discovered in Lake Laurance Reservoir in the 1990s. Creel surveys have shown that large adult bass are caught occasionally in the reservoir and schools of bass fry have been seen by district fish biologist (Rod French, ODFW, personal communication), suggesting that they are spawning successfully. This illegal introduction poses a potential threat to the Clear Branch bull trout population, but its magnitude is unknown because the bass population size and degree of interaction between the two species are unknown. Bull trout and smallmouth bass have significantly different temperature preferences and tolerances, with bull trout being one of the most sensitive coldwater species and bass being a warm water species. Lake Laurance, a relatively high-altitude reservoir at 890 m (2,920 feet), does not provide ideal bass habitat so these two species may have largely non-overlapping distributions or differing activity periods (Terry Shrader, ODFW warmwater fish biologist, personal communication). However, based on past reservoir temperature data (Berger et al. 2005), there are periods in the reservoir when there is potential for bull trout and bass interaction: periods when bull trout are susceptible to bass predation and when juvenile fish might compete for resources. Spawning activity of the Hood River local population has been observed in a few locations within the Middle Fork of Hood River (Figure 1). Although consistent and extensive spawning areas for this population are not known, some of the locations where juvenile rearing or potential bull trout redds have been observed include the Middle Fork Hood River and some of its tributaries: Bear Creek, Compass Creek and Coe Branch (USFWS 2004). However, Coe Branch, Compass Creek, and the Middle Fork are glacial streams with a high volume of sand and silt which may compromise spawning success. No bull trout spawning or rearing has been observed on the East and West Forks of Hood River. The Middle Fork and mainstem Hood River provide foraging, migration and overwintering habitat. Hood River bull trout are also known to migrate into the Columbia River. Two bull trout tagged at Powerdale Dam (RK 7.2 of mainstem Hood River) were recovered near Drano Lake in Washington State; and one was captured 11 kilometers downstream of the confluence of the Hood and Columbia Rivers (USFWS 2004). Every year (usually between May and July), adult bull trout, presumably migrating upstream from the Columbia River, are captured and anchor tagged at Powerdale Dam. Although some of these tagged fish have been observed upstream (one in Coe Branch and three below Clear Branch dam), the spawning destination of fluvial adults within the Hood River basin is largely unknown. Dispersing juvenile bull trout and migrating adults in this local population are threatened by flow diversions with inadequate screening and passage facilities. Several structures are suspected to impede upstream migration or entrain juvenile and adult bull trout into irrigation works (Pribyl et al. 1996, HRWG 1999). These structures include: the diversion at Clear Branch Dam (passage and screening), Coe Branch (passage and screening), and the Farmers Irrigation District diversion (screening) on the mainstem Hood River (HRWG 1999). However, little research has been conducted to assess the impacts of these structures on migrating bull trout. Beyond a general knowledge of the distribution of Hood River bull trout and the nature of anthropogenic factors that potentially restrict their life history and habitat connectivity, little is known about this recovery unit. Baseline information about adult abundance is lacking for both local populations, the potential of a source (Clear Branch) and sink (Hood River) relationship between the two local populations has not been explored, and the migratory life history of adult fish caught at Powerdale Dam is unknown. The degree to which irrigation and hydropower diversions hamper connectivity within the Hood River basin is also poorly understood. Migratory life histories have been viewed as key to species persistence (Rieman and McIntyre 1995; Dunham and Rieman 1999), and understanding movement patterns and associated habitat requirements are critical to maintaining those migratory forms (Muhlfeld and Morotz 2005; Hostettler 2005). Gaining this information is also critical to evaluating bull trout recovery in the Hood River Subbasin (Coccoli 2004). The Oregon Department of Fish and Wildlife (ODFW) initiated a study in 2006 to improve our understanding of the abundance, life history, and potential limiting factors of the bull trout in this recovery unit. This report describes findings for the first two years of the study (2006-2007). Specific study objectives for the first two years were: 1. Determine the migratory life history of Hood River bull trout and assess the potential impacts of flow diversions and two new falls on the Middle Fork Hood River (scoured by the November 2006 glacial outburst) on bull trout migrations. 2. Determine current distribution of bull trout reproduction and early rearing in historical and potential bull trout streams in the Hood River Subbasin. 3. Determine the juvenile and adult life history the Clear Branch local population and develop a statistically reliable and cost-effective protocol for monitoring the abundance of adult Clear Branch bull trout. 4. Assess the potential impact of smallmouth bass on bull trout in Laurance Lake Reservoir. Title: Hood River Bull Trout Abundance, Life History, and Habitat Connectivity, 2007 Progress Reports 2007 Abstract -- Hood River bull trout are thought to exist as two independent reproductive units (USFWS 2004), known as local populations (Rieman and McIntyre 1995). The Clear Branch local population is isolated above Clear Branch Dam, which provides limited downstream fish passage during infrequent and sporadic periods of spill and no upstream passage. Bull trout in this population inhabit Laurance Lake Reservoir and tributaries upstream of Clear Branch Dam. The Hood River local population occurs in the mainstem Hood River and Middle Fork Hood River downstream of the Clear Branch Dam and a small number of adult bull trout migrate each year into the Hood River from the Columbia River (Figure 1). The status of both populations is extremely precarious. The Clear Branch population is at risk of a random extinction event due to low numbers, negative interactions with non-native smallmouth bass, isolation and limited spawning habitat (USFWS, 1998). The Hood River population also appears to be small and is threatened by passage barriers, unscreened irrigation systems, impaired water quality and periodic siltation of spawning substrate by glacial outbursts. Clear Branch bull trout spawn in Clear Branch and Pinnacle Creek. After rearing in these two natal streams for an unknown time period, most are believed to migrate downstream to Laurance Lake Reservoir. Clear Branch bull trout have been documented passing over the dam spillway during high water events (Pribyl et al. 1996) and may provide a recruitment source for the Hood River local population. Adult bull trout tagged at Powerdale Dam have been observed at Coe Branch irrigation diversion and in a trap at the base of Clear Branch dam. These fish may have been attempting to reach spawning areas located upstream of the dam. However, the success of bull trout migrating downstream via the spillway or the possibility of successfully navigating through the diversion network has never been determined. Depending on the water year, the Middle Fork Irrigation District (MFID) may not spill at all, or the timing of the spill may not coincide with the timing of downstream migration, which is currently unknown (East Fork Hood River and Middle Fork Hood River Watershed analysis). Smallmouth bass were discovered in Lake Laurance Reservoir in the 1990s. Creel surveys have shown that large adult bass are caught occasionally in the reservoir and schools of bass fry have been seen by district fish biologist (Rod French, ODFW, personal communication), suggesting that they are spawning successfully. This illegal introduction poses a potential threat to the Clear Branch bull trout population, but its magnitude is unknown because the bass population size and degree of interaction between the two species are unknown. Bull trout and smallmouth bass have significantly different temperature preferences and tolerances, with bull trout being one of the most sensitive coldwater species and bass being a warm water species. Lake Laurance, a relatively high-altitude reservoir at 890 m (2,920 feet), does not provide ideal bass habitat so these two species may have largely non-overlapping distributions or differing activity periods (Terry Shrader, ODFW warmwater fish biologist, personal communication). However, based on past reservoir temperature data (Berger et al. 2005), there are periods in the reservoir when there is potential for bull trout and bass interaction: periods when bull trout are susceptible to bass predation and when juvenile fish might compete for resources. Spawning activity of the Hood River local population has been observed in a few locations within the Middle Fork of Hood River (Figure 1). Although consistent and extensive spawning areas for this population are not known, some of the locations where juvenile rearing or potential bull trout redds have been observed include the Middle Fork Hood River and some of its tributaries: Bear Creek, Compass Creek and Coe Branch (USFWS 2004). However, Coe Branch, Compass Creek, and the Middle Fork are glacial streams with a high volume of sand and silt which may compromise spawning success. No bull trout spawning or rearing has been observed on the East and West Forks of Hood River. The Middle Fork and mainstem Hood River provide foraging, migration and overwintering habitat. Hood River bull trout are also known to migrate into the Columbia River. Two bull trout tagged at Powerdale Dam (RK 7.2 of mainstem Hood River) were recovered near Drano Lake in Washington State; and one was captured 11 kilometers downstream of the confluence of the Hood and Columbia Rivers (USFWS 2004). Every year (usually between May and July), adult bull trout, presumably migrating upstream from the Columbia River, are captured and anchor tagged at Powerdale Dam. Although some of these tagged fish have been observed upstream (one in Coe Branch and three below Clear Branch dam), the spawning destination of fluvial adults within the Hood River basin is largely unknown. Dispersing juvenile bull trout and migrating adults in this local population are threatened by flow diversions with inadequate screening and passage facilities. Several structures are suspected to impede upstream migration or entrain juvenile and adult bull trout into irrigation works (Pribyl et al. 1996, HRWG 1999). These structures include: the diversion at Clear Branch Dam (passage and screening), Coe Branch (passage and screening), and the Farmers Irrigation District diversion (screening) on the mainstem Hood River (HRWG 1999). However, little research has been conducted to assess the impacts of these structures on migrating bull trout. Beyond a general knowledge of the distribution of Hood River bull trout and the nature of anthropogenic factors that potentially restrict their life history and habitat connectivity, little is known about this recovery unit. Baseline information about adult abundance is lacking for both local populations, the potential of a source (Clear Branch) and sink (Hood River) relationship between the two local populations has not been explored, and the migratory life history of adult fish caught at Powerdale Dam is unknown. The degree to which irrigation and hydropower diversions hamper connectivity within the Hood River basin is also poorly understood. Migratory life histories have been viewed as key to species persistence (Rieman and McIntyre 1995; Dunham and Rieman 1999), and understanding movement patterns and associated habitat requirements are critical to maintaining those migratory forms (Muhlfeld and Morotz 2005; Hostettler 2005). Gaining this information is also critical to evaluating bull trout recovery in the Hood River Subbasin (Coccoli 2004). The Oregon Department of Fish and Wildlife (ODFW) initiated a study in 2006 to improve our understanding of the abundance, life history, and potential limiting factors of the bull trout in this recovery unit. This report describes findings for the first two years of the study (2006-2007). Specific study objectives for the first two years were: 1. Determine the migratory life history of Hood River bull trout and assess the potential impacts of flow diversions and two new falls on the Middle Fork Hood River (scoured by the November 2006 glacial outburst) on bull trout migrations. 2. Determine current distribution of bull trout reproduction and early rearing in historical and potential bull trout streams in the Hood River Subbasin. 3. Determine the juvenile and adult life history the Clear Branch local population and develop a statistically reliable and cost-effective protocol for monitoring the abundance of adult Clear Branch bull trout. 4. Assess the potential impact of smallmouth bass on bull trout in Laurance Lake Reservoir. Close