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• 1. [Article] Proceedings of the Wild Trout - Catchable Trout Symposium

  Abstract -- None

  Citation × Citation Citation Abstract Copy Title: Proceedings of the Wild Trout - Catchable Trout Symposium Abstract -- None Title: Proceedings of the Wild Trout - Catchable Trout Symposium Abstract -- None Close

• 2. [Article] NF - Effect of Bull Trout and Brook Trout Interactions on Foraging Habitat, Feeding Behavior, and Growth

  Abstract -- Observations of free-ranging sympatric bull trout Salvelinus confluentus and nonnative brook trout S. fontinalis in two eastern Oregon headwater streams provided little evidence of habitat ...

  Citation × Citation Citation Abstract Copy Title: NF - Effect of Bull Trout and Brook Trout Interactions on Foraging Habitat, Feeding Behavior, and Growth Abstract -- Observations of free-ranging sympatric bull trout Salvelinus confluentus and nonnative brook trout S. fontinalis in two eastern Oregon headwater streams provided little evidence of habitat partitioning. Both species held focal feeding points in similar microhabitats and fed primarily from the water column rather than from the surface or benthos. In an instream experiment, 20 enclosures were assigned one of three treatments: two bull trout, four bull trout, or a mix of two bull trout and two brook trout. In the enclosures, macroinvertebrate drift was restricted and trout densities were elevated, creating an environment of reduced food and habitat resources. Under these conditions, there was no indication of a niche shift by bull trout; feeding behavior and habitat use by bull trout did not differ depending on the presence or absence of brook trout. Brook trout in the mixed-species treatment were the most aggressive, maintained dominance in 75% of the enclosures, and exhibited significantly higher growth than sympatric bull trout. However, the effects of intra-and interspecific interactions on bull trout growth were equivalent. Given the absence of resource partitioning and a niche shift by bull trout in the presence of brook trout (despite obvious interference interactions), we suggest that the displacement of bull trout by brook trout is likely when resources are scarce. Title: NF - Effect of Bull Trout and Brook Trout Interactions on Foraging Habitat, Feeding Behavior, and Growth Abstract -- Observations of free-ranging sympatric bull trout Salvelinus confluentus and nonnative brook trout S. fontinalis in two eastern Oregon headwater streams provided little evidence of habitat partitioning. Both species held focal feeding points in similar microhabitats and fed primarily from the water column rather than from the surface or benthos. In an instream experiment, 20 enclosures were assigned one of three treatments: two bull trout, four bull trout, or a mix of two bull trout and two brook trout. In the enclosures, macroinvertebrate drift was restricted and trout densities were elevated, creating an environment of reduced food and habitat resources. Under these conditions, there was no indication of a niche shift by bull trout; feeding behavior and habitat use by bull trout did not differ depending on the presence or absence of brook trout. Brook trout in the mixed-species treatment were the most aggressive, maintained dominance in 75% of the enclosures, and exhibited significantly higher growth than sympatric bull trout. However, the effects of intra-and interspecific interactions on bull trout growth were equivalent. Given the absence of resource partitioning and a niche shift by bull trout in the presence of brook trout (despite obvious interference interactions), we suggest that the displacement of bull trout by brook trout is likely when resources are scarce. Close

• 3. [Article] Feeding behavior and diet of native bull trout Salvelinus confluentus and introduced brook trout S. fontinalis in two Eastern Oregon streams

  One of the greatest threats to native bull trout Salvelinus confluentus populations is the presence of non-native brook trout S. fontinalis. This study, conducted in two second-order Eastern Oregon streams, ...

  Citation × Citation Citation Abstract Copy Title: Feeding behavior and diet of native bull trout Salvelinus confluentus and introduced brook trout S. fontinalis in two Eastern Oregon streams Author: Gunckel, Stephanie L. One of the greatest threats to native bull trout Salvelinus confluentus populations is the presence of non-native brook trout S. fontinalis. This study, conducted in two second-order Eastern Oregon streams, investigates the effect of brook trout on the feeding behavior arid diet of bull trout. Feeding behavior, microhabitat use, and agonistic interactions were examined in a controlled in-stream experiment where twenty enclosures were randomly assigned one of three treatments: two bull trout, four bull trout, or a mix of two bull trout and two brook trout. Results provide little evidence of a niche shift for bull trout in the presence of brook trout or of resource partitioning between sympatric bull trout and brook trout. All fish held focal feeding points in similar microhabitats and fed primarily from the water column. Brook trout showed the greatest growth, were highly aggressive, and consistently dominated bull trout of equal size. Examination of stomach contents revealed allopatric bull trout, sympatric bull and brook trout fed primarily on larvae of Ephemeroptera, Trichoptera, and aquatic Diptera and terrestrial insects. Sympatric bull trout and brook trout had a high degree of dietary overlap. All fish exhibited size selective predation, and piscivory was rare. Similar habitat use, feeding behavior and diet of bull trout and brook trout, and aggressive interactions between these species suggest that, when habitat and prey resources are scarce, direct interference competition is likely, and the dominant behavior of brook trout may potentially displace bull trout. Title: Feeding behavior and diet of native bull trout Salvelinus confluentus and introduced brook trout S. fontinalis in two Eastern Oregon streams Author: Gunckel, Stephanie L. One of the greatest threats to native bull trout Salvelinus confluentus populations is the presence of non-native brook trout S. fontinalis. This study, conducted in two second-order Eastern Oregon streams, investigates the effect of brook trout on the feeding behavior arid diet of bull trout. Feeding behavior, microhabitat use, and agonistic interactions were examined in a controlled in-stream experiment where twenty enclosures were randomly assigned one of three treatments: two bull trout, four bull trout, or a mix of two bull trout and two brook trout. Results provide little evidence of a niche shift for bull trout in the presence of brook trout or of resource partitioning between sympatric bull trout and brook trout. All fish held focal feeding points in similar microhabitats and fed primarily from the water column. Brook trout showed the greatest growth, were highly aggressive, and consistently dominated bull trout of equal size. Examination of stomach contents revealed allopatric bull trout, sympatric bull and brook trout fed primarily on larvae of Ephemeroptera, Trichoptera, and aquatic Diptera and terrestrial insects. Sympatric bull trout and brook trout had a high degree of dietary overlap. All fish exhibited size selective predation, and piscivory was rare. Similar habitat use, feeding behavior and diet of bull trout and brook trout, and aggressive interactions between these species suggest that, when habitat and prey resources are scarce, direct interference competition is likely, and the dominant behavior of brook trout may potentially displace bull trout. Close

• 4. [Article] Distribution and habitat use of bull trout following the removal of nonnative brook trout

  Invasion by nonnative brook trout (Salvelinus fontinalis) often results in replacement of bull trout (Salvelinus confluentus) in western North America, but the causal mechanisms are not well understood. ...

  Citation × Citation Citation Abstract Copy Title: Distribution and habitat use of bull trout following the removal of nonnative brook trout Author: Renner, Dirk Invasion by nonnative brook trout (Salvelinus fontinalis) often results in replacement of bull trout (Salvelinus confluentus) in western North America, but the causal mechanisms are not well understood. Removal of brook trout from 1992 to 2000 from Sun Creek in southern Oregon, provided an opportunity to investigate the changes in distribution and abundance of bull trout. This study investigated bull trout distribution over from 1994 to 2003, during and following the extirpation of brook trout in 2000. In 2001 over, 8 km of contiguous stream habitat was examined to investigate bull trout habitat utilization. Bull trout abundance increased almost 300% after the removal of brook trout; however, bull trout distribution did not shift either upstream or downstream into habitat previously occupied by brook trout. This finding suggested that the occupied habitat was either critical for bull trout persistence or that factors restricted dispersal. Temperature did not appear to limit bull trout distribution remaining below 17°C with averages less than 10°C throughout Sun Creek. The downstream distribution of bull trout coincided with a point source increase of turbidity. In regions of the stream where turbidity was low bull trout abundance was positively associated with deep pools, higher average temperatures, and correlated with high densities of springs. The results of this study suggest that brook trout did not displace bull trout, underscoring the importance that point source disturbances (i.e. turbidity) can have on trout distributions. These findings reiterate the value of sampling contiguous streams as a means to identifying factors influencing trout distribution throughout a stream system. Title: Distribution and habitat use of bull trout following the removal of nonnative brook trout Author: Renner, Dirk Invasion by nonnative brook trout (Salvelinus fontinalis) often results in replacement of bull trout (Salvelinus confluentus) in western North America, but the causal mechanisms are not well understood. Removal of brook trout from 1992 to 2000 from Sun Creek in southern Oregon, provided an opportunity to investigate the changes in distribution and abundance of bull trout. This study investigated bull trout distribution over from 1994 to 2003, during and following the extirpation of brook trout in 2000. In 2001 over, 8 km of contiguous stream habitat was examined to investigate bull trout habitat utilization. Bull trout abundance increased almost 300% after the removal of brook trout; however, bull trout distribution did not shift either upstream or downstream into habitat previously occupied by brook trout. This finding suggested that the occupied habitat was either critical for bull trout persistence or that factors restricted dispersal. Temperature did not appear to limit bull trout distribution remaining below 17°C with averages less than 10°C throughout Sun Creek. The downstream distribution of bull trout coincided with a point source increase of turbidity. In regions of the stream where turbidity was low bull trout abundance was positively associated with deep pools, higher average temperatures, and correlated with high densities of springs. The results of this study suggest that brook trout did not displace bull trout, underscoring the importance that point source disturbances (i.e. turbidity) can have on trout distributions. These findings reiterate the value of sampling contiguous streams as a means to identifying factors influencing trout distribution throughout a stream system. Close

• 5. [Image] Distribution and habitat use of bull trout following the removal of nonnative brook trout

  	ill.; Printout; Thesis (M.S.)--Oregon State University, 2006; Includes bibliographical references (leaves 55-61)
  	Citation × Citation Citation Abstract Copy Title: Distribution and habitat use of bull trout following the removal of nonnative brook trout Author: Renner, Dirk Year: 2005, 2009 ill.; Printout; Thesis (M.S.)--Oregon State University, 2006; Includes bibliographical references (leaves 55-61) Title: Distribution and habitat use of bull trout following the removal of nonnative brook trout Author: Renner, Dirk Year: 2005, 2009 ill.; Printout; Thesis (M.S.)--Oregon State University, 2006; Includes bibliographical references (leaves 55-61) Close

• 6. [Article] Threemile Creek Bull Trout Protection Final Report 1998

  Abstract -- Brook Trout were removed from Threemile Creek by electrofishing and night-snorkel spear-fishing. Electrofishing removal was conducted on 11 reaches and a total of 45 passes were completed. ...

  Citation × Citation Citation Abstract Copy Title: Threemile Creek Bull Trout Protection Final Report 1998 Abstract -- Brook Trout were removed from Threemile Creek by electrofishing and night-snorkel spear-fishing. Electrofishing removal was conducted on 11 reaches and a total of 45 passes were completed. Fifty brook trout were removed. Night-snorkeling was conducted in the five reach, intergrade zone where both bull and brook trout were found. Two comprehenzive passes were completed in the first three reaches, and three passes were completed in the last two reaches. A total of 10 brook trout and 8 brook/bull trout hybrids were removed. Additionally 39 brook trout were removed from a fire pond above Threemile Creek. Mollusk and amphibian surveys were also conducted; and temperature was collected in the Threemile Creek Project Area. Title: Threemile Creek Bull Trout Protection Final Report 1998 Abstract -- Brook Trout were removed from Threemile Creek by electrofishing and night-snorkel spear-fishing. Electrofishing removal was conducted on 11 reaches and a total of 45 passes were completed. Fifty brook trout were removed. Night-snorkeling was conducted in the five reach, intergrade zone where both bull and brook trout were found. Two comprehenzive passes were completed in the first three reaches, and three passes were completed in the last two reaches. A total of 10 brook trout and 8 brook/bull trout hybrids were removed. Additionally 39 brook trout were removed from a fire pond above Threemile Creek. Mollusk and amphibian surveys were also conducted; and temperature was collected in the Threemile Creek Project Area. Close

• 7. [Article] Threemile Creek Bull Trout Protection, 1997 Final Report (OWEB #97-112-007)

  Abstract -- Brook trout removal activities were conducted on Threemile Creek beginning in late June, and ending in late September 1997. Removal efforts consisted of electrofishing in the brook trout zone ...

  Citation × Citation Citation Abstract Copy Title: Threemile Creek Bull Trout Protection, 1997 Final Report (OWEB #97-112-007) Abstract -- Brook trout removal activities were conducted on Threemile Creek beginning in late June, and ending in late September 1997. Removal efforts consisted of electrofishing in the brook trout zone and night snorkel spearing in the bull trout intergrade zone (both brook trout and bull trout present). A total of 121 brook trout and one hybrid were removed by electrofishing. Of the 121 brook trout removed, 92 were greater than 90 mm in length. During night snorkel spearing 10 brook trout and 8 hybrids were removed and a total of 54 bull trout were observed. Macroinvertebrate and amphibian surveys were conducted in early September, and temparature was monitored throughout the project area. Experimental trapping was conducted, but no fish were collected during any trapping effort. Title: Threemile Creek Bull Trout Protection, 1997 Final Report (OWEB #97-112-007) Abstract -- Brook trout removal activities were conducted on Threemile Creek beginning in late June, and ending in late September 1997. Removal efforts consisted of electrofishing in the brook trout zone and night snorkel spearing in the bull trout intergrade zone (both brook trout and bull trout present). A total of 121 brook trout and one hybrid were removed by electrofishing. Of the 121 brook trout removed, 92 were greater than 90 mm in length. During night snorkel spearing 10 brook trout and 8 hybrids were removed and a total of 54 bull trout were observed. Macroinvertebrate and amphibian surveys were conducted in early September, and temparature was monitored throughout the project area. Experimental trapping was conducted, but no fish were collected during any trapping effort. Close

• 8. [Article] Oregon's Trout Plan: A Plan for the Management of Oregon's Trout 1987

  Abstract -- The Statewide Trout Management Plan is part of the Oregon Department of Fish and Wildlife's (ODFW) planning program to provide a comprehensive, systematic, long-term approach to the management ...

  Citation × Citation Citation Abstract Copy Title: Oregon's Trout Plan: A Plan for the Management of Oregon's Trout 1987 Abstract -- The Statewide Trout Management Plan is part of the Oregon Department of Fish and Wildlife's (ODFW) planning program to provide a comprehensive, systematic, long-term approach to the management of Oregon's fish resources. The Plan contains specific goals, objectives, strategies, and guidelines for the statewide management of trout, which are based on state laws, as well as general goals and policies adopted by the Oregon Fish and Wildlife Commission, (hereafter referred to as the Commission). In turn, the Plan provides direction for basin, subbasin, and mini plans developed for individual rivers and water bodies. The relationship of the Statewide Trout Management Plan to other ODFW plans is further discussed in Appendix A. This Statewide Management Plan will direct future trout management and will be reviewed in 6 years. The plan contains brief descriptions of Oregon's trout waters, species, anglers, and economic consequences. The importance of habitat and the use of angling regulations are also discussed. The plan covers all species of native and introduced resident trout and Pacific salmon that are managed in the resident trout program (Atlantic salmon, kokanee, coho salmon, and Chinook salmon) and the anadromous form (searun) of cutthroat trout. Appendix B contains a complete list of fish treated as trout in the plan. Title: Oregon's Trout Plan: A Plan for the Management of Oregon's Trout 1987 Abstract -- The Statewide Trout Management Plan is part of the Oregon Department of Fish and Wildlife's (ODFW) planning program to provide a comprehensive, systematic, long-term approach to the management of Oregon's fish resources. The Plan contains specific goals, objectives, strategies, and guidelines for the statewide management of trout, which are based on state laws, as well as general goals and policies adopted by the Oregon Fish and Wildlife Commission, (hereafter referred to as the Commission). In turn, the Plan provides direction for basin, subbasin, and mini plans developed for individual rivers and water bodies. The relationship of the Statewide Trout Management Plan to other ODFW plans is further discussed in Appendix A. This Statewide Management Plan will direct future trout management and will be reviewed in 6 years. The plan contains brief descriptions of Oregon's trout waters, species, anglers, and economic consequences. The importance of habitat and the use of angling regulations are also discussed. The plan covers all species of native and introduced resident trout and Pacific salmon that are managed in the resident trout program (Atlantic salmon, kokanee, coho salmon, and Chinook salmon) and the anadromous form (searun) of cutthroat trout. Appendix B contains a complete list of fish treated as trout in the plan. Close

• 9. [Image] Trout Farming in Montana

  	Due to the abundant supply of clean fresh water, many areas of Montana are natural locations for trout farming. Many trout ponds are planted and maintained privately for the sole use of the owner; however, ...
  	Citation × Citation Citation Abstract Copy Title: Trout Farming in Montana Author: Quarve, P.L. Year: 1973 Due to the abundant supply of clean fresh water, many areas of Montana are natural locations for trout farming. Many trout ponds are planted and maintained privately for the sole use of the owner; however, the opportunity exists for commercial trout farming in Montana. Some commercial trout farming is currently being done, but this is only a small fraction of what could be developed Title: Trout Farming in Montana Author: Quarve, P.L. Year: 1973 Due to the abundant supply of clean fresh water, many areas of Montana are natural locations for trout farming. Many trout ponds are planted and maintained privately for the sole use of the owner; however, the opportunity exists for commercial trout farming in Montana. Some commercial trout farming is currently being done, but this is only a small fraction of what could be developed Close

• 10. [Article] Catch, Migration, Growth and Survival of Stocked Coastal Cutthroat Trout in Munsel Lake, Oregon

  The latest phase of a study of the migration, survival, growth, and catch of coastal cutthroat trout, conducted to compare cutthroat trout and rainbow trout. The document describes the geological and biological ...

  Citation × Citation Citation Abstract Copy Title: Catch, Migration, Growth and Survival of Stocked Coastal Cutthroat Trout in Munsel Lake, Oregon Author: Oregon State Game Commission, Skeesick, Delbert G. The latest phase of a study of the migration, survival, growth, and catch of coastal cutthroat trout, conducted to compare cutthroat trout and rainbow trout. The document describes the geological and biological characteristics of Munsel Creek weir, where the studies were conducted. It also includes graphs of the data and a summary of the results. Title: Catch, Migration, Growth and Survival of Stocked Coastal Cutthroat Trout in Munsel Lake, Oregon Author: Oregon State Game Commission, Skeesick, Delbert G. The latest phase of a study of the migration, survival, growth, and catch of coastal cutthroat trout, conducted to compare cutthroat trout and rainbow trout. The document describes the geological and biological characteristics of Munsel Creek weir, where the studies were conducted. It also includes graphs of the data and a summary of the results. Close

• 11. [Article] Lake Billy Chinook Creel Survey, Boat and Bank Anglers - 2009 Estimated Catch and Effort, Sampled Catch and Effort, and Estimated Catch Rates

  Abstract -- Lake Billy Chinook Creel Survey, Boat and Bank Anglers - March 1-October 31, 2009

  Citation × Citation Citation Abstract Copy Title: Lake Billy Chinook Creel Survey, Boat and Bank Anglers - 2009 Estimated Catch and Effort, Sampled Catch and Effort, and Estimated Catch Rates Abstract -- Lake Billy Chinook Creel Survey, Boat and Bank Anglers - March 1-October 31, 2009 Title: Lake Billy Chinook Creel Survey, Boat and Bank Anglers - 2009 Estimated Catch and Effort, Sampled Catch and Effort, and Estimated Catch Rates Abstract -- Lake Billy Chinook Creel Survey, Boat and Bank Anglers - March 1-October 31, 2009 Close

• 12. [Article] Lake Billy Chinook Creel Survey, Boat and Bank Anglers - 2010 Estimated Catch and Effort, Sampled Catch and Effort, and Estimated Catch Rates

  Abstract -- Lake Billy Chinook Creel Survey, Boat and Bank Anglers - March 1-October 31, 2010

  Citation × Citation Citation Abstract Copy Title: Lake Billy Chinook Creel Survey, Boat and Bank Anglers - 2010 Estimated Catch and Effort, Sampled Catch and Effort, and Estimated Catch Rates Abstract -- Lake Billy Chinook Creel Survey, Boat and Bank Anglers - March 1-October 31, 2010 Title: Lake Billy Chinook Creel Survey, Boat and Bank Anglers - 2010 Estimated Catch and Effort, Sampled Catch and Effort, and Estimated Catch Rates Abstract -- Lake Billy Chinook Creel Survey, Boat and Bank Anglers - March 1-October 31, 2010 Close

• 13. [Article] Migratory Patterns, Structure, Abundance, and Status of Bull Trout Populations from Subbasins in the Columbia Plateau and Blue Mountain Provinces, 2005 Annual Report

  Abstract -- Methods of estimating the abundance of adult bull trout, migration and temperature patterns of adult bull trout in the Lostine River, seasonal movements of subadult fluvial bull trout in Mill ...

  Citation × Citation Citation Abstract Copy Title: Migratory Patterns, Structure, Abundance, and Status of Bull Trout Populations from Subbasins in the Columbia Plateau and Blue Mountain Provinces, 2005 Annual Report Abstract -- Methods of estimating the abundance of adult bull trout, migration and temperature patterns of adult bull trout in the Lostine River, seasonal movements of subadult fluvial bull trout in Mill Creek, spatial distribution of bull trout Redds in the John Day basin and evaluation of various statistical sampling designs, analysis and synthesis of project results, life history of Mill Creek fluvial bull trout using PIT tags and cohort analysis. Title: Migratory Patterns, Structure, Abundance, and Status of Bull Trout Populations from Subbasins in the Columbia Plateau and Blue Mountain Provinces, 2005 Annual Report Abstract -- Methods of estimating the abundance of adult bull trout, migration and temperature patterns of adult bull trout in the Lostine River, seasonal movements of subadult fluvial bull trout in Mill Creek, spatial distribution of bull trout Redds in the John Day basin and evaluation of various statistical sampling designs, analysis and synthesis of project results, life history of Mill Creek fluvial bull trout using PIT tags and cohort analysis. Close

• 14. [Article] MWBTRP - Middle Fork Willamette Basin Bull Trout Rehabilitation and Monitoring Project, Annual Progress Report 2005

  Abstract -- Bull trout in the Middle Fork Willamette Basin once moved uninhibited back and forth from spawning and rearing habitats near Diamond Peak to foraging and overwintering habitats lower in the ...

  Citation × Citation Citation Abstract Copy Title: MWBTRP - Middle Fork Willamette Basin Bull Trout Rehabilitation and Monitoring Project, Annual Progress Report 2005 Abstract -- Bull trout in the Middle Fork Willamette Basin once moved uninhibited back and forth from spawning and rearing habitats near Diamond Peak to foraging and overwintering habitats lower in the basin. Construction of Dexter, Lookout Point and Hills Creek dams in the 1950s and 1960s without fish passage fragmented the habitat and limited the range of the population to above Hills Creek Dam. This population declined and the last confirmed bull trout sighting above Hills Creek dam was a photograph taken by an angler in 1990. Buchanan et al. (1997) described bull trout in the Middle Fork Willamette River as “probably extinct” after extensive surveys from 1993 through 1997 failed to observe any bull trout. In 1997 the US Forest Service and the Oregon Department of Fish and Wildlife began a program to reestablish bull trout in the Middle Fork Willamette. More than 10,000 bull trout fry have been transferred from the relatively healthy McKenzie population to the Middle Fork Willamette River. Adult bull trout are once again present in the Middle Fork Willamette, although natural reproduction has not been documented. Title: MWBTRP - Middle Fork Willamette Basin Bull Trout Rehabilitation and Monitoring Project, Annual Progress Report 2005 Abstract -- Bull trout in the Middle Fork Willamette Basin once moved uninhibited back and forth from spawning and rearing habitats near Diamond Peak to foraging and overwintering habitats lower in the basin. Construction of Dexter, Lookout Point and Hills Creek dams in the 1950s and 1960s without fish passage fragmented the habitat and limited the range of the population to above Hills Creek Dam. This population declined and the last confirmed bull trout sighting above Hills Creek dam was a photograph taken by an angler in 1990. Buchanan et al. (1997) described bull trout in the Middle Fork Willamette River as “probably extinct” after extensive surveys from 1993 through 1997 failed to observe any bull trout. In 1997 the US Forest Service and the Oregon Department of Fish and Wildlife began a program to reestablish bull trout in the Middle Fork Willamette. More than 10,000 bull trout fry have been transferred from the relatively healthy McKenzie population to the Middle Fork Willamette River. Adult bull trout are once again present in the Middle Fork Willamette, although natural reproduction has not been documented. Close

• 15. [Article] Factors influencing spawning migration of bull trout (Salvelinus confluentus) in the North Fork Skokomish River, Olympic National Park, Washington

  Distribution and life history characteristics of lacustrine-adfluvial bull trout (Salvelinus confluentus) were described in the North Fork Skokomish River Basin (including Lake Cushman, a reservoir) from ...

  Citation × Citation Citation Abstract Copy Title: Factors influencing spawning migration of bull trout (Salvelinus confluentus) in the North Fork Skokomish River, Olympic National Park, Washington Author: Brenkman, Samuel J. Distribution and life history characteristics of lacustrine-adfluvial bull trout (Salvelinus confluentus) were described in the North Fork Skokomish River Basin (including Lake Cushman, a reservoir) from 1994 to 1996. Day snorkeling was conducted in the river to determine initiation of the bull trout spawning migration, abundance of spawners, and duration of spawning. Declining photoperiod, increased river discharge, and decreased water temperature appeared to influence timing of migration and spawning. Lacustrine-adfluvial bull trout typically entered the North Fork Skokomish River in October although some fish entered as early as May. Mean lengths of spawners consistently increased from June to December 1996, and early migrating bull trout were shorter than those fish that entered after river discharge increased in October. The presence of two phases of the spawning migration may be indicative of two populations spawning in the river. Bull trout spawned between mid-September and December in the river and tributaries after water temperatures declined. All spawning occurred at temperatures less than 7.5°C. Comparisons with studies of other lacustrine-adfiuvial bull trout populations that inhabit river and reservoir complexes suggested that bull trout exhibit specific migratory strategies related to local environmental conditions. In the North Fork Skokomish River, changes in abundance of bull trout, mountain whitefish (Prosopium wilhamsom), cutthroat trout (Oncorhynchus dark), and rainbow trout (Oncorhynchus mykiss) revealed distinct temporal segregation among these species. Olympic National Park, a designated Biosphere Reserve, contains one of the largest remaining areas of relatively pristine habitat in the range of bull trout. Knowledge of responses of bull trout to changes in river discharge and temperature from relatively undisturbed systems, such as the North Fork Skokomish River, may be useful in understanding patterns observed in degraded environments. Title: Factors influencing spawning migration of bull trout (Salvelinus confluentus) in the North Fork Skokomish River, Olympic National Park, Washington Author: Brenkman, Samuel J. Distribution and life history characteristics of lacustrine-adfluvial bull trout (Salvelinus confluentus) were described in the North Fork Skokomish River Basin (including Lake Cushman, a reservoir) from 1994 to 1996. Day snorkeling was conducted in the river to determine initiation of the bull trout spawning migration, abundance of spawners, and duration of spawning. Declining photoperiod, increased river discharge, and decreased water temperature appeared to influence timing of migration and spawning. Lacustrine-adfluvial bull trout typically entered the North Fork Skokomish River in October although some fish entered as early as May. Mean lengths of spawners consistently increased from June to December 1996, and early migrating bull trout were shorter than those fish that entered after river discharge increased in October. The presence of two phases of the spawning migration may be indicative of two populations spawning in the river. Bull trout spawned between mid-September and December in the river and tributaries after water temperatures declined. All spawning occurred at temperatures less than 7.5°C. Comparisons with studies of other lacustrine-adfiuvial bull trout populations that inhabit river and reservoir complexes suggested that bull trout exhibit specific migratory strategies related to local environmental conditions. In the North Fork Skokomish River, changes in abundance of bull trout, mountain whitefish (Prosopium wilhamsom), cutthroat trout (Oncorhynchus dark), and rainbow trout (Oncorhynchus mykiss) revealed distinct temporal segregation among these species. Olympic National Park, a designated Biosphere Reserve, contains one of the largest remaining areas of relatively pristine habitat in the range of bull trout. Knowledge of responses of bull trout to changes in river discharge and temperature from relatively undisturbed systems, such as the North Fork Skokomish River, may be useful in understanding patterns observed in degraded environments. Close

• 16. [Image] Bull trout restoration and brook trout eradication at Crater Lake National Park, Oregon

  	ill., 1 map (sketched) ; Report title; "Drought conditions are continuing in 1994, at the writing of this report in March of 1994, Crater Lake National Park had received approximately 50% of the annual ...
  	Citation × Citation Citation Abstract Copy Title: Bull trout restoration and brook trout eradication at Crater Lake National Park, Oregon Author: Buktenica, Mark. Year: 1994, 2008, 2009 ill., 1 map (sketched) ; Report title; "Drought conditions are continuing in 1994, at the writing of this report in March of 1994, Crater Lake National Park had received approximately 50% of the annual average accumulated precipatation to date." - P. 17.; Title: Bull trout restoration and brook trout eradication at Crater Lake National Park, Oregon Author: Buktenica, Mark. Year: 1994, 2008, 2009 ill., 1 map (sketched) ; Report title; "Drought conditions are continuing in 1994, at the writing of this report in March of 1994, Crater Lake National Park had received approximately 50% of the annual average accumulated precipatation to date." - P. 17.; Close

• 17. [Article] Bull Trout (Salvelinus confluentus) Population and Habitat Survey in the McKenzie and Middle Fork Willamette Basins, 2001

  Our study area includes the three McKenzie populations, and a reintroduced population in the Middle Fork Willamette and tributaries above Hills Creek Reservoir. We monitored bull trout populations in the ...

  Citation × Citation Citation Abstract Copy Title: Bull Trout (Salvelinus confluentus) Population and Habitat Survey in the McKenzie and Middle Fork Willamette Basins, 2001 Author: Taylor, Greg Our study area includes the three McKenzie populations, and a reintroduced population in the Middle Fork Willamette and tributaries above Hills Creek Reservoir. We monitored bull trout populations in the McKenzie and Middle Fork Willamette basins using a combination of sampling techniques that include spawning surveys, juvenile trapping, electronic fish counters, and night snorkeling. We continued to reintroduce bull trout fry from Anderson Creek (McKenzie Basin) to the Middle Fork Willamette above Hills Creek Reservoir in an attempt to rehabilitate the bull trout population in the Middle Fork Willamette Basin. By monitoring population trends and determining life history characteristics of bull trout in McKenzie and Middle Fork Willamette basins, we can make informed management decisions that will help maintain long term and sustainable bull trout populations in the upper Willamette Basin. Title: Bull Trout (Salvelinus confluentus) Population and Habitat Survey in the McKenzie and Middle Fork Willamette Basins, 2001 Author: Taylor, Greg Our study area includes the three McKenzie populations, and a reintroduced population in the Middle Fork Willamette and tributaries above Hills Creek Reservoir. We monitored bull trout populations in the McKenzie and Middle Fork Willamette basins using a combination of sampling techniques that include spawning surveys, juvenile trapping, electronic fish counters, and night snorkeling. We continued to reintroduce bull trout fry from Anderson Creek (McKenzie Basin) to the Middle Fork Willamette above Hills Creek Reservoir in an attempt to rehabilitate the bull trout population in the Middle Fork Willamette Basin. By monitoring population trends and determining life history characteristics of bull trout in McKenzie and Middle Fork Willamette basins, we can make informed management decisions that will help maintain long term and sustainable bull trout populations in the upper Willamette Basin. Close

• 18. [Article] Stream habitat utilization and behavior of sympatric and allopatric wild cutthroat trout (Salmo clarki) and hatchery coho salmon (Oncorhynchus kitsutch)

  The behavior and stream habitat utilization of juvenile hatchery-reared coho salmon (Ovicozihynchus kisutch) and wild cutthroat trout (Salmo clarki) were examined to assess the nature of interactions between ...

  Citation × Citation Citation Abstract Copy Title: Stream habitat utilization and behavior of sympatric and allopatric wild cutthroat trout (Salmo clarki) and hatchery coho salmon (Oncorhynchus kitsutch) Author: Jacobs, Steven Edward The behavior and stream habitat utilization of juvenile hatchery-reared coho salmon (Ovicozihynchus kisutch) and wild cutthroat trout (Salmo clarki) were examined to assess the nature of interactions between the species potentially resulting from introductions of hatchery coho salmon in streams. Habitat utilization was monitored in Mill Creek, Polk Co., Oregon by manipulating the composition of fish within three study sections to include either allopatric or sympatric populations of hatchery coho salmon and wild cutthroat trout. In allopatry, coho salmon and cutthroat trout selected feeding microhabitat that was similar in physical characteristics and exhibited extensive dietary overlap. When the two species occurred in sympatry, feeding microhabitat used by coho salmon was altered, however, that of cutthroat trout was comparable to allopatric cutthroat trout. No discernable differences in dietary composition between allopatric and sympatric fish were detected. While allopatric cutthroat trout always gained mass. ailopatric coho salmon always lost mass. Stomach fullness indices were higher for allopatric cutthroat trout than allopatric coho salmon. Sympatric cutthroat trout had comparable or greater gains of mass, indices of stomach fullness, and hepatic glycogen reserves relative to allopatric cutthroat trout. Conversely, sympatric coho salmon had greater losses of mass, reduced hepatic glycogen reserves, and apparently lower indices of stomach fullness than allopatric salmon. Behavioral observations made through the use of an in-stream viewing chamber in Berry Creek, Benton Co., Oregon, indicated that in allopatry populations of hatchery coho salmon and wild cutthroat trout were structured as linear dominance hierarchies that were organized by quantitatively and qualitatively similar aggressive interactions. In sympatry, however, cutthroat trout were more aggressive and socially dominant to coho salmon. The shift in use of micro-habitat and reduction in habitat utilization effectiveness of hatchery coho salmon in the presence of cutthroat trout can, thus, be interpreted to occur as a result of interference competition mediated through interspecific aggression. Title: Stream habitat utilization and behavior of sympatric and allopatric wild cutthroat trout (Salmo clarki) and hatchery coho salmon (Oncorhynchus kitsutch) Author: Jacobs, Steven Edward The behavior and stream habitat utilization of juvenile hatchery-reared coho salmon (Ovicozihynchus kisutch) and wild cutthroat trout (Salmo clarki) were examined to assess the nature of interactions between the species potentially resulting from introductions of hatchery coho salmon in streams. Habitat utilization was monitored in Mill Creek, Polk Co., Oregon by manipulating the composition of fish within three study sections to include either allopatric or sympatric populations of hatchery coho salmon and wild cutthroat trout. In allopatry, coho salmon and cutthroat trout selected feeding microhabitat that was similar in physical characteristics and exhibited extensive dietary overlap. When the two species occurred in sympatry, feeding microhabitat used by coho salmon was altered, however, that of cutthroat trout was comparable to allopatric cutthroat trout. No discernable differences in dietary composition between allopatric and sympatric fish were detected. While allopatric cutthroat trout always gained mass. ailopatric coho salmon always lost mass. Stomach fullness indices were higher for allopatric cutthroat trout than allopatric coho salmon. Sympatric cutthroat trout had comparable or greater gains of mass, indices of stomach fullness, and hepatic glycogen reserves relative to allopatric cutthroat trout. Conversely, sympatric coho salmon had greater losses of mass, reduced hepatic glycogen reserves, and apparently lower indices of stomach fullness than allopatric salmon. Behavioral observations made through the use of an in-stream viewing chamber in Berry Creek, Benton Co., Oregon, indicated that in allopatry populations of hatchery coho salmon and wild cutthroat trout were structured as linear dominance hierarchies that were organized by quantitatively and qualitatively similar aggressive interactions. In sympatry, however, cutthroat trout were more aggressive and socially dominant to coho salmon. The shift in use of micro-habitat and reduction in habitat utilization effectiveness of hatchery coho salmon in the presence of cutthroat trout can, thus, be interpreted to occur as a result of interference competition mediated through interspecific aggression. Close

• 19. [Article] Experimental analysis of intra- and interspecific competitive interactions between cutthroat trout and sculpins in small streams

  In the Pacific Northwest ecoregion of North America, sculpins represent a major constituent of freshwater assemblages in coastal rivers. Based on their prevalence and abundance, sculpins are likely important ...

  Citation × Citation Citation Abstract Copy Title: Experimental analysis of intra- and interspecific competitive interactions between cutthroat trout and sculpins in small streams Author: Ramirez, Ben S. In the Pacific Northwest ecoregion of North America, sculpins represent a major constituent of freshwater assemblages in coastal rivers. Based on their prevalence and abundance, sculpins are likely important ecologically, yet little is known of their interactions with co-occurring species, such as widely studied salmon and trout (salmonines). In this study, I evaluated inter- and intraspecific interactions involving cottids (Cottus sp.) and coastal cutthroat trout (Oncorhynchus clarkii clarkii). I used a response surface experimental design to independently evaluate effects of cutthroat trout and sculpin biomass on growth and behavior. There was evidence of both intra- and interspecific interactions between cutthroat trout and sculpins, but the interactions were asymmetrical with biomass of cutthroat trout driving both intra- and interspecific interactions, whereas sculpins had little influence overall. Cutthroat trout biomass was positively related to conspecific aggressive interactions and negatively related to growth. Sculpin exhibited increased use of cover during the day in response to greater biomass of cutthroat trout, but not sculpin biomass. Nocturnal use of cover by sculpins was unaffected by biomass of either species. This experiment provides insights into the species interactions and the mechanisms that may allow sculpins and salmonines to coexist in nature. As cutthroat trout appear to be superior competitors, coexistence between sculpins and cutthroat trout may depend on some form of refuge, either in the form of in-stream cover or crypsis coupled with diel resource segregation. Cutthroat trout are usually active during the day, indicating that nocturnal foraging by sculpins may in part represent a behavior that minimizes interspecific competition with cutthroat trout. Title: Experimental analysis of intra- and interspecific competitive interactions between cutthroat trout and sculpins in small streams Author: Ramirez, Ben S. In the Pacific Northwest ecoregion of North America, sculpins represent a major constituent of freshwater assemblages in coastal rivers. Based on their prevalence and abundance, sculpins are likely important ecologically, yet little is known of their interactions with co-occurring species, such as widely studied salmon and trout (salmonines). In this study, I evaluated inter- and intraspecific interactions involving cottids (Cottus sp.) and coastal cutthroat trout (Oncorhynchus clarkii clarkii). I used a response surface experimental design to independently evaluate effects of cutthroat trout and sculpin biomass on growth and behavior. There was evidence of both intra- and interspecific interactions between cutthroat trout and sculpins, but the interactions were asymmetrical with biomass of cutthroat trout driving both intra- and interspecific interactions, whereas sculpins had little influence overall. Cutthroat trout biomass was positively related to conspecific aggressive interactions and negatively related to growth. Sculpin exhibited increased use of cover during the day in response to greater biomass of cutthroat trout, but not sculpin biomass. Nocturnal use of cover by sculpins was unaffected by biomass of either species. This experiment provides insights into the species interactions and the mechanisms that may allow sculpins and salmonines to coexist in nature. As cutthroat trout appear to be superior competitors, coexistence between sculpins and cutthroat trout may depend on some form of refuge, either in the form of in-stream cover or crypsis coupled with diel resource segregation. Cutthroat trout are usually active during the day, indicating that nocturnal foraging by sculpins may in part represent a behavior that minimizes interspecific competition with cutthroat trout. Close

• 20. [Article] Substitutional relationships between rainbow trout and pansize salmon : a market demand analysis

  The fundamental objective of this analysis was to isolate and identify the factors governing the demand for domestically produced rainbow trout in a representative west coast market, and assess the impact ...

  Citation × Citation Citation Abstract Copy Title: Substitutional relationships between rainbow trout and pansize salmon : a market demand analysis Author: Queirolo, Lewis E. The fundamental objective of this analysis was to isolate and identify the factors governing the demand for domestically produced rainbow trout in a representative west coast market, and assess the impact on that demand, if any, of the introduction of pansize salmon. The approach taken in this market demand study was to identify those variables hypothesized to determine supply and demand for rainbow trout. Several testable hypotheses concerning the anticipated relationships were specified. It was hypothesized that a negative relationship would exist between the price of trout at the brokerage level and the quantity demanded at that level. Conversely, the price of trout at the wholesale level was hypothesized to be positively correlated with the quantity of rainbow trout demanded at the brokerage level. Further, the signs on the coefficients of variables accounting for the wholesale prices of substitute items were expected to be negative, while comparable prices at the brokerage level should be positive, based upon the hypothesis. It was hypothesized that the presence of Japanese trout in the market place would have a negative impact on the quantity of domestically produced trout demanded. Personal disposable income was hypothesized to be positively correlated with the quantity of trout demanded. Expectations were that seasonal factors tend to cause trout demand to fluctuate cyclically. An econometric simultaneous equations model was specified from which estimates of the parameters of the demand equation were obtained using Two Stage Least Squares techniques. A recognition of the limitations associated with the available data set necessitates the emphasizing of the preliminary nature of these results. Data on quantities and prices of rainbow trout and equivalent price series for hypothesized substitutes were obtained through personal interviews with market participants and close observers thereof. The results of the study, while preliminary, tend to support the original set of hypotheses concerning the interrelationships between quantity of domestic trout demanded and own-price, the price of close substitutes and seasonal demand fluctuations. Somewhat unexpectedly, the regression seems to have uncovered a negative income/quantity demanded relationship for rainbow trout. This raises some interesting questions which might best be addressed in terms of hypotheses for future analysis. Title: Substitutional relationships between rainbow trout and pansize salmon : a market demand analysis Author: Queirolo, Lewis E. The fundamental objective of this analysis was to isolate and identify the factors governing the demand for domestically produced rainbow trout in a representative west coast market, and assess the impact on that demand, if any, of the introduction of pansize salmon. The approach taken in this market demand study was to identify those variables hypothesized to determine supply and demand for rainbow trout. Several testable hypotheses concerning the anticipated relationships were specified. It was hypothesized that a negative relationship would exist between the price of trout at the brokerage level and the quantity demanded at that level. Conversely, the price of trout at the wholesale level was hypothesized to be positively correlated with the quantity of rainbow trout demanded at the brokerage level. Further, the signs on the coefficients of variables accounting for the wholesale prices of substitute items were expected to be negative, while comparable prices at the brokerage level should be positive, based upon the hypothesis. It was hypothesized that the presence of Japanese trout in the market place would have a negative impact on the quantity of domestically produced trout demanded. Personal disposable income was hypothesized to be positively correlated with the quantity of trout demanded. Expectations were that seasonal factors tend to cause trout demand to fluctuate cyclically. An econometric simultaneous equations model was specified from which estimates of the parameters of the demand equation were obtained using Two Stage Least Squares techniques. A recognition of the limitations associated with the available data set necessitates the emphasizing of the preliminary nature of these results. Data on quantities and prices of rainbow trout and equivalent price series for hypothesized substitutes were obtained through personal interviews with market participants and close observers thereof. The results of the study, while preliminary, tend to support the original set of hypotheses concerning the interrelationships between quantity of domestic trout demanded and own-price, the price of close substitutes and seasonal demand fluctuations. Somewhat unexpectedly, the regression seems to have uncovered a negative income/quantity demanded relationship for rainbow trout. This raises some interesting questions which might best be addressed in terms of hypotheses for future analysis. Close