Common use of REDUCE NEGATIVE IMPACTS OF NONNATIVE FISHES AND SPORTFISH MANAGEMENT ACTIVITIES Clause in Contracts

REDUCE NEGATIVE IMPACTS OF NONNATIVE FISHES AND SPORTFISH MANAGEMENT ACTIVITIES. Fifty-two fish species occur in the Upper Basin, but only 13 of those are native species. Many of the nonnative fishes have been successful due to changes in the river system that favor their survival over that of native fishes. Competition with and predation by nonnative species is widely assumed to have played a role in the decline of the endangered fishes (Xxxx and Xxxxxxxx 1996). However, evidence of direct impacts of introduced species on native fishes is difficult to obtain (Xxxxxxxxxx 1981) and often is masked by human-caused habitat alterations (Xxxxx 1976). In studies on the Green River, researchers documented that young Colorado pikeminnow constituted 5% of the diet of northern pike, even though young Colorado pikeminnow made up a much smaller portion of the available food base in the river (Xxxxx and Xxxxxxx 1996). Researchers estimated that a single northern pike could consume 100 or more young Colorado pikeminnow per year. Also, northern pike are known to prey on adult Colorado pikeminnow, native roundtail chub (Gila robusta), flannelmouth and bluehead suckers, and may also feed on humpback chubs in the Yampa River. Colorado has completed a fisheries management plan for the Yampa River basin (a revision is pending). Smallmouth bass in the Yampa River have rapidly increased in abundance and pose a significant predatory and competitive threat to the endangered fishes. Recovery Program activities related to nonnative fishes initially focused on identifying impacts/interactions and developing nonnative fish stocking procedures. Nonnative fish control strategies were developed to identify and prioritize options for controlling or removing nonnative fishes from river reaches occupied by the endangered fishes as well as other reaches that serve as production areas for nonnatives that subsequently disperse into occupied habitat (Xxxx and Xxxxxxxx 1996; Xxxxxxx et al. 1996; Xxxxxxx and Xxxxxx 1991). In February 2004, the Recovery Program adopted a nonnative fish management policy that addresses the process of identifying and implementing nonnative fish management actions needed to recover the endangered fishes. Through 2006, emphasis has been focused on the control activities identified in these strategies. All nonnative fish control activities are being evaluated for effectiveness and continued as appropriate. The States and the Service also have developed final procedures for stocking of nonnative fishes in the Upper Basin (USFWS 1996a, 1996b). The procedures are designed to reduce the impact on native fishes due to stocking of nonnative fishes in the Upper Basin and clarify the role of the States, the Service, and others in the review of stocking proposals. A memorandum of understanding has been signed by the States and the Service implementing the Stocking Procedures. The Stocking Procedures will be reviewed for possible revisions in 2007.

REDUCE NEGATIVE IMPACTS OF NONNATIVE FISHES AND SPORTFISH MANAGEMENT ACTIVITIES. Fifty-two ‌ The introduction, establishment, and proliferation of nonnative fishes are considered the primary threat to the recovery of four Colorado River endangered fishes. Unfortunately, in the upper Colorado River basin, despite years of significant effort, the nonnative threat remains largely uncontrolled. Only 13 of more than 50 fish species that now occur in the Upper Basin, but only 13 of those Basin are native species(Bezzerides and Bestgen 2002). Many Over the last 100 years, native fishes have decreased in range and abundance, while introduced fishes have concurrently become more widespread and abundant (Xxxxxxx & Xxxx 1989, Xxxxxxxx et al. 1994; Xxxxxxxxxx & Bestgen 2002; Xxxxxxx & Xxxxx 2014). An increasing body of evidence characterizes the negative interactions of nonnative fishes have been successful due to changes in the river system that favor their survival over that of native fishes. Competition with and predation by nonnative species is widely assumed to have played a role in the decline of the endangered fishes (Xxxx Xxxxxxx & Xxxxxx 1991; Xxxxxxxx 1991; Xxxxxxx et al. 1998; Xxxxxxxxxx & Bestgen 2002; Xxxxxxx & Xxxxx 2014), including predation and Xxxxxxxx 1996competition. Direct evidence of predation includes native fish tags being detected in predatory fishes (Xxxxxxxxx et al. 2017), native fishes obtained from stomach contents of nonnative fishes (Xxxxxxx and Xxxxx 2014), and by visual observation of predation. Other means by which nonnative fishes may adversely affect native fishes are by competition for food and niche space. Warm water game fish, primarily stocked in reservoirs for recreational purposes, are thought to have the greatest adverse effect on endangered native fishes. Of those species, large-bodied predators are considered the most problematic – specifically centrarchids (smallmouth bass), esocids (northern pike), and percids (walleye). HoweverFor example, evidence during the 1990s, the Yampa River experienced a dramatic increase in northern pike and smallmouth bass numbers. Predation by these two piscivorous species wreaked havoc on the native fish community. Biologists documented significant declines of direct impacts of introduced species on native fishes is difficult to obtain fish densities in the Yampa River since that time (Xxxxxxxxxx 1981) and often is masked by human-caused habitat alterations (Xxxxx 1976Bestgen et al. 2015). In studies on the Green River, researchers documented that young Colorado pikeminnow constituted 5% of the diet of northern pike, even though young Colorado pikeminnow made up a much smaller portion of the available food base in the river (Xxxxx and Xxxxxxx 1996). Researchers estimated that a single northern pike could consume 100 or more young Colorado pikeminnow per year. AlsoIn addition, northern pike are known to prey on large-bodied native fishes (Xxxxxxxx 2001, Xxxxxxx et al. 2005, Xxxxxx and Xxxxxx 2010) including adult Colorado pikeminnow, native roundtail chub (Gila robusta), flannelmouth xxxxxxxxxxxx and bluehead suckers, and may also feed on humpback chubs in the Yampa River. More recently, Xxxxxxx and Xxxxx documented juvenile Colorado has completed pikeminnow in the guts of nonnative walleye and reported a fisheries management plan for simultaneous decline in Colorado pikeminnow abundance in the Yampa lower Colorado River basin between 2010 and 2014, while walleye populations were increasing (a revision is pendingXxxxxxx and Xxxxx 2014). Smallmouth bass Recently, numbers of walleye have increased in the Yampa Green and lower Colorado rivers and burbot have been discovered in the Green River have rapidly increased in abundance and below Flaming Gorge Dam. Both of these species also pose a significant predatory and competitive threat to the native and endangered fishesfishes (Xxxxxxx and Xxxxx 2014, Xxxxxxxx et al. 2011). Recovery Program activities related to nonnative fishes initially focused on identifying impacts/interactions and developing nonnative fish stocking procedures. Nonnative fish control strategies were developed to identify and prioritize options for controlling or removing nonnative fishes from river reaches occupied by the endangered fishes as well as other reaches that serve as production areas for nonnatives that subsequently disperse into occupied habitat (Xxxx and Xxxxxxxx 1996; Xxxxxxx et al. 1996; Xxxxxxx and Xxxxxx 1991). In February 2004, the Recovery Program adopted a nonnative fish management policy that addresses the process of identifying and implementing nonnative fish management actions needed to recover the endangered fishesfishes (Upper Colorado River Endangered Fish Recovery Program 2004). Through 20062009, emphasis has been was focused on the control activities identified in these strategies. Development of a new basin wide strategy for the management of nonnative aquatic species began in 2009, and was finalized in early 2014 (Nonnative Fish ad hoc Committee 2014). This strategy emphasizes prevention as a major component in efforts to control existing invasive impacts and to avoid similar impacts arising from existing or new species in additional locations within the Upper Basin. All nonnative fish control activities are being evaluated for effectiveness annually. By thoroughly evaluating the smallmouth bass and continued northern pike control strategies in the Yampa River basin, the Larval Fish Lab at CSU provided the Program with guiding principles for nonnative removal in the entire basin. Specifically, both of these comprehensive evaluations indicate that the Recovery Program should focus on disrupting reproduction in the river and preventing immigration into river habitats, such as appropriateby limiting the escapement of these species from reservoirs. Disrupting in-river reproduction and preventing reservoir escapement are now the two key tenets of nonnative fish management. Limiting reproduction is accomplished through targeted removal of smallmouth bass during the spawn (the Surge) and by netting northern pike in backwaters in the Yampa River. Landscape scale spawning disruptions of smallmouth bass via water management are also being considered (Bestgen and Xxxx 2016). Reservoir escapement is primarily prevented through installation of physical screens on outlets or channels and nets on spillways. Currently Starvation3, Elkhead and Rifle Gap Reservoirs, and Highline Lake, all have screened releases, while Xxxxxxx and Red Fleet Reservoirs, and Lake Catamount, are planned for screening in the future. The States and the Service also have developed final procedures for stocking of nonnative fishes in the Upper Basin (USFWS 1996a, 1996b). The procedures are designed to reduce the impact on native fishes due to from stocking of nonnative fishes in the Upper Basin and clarify the role of the States, the Service, and others in the review of stocking proposals. A memorandum of understanding cooperative agreement has been signed by the States and the Service implementing the Stocking Procedures. The Stocking Procedures will be reviewed were revised in 2009 (USFWS 2009) and the cooperative agreement was updated. In 2013, the Colorado Wildlife Commission updated changes to Colorado’s Wildlife Regulations that apply the provisions of the revised Stocking Procedures to the private aquaculture industry, in waters of both the Upper Colorado and San Xxxx River. The provisions of the revised Stocking Procedures also are part of Utah’s stocking policy (including private aquaculture, which can only stock sterile salmonids without specific State review and approval). All private fish stocking in Wyoming also is subject to State review. Harvest regulations also play a key role in nonnative fish management. The Upper Basin States have liberalized bag and possession limits for possible revisions the ‘worst of the worse’ predators (northern pike, smallmouth bass, walleye, and burbot). Utah and Wyoming have implemented must kill regulations for these species where appropriate. Colorado Parks and Wildlife has developed a “catch and keep” outreach strategy, paired with unlimited harvest and harvest incentives in 2007regulation, as opposed to must kill regulations. The Colorado Wildlife Commission ratified unlimited harvest regulations for smallmouth bass and northern pike on the western slope, which took effect on April 1, 2016.

REDUCE NEGATIVE IMPACTS OF NONNATIVE FISHES AND SPORTFISH MANAGEMENT ACTIVITIES. Fifty-two ‌ The introduction, establishment, and proliferation of nonnative fishes are considered the primary threat to the recovery of four Colorado River endangered fishes. Unfortunately, in the upper Colorado River basin, despite years of significant effort, the nonnative threat remains largely uncontrolled. Only 13 of more than 50 fish species that now occur in the Upper Basin, but only 13 of those Basin are native species(Bezzerides and Bestgen 2002). Many Over the last 100 years, native fishes have decreased in range and abundance, while introduced fishes have concurrently become more widespread and abundant (Xxxxxxx & Xxxx 1989, Xxxxxxxx et al. 1994; Xxxxxxxxxx & Bestgen 2002; Xxxxxxx & Xxxxx 2014). An increasing body of evidence characterizes the negative interactions of nonnative fishes have been successful due to changes in the river system that favor their survival over that of native fishes. Competition with and predation by nonnative species is widely assumed to have played a role in the decline of the endangered fishes (Xxxx Xxxxxxx & Xxxxxx 1991; Xxxxxxxx 1991; Xxxxxxx et al. 1998; Xxxxxxxxxx & Bestgen 2002; Xxxxxxx & Xxxxx 2014), including predation and Xxxxxxxx 1996competition. Direct evidence of predation includes native fish tags being detected in predatory fishes (Xxxxxxxxx et al. 2017), native fishes obtained from stomach contents of nonnative fishes (Xxxxxxx and Xxxxx 2014), and by visual observation of predation. Other means by which nonnative fishes may adversely affect native fishes are by competition for food and niche space. Warm water game fish, primarily stocked in reservoirs for recreational purposes, are thought to have the greatest adverse effect on endangered native fishes. Of those species, large-bodied predators are considered the most problematic – specifically centrarchids (smallmouth bass), esocids (northern pike), and percids (walleye). HoweverFor example, evidence the Yampa River experienced a dramatic increase in northern pike and smallmouth bass numbers in the 1990s and 2000s, respectively. Predation by these two piscivorous species wreaked havoc on the native fish community. Biologists documented significant declines of direct impacts of introduced species on native fishes is difficult to obtain fish densities in the Yampa River since that time (Xxxxxxxxxx 1981) and often is masked by human-caused habitat alterations (Xxxxx 1976Bestgen et al. 2015). In studies on the Green River, researchers documented that young Colorado pikeminnow constituted 5% of the diet of northern pike, even though young Colorado pikeminnow made up a much smaller portion of the available food base in the river (Xxxxx and Xxxxxxx 1996). Researchers estimated that a single northern pike could consume 100 or more young Colorado pikeminnow per year. AlsoIn addition, northern pike are known to prey on large-bodied native fishes (Xxxxxxxx 2001, Xxxxxxx et al. 2005, Xxxxxx and Xxxxxx 2010) including adult Colorado pikeminnow, native roundtail chub (Gila robusta), flannelmouth and xxxxxxxxxxxx and bluehead suckers. Recently, and may also feed on humpback chubs numbers of walleye have increased in the Yampa River. Green and lower Colorado has completed rivers; Xxxxxxx and Xxxxx documented juvenile Colorado pikeminnow in the guts of nonnative walleye and reported a fisheries management plan for simultaneous decline in Colorado pikeminnow abundance in the Yampa lower Colorado River basin between 2010 and 2014 (a revision is pendingXxxxxxx and Xxxxx 2014). Smallmouth bass Burbot have been discovered in the Yampa Green River have rapidly increased in abundance below Flaming Gorge Dam. Xxxxxxx and burbot pose a significant predatory and competitive threat to the native and endangered fishesfishes (Xxxxxxx and Xxxxx 2014, Xxxxxxxx et al. 2011). Recovery Program activities related to nonnative fishes initially focused on identifying impacts/interactions and developing nonnative fish stocking procedures. Nonnative fish control strategies were developed to identify and prioritize options for controlling or removing nonnative fishes from river reaches occupied by the endangered fishes as well as other reaches that serve as production areas for nonnatives that subsequently disperse into occupied habitat (Xxxx and Xxxxxxxx 1996; Xxxxxxx et al. 1996; Xxxxxxx and Xxxxxx 1991). In February 2004, the Recovery Program adopted a nonnative fish management policy that addresses the process of identifying and implementing nonnative fish management actions needed to recover the endangered fishesfishes (Upper Colorado River Endangered Fish Recovery Program 2004). Through 20062009, emphasis has been was focused on the control activities identified in these strategies. Development of a new basin wide strategy for the management of nonnative aquatic species began in 2009, and was finalized in early 2014 (Nonnative Fish ad hoc Committee 2014). This strategy emphasizes prevention as a major component in efforts to control existing invasive impacts and to avoid similar impacts arising from existing or new species in additional locations within the Upper Basin. All nonnative fish control activities are being evaluated for effectiveness annually. By thoroughly evaluating the smallmouth bass and continued northern pike control strategies in the Yampa River basin, the Larval Fish Lab at CSU provided the Program with guiding principles for nonnative removal in the entire basin. Specifically, both of these comprehensive evaluations indicate that the Recovery Program should focus on disrupting reproduction in the river and preventing immigration into river habitats, such as appropriateby limiting the escapement of these species from reservoirs. Disrupting in-river reproduction and preventing reservoir escapement are now the two key tenets of nonnative fish management. Limiting reproduction is accomplished through targeted removal of smallmouth bass during spawning (the Surge) and by netting northern pike in backwaters in the Yampa River. Landscape scale spawning disruptions of smallmouth bass via water management are also being considered (Bestgen and Xxxx 2016; Bestgen 2018). Reservoir escapement is primarily prevented through installation of physical screens on outlets or channels and nets on spillways. Currently Starvation4, Elkhead, and Rifle Gap reservoirs, and Highline Lake, all have screened releases, while Xxxxxxx and Red Fleet reservoirs, and Lake Catamount, are planned for screening in the future. The States and the Service also have developed final procedures for stocking of nonnative fishes in the Upper Basin (USFWS 1996a, 1996b). The procedures are designed to reduce the impact on native fishes due to from stocking of nonnative fishes in the Upper Basin and clarify the role of the States, the Service, and others in the review of stocking proposals. A memorandum of understanding cooperative agreement has been signed by the States and the Service implementing the Stocking Procedures. The Stocking Procedures will be reviewed were revised in 2009 (USFWS 2009) and the cooperative agreement was updated. The 2009 Stocking Procedures call for possible revisions a review after 10-years, which is scheduled for 2019. In 2013, the Colorado Wildlife Commission updated changes to Colorado’s Wildlife Regulations that apply the provisions of the revised Stocking Procedures to the private aquaculture industry, in 2007waters of both the Upper Colorado and San Xxxx River. The provisions of the revised Stocking Procedures also are part of Utah’s stocking policy (including private aquaculture, which can only stock sterile salmonids without specific State review and approval). All private fish stocking in Wyoming also is subject to State review. Harvest regulations also play a key role in nonnative fish management. The Upper Basin States have liberalized bag and possession limits for the ‘worst of the worse’ predators (northern pike, smallmouth bass, walleye, and burbot). Utah and Wyoming have implemented must kill regulations for these species where appropriate. Colorado Parks and Wildlife has developed a “catch and keep” outreach strategy, paired with unlimited harvest and harvest incentives in regulation, as opposed to must kill regulations. The Colorado Parks and Wildlife Commission ratified unlimited harvest regulations for smallmouth bass and northern pike on the western slope, which took effect on April 1, 2016. The Recovery Program now implements a comprehensive strategy for nonnative fish management, focusing on in-river removal, reservoir escapement, and policy and outreach components. Over the past decade, the Recovery Program has committed millions of dollars and thousands of hours to removing these problematic predators from hundreds of miles of rivers in the upper Colorado River basin. What began over fifteen years ago as a pilot removal effort in 6 miles of the Yampa River now constitutes a basin-wide removal effort in more than 600 river miles, with some river reaches receiving up to 10 to 15 passes to disrupt spawning. In addition to this labor intensive effort, Recovery Program stakeholders are now preventing individuals from escaping reservoirs, implementing appropriate stocking and harvest policies, and conducting outreach on the problems of nonnative fish.

REDUCE NEGATIVE IMPACTS OF NONNATIVE FISHES AND SPORTFISH MANAGEMENT ACTIVITIES. Fifty-two fish species occur in the Upper Basin, but only 13 of those are native species. No crayfish species are native to the Colorado River Basin (Xxxxxxxxx 2005). Many of the nonnative fishes aquatic species have been successful due to changes in the river system that favor their survival over that of native fishes. Competition with and predation by nonnative species is widely assumed to have played a role in the decline of the endangered fishes (Xxxx and Xxxxxxxx 1996). However, evidence of direct impacts of introduced species on native fishes is difficult to obtain (Xxxxxxxxxx 1981) and often is masked by human-caused habitat alterations (Xxxxx 1976). In studies on the Green River, researchers documented that young Colorado pikeminnow constituted 5% of the diet of northern pike, even though young Colorado pikeminnow made up a much smaller portion of the available food base in the river (Xxxxx and Xxxxxxx 1996). Researchers estimated that a single northern pike could consume 100 or more young Colorado pikeminnow per year. Also, northern pike are known to prey on large-bodied native fishes (Xxxxxxxx 2001, Xxxxxxx et al. 2005, Xxxxxx and Xxxxxx 2010) including adult Colorado pikeminnow, native roundtail chub (Gila robusta), flannelmouth and bluehead suckers, and may also feed on humpback chubs in the Yampa River. Colorado has completed revised a fisheries management plan for the Yampa River basin (a revision is pendingCDOW 2010). Smallmouth bass in the Yampa River have rapidly increased in abundance and pose a significant predatory and competitive threat to the native and endangered fishesfishes (Bestgen et al. 2008, Xxxxxxx et al. 2008). Recovery Program activities related to nonnative fishes initially focused on identifying impacts/interactions and developing nonnative fish stocking procedures. Nonnative fish control strategies were developed to identify and prioritize options for controlling or removing nonnative fishes from river reaches occupied by the endangered fishes as well as other reaches that serve as production areas for nonnatives that subsequently disperse into occupied habitat (Xxxx and Xxxxxxxx 1996; Xxxxxxx et al. 1996; Xxxxxxx and Xxxxxx 1991). In February 2004, the Recovery Program adopted a nonnative fish management policy that addresses the process of identifying and implementing nonnative fish management actions needed to recover the endangered fishesfishes (Upper Colorado River Endangered Fish Recovery Program 2004). Through 20062009, emphasis has been focused on the control activities identified in these strategies. All nonnative fish control activities are being evaluated for effectiveness and continued as appropriate. Development of a new basinwide strategy for the management of nonnative aquatic species began in 2009. This strategy will emphasize prevention as a major component in efforts to control existing invasive impacts and to avoid similar impacts arising from existing or new species in additional locations within the Upper Basin. The States and the Service also have developed final procedures for stocking of nonnative fishes in the Upper Basin (USFWS 1996a, 1996b). The procedures are designed to reduce the impact on native fishes due to stocking of nonnative fishes in the Upper Basin and clarify the role of the States, the Service, and others in the review of stocking proposals. A memorandum of understanding cooperative agreement has been signed by the States and the Service implementing the Stocking Procedures. The Stocking Procedures will be reviewed for possible revisions were revised in 20072009 (USFWS 2009) and the cooperative agreement was updated.

REDUCE NEGATIVE IMPACTS OF NONNATIVE FISHES AND SPORTFISH MANAGEMENT ACTIVITIES. Fifty-two The introduction, establishment, and proliferation of nonnative fishes are considered the primary threat to the recovery of four Colorado River endangered fishes. Unfortunately, in the upper Colorado River basin, despite years of significant effort, the nonnative threat remains largely uncontrolled. Only 13 of more than 50 fish species that now occur in the Upper Basin, but only 13 of those Basin are native species(Bezzerides and Bestgen 2002). Many Over the last 100 years, native fishes have decreased in range and abundance, while introduced fishes have concurrently become more widespread and abundant (Xxxxxxx & Xxxx 1989, Xxxxxxxx et al. 1994; Xxxxxxxxxx & Bestgen 2002; Xxxxxxx & Xxxxx 2014). An increasing body of evidence characterizes the negative interactions of nonnative fishes have been successful due to changes in the river system that favor their survival over that of native fishes. Competition with and predation by nonnative species is widely assumed to have played a role in the decline of the endangered fishes (Xxxx Xxxxxxx & Xxxxxx 1991; Xxxxxxxx 1991; Xxxxxxx et al. 1998; Xxxxxxxxxx & Bestgen 2002; Xxxxxxx & Xxxxx 2014), including predation and Xxxxxxxx 1996competition. Direct evidence of predation includes native fishes obtained from stomach contents of nonnative fishes (Xxxxxxx and Xxxxx 2014) and by visual observation of predation. Other means by which nonnative fishes may adversely affect native fishes are by competition for food and niche space. Warm water game fish, primarily stocked in reservoirs for recreational purposes, are thought to have the greatest adverse effect on endangered native fishes. Of those species, large-bodied predators are considered the most problematic – specifically centrarchids (smallmouth bass), esocids (northern pike), and percids (walleye). HoweverFor example, evidence during the 1990s, the Yampa River experienced a dramatic increase in northern pike and smallmouth bass numbers. Predation by these two piscivorous species wreaked havoc on the native fish community. Biologists documented significant declines of direct impacts of introduced species on native fishes is difficult to obtain fish densities in the Yampa River since that time (Xxxxxxxxxx 1981) and often is masked by human-caused habitat alterations (Xxxxx 1976Bestgen et al. 2015). In studies on the Green River, researchers documented that young Colorado pikeminnow constituted 5% of the diet of northern pike, even though young Colorado pikeminnow made up a much smaller portion of the available food base in the river (Xxxxx and Xxxxxxx 1996). Researchers estimated that a single northern pike could consume 100 or more young Colorado pikeminnow per year. AlsoIn addition, northern pike are known to prey on large-bodied native fishes (Xxxxxxxx 2001, Xxxxxxx et al. 2005, Xxxxxx and Xxxxxx 2010) including adult Colorado pikeminnow, native roundtail chub (Gila robusta), flannelmouth xxxxxxxxxxxx and bluehead suckers, and may also feed on humpback chubs in the Yampa River. More recently, Xxxxxxx and Xxxxx documented juvenile Colorado has completed pikeminnow in the guts of nonnative walleye and reported a fisheries management plan for simultaneous decline in Colorado pikeminnow abundance in the Yampa lower Colorado River basin between 2010 and 2014, while walleye populations were increasing (a revision is pendingXxxxxxx and Xxxxx 2014). Smallmouth bass Recently, numbers of walleye have increased in the Yampa Green and lower Colorado rivers and burbot have been discovered in the Green River have rapidly increased in abundance and below Flaming Gorge Dam. Both of these species also pose a significant predatory and competitive threat to the native and endangered fishesfishes (Xxxxxxx and Xxxxx 2014, Xxxxxxxx et al. 2011). Recovery Program activities related to nonnative fishes initially focused on identifying impacts/interactions and developing nonnative fish stocking procedures. Nonnative fish control strategies were developed to identify and prioritize options for controlling or removing nonnative fishes from river reaches occupied by the endangered fishes as well as other reaches that serve as production areas for nonnatives that subsequently disperse into occupied habitat (Xxxx and Xxxxxxxx 1996; Xxxxxxx et al. 1996; Xxxxxxx and Xxxxxx 1991). In February 2004, the Recovery Program adopted a nonnative fish management policy that addresses the process of identifying and implementing nonnative fish management actions needed to recover the endangered fishesfishes (Upper Colorado River Endangered Fish Recovery Program 2004). Through 20062009, emphasis has been was focused on the control activities identified in these strategies. Development of a new basinwide strategy for the management of nonnative aquatic species began in 2009, and was finalized in early 2014 (Nonnative Fish ad hoc Committee 2014). This strategy emphasizes prevention as a major component in efforts to control existing invasive impacts and to avoid similar impacts arising from existing or new species in additional locations within the Upper Basin. All nonnative fish control activities are being evaluated for effectiveness annually. By thoroughly evaluating the smallmouth bass and continued northern pike control strategies in the Yampa River basin, the Larval Fish Lab at CSU provided the Program with guiding principles for nonnative removal in the entire basin. Specifically, both of these comprehensive evaluations indicate that the Recovery Program should focus on disrupting reproduction in the river and preventing immigration into river habitats, such as appropriateby limiting the escapement of these species from reservoirs. Disrupting in-river reproduction and preventing reservoir escapement are now the two key tenets of nonnative fish management. Limiting reproduction is accomplished through targeted removal of smallmouth bass during the spawn (the Surge) and by netting northern pike in backwaters in the Yampa River. Landscape scale spawning disruptions of smallmouth bass via water management are also being considered (Bestgen and Xxxx 2016). Reservoir escapement is primarily prevented through installation of physical screens on outlets or channels and nets on spillways. Currently Elkhead and Rifle Gap Reservoirs, and Highline Lake, all have screened releases, while Xxxxxxx, Red Fleet and Starvation Reservoirs, and Lake Catamount, are planned for screening in the future. The States and the Service also have developed final procedures for stocking of nonnative fishes in the Upper Basin (USFWS 1996a, 1996b). The procedures are designed to reduce the impact on native fishes due to from stocking of nonnative fishes in the Upper Basin and clarify the role of the States, the Service, and others in the review of stocking proposals. A memorandum of understanding cooperative agreement has been signed by the States and the Service implementing the Stocking Procedures. The Stocking Procedures will be reviewed were revised in 2009 (USFWS 2009) and the cooperative agreement was updated. In 2013, the Colorado Wildlife Commission updated changes to Colorado’s Wildlife Regulations that apply the provisions of the revised Stocking Procedures to the private aquaculture industry, in waters of both the Upper Colorado and San Xxxx River. The provisions of the revised Stocking Procedures also are part of Utah’s stocking policy (including private aquaculture, which can only stock sterile salmonids without specific State review and approval). All private fish stocking in Wyoming also is subject to State review. Harvest regulations also play a key role in nonnative fish management. The Upper Basin States have liberalized bag and possession limits for possible revisions the ‘worst of the worse’ predators (northern pike, smallmouth bass, walleye, and burbot). Utah and Wyoming have implemented must kill regulations for these species where appropriate. Colorado Parks and Wildlife has developed a “catch and keep” outreach strategy, paired with unlimited harvest and harvest incentives in 2007regulation, as opposed to must kill regulations. The Colorado Wildlife Commission ratified unlimited harvest regulations for smallmouth bass and northern pike on the western slope which took effect on April 1, 2016. The Recovery Program now implements a comprehensive strategy for nonnative fish management, focusing on in-river removal, reservoir escapement, and policy and outreach components. Over the past decade, the Recovery Program has committed millions of dollars and thousands of hours to removing these problematic predators from hundreds of miles of rivers in the upper Colorado River basin. What began over fifteen years ago as a pilot removal effort in 6 miles of the Yampa River now constitutes a basin-wide removal effort in more than 600 river miles, with some river reaches receiving up to 10 to 15 passes to disrupt spawning. In addition to this labor intensive effort, Recovery Program stakeholders are now preventing individuals from escaping reservoirs, implementing appropriate stocking and harvest policies, and conducting outreach on the problems of nonnative fish.

REDUCE NEGATIVE IMPACTS OF NONNATIVE FISHES AND SPORTFISH MANAGEMENT ACTIVITIES. Fifty-two ‌ The introduction, establishment, and proliferation of nonnative fishes are considered the primary remaining threat to the recovery of four Colorado River endangered fishes. Only 13 of more than 50 fish species that now occur in the Upper Basin, but only 13 of those Basin are native species(Bezzerides and Bestgen 2002). Many Over the last 100 years, native fishes have decreased in range and abundance, while introduced fishes have concurrently become more widespread and abundant (Xxxxxxx & Xxxx 1989, Xxxxxxxx et al. 1994; Xxxxxxxxxx & Bestgen 2002; Xxxxxxx & Xxxxx 2014). An increasing body of evidence characterizes the negative interactions of nonnative fishes have been successful due to changes in the river system that favor their survival over that of native fishes. Competition with and predation by nonnative species is widely assumed to have played a role in the decline of the endangered fishes (Xxxx Xxxxxxx & Xxxxxx 1991; Xxxxxxxx 1991; Xxxxxxx et al. 1998; Xxxxxxxxxx & Bestgen 2002; Xxxxxxx & Xxxxx 2014), including predation and Xxxxxxxx 1996competition. Direct evidence of predation includes native fish tags being detected in predatory fishes (Xxxxxxxxx et al. 2017), native fishes obtained from stomach contents of nonnative fishes (Xxxxxxx et al. 2015, Xxxxxxx et al. 2019)), and by visual observation of predation. Other means by which nonnative fishes may adversely affect native fishes are by competition for food and niche space. Despite years of significant effort and some notable success stories, nonnative fish remain a significant obstacle to recovery of endangered fish. Warm water game fish stocked in reservoirs for recreational purposes subsequently escaped and established populations in the rivers. Of those species, large-bodied predators are considered the most problematic – specifically centrarchids (smallmouth bass [Micropterus dolomieu]), esocids (northern pike [Esox lucius]), and percids (walleye [Sander vitreus]). HoweverFor example, evidence of direct impacts of introduced species on native fishes is difficult to obtain (Xxxxxxxxxx 1981) and often is masked by human-caused habitat alterations (Xxxxx 1976). In studies on the Green River, researchers documented that young Colorado pikeminnow constituted 5% of the diet of northern pike, even though young Colorado pikeminnow made up a much smaller portion of the available food base in the river (Xxxxx and Xxxxxxx 1996). Researchers estimated that a single northern pike could consume 100 or more young Colorado pikeminnow per year. Also, northern pike are known to prey on adult Colorado pikeminnow, native roundtail chub (Gila robusta), flannelmouth and bluehead suckers, and may also feed on humpback chubs in the Yampa River. Colorado has completed a fisheries management plan for the Yampa River basin (experienced a revision is pending)dramatic increase in northern pike and smallmouth bass numbers in the 1990s and 2000s, respectively. Smallmouth bass Predation by these two piscivorous species wreaked havoc on the native fish community. Biologists documented significant declines of native fish densities in the Yampa River since that time (Bestgen et al. 2015). Today, smallmouth bass populations are the dominant predator in the fish community of the middle Yampa River (upstream of Dinosaur National Monument), the middle Green River (between Whirlpool and Desolation Canyons), and the Grand Valley reach of the Colorado River. Smallmouth bass are increasing in density and range in the White River as well, threatening the strong native fish community in that tributary. Northern pike are primarily found in the Yampa River upstream of Xxxxx, Colorado. However, adults are present downstream in the Yampa and Green rivers. Recently, numbers of walleye have rapidly increased in the lower Green and lower Colorado rivers and predation of juvenile pikeminnow has been documented (Xxxxxxx and Xxxxx 2014). Simultaneously, a decline in Colorado pikeminnow abundance was reported in the lower Colorado River between 2010 and 2015, which researchers attribute to a lack sufficient recruitment to offset adult mortality (Xxxxxxx et al. 2020). Increasing density of walleye pose a significant predatory and competitive threat to the native and endangered fishesfishes (Xxxxxxx and Xxxxx 2014, Xxxxxxxx et al. 2011). Other species are also of concern to endangered fish recovery and are removed when encountered in endangered fish habitat. Largemouth bass, striped bass, green sunfish, and large (>450mm) channel catfish. can prey on endangered species . White sucker can hybridize with native suckers, reducing genetic diversity of native populations. Gizzard shad are a preferred food source for walleye and can support that nonnative predator. Recovery Program activities related to nonnative fishes initially focused on identifying impacts/interactions and developing nonnative fish stocking procedures. Nonnative fish control strategies were developed to identify and prioritize options for controlling or removing nonnative fishes from river reaches occupied by the endangered fishes as well as other reaches that serve as production areas for nonnatives that subsequently disperse into occupied habitat (Xxxx and Xxxxxxxx 1996; Xxxxxxx et al. 1996; Xxxxxxx and Xxxxxx 1991). In February 2004, the Recovery Program adopted a nonnative fish management policy that addresses the process of identifying and implementing nonnative fish management actions needed to recover the endangered fishesfishes (Upper Colorado River Endangered Fish Recovery Program 2004). Through 20062009, emphasis has been was focused on the control activities identified in these strategies. Development of a new basin wide strategy for the management of nonnative aquatic species began in 2009, and was finalized in early 2014 (Nonnative Fish ad hoc Committee 2014). This strategy emphasizes prevention as a major component in efforts to control existing invasive impacts and to avoid similar impacts arising from existing or new species in additional locations within the Upper Basin. Illegal introductions of nonnative fish have, and continue to, spread harmful species to new waters and often necessitate difficult and expensive treatments to remove, control, or contain them. All nonnative fish control activities are being evaluated for effectiveness annually. By thoroughly evaluating the smallmouth bass and continued northern pike control strategies in the Yampa River basin, the Larval Fish Lab at Colorado State University (CSU) provided the Program with guiding principles for nonnative removal in the entire basin (Breton et al. 2014; Xxxxxxx et al. 2015). Specifically, both of these comprehensive evaluations indicate that the Recovery Program should focus on disrupting reproduction in the river and preventing immigration into river habitats, such as appropriateby limiting the escapement of these species from reservoirs. Disrupting in-river reproduction and preventing reservoir escapement are now the two key tenets of nonnative fish management. Limiting reproduction is accomplished through targeted removal of smallmouth bass during spawning (the Surge) and by netting northern pike in backwaters in the Yampa River. Landscape scale spawning disruptions of smallmouth bass via water management are also being considered (Bestgen and Xxxx 2016; Bestgen 2018; Xxxxxx et al. 2019; in review). Reservoir escapement is primarily prevented through installation of physical screens on outlets or channels and nets on spillways. Currently Starvation4, Elkhead, Xxxxxxx, Red Fleet, and Rifle Gap reservoirs, and Highline Lake, all have screened releases, while Xxxxxxx Reservoir and Lake Catamount, are planned for screening in the future. Walleye and other species also move upstream from Lake Xxxxxx, but a solution to prevent their escapement has not been developed. The States and the Service also have developed final procedures for stocking of nonnative fishes in the Upper Basin (USFWS 1996a, 1996b). The procedures are designed to reduce the impact on native fishes due to from stocking of nonnative fishes in the Upper Basin and clarify the role of the States, the Service, and others in the review of stocking proposals. A memorandum of understanding cooperative agreement has been signed by the States and the Service implementing the Stocking Procedures. The Stocking Procedures were revised in 2009 (USFWS 2009) and the cooperative agreement was updated. The 2009 Stocking Procedures call for a review after 10-years, which was scheduled for 2019. The Recovery Program will be reviewed for possible revisions review the Stocking Procedures in 2007coming years.

REDUCE NEGATIVE IMPACTS OF NONNATIVE FISHES AND SPORTFISH MANAGEMENT ACTIVITIES. Fifty-two fish species occur in the Upper Basin, but only 13 of those are native species. Nonnative species include all crayfish, as no species of crayfish are native to the Colorado River Basin (Xxxxxxxxx 2005). Many of the nonnative fishes aquatic species have been successful due to changes in the river system that favor their survival over that of native fishes. Competition with and predation by nonnative species is widely assumed to have played a role in the decline of the endangered fishes (Xxxx and Xxxxxxxx 1996). However, Although evidence of direct impacts of introduced species on native fishes is can be difficult to obtain (Xxxxxxxxxx 1981) and often is masked by human-caused habitat alterations (Xxxxx 1976)) . In studies on the Green River, researchers documented that young Colorado pikeminnow constituted 5% of the diet of northern pike, even though young Colorado pikeminnow made up a much smaller portion of the available food base in the river (Xxxxx and Xxxxxxx 1996). Researchers estimated that a single northern pike could consume 100 or more young Colorado pikeminnow per year. AlsoIn addition, northern pike are known to prey on large-bodied native fishes (Xxxxxxxx 2001, Xxxxxxx et al. 2005, Xxxxxx and Xxxxxx 2010) including adult Colorado pikeminnow, native roundtail chub (Gila robusta), flannelmouth xxxxxxxxxxxx and bluehead suckers, and may also feed on humpback chubs in the Yampa River. Colorado has completed revised a fisheries management plan for the Yampa River basin (a revision is pendingCDOW 2010). Smallmouth bass and northern pike in the Yampa River have rapidly increased in abundance and pose a significant predatory and competitive threat to the native and endangered fishesfishes (Bestgen et al. 2008, Xxxxxxx et al. 2008, and Xxxxxxxx 2012). Recovery Program activities related to nonnative fishes initially focused on identifying impacts/interactions and developing nonnative fish stocking procedures. Nonnative fish control strategies were developed to identify and prioritize options for controlling or removing nonnative fishes from river reaches occupied by the endangered fishes as well as other reaches that serve as production areas for nonnatives that subsequently disperse into occupied habitat (Xxxx and Xxxxxxxx 1996; Xxxxxxx et al. 1996; Xxxxxxx and Xxxxxx 1991). In February 2004, the Recovery Program adopted a nonnative fish management policy that addresses the process of identifying and implementing nonnative fish management actions needed to recover the endangered fishesfishes (Upper Colorado River Endangered Fish Recovery Program 2004). Through 20062009, emphasis has been focused on the control activities identified in these strategies. All nonnative fish control activities are being evaluated for effectiveness and continued as appropriate. Development of a new basinwide strategy for the management of nonnative aquatic species began in 2009. This strategy will emphasize prevention as a major component in efforts to control existing invasive impacts and to avoid similar impacts arising from existing or new species in additional locations within the Upper Basin. The States and the Service also have developed final procedures for stocking of nonnative fishes in the Upper Basin (USFWS 1996a, 1996b). The procedures are designed to reduce the impact on native fishes due to stocking of nonnative fishes in the Upper Basin and clarify the role of the States, the Service, and others in the review of stocking proposals. A memorandum of understanding cooperative agreement has been signed by the States and the Service implementing the Stocking Procedures. The Stocking Procedures will be reviewed for possible revisions were revised in 20072009 (USFWS 2009) and the cooperative agreement was updated. In 2013, the Colorado Wildlife Commission updated changes to Colorado’s Wildlife Regulations that apply the provisions of the revised Stocking Procedures to the private aquaculture industry, in waters of both the Upper Colorado and San Xxxx River. The provisions of the revised Stocking Procedures also are part of Utah’s stocking policy (including private aquaculture, which can only stock sterile salmonids without specific State review and approval). All private fish stocking in Wyoming also is subject to State review.