Rationale and Hypotheses. Early life-stage Colorado pikeminnow (Ptychocheilus lucius) monitoring is an ongoing effort in the Green River basin to evaluate spawning success. Monitoring of juvenile Colorado pikeminnow occurs in conjunction with adult population estimates in the Green and Colorado rivers. However, survival of young-of-year (YOY) can vary greatly between years independent of spawning success and can have an impact on the juvenile component of Colorado pikeminnow populations. For example, biotic and abiotic factors such as flow variation, backwater temperatures, competition and predation by nonnative fish (e.g., piscivores and small-bodied cyprinids), and over-winter mortality can hinder age-0 survival, resulting in a smaller number of juvenile Colorado pikeminnow available for recruitment into the adult population (Bestgen et al. 2006; Bestgen and Xxxx 2016; Xxxxx and Xxxxx 2019). Recruitment of other native species such as bluehead sucker (Catostomus discobolus), flannelmouth sucker (C. latipinnis), roundtail chub (Gila robusta), and speckled dace (Rhinichthys osculus) is affected similarly. As a result of decreased recruitment, control actions targeting nonnative piscivorous species, primarily smallmouth bass (Micropterus dolomieu), northern pike (Esox lucius), and walleye (Sander vitreus), are being evaluated across the upper Colorado River basin to determine the level of reduction necessary to minimize the threat to the recovery of Colorado pikeminnow and other endangered Colorado River fishes. Successful implementation of nonnative fish removal will likely be measured by the response of endangered fish and other native species (i.e., increased abundance), and will likely be evident in early life-stages of the native fish community (Bestgen et al. 2007a). An adult response to nonnative removal may not be detectable initially for a number of reasons (e.g., Xxxxxxxxx et al. 2012), including large home range of adults and slow maturation. Furthermore, a positive response by adult endangered species may be difficult to measure statistically without extensive observations due to generation times of endangered fish populations (e.g., Bestgen et al. 2007b). Data necessary to evaluate the recovery status of Colorado pikeminnow will be generated by current and future YOY sampling conducted during this project. For instance, documenting size and relative abundance of YOY Colorado pikeminnow and other native species (e.g., UDWR 2006) may provide valuable information about the...
Rationale and Hypotheses. STReaMS, the central database of the Recovery Programs, creates a consolidated system to assist researchers and stakeholders with uploading, managing, editing and accessing data. Data support the recovery of endangered species and removal of nonnative fishes, assessment of effects of non-native fish removal, effects of new flow and temperature regimes based on the fish community response, and effects of continued water development.
Rationale and Hypotheses. In FY01, the Recovery Implementation Program (RIP) revised the RIP Recovery Action Plan to include evaluating and revising, as needed, flow recommendations for the endangered fish throughout the Upper Colorado River Basin. Flaming Gorge Flow and Temperature Recommendations (FGFTR; Xxxx et al. 2000) were approved by the RIP in FY01. A Record of Decision was written in 2005 and flow and temperature recommendations have been implemented. Another change in operations at Flaming Gorge Dam has resulted from implementation of the Larval Trigger Study Plan, and has effects primarily on timing and magnitude of releases in spring from Flaming Gorge Dam. An expectation of implementation of flow and temperature recommendations was that native and endangered fishes will benefit via expanded distribution and abundance. It is also possible that new flow and temperature regimes for native endangered fishes may also enhance distribution and abundance of certain nonnative fishes. This is a major concern of managers of the Colorado River Basin, where expanding non-native fish populations are detracting from conservation efforts. Effects of full implementation of new flow and temperature regimes of the Green River downstream from Flaming Gorge Dam need to be evaluated to determine relative benefits to native and endangered fishes and other non-native elements of the fish community. An increased emphasis was placed on non-native fish removal in this study beginning in 2005. Expanded populations of non-native fish predators have been detected since 2002 due in part, to warmer water temperatures and lower flows. The proposed non-native fish removal and native fish monitoring study is a logical extension of work conducted by Xxxxxxx and Xxxxx (2000), more recent sampling in 2002 to 2014 (Xxxxxxx et al. 2006, Xxxxxxx et al. 2007). That more recent work was conducted to evaluate changes in the fish community that occurred since 1996 in response to partial implementation of new flow recommendations and to expansion and removal of non-native predaceous fishes in the Green River. Aspects of the new flow and temperature recommendations and the Larval Trigger Study Plan that were realized since 1996 was relatively higher spring peak flows in 1997, 1999, 2011-2014 and low and warm flows in the summer seasons from 2002 to 2007, followed by relatively high flows from 2008-2011 and 2014, and lower flows in 2012 and 2013. A number of changes in the fish community were observed during samplin...
Rationale and Hypotheses. The Upper Colorado River Endangered Fish Recovery Program has determined that control of nonnative fish in the upper Colorado River basin is essential to the recovery of the four endangered fish species (USFWS 2002a-c): Colorado pikeminnow (Ptychocheilus lucius), razorback sucker (Xyrauchen texanus), humpback chub (Gila cypha), and bonytail (G. elegans). The highest catch rates of adult and sub-adult Colorado pikeminnow in the Green River sub-basin were observed in the White River during earlier Colorado pikeminnow abundance estimates (Bestgen et al. 2010). Furthermore, adult razorback sucker, many in spawning condition, have recently been collected in the White River during spring sampling (STReaMs Database) and larval razorback sucker were documented for the first time in June 2011 (Xxxxxx et al. 2013a), suggesting this species is now utilizing this system for spawning purposes. Additionally, the White River is a stronghold for unlisted native species (Xxxxxxx and Xxxxx 1981; Xxxxxxxx et al. 1994; Xxxxx and Xxxxxxx 2009, 2010), thus providing an important forage base for Colorado pikeminnow (Osmundson et al. 1998). Smallmouth bass (Micropterus dolomieu) have been documented in the White River for over three decades (Xxxxxx 1975), yet proliferation of this population did not occur until recently. However, 41 smallmouth bass were collected during one low flow native species sampling pass (42.5 mile reach in Utah) conducted during 2009 (Xxxxx and Xxxxxxx 2010). In addition, increasing numbers of smallmouth bass were collected from 2011-2013 during Colorado pikeminnow abundance estimate sampling. During our initial investigation in 2012, we learned that the majority of smallmouth bass were found in the first ten miles below Xxxxxx Draw Dam, and densities decreased dramatically downstream of this area (Xxxxx et al. 2012). This has continued to be the overall distribution of bass in the river, but adult and sub-adult densities have increased in downstream reaches, particularly after low discharge and warm river conditions that are conducive to bass reproduction (Xxxxxx et al. 2013b). More recent removal efforts have demonstrated that smallmouth bass have successfully reproduced and recruited every year since 2012 regardless of hydrology, and as a result, bass densities have continued to increase (Xxxxx et al. 2018).
Rationale and Hypotheses. General The fish passage at Redlands Power and Water Diversion Dam, on the Lower Gunnison River, was completed by 1996. It was designed for selective fish passage, with a fish trap at the upstream terminus of the ladder. Fishes are collected, counted and sorted (non-native fish are removed, native fish and salmonids are allowed to make passage upstream), endangered fish (Bonytail [Gila elegans], Colorado Pikeminnow [Ptychocheilus lucius], Humpback Chub [Gila cypha], Razorback Sucker [Xyrauchen texanus]) and Roundtail (Gila robusta) are checked for a PIT tag, and endangered fish without a PIT tag have one implanted. Beginning in 2015, all Colorado Pikeminnow are translocated upstream to either Xxxxxxxxx or Delta along with other endangered fish collected the same day. Project Results to Date The Redlands Fish Passage was first operational in 1996 and the total number of fishes processed through the end of 2016 is 184,428. Native fishes comprised 73% of the total number of fishes collected in 2015 and 2016, compared to 94% in 1996 and 1997, 93% in 1998 and 1999, 92% in 2000, 83% in 2001 and 2013, 66% in 2002, 68% in 2003 and 2014, 77% in 2004, 74% in 2005, 85% in 2006, 83% in 2007, 76% in 2008, 86% in 2009, 87% in 2010, and 81% in 2011. From 2001–2003, and again from 2012–2016, there was a significant downward trend in the relative percentage of native fishes compared to the first 5 years that the ladder was operated and monitored when the relative percentage of native fishes was somewhat constant at about 92% per year. Endangered fish totals from 1996 to 2016 include 180 Colorado pikeminnow, 35 Razorback Sucker, 90 Bonytail, and 1 Humpback Chub. Overall, native fish still continue to comprise about 82% of all fish processed during this 21-year period (Xxxxxxx and Xxxxx 2016). A final report was completed in July 2001 and distributed in late-August 2001. This report evaluated the use of the fishway by all fishes, with particular reference to the native, listed fish, Colorado pikeminnow, from 1996-2000 (Xxxxxxx 2001).
Rationale and Hypotheses. General The fish passage at Government Highline Diversion Dam (or Grand Valley Water User’s Dam [GVWU]) on the Upper Colorado River at the lower end of Debeque Canyon was completed by 1 August 2004. Although the passage was completed in August 2004, it was not operated in 2004. It was also designed for selective fish passage, similar to that at the Redlands fish passageway. In both 2005 and 2006, it was operated only on a trial basis and in 2007 it was only operated for about 5 weeks at the height and immediately following spring runoff to remove sediment from the head end of the fish passage and attraction flow intakes. In 2008, with the completion of fish passage downstream at the Price Stubb Dam in April 2008, the fish trap was operated full time from the first of May to mid-October. Low flows in 2012, didn’t allow for operation of the fish passageway and it was operated in 2013 and 2014. Project Results to Date The purpose of this project is to collect and summarize annual data on the number of large- bodied fish, different fish species, and seasonal distribution of fish that use the fish passageway at the Government Highline Diversion Dam on the Upper Colorado River in Debeque Canyon. In 2014, the fish trap was operated continuously between 22 April and 16 October. This is the fifth year that the fish passageway at Government Highline has been operated continuously since being completed in August 2004. The fish trap was operated for only 12 days in 2005, 41 days in 2006, and 49 days in 2013. The fish trap was not operated during 2004, 2007, and 2012. Through 2014, twenty nine adult Razorback Sucker (Xyrauchen texanus), six Humpback Chub (Gila cypha), one Colorado Pikeminnow (Ptychocheilus lucius), and thirty six Xxxxxxxx (Gila elegans) have used the fish-way. Twenty four thousand six hundred seventy fish were processed in the fish trap during 2014. Through 2014, 105,142 fish have used the fish passage at Government Highline Diversion Dam. Native fishes comprised 82% of the total fish collected through 2014 (Xxxxxxx and Xxxxx 2014).
Rationale and Hypotheses. Since the mid-1990s, the San Xxxx River Basin Recovery Implementation Program (SJRBRIP) has been stocking Razorback Sucker into the San Xxxx River to help make progress towards recovery for this endangered fish species. As a part of this strategy Razorback Sucker are being reared in several hatchery, as well as grow-out pond facilities, to augment the riverine population of this species. The Ouray National Fish Hatchery – Grand Valley Unit (NFH-GVU) is a sub-unit of the Grand Junction Fish and Wildlife Conservation Office (FWCO). The Ouray NFH-GVU consists of several distinct facilities located in and around Grand Junction, CO. One of these facilities is the Horsethief Canyon Native Fish Facility (HCNFF) pond complex (about 7½ miles west of the main hatchery building) near Fruita, CO. The other facility used for this SOW is the 24-Road Hatchery, an intensive water reuse hatchery building, utilizing a municipal water source, thus insuring good water quality, clarity, and freedom from parasites.
Rationale and Hypotheses. This project is directly related to Section IV. Manage genetic integrity and augment or restore populations (stocking endangered fishes) of the 2023 RIPRAP document (UCREFRP 2023). One of seven elements in the Recovery Program is native fish stocking. The goal of this element is to produce sufficient captive-reared endangered fishes for conducting laboratory and field research and to develop brood stocks with genetic diversity similar to the wild stock used as founders (Xxxxxxxxxx and Xxxxxxx 1994). The need for captive-reared endangered fish and propagation facilities was first codified in Wydoski (1994). Endangered fishes have been cultured and reared in the upper basin since 1987. Propagation began in the Grand Valley in 1991 with construction of Horsethief Xxxxxxx Xxxxx at Horsethief State Wildlife Area (HSWA). These six xxxxxxx xxxxx were constructed to develop and hold broodstock consisting of the last wild razorback suckers captured from the upper Colorado River. Production of razorback suckers began in 1996 when an intensive-rearing, water-reuse hatchery building (00-Xxxx Xxxxxxxx) was built. The 24-Road Hatchery was expanded in 1998. During the 2000s, numerous constructed and leased grow-out ponds were used to rear razorback suckers large enough for stocking into the rivers of the upper basin. However, these ponds were not only geographically widespread, but also very disparate in terms of shape, size, and depth, ease of access, security, productivity, fish health/condition, and rates of return. From 2010-2017, all of these leases on these ponds were allowed to expire. The Recovery Program no longer maintains any leased ponds. Likewise, the six original xxxxxxx xxxxx constructed in 1991 at HSWA are no longer being used. A few “lease free” grow-out ponds (e.g., Beswick’s Pond and CDOT Pond on the Colorado River and Xxxxx Xxxxx Pond on the Gunnison River) are still utilized. The Horsethief Canyon Native Fish Facility (HCNFF) ponds, completed in 2012, replaced the older, less efficient, leased grow-out ponds. This facility located near Fruita, CO consists of 22 (6.2 total acres of) lined ponds has enabled Ouray NFH-GVU to better standardize production, rearing, and management of endangered fish. To summarize, the Ouray NFH-GVU currently consists of several separate facilities, all of which are managed by hatchery staff to achieve the same goal. These include the 24-Road Hatchery building, the HCNFF ponds, and a few other “lease free” grow-out ponds. ...
