|Scientific Name:||Ptychocheilus lucius|
|Species Authority:||Girard, 1856|
|Red List Category & Criteria:||Vulnerable D2 ver 3.1|
|Reviewer(s):||Smith, K. & Darwall, W.R.T.|
|Facilitator/Compiler(s):||Hammerson, G.A. & Ormes, M.|
This species is listed as Vulnerable because the number of locations does not exceed five. Extent of occurrence is larger than 20,000 sq km. Area of occupancy is less than 2,000 sq km (much less than 2,000 if only spawning or nursery areas are considered). Distribution and abundance are relatively stable. Wild population includes several thousand adults.
|Range Description:||Historical range included rivers of the Colorado River basin: mainstem Colorado River and major tributaries (Gunnison, White, Yampa, Dolores, San Juan, Uncompahgre, Animas, and Green rivers), from Mexico and Arizona to Wyoming.
Present distribution is drastically reduced. By the mid-1980s, this species occurred only in the Upper Colorado River basin of Colorado, Utah, New Mexico, and Wyoming; mainly in the Green River in Utah and in the Yampa and Colorado rivers in Colorado and portions of Utah; wild fish have not been seen below Glen Canyon Dam since 1968. Adults predominate in the White and Yampa rivers, young in the Green River (Tyus 1986); juveniles reported as rare in the Green River system (see Karp and Tyus 1990).
Spawning occurs in the Green River sub-basin in the lower Yampa River and in Gray Canyon (a segment of the Green River above its confluence with the Price River); nursery areas include the Green River between the Colorado River and the San Rafael River, and a segment of the Green River upstream and downstream from the confluences of the Duchesne and White rivers (Tyus 1991). Spawning also may occur in Labyrinth and Stillwater canyons of the lower Green River, but if so, populations apparently are small (Tyus 1991). River mile 130 on the Colorado River, near the Colorado-Utah state line, has been identified as a spawning site used in multiple years (see Federal Register, 21 March 1994). The presence of small larvae in the upper main-stem Colorado and San Juan rivers indicates successful reproduction, but low numbers suggest limited reproduction or recruitment (Tyus 1991). Colorado Pikeminnows were recently recorded in the Little Snake River, Colorado (Wick et al. 1991) and Wyoming (Marsh et al. 1991). The species was reconfirmed as occurring in the San Juan River from 4.4 km downstream from Shiprock, New Mexico, to Lake Powell, Utah (young of year were found near Lake Powell and near the confluence of the San Juan River and Montezuma Creek and near the confluence of the San Juan River and the Mancos River) (Platania et al. 1991). See also Sublette et al. (1990) for relatively recent records from New Mexico and southeastern Utah.
Beginning in the mid-1980s, an experimental population was being established in the Salt and Verde rivers, Arizona (USFWS 1990, Minckley and Deacon 1991).
|Range Map:||Click here to open the map viewer and explore range.|
This species is represented by three wild populations, in the Green River, upper Colorado River, and San Juan River subbasins (USFWS 2011).
Green River population included roughly 4,000 adults in 2008 (USFWS 2011). Colorado River population included several hundred adults in in mid-2000s (USFWS 2011).
About 983 stocked Colorado Pikeminnows were recaptured from the San Juan River in 2004–2008 (see USFWS 2011).
Common in the lower Colorado River basin in Arizona and California until the 1930s, essentially gone from most of the historical range by the early 1970s; now occupies perhaps 25% of former range.
Trend over the past 10 years or three generations has been relatively stable. Green River adult population declined then increased in the early 2000s; recruitment increased during this period (USFWS 2011). Colorado River adult population and recruitment were relatively stable in the 1990s and 2000s (USFWS 2011).
|Habitat and Ecology:||
Habitat includes medium to large rivers. Young prefer small, quiet backwaters. Adults use various habitats, including deep turbid strongly flowing water, eddies, runs, flooded bottoms, or backwaters (especially during high flow). Lowlands inundated during spring high flow appear to be important habitats. Recorded mainly in shoreline habitat over sand (Tyus and McAda 1984). In winter, this species is most common in shallow, ice-covered shoreline areas. See Tyus and Karp (1989) for details on seasonal habitat use and distribution in the Yampa River, Colorado (upper Yampa is winter concentration area for adults).
Reproductively active adults seek faunally depauperate white-water canyons for deposition of gametes (Tyus 1991). Appears to select river canyons that receive freshwater input of groundwater from sandstone/limestone seeps (Tyus 1985). In lower Yampa River, spawns where large, deep pools and eddies (resting and feeding areas) are intermingled with riffles and runs and cobble bars of gravel, cobble, and boulder substrates (Tyus and Karp 1989, Tyus 1991). Returns to previous spawning site. Larvae drift downstream after hatching, then move to shoreline areas and backwaters. Larvae moved downstream out of the Yampa River in 3–15 days (see Tyus 1991). Young-of-year (postlarval) occupy shallow, alongshore, ephemeral backwaters formed in late summer by receding water levels (Tyus 1991). Juveniles tend to occur downstream from area occupied by adults, though larger juveniles are not uncommon in shoreline habitats similar to those occupied by adults (Tyus 1991).
|Use and Trade:||This species is not utilized.|
This species' decline probably resulted from a combination of threats, including direct loss of habitat, changes in flow and temperature, and blockage of migration routes by the construction of large reservoirs. In addition, interactions with non-native fishes may have had a decimating effect in waters not affected by dams (USFWS 2011).
Uncertainty surrounding the effects of climate change to Colorado Pikeminnow should be considered for each of the threats as those impacts are realized. For example, the potential for alteration of flows in the basin as a result of climate change should be in the recovery goals. Climate change could have large impacts on the basin's aquatic ecosystem, including (but not limited to): change in the timing of peak flows from an earlier snowmelt; change in the size of peak flows because of altered snowpacks; and higher water temperatures from increased air temperature. Not only would climate change affect the ecology of the species because of the factors listed above, but it also would greatly affect the management of the programs through changes in politics and economics, such as: greater evaporation losses in the larger reservoirs may reduce flexibility of operations; and drier conditions in the basin may cause irrigators to call on their water rights more often or request more water rights. Source: USFWS (2011).
|Conservation Actions:||Promote maintenance and/or return of rivers to natural conditions through protection and appropriate dam management. Maintenance of natural flow conditions in the Yampa River, which is important in shaping the flow conditions in the Green River, is critical to the recovery of this and other rare Colorado River fishes (Tyus and Karp 1989). Prohibit/discourage introductions of non-native fishes; eliminate/reduce existing exotic fishes.|
|Citation:||NatureServe 2013. Ptychocheilus lucius. The IUCN Red List of Threatened Species. Version 2015.2. <www.iucnredlist.org>. Downloaded on 05 September 2015.|
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