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These data were used to examine the effectiveness of a non-lethal tool (Bioelectrical Impedance Analysis, "BIA") to estimate the physiological condition of endangered and threatened fishes in the Colorado River Basin. We conducted laboratory trials using hatchery-raised Humpback Chub and Bonytail and wild-captured Roundtail Chub, where fish were subjected to different feeding trials to elucidate a response in physiological condition and different temperature treatments to approximate field conditions. At the end of each 6-week trial fish were removed from tanks, lateral and dorsal measurements of BIA were taken, and fish were sacrificed for proximate composition analysis (lipid, protein, water, ash, dry mass, energy...
This report represents a river reach application of the reset concept to examine survival and growth of larval razorback sucker and bonytail in floodplains. The floodplain reset concept refers to eliminating residual fish populations from floodplains prior to their connection to the river during spring flood flows. Despite drought conditions, sufficient river flows allowed the evaluation of the reset concept to enhance larval razorback sucker Xyrauchen texanus and bonytail Gila elegans survival during 2003-2004. Species composition in study floodplains shifted from communities dominated by riverine species to to those preferring lentic conditions following recruitment within floodplains. The number, biomass, and...
nthropogenic selenium contamination of aquatic ecosystems was first associated with cooling reservoirs of coal-fired power plants in the late 1970s, and later with drainage water from agricultural irrigation activities in the 1980s. In the 1990s, selenium contamination has been raised as a concern in the recovery of currently endangered fish in the Colorado River system. Widespread contamination from seleniferous drain waters from agriculture has been documented in the upper and lower Colorado River basins. Historically, irrigation started in the upper Colorado River basin in the late 1880s. In the 1930s, selenium concentrations in various drains, tributaries, and major rivers in the upper and lower Colorado River...
The upper Colorado River basin, which is composed of the Colorado River and its tributaries upstream of Lake Powell, is home to 14 native fish species, four of which are now endangered. These four fish  the Colorado pikeminnow (Ptychocheilus lucius), razorback sucker (Xyrauchen taxanus), bonytail (Gila elegans) and humpback chub (Gila cypha evolved in the Colorado River basin and exist nowhere else on earth (www.r6.fws.gov/coloradoriver). The Dolores River is a significant tributary to the Colorado River and thus the status if its native fish community is of keen interest to state and federal agencies that manage native fish.
Despite successful reproduction by razorback suckers (Xyrauchen texanus) in the middle Green River, recruitment beyond the larval stage has not been recently observed. Bonytail (Gila elegans) are essentially extirpated in the wild and nearly all bonytail present in the Green River are hatchery-stocked fish. Floodplain wetlands may provide important rearing habitat for both larval razorback sucker and bonytail. However, survival of razorback suckers in restored floodplain habitat has not been observed since 1997, even when larvae were introduced directly into floodplain sites. Large nonnative fish populations in floodplain habitats have likely suppressed survival. The recent drought eliminated, or reset, nonnative...
Floodplain restoration is an important element of the Upper Colorado River Endangered Fish Recovery Program. Floodplain restoration was initiated in 1996 by lowering natural and manmade levees that were preventing natural floodplain function by limiting the frequency and duration of river-floodplain connection.
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The Colorado pikeminnow, razorback sucker, humpback chub and bonytail are endangered fish species that once thrived in the Colorado River system. Dam installation and the introduction of nonnative fish changed the river environment and put these fish at risk. Established in 1988, the Upper Colorado River Endangered Fish Recovery Program is a partnership of public and private organizations working to recover these endangered species while allowing continued and future water development.
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Bonytail (Gila elegans) status data created for the Western Division of the American Fisheries Society (WDAFS)


    map background search result map search result map Bonytail (Gila elegans) distribution and status by HUC8 Bioelectrical impedance analysis for an endangered desert fish—Data Bioelectrical impedance analysis for an endangered desert fish—Data Bonytail (Gila elegans) distribution and status by HUC8