scholarly journals Effects of Glen Canyon Dam discharges on water velocity and temperatures at the confluence of the Colorado and Little Colorado Rivers and implications for habitat for young-of-year humpback chub (Gila cypha-

2010 ◽  
Author(s):  
Frank R. Protiva ◽  
Barbara E. Ralston ◽  
Dennis M. Stone ◽  
Keith A. Kohl ◽  
Michael D. Yard ◽  
...  
Keyword(s):  
Water Velocity ◽  
Glen Canyon Dam ◽  
Humpback Chub ◽  
Glen Canyon

scholarly journals Body Condition of Endangered Humpback Chub in Relation to Temperature and Discharge in the Lower Colorado River

2017 ◽  
Vol 8 (1) ◽  
pp. 333-342 ◽  
Author(s):  
Forest P. Hayes ◽  
Michael J. Dodrill ◽  
Brandon S. Gerig ◽  
Colton Finch ◽  
William E. Pine III
Keyword(s):  
Colorado River ◽  
Grand Canyon ◽  
Management Program ◽  
Parameter Estimates ◽  
Water Release ◽  
Fish Removal ◽  
Glen Canyon Dam ◽  
Management Actions ◽  
Humpback Chub ◽  
Glen Canyon

Abstract Determining the population status of endangered Humpback Chub Gila cypha is a major component of the adaptive management program designed to inform operation of Glen Canyon Dam upstream from Grand Canyon, Arizona. In recent decades, resource managers have identified a portfolio of management actions (with intermittent implementation) to promote population recovery of Humpback Chub, including nonnative fish removal, changes in water release volumes and discharge ramping schedules, and reductions in hydropower peaking operations. The Humpback Chub population in Grand Canyon has increased over this same period, causal factors for which are unclear. We took advantage of unusual hydrology in the Colorado River basin in 2011 to assess trends in juvenile Humpback Chub length–weight relationships and condition in the Colorado River below Glen Canyon Dam as well as in the unregulated Little Colorado River. Within each river, we observed higher length–weight b-parameter estimates (exponent of the standard power equation) at higher water temperatures. We also found higher slope estimates for the length–weight relationship at higher temperatures in the Little Colorado River. Slope estimates were more variable in the Colorado River, where mean water temperatures were more uniform. The next step is to examine whether Humpback Chub length–weight relationships influence population metrics such as abundance or survival. If these relationships exist, then monitoring condition in juvenile Humpback Chub would provide a quick and low-cost technique for assessing population response to planned management experiments or changing environmental conditions.

Long-Term Monitoring of an Endangered Desert Fish and Factors Influencing Population Dynamics

2013 ◽  
Vol 4 (1) ◽  
pp. 163-177 ◽  
Author(s):  
David R. Van Haverbeke ◽  
Dennis M. Stone ◽  
Lewis G Coggins ◽  
M. J. Pillow
Keyword(s):  
Colorado River ◽  
Adult Life ◽  
Grand Canyon ◽  
Management Program ◽  
Glen Canyon Dam ◽  
Abundance Estimates ◽  
Humpback Chub ◽  
Native Fishes ◽  
Glen Canyon ◽  
Flannelmouth Sucker

AbstractThe lower perennial corridor of the Little Colorado River in Grand Canyon, Arizona, is numerically dominated by endemic desert fishes and therefore significant for conservation of these species. From 2000 to 2012, the U.S. Fish and Wildlife Service conducted monitoring of native fishes in the Little Colorado River near its confluence with the Colorado River. The primary focus of these efforts was to estimate the spring and fall abundance of native fishes, especially the federally endangered humpback chub Gila cypha. Because humpback chub in Grand Canyon are influenced by operations of Glen Canyon Dam, our efforts provide managers of the Glen Canyon Dam Adaptive Management Program with abundance estimates and trends of humpback chub in the Little Colorado River, the most important tributary in Grand Canyon for spawning and production of this species. From 2001 to 2006, the spring abundance estimates of humpback chub ≥150 and ≥200 mm remained relatively low (≤3,419 and ≤2,002 fish, respectively), thereafter significantly increasing to highs of 8,083 and 6,250, respectively, by spring 2010. Also from 2000 to 2006, the fall abundance estimates of humpback chub were substantially below those abundances estimated after 2006. In addition, flannelmouth sucker Catostomus latipinnis and bluehead sucker Catostomus discobolus showed post-2006 increases in relative abundance, suggesting a systemwide event occurred that was beneficial to native fishes. Most of the increases of humpback chub occurred during the spring season in the reaches of the Little Colorado River between 5 and 13.57 km upstream from the confluence. Successful production of age 0 year classes of humpback chub may be partially driven by hydrograph dynamics of the Little Colorado River, whereas water temperatures and predation pressures in the mainstem Colorado River likely influence survivorship of native fishes into subadult and adult life stages.

Macroinvertebrate diets reflect tributary inputs and turbidity-driven changes in food availability in the Colorado River downstream of Glen Canyon Dam

2013 ◽  
Vol 32 (2) ◽  
pp. 397-410 ◽  
Author(s):  
Holly A. Wellard Kelly ◽  
Emma J. Rosi-Marshall ◽  
Theodore A. Kennedy ◽  
Robert O. Hall ◽  
Wyatt F. Cross ◽  
...  
Keyword(s):  
Food Availability ◽  
Colorado River ◽  
Glen Canyon Dam ◽  
Glen Canyon
Sign in / Sign up

Export Citation Format

Share Document