Use of ultrasonic imaging and Ovaprim® to evaluate egg maturation of humpback chub Gila cypha

Authors: Morgan E. Brizendine, David L. Ward, Scott A. Bonar

Year: 2013 (xlv)

Abstract

Although nine known aggregations of humpback chub, Gila cypha, currently exist in the main stem Colorado River, little is known about their reproduction. It has been hypothesized that water temperatures of the main stem Colorado River below Glen Canyon Dam are too low for female humpback chub to develop eggs for spawning due to hypolimnetic dam releases. In this study, we will evaluate use of ultrasonic imaging and Ovaprim® to identify egg development in female humpback chub. In addition, we will document locations of female chub with developing eggs in the Colorado River drainage, especially the main stem below Glen Canyon Dam. Based on our initial results, we conclude that ultrasonic imaging is an effective method for identifying egg development in female humpback chub.