Swimming Performance of Three Gila Species: Gila elegans, G. cypha, and G. robusta

Authors: Amy Chandos, Kirk Young, Matt O’Neill, David Ward, Wilson Montgomery

Year: 2016 (xlviii)

Abstract

The Colorado River is one of the most visibly altered aquatic systems in the South Western United States. Due to the altered flow regimes, lower average temperatures, and the introduction of highly successful non-native aquatic species, many native fish species have experienced severe population declines or complete extirpation. Species such as Bonytail Gila elegans, Humpback Chub G. cypha, and Roundtail chub G. robusta are tallied among these species, and reintroduction efforts have been relatively unsuccessful. To examine the effects of temperature on the swimming performance of G. elegans, G. cypha, and G. robusta juvenile fish obtained from the US Fish and Wildlife Dexter National Fish Hatchery and Technology were acclimated to 10’ C, 20’ C, and 30’ C. Fish were then placed in a Brett- type respirometer and underwent a stepped velocity test to determine the critical swimming speed (Ucrit). Ucrit is defined as the swimming velocity that a fish can sustain for a given period of time. The Ucrit was compared between all three species. This talk will evaluate the effects of temperature on swimming performance of juvenile G. elegans, G. cypha, and G. robusta.