Characterizing Growth and Condition of Endangered Humpback Chub in the Lower Colorado River

This paper is a preface to the two papers that follow in this issue. The two papers (by Pine et al. and Hayes et al.) use long-term fish sampling data from ongoing Humpback Chub monitoring efforts and archival otolith samples (from museums) collected in the lower Colorado and Little Colorado Rivers during periods of both cold- and warm-water conditions to assess whether Humpback Chub growth characteristics may have responded to changes in water temperature. Growth patterns are often of interest to resource managers because growth integrates a large range of environmental and ecological factors, including habitat conditions. Together, these papers contribute information to a large collection of recent studies, developing a line of evidence designed to inform management decisions related to water releases, dam operations, and management actions that could be taken to aid recovery of native fish populations in regulated river systems around the world.