Humpback Chub in Grand Canyon: Applied Research and Long-Term Monitoring in Support of Adaptive Management

Unlike most Southwest US native fishes, the Grand Canyon population of endangered humpback chub has increased, naturally without hatchery supplementation, over the last decade. This population is subject to intensive monitoring and research to quantify the distribution and abundance of several life-history stages and identify key drivers of humpback chub population dynamics and their relative importance. The Glen Canyon Dam Adaptive Management Program, a federal advisory committee, uses this information to make recommendations regarding Glen Canyon Dam operations, the implementation of management actions to protect native fishes and other natural resources, and the execution of large-scale experiments to reduce uncertainty and test hypotheses. Examples include nonnative fish removal, translocation of humpback chub to tributary streams, controlled floods, and flow manipulation. Results from associated resource monitoring provide feedback to managers and stakeholders regarding the effectiveness of particular actions. More quantitative approaches to monitoring the status and trends of populations of humpback chub and nonnative rainbow trout, a predator and potential competitor of native fishes, have been implemented in recent years. This has helped reduce uncertainty and facilitates ongoing efforts to quantify the relative influence of biotic and abiotic factors driving population dynamics of humpback chub and other fishes in Grand Canyon.