Rainbow Trout

Threatened humpback chub are a native fish found only in the Colorado River Basin. Once found in warm-water canyons in the Basin, the largest population now persists in the Colorado River in Grand Canyon National Park, downstream of Glen Canyon Dam and Lake Powell, the reservoir upstream, created by the dam.

Partners in Science is a collaborative effort between Grand Canyon Monitoring and Research Center, Grand Canyon Youth, and the National Park Service to provide opportunities for youth to engage in scientific field research in Grand Canyon. This partnership connects youth from diverse backgrounds with the Nation’s natural and cultural resources on 2-3 river-based expeditions on the Colorado River...

The Southwest Biological Science Center (SBSC) conducts and provides scientific information as part of our mission and Federal Trust Responsibility to strengthen relationships and build partnerships with sovereign tribal nations. Here, we highlight a few examples of projects with tribal partners.

Rainbow trout are a desirable sport fish that have been introduced in many locations around the world, including the Colorado River. Although introductions of rainbow trout and other nonnative fishes provide recreational fishing opportunities, they can also pose threats to native fish populations. The Glen Canyon Dam Adaptive Management Program has tasked scientists and managers with identifying...

The Grand Canyon Monitoring and Research Center, a branch of the Southwest Biological Science Center, conducts scientific assessments of the Colorado River in Grand Canyon, focused primarily on Lake Powell and the river ecosystem downstream of Glen Canyon Dam. On this page, we'd like to share related interactive tools and projects by other USGS Centers that cover science across the upper and lower...

USGS Southwest Biological Science Center's Grand Canyon Monitoring and Research Center provided scientific expertise to evaluate potential effects of reservoir management on various resources in Lake Powell and Grand Canyon. This information, published in a cooperator report, was requested and used by the Bureau of Reclamation for decision-making on water flows from Glen Canyon Dam.

The Grand Canyon Monitoring and Research Center currently functions under a Triennial Work Plan (TWP) which is thoroughly reviewed and vetted both internally within the Center and through the GCDAMP Technical Work Group (TWG) and the Adaptive Management Work Group (AMWG). These advisory panels have been a part of the Glen Canyon Dam adaptive management process since the inception of the GCDAMP...

Glen Canyon Dam has altered ecological processes of the Colorado River in Grand Canyon. Before the dam was built, the Colorado River experienced seasonable variable flow rates, including springtime flooding events. These spring floods scoured the river bottom and enhanced natural processes that sustained the Colorado River ecosystem. Since the dam’s construction in 1963, springtime floods have...

Introduced rainbow trout and brown trout are considered a threat to the endangered humpback chub in the Colorado River in Grand Canyon. These introduced species eat native fish, but impacts are difficult to assess because predation vulnerability depends on the physical conditions under which predation takes place. We studied how predation vulnerability of juvenile humpback chub changes in response...

All aquatic invertebrates drift downstream at some point in their life cycle. Invertebrates may drift to find more preferable habitats, to leave the water during their transition from aquatic larvae to terrestrial adults, or accidentally such as when swept off the riverbed by a flood. Regardless, when they enter the drift, invertebrates become particularly susceptible to predation by several...

Aquatic insects live in the water as larvae most of their lives, then emerge onto land for a brief period as winged adults. Sampling these emerged adults on land is therefore a useful tool for understanding the condition of the aquatic insect population that is in the water, particularly in large rivers where sampling the larvae on the river bed is impractical. Our group uses a variety of methods...