Efforts to Control Invasive Fish in Glen Canyon’s Slough

In the serene landscapes of Glen Canyon National Recreation Area, a battle is being waged against invasive fish species that threaten native aquatic life. Federal authorities have embarked on an initiative to reconnect a local slough with the Colorado River, aiming to protect endangered species from the encroaching smallmouth bass and other nonnative fish.

Understanding the Slough and Its Threat

The “minus twelve mile slough,” located approximately twelve miles from Lees Ferry boat ramp, has become a focal point in this ecological struggle. This backwater section, often misunderstood in its role, has become an unexpected breeding ground for smallmouth bass. According to Park Service fish biologist Jeff Arnold, “smallmouth bass are a voracious predator which can affect the local rainbow trout fishery and also downstream threatened and endangered fish species like the humpback chub and the razorback sucker.”

Restoration Efforts Underway

Efforts are currently in progress to reestablish a connection between the slough and the main river channel. This construction project aims to create a continuous flow of water, discouraging the conditions favorable for smallmouth bass spawning. The colder, faster-moving water from the main river is expected to deter these invasive fish, along with other species like green sunfish and common carp, from establishing themselves in the area.

Additional Measures

In addition to restructuring the slough, the Park Service employs electrofishing techniques during summer. This method allows the selective removal of undesirable fish such as smallmouth bass and carp, while ensuring the survival of native species like the flannelmouth sucker and rainbow trout.

The Bigger Picture

The Glen Canyon area is renowned as a Blue Ribbon trout fishery, attracting anglers nationwide and significantly contributing to the local economy. Protecting this ecosystem is crucial not only for its economic value but also for the preservation of endangered fish species in the downstream Grand Canyon. Jeff Arnold emphasizes the importance of these efforts, noting the potential threat posed by the invasive species if they spread further.