9350

• UCREFRP Catalog Number: 9350
• Author: Hawkins, J., T. Modde and J. Bundy.
• Title: Ichthyogauna of the Little Snake River, Colorado, 1995 with Notes on Movements of Humpback Chub.
• USFW Year: 2001.
• USFW - Doc Type: Denver.
• Copyright Material: NO

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EXECUTIVE SUMMARY

The Little Snake River, a tributary of the Yampa River in the Colorado River
Basin, provides habitat for endangered Colorado pikeminnow (Ptychocheilus lucius)
and humpback chub (Gila cypha). As an unregulated river, the Little Snake River,
exhibits extreme hydrological conditions influenced by the geology, topography, and
climate of the Southern Rocky Mountains and the arid Wyoming Basin which it
drains. Effects of these hydrological conditions on the fish community are
unknown but potentially important given occurrence of endangered fish and the
relatively low abundance of nonnative species in the Little Snake River.

The goals of this study were to better understand the longitudinal and
seasonal composition of the fish community in the Little Snake River with an
emphasis on location and movements of humpback chub. Objectives included:
1. Describe longitudinal composition of the Little Snake River fish community.
2. Describe seasonal changes in composition of the Little Snake River fish
community during spring, summer, and autumn.
3. Determine resident fishes in the Little Snake River.
4. Characterize location and movements of humpback chub in the Little Snake
River using PIT tag recaptures and radio telemetry.
5. Determine which species reproduce in the Little Snake River using larval
collections.
All objectives were achieved.

Three adult Colorado pikeminnow (51 0-830-mm total length) and four adult
humpback chub (250- 292-mm total length) were captured in 1995 in the Little
Snake River, 5.6 to 14.5 km upstream of the Yampa River. All were captured in
June and July as flows were declining from snowmelt runoff. Humpback chub

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