8006

• UCREFRP Catalog Number: 8006
• Author: Hawkins, J. A., E. J. Wick and D. E. Jennings.
• Title: Icthyofauna of the Little Snake River, Colorado, 1994 - Final Report.
• USFW Year: 1997.
• USFW - Doc Type: Denver, CO.
• Copyright Material: NO

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EXECUTIVE SUMMARY

The Little Snake River is the largest tributary of the Yampa River and is used
seasonally by two endangered fishes: Colorado squawfish (Ptychocheilus lucius)
and humpback chub (Gila cypha). The goal of this study was to determine the
importance of the Little Snake River to endangered fishes. We also wanted to
characterize fish composition and reproduction in the Little Snake River. Our
objectives were to identify when and why Colorado squawfish and humpback chub
occupy the Little Snake River and identify the fish composition of the Little Snake
River during runoff and base-flow. The objectives were achieved only partially
because endangered fishes were not captured, preventing an assessment of
endangered fish use of the Little Snake River. This study was done in 1994, a
similar study was conducted in 1995 with similar objectives.

The study area included three sites chosen based on their unique
geomorphology on the Little Snake River. All sites were on Bureau of Land
Management lands in Moffat County, Colorado. Water temperature was recorded
hourly from May 16 - Oct 24 on the Yampa and Little Snake rivers. Fish were
collected with a variety of gear that depended on river access, discharge level, and
habitat conditions. Sampling gear included electrofishing, trammel nets, gill nets,
angling, seines, dipnet, and cast net. Fish were collected on two occasions during
runoff and on two occasions during baseflow. Also during baseflow, we sampled
one site with a four-pass removal sampling design using bank electrofishing to
obtain a population estimate of each species within a typical refugia pool.

During 1994, total discharge at 207,300 acre feet was extremely low on the
Little Snake River. Maximum daily discharge peaked twice, once on April 25 at
68 m3/sec and again on May 15 at 58 m3/sec. From mid-July through
mid-September, discharge was less than 0.03 m3/sec, including 19 days of near
zero discharge. Little Snake River water temperatures were higher than those in

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