9548

• UCREFRP Catalog Number: 9548
• Author: Finney, S.
• Title: Adult and Juvenile Humpback Chub Monitoring for the Yampa River Population, 2003-2004.
• USFW Year: 2006.
• USFW - Doc Type: 133,
• Copyright Material: NO

Introduction
The humpback chub (Gila cypha) is an endangered species native to the Colorado
River Basin that and was listed on the Endangered Species Act in 1967 (32 FR 4001).
The fish evolved in swift water areas in narrow canyon bound reaches of the mainstem
Colorado River and its major tributaries. Humpback chub are seldom locally abundant
and typically occur intermittently (Douglas and Marsh 1996).
The Upper Colorado River Basin contains five geographically separate
populations of humpback chub located in Yampa Canyon, Desolation/Gray Canyons,
Westwater Canyon, Black Rocks Canyon, and Cataract Canyon (Haines and Modde
2002). The "Yampa" population of humpback chub includes fish that may be found in
Yampa, Lodore, Whirlpool, and Split Mountain canyons and is one of the smallest
existing populations of humpback chub (USFWS 2002).
Recent work has been done to study the abundance and distribution of the Yampa
population (see Karp and Tyus 1990 and Haines and Modde 2002), both studies focusing
primarily on the Yampa River itself. Karp and Tyus (1990) captured 109 unique
humpback chub in Yampa Canyon and 3 in Whirlpool Canyon and 11 of 76 tagged fish
were recaptured. Haines and Modde (2002) captured 83 adult humpback chub in Yampa
Canyon and calculated a population estimate of 391, although the estimate was imprecise.
Recent collections of humpback chub in Yampa Canyon were upstream of river kilometer
(rkm) 17. A review of historic collections from the Yampa River indicate that humpback
chub was previously abundant in Yampa Canyon (Tyus 1998).
Recovery goals for humpback chub require no net loss in the size of existing