9432

• UCREFRP Catalog Number: 9432
• Author: Modde, T. and M. Fuller.
• Title: Feasibility of Channel Catfish Reduction in the Lower Yampa River.
• USFW Year: 2002.
• USFW - Doc Type: Vernal.
• Copyright Material: NO

Introduction

Introduced species were cited as a major factor in the extinction of73% offish taxa lost in

North America (Miler et al. 1989). In the upper Colorado River basin over 42 nonnative fish

species have become established compared to only 13 native species (Tyus et al. 1982). Although

not all nonnative fishes in the upper Colorado River basin impact native large river fishes, regional

experts felt 27 nonnative fishes have some impact on native fishes (Hawkins and Nesler 1991).

The same experts ranked channel catfish Ictalurus punctatus first among species causing problems

for native fishes (Hawkins and Nesler 1991). Specific documentation of channel catfish predation

on razorback sucker Xyrauchen texanus, Colorado pikeminnow Ptychocheilus lucius, and

humpback chub Gila cypha was provided by Tyus and Saunders (1996). This study was initiated

to explore the feasibility of reducing channel catfish abundance in the Yampa River to assist in the

recovery of humpback chub and Colorado pikeminnow in the Yampa River.

By the early 1900's naturalized populations of channel catfish were established throughout

the mainstem Colorado River. Dill (1944) noted declining native fish populations in the Colorado

River in the 1930's coincident with increases in nonnative fishes, especially channel catfish.

Despite earlier stockings elsewhere in the basin, the first record of catfish stocked into the Yampa

River was in 1944 (Tyus 1998). Based on interviews with early researchers, Tyus (1998)

speculated that channel catfish abundance in the lower Yampa River was a major factor in the

decline of the humpback chub in Yampa Canyon. The Yampa River supports a small population

of humpback chub in the Colorado River Basin and must be maintained at existing abundance for

the recovery of the the species (USFWS 2001). Thus, channel catfish reduction in Yampa Canyon

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