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

Mountain Canyon and the middle Green River. Crowl and Badame (2000) reported that over 95%

of catfish captured in fyke nets in 1997 were less than 200 mm total, and that mean length of fish

captured with electrofishing was 235 mm. Mean length of catfish captured by electrofishing from

Yampa Canyon in 1999 was 291 mm compared to 447 mm and 529 mm from reaches above Cross

Mountain Canyon (rk 102 and rk 177, respectively) by Anderson (2000). Although Crowl and

Badame (2000) captured larger fish, the biomass removed was dominated by small fish. Similarly,

use ofage-O and juvenile channel catfish in backwaters of the Green River have been reported by

Haines and Tyus (1990) and McAda et al. (1998). Our data, Nesler (1995) and Miller (1982)
observed very few juvenile channel catfish in Yampa Canyon. Nesler (1995) suggested that
channel catfish in the Yampa River were near their elevational distribution limit and that catfish

recruitment sOn the contrary, using multiple gear types, juvenile fish were absent from the lower

Yampa River. It may be uncertain as to how many large channel catfish reside in Yampa Canyon,

however, it is apparent that the average length of channel catfish in the Yampa River above Cross

Mountain Canyon is much larger. A size related distribution of catfish was also observed in the

San Juan River. Brooks et al. (2000) showed larger fish found in upstream reaches oftheir San

Juan River study area below Navajo Dam. Smith and Brooks (2000) targeted the larger individuals

in the San Juan population because larger fish may be more predacious on native fishes and by

removing the majority of spawners, recruitment to the lower reaches will be reduced. A similar

strategy to remove larger fish from upstream reaches may be productive in Yampa River system.

Both Nesler (1995) and Anderson (2000) showed that catfish above Yampa Canyon are much

larger and therefore much more fecund than most fish below Cross Mountain Canyon. In

addition, densities are equivalent or lower to those in our study area and the logistics of removal in

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