9556

• UCREFRP Catalog Number: 9556
• Author: Bestgen, K. R., K. A. Zelasko and C. T. Wilcox.
• Title: Non-native fish removal in the Green River, Lodore and Whirlpool canyons, 2002-2006, and fish community response to altered flow and temperature regimes, and non-native fish expansion.
• USFW Year: 2007.
• USFW - Doc Type: 115,
• Copyright Material: NO

native and 21 non-native species and 6 hybrid combinations were captured by all sampling gears
during the 2005-2006 period (Table 4).
All told, 238,316 non-native fishes were captured during this study, most of those being
removed. Since 2005 when removal was permitted for al] potentially predaceous species except
salmonids, we removed 1,176 potentially problematic large-bodied fishes captured by
electrofishing in 2005 (Table 5, another 411 brown trout or other salmonids were released), and
another 1,124 in 2006 (another 410 brown trout or other salmonids were released). Totals for
both years included 299 smallmouth bass, 24 northern pike, and 894 channel catfish.
In the 2002-2004 period, flannelmouth sucker Catostomus latipinnis was the most
common native fish captured by all sampling gears, followed by bluehead sucker Catostomus
disc•obolus, mountain whitefish Prosopium williamsoni, speckled dace Rhinichthys osc•ulus,
roundtail chub, mottled sculpin Cottus bairdi, Colorado pikeminnow, bonytail Gila elegaras, and
humpback chub. In 2005-2006, bluehead sucker was the most abundant native fish captured by
all gears, followed by flannelmouth sucker, speckled dace, roundtail chub, mountain whitefish,
mountain sucker, Colorado pikeminnow, bonytail, humpback chub, and razorback sucker. Most
changes were due to differences in the number of native fish captured in seine samples. No
razorback suckers or mountain suckers Catostomus platyrhynchus were captured during 2002-
2004 but each was captured in the 2005-2006 period; one razorback sucker adult was captured
by electrofishing in 2006 in lower Whirlpool Canyon, and many mountain sucker were seined in
tributary Vermillion Creek in 2005. Both taxa were previously collected in the study area
(Holden and Crist 1981; Bestgen and Crist 2000).
Composition of the fish community in Browns Park, Lodore Canyon, Whirlpool Canyon,
and Island-Rainbow Park reaches by gear type, 2002-2004 and 2005-2006.1n 2002-2004,
electrofishing captured nine native fishes, 16non-natives, and seven hybrids. The most
abundant non-native taxa were brown trout, common carp, and channel catfish (Table 6). In
2005-2006, channel catfish, brown trout, and common carp were most abundant in electrofishing
samples. smallmouth bass were less abundant in 2005-2006 than in 2002-2004.
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