9465

• UCREFRP Catalog Number: 9465
• Author: Burdick, B.
• Title: Monitoring and Evaluating Various Sizes of Domestic-Reared Razorback Sucker Stocked in the Upper Colorado and Gunnison Rivers
• USFW Year: 2003.
• USFW - Doc Type: 1995-2001.
• Copyright Material: NO

backwaters. Stocked fish were not site-acclimated, i.e., they were not tempered to river
temperatures nor were they held in quiet riverine habitats behind barrier nets (see Mueller and
Foster 1999). In the Gunnison River, razorback sucker were stocked at two sites. In 1995, fish
were stocked at RM 59.3. All other razorback sucker were subsequently stocked at RM 57.0. In
the Upper Colorado River, fish were stocked at three sites. Two sites were near Parachute,
Colorado (RM 226.5 and 229.9 ), and the other in the 15-mile reach near Corn Lake (RM 177.4).
Fish Sampling
Electrofishing from aluminum jon boats and rubber rafts was the primary means used to
sample for stocked razorback sucker during scheduled monitoring trips from 1996-2001.
Whenever feasible, two electrofishing craft were used simultaneously and proceeded sampling
downstream. Oar-powered eectrofishing rafts mainly sampled shoreline habitats. Electrofishing
from motorized jon boats sampled all possible habitats which included shorelines, backwaters, and
eddies. Seines (6-mm bar mesh, 9-m long X 1.8-m deep) were used to sample backwater and
slow-velocity habitats in the Gunnison River from RM 59.3 to RM 4.8 for stocked razorback
sucker only during the fall of 1995. Sampling for stocked razorback sucker generally was
conducted following spring runoff and occurred from mid-July through mid-October.
During October 1996, the river reach from Confluence Park (RM 57) to Roubideau Creek
(RM 50.3) was sampled on three different occasions (Appendix B). Some of this work was
associated with the northern pike removal project in the Gunnison River (McAda 1997 [RP No.
58]). The reaches from Roubideau Creek to Bridgeport (RM 29.3) were sampled at least once
with an aluminum jon boat. During 1997, only one rotation was conducted during late-July and
early-August on the Gunnison River between Confluence Park and Redlands Diversion Darn (RM
3.9). During 1998, all Gunnison River reaches were sampled twice except for the 10.8-mile reach
from Whitewater (RM 14.7) to Redlands Diversion Dam (RM 3.9). During 1999, 2000, and
2001, the Gunnison River from Confluence Park to Redlands Diversion Dam was sampled twice,
two electrofishing craft were used for each trip. The 2.3-mile reach of the Lower Gunnison River
from the Redlands Diversion Dam to the confluence with the Colorado River was also sampled
during 2001.
Since juvenile razorback sucker were stocked for the first time in the Upper Colorado
River in 1999, the reach between Rifle to Beavertail boat landing was sampled in 2000. In 2001,
the same reach was again sampled in the Upper Colorado River along with reaches from Price-
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