7617

• UCREFRP Catalog Number: 7617
• Author: Platania, S. P. and K. R. Bestgen.
• Title: Survey of the Fishes of the Lower San Juan River, New Mexico.
• USFW Year: 1987.
• USFW - Doc Type: Albuquerque, New Mexico.
• Copyright Material: NO

faced cliff. Because of high velocity, there was no chance to go
back through the run, and measurements of the habitat were
impossible.
The two YOY Colorado squawfish were taken in a backwater and
a secondary channel with diminished flow on 4 October 1987. The
fish were collected at River Mile 143, 3 river miles above Mancos
River and River Mile 139.5, 0.5 miles below the Mancos. The
specimen (30.0 mm TL) from the upstream sample, was taken from a
warm (260 C), shallow (0.3 m), 100 x 20 m backwater which was
almost isolated from the main channel. The substrate was
primarily cobble but had a thick layer (15-18 cm) of silt.
The second individual (38.3'mm TL) was taken from an
extremely long side or secondary channel (300 m) with reduced
flow and a maximum depth of 0.5 m. The channel width varied from
10-40 m. Substrate, as with the upstream location, was primarily.
silt-laden cobble. There was, hgwever, clean cobble at both the
upper and lowermost ends of this side channel.
Both specimens have been sent to the Larval Fish Laboratory
at Colorado State University for verification of identification.
Additional unsorted larval fish samples collected in August may
contain Colorado squawfish.
razorback sucker
In the Upper Colorado River basin, the razorback sucker is
distributed throughout the "flatwater" sections of the lower
Yampa and mainstem Green rivers (Tyus et al. 1987). It is known
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