9668

• UCREFRP Catalog Number: 9668
• Author: Crowl, T. A. and e. al.
• Title: Bonytail Draft 1998 Annual Report, February 2000.
• USFW Year: 2000.
• USFW - Doc Type: Logan, UT.
• Copyright Material: NO

or high velocity as the other main effect.
RESULTS
Substrate Experiments
There were three substrate types available for each replicate. In the first set of trials
(sand, gravel, and sand/gravel replicates), substrate preference was not independent of
the time of observation (e.g. day versus night) as determined by a R x C test (x2=21.88,
df=2, p< 0.001). During the day, bonytail chose gravel 50% of the time, sand 30% and
sand/gravel 20% (Fig. 1.1). However, at night bonytail chose gravel 34% of the time,
sand 40% and sand/gravel 26%.

? 50
? Night
? Day
L
40

O 30
.F+

20
V
L
Q 10
M
0
Sand Sand & Gravel Gravel
Substrate Treatment
Figure 1.1 Substrate selection by bonytail without red shiners present (low flow).
In trials with sand, gravel, and cobble as available substrates, substrate selection was
independent of the time of observation (x2=0, df=2, p=0.999). In these replicates,
bonytail showed a much more significant preference for substrate, selecting for cobble
substrate 100% of the time; there was no variance (Fig. 1.2)
15