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

Substrate Experiments
The substrate tanks were divided into three sections for three or four different substrate
types, which included sand, coarse gravel (3-6 cm diameter), sand/gravel and cobble
(10-15 cm diameter). Substrate experiments were run without flow, in order to isolate
bonytail preferences for substrate. Five bonytail were added to this experimental
habitat and allowed to acclimate for at least five days. Their average weight and length
were 8.5 grams and 95 mm respectively. After the acclimation period, observations
were done between 0700-0900 (dark) and 1500-1700 (light). Each tank was observed
for 20 minutes in which the vertical (depth) and horizontal positions of the fish were
marked simultaneously every five minutes. Available vertical positions included bottom,
middle, and surface (0-8 cm, 8.1-16 cm, and 16.1-24 cm from the bottom, respectively).
Observations lasted at least three days, which included three day and three night
observations.
Flow Experiments
The flow tanks were similar to the substrate tanks except for the addition of brick
barriers to simulate backwater type flow. Flow experiments were run without added
substrate, in order to isolate bonytail preferences for flow. Low (1 pump), medium (2
pumps), and high (3 pumps) velocity treatments were used. Five bonytail were added
to each experimental habitat and allowed to acclimate for at least five days. Their
average weight and length were 8.5 grams and 95 mm respectively. During the
experiments, observations were made during 0700-0900 and 1500-1700. Each tank
was observed for 20 minutes in which the vertical (depth) and horizontal positions for
each fish were noted every five minutes. Available vertical positions included bottom,
middle, and surface (0-8 cm, 8.1-16 cm, and 16.1-24 cm from the bottom, respectively).
Experiments included at least three day and three night observational periods.
Velocities were mapped with a flow meter at three depths; deep, mid-depth, and
shallow (3 cm, 10 cm, and 23 cm from the bottom, respectively). Three readings were
taken every 20 cm (horizontal distance). A transparency of the flow key was made and
overlapped onto the data sheets with the fish positions to determine nose velocities of
12