7785

• UCREFRP Catalog Number: 7785
• Author: Thompson, J. M.
• Title: The Role of Size, Condition, and Lipid Content in the Overwinter Survival of Age-0 Colorado Squawfish.
• USFW Year: 1989.
• USFW - Doc Type: Colorado State University,
• Copyright Material: NO

I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I

10

mortality. Following acclimation of the fish to reduced
temperatures, water temperature was maintained at 3.5 ~
1.50 C by adjusting ambient air temperature inside the
chamber. Photoperiod (10L/14D) was regulated by timers for
the full 210-day experimental period. The first and last
half-hour of the light phase was only 50% as bright to allow
fish to adjust to changes in illumination.
Hurlbert (1984) recommended an experimental design in
which all experimental units of all treatments were supplied
by the same maintenance system. The aquarium set-up was a
closed system in which dechlorinated city water continuously
circulated through all aquaria. Water was pumped from a
biological filter tank through a 30-watt ultraviolet
sterilizer into 1.3-cm PVC piping, which delivered water to
all aquaria. Inflow to each aquarium was controlled by
individual valves. . Outflow from each aquarium was via a
slotted standpipe, and water drained from all three levels
into drainpipes suspended below the bottom tier of shelves.
Water in the drainpipes flowed by gravity to a slotted
spraybar, which distributed water evenly over the biological
filter media. Filtered water was then pumped back through
the system. Use of a single filter system for all aquaria
ensured that a single chance motor failure or contamination
event would affect all experimental units equally and would
not produce a "treatment effect" (Hurlbert 1984).