9333

• UCREFRP Catalog Number: 9333
• Author: Wright, B. R. and J. A. Sorensen.
• Title: Feasibility of Developing and Maintaining a Sport Fishery in the Salt River project Canals, Phoenix, Arizona.
• USFW Year: 1995.
• USFW - Doc Type: Phoenix.
• Copyright Material: NO

FEASIBILITY OF DEVELOPING AND MAINTAINING A SPORT FISHERY IN THE SALT RIVER PROJECT CANALS
control sections. We obtained this information to
supplement our contaminant analysis and to
evaluate potentially adverse conditions to fish
survival in the SRP canal system.
Abiotic Factors
Temperature and dissolved oxygen (DO) are
water quality parameters that can affect fish
survival (Piper et al. 1983). Levels of pH also
influence fish survival when extremely acidic or
basic water conditions persist for long periods
(Piper et al. 1983). Specific conductivity is the
ability of an aqueous solution to carry an
electrical current (Standard Methods 1989) and
directly affects electrofishing efficiency. Highly
conductive water provides a greater area of effect
for the shocking boat's electrode, thus affecting
more fish and increasing sample sizes. Heavy
turbidity in water is caused by fine, suspended
sediment and organic matter. Turbidity impairs
the visual-hunting ability of certain predatory fish
as well as decreasing the levels of photosynthetic
primary production of algae and phytoplankton
(Piper et al. 1983, O'Brien 1990).
From February 1992 to July 1994, we
collected monthly water quality measurements at
9 stations on the Arizona Canal (Appendix C) to
study environmental conditions that might affect a
sport fishery. Quarterly water quality
measurements were also collected from 19 stations
on the other SRP canals from March 1992 to July
1994 (Appendix C). Water quality stations were
established at the beginning, middle, and end of
each canal except for the Cross-Cut Canal, which
had only 1 station. Water quality measurements
were recorded during daylight hours. A Horiba
U-10 Water Quality Checker was used to record
water temperature (C), dissolved oxygen (mg/L),
pH, specific conductivity (mS/cm), and turbidity.
Turbidity values were represented by
nephelometric turbidity units (NTU), the standard
measurement of the intensity of light scattering by
suspended particles in aqueous solution (Standard
Methods 1989). Readings were taken at the
surface and at depths of 0.5 in and 1.0 in. Secchi
disk measurements of water transparency were
also recorded.
Water quality values were compared among
stations on the Arizona Canal to evaluate any
spatial differences that might influence fish
distribution. Monthly variations in mean
temperature and DO across all stations were
plotted to show seasonal extremes. Mean values
of temperature, DO, pH, conductivity, turbidity,
and Secchi depth measurements from the Arizona
Canal (across all stations and months) were
compared to the mean water quality aspects of the
other 7 SRP canals. We averaged the 3 depth
measurements for analysis.
Biotic Factors
Chlorophyll a. The ratio of chlorophyll a
(CHLA) to pheophytin a (PHEA) can indicate the
amount of primary production (i.e., the lowest
trophic level of the food base) in an aquatic
system because it is a measure of the
photosynthetic activity of phytoplankton. A
CHLAYHEA ratio of >_ 1.7 indicates high CHLA
values and excellent physiological condition of
phytoplankton. A ratio of 1.0 indicates pure
PHEA, the degradation product of acidified
CHLA, and reflects a poor condition. From
January 1993 to July 1994, we collected and
analyzed water samples to estimate concentrations
of CHLA and PHEA in the 8 SRP canals. Nine
stations were sampled monthly on the Arizona
Canal, and 13 stations were sampled quarterly on
the other SRP canals (Appendix C). All sampling
occurred during daylight hours concurrent with
other water quality sampling. Water samples
were collected at 0.5 in below the surface using a
1-L, horizontal, van Dorn-type water bottle. We
collected a 3 L composite sample of water from
each station. Samples were stored in amber,
polyethylene bottles and kept on ice in the field.
Water samples were then refrigerated in the
laboratory at 4 C until analysis.
We used analytical procedures outlined in
Standard Methods (1989) for CHLA analyses.
Samples were filtered through separate glass fiber
filters (Whatman type 934-AHO, 45-µm porosity,
47-mm diameter). Sample volumes ranged from
400 to 3,000 ml of water depending on the
amount of suspended sediment and organic
matter. Filters were macerated and CHLA was
extracted using 90% aqueous acetone for 24 hrs.
Spectrophotometric analysis was conducted using
a Perkin-Elmer Lambda-2 UV/Visible
spectrophotometer. A test blank of 90% aqueous
acetone was run prior to each sample series.
Known calibration standards (1.7 ratio of
CHLA:PHEA) were tested for quality control
purposes.
Benthos. Benthic samples were collected from
8 stations on the Arizona Canal (Appendix C) to
determine macroinvertebrate standing stocks and
B. R. WRIGHT AND I A. SORENSEN 1995 ARIZONA GAME & FISH DEPARTMENT, TECH. REP. 18 15