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- FEASIBILITY OF DEVELOPING AND MAINTAINING A SPORT FISHERY IN THE SALT RIVER PROJECT CANALS relative abundance. Benthic macroinvertebrates are animals that live in the bottom substrate, as well as on the substrate surface and on aquatic vegetation (Thorp and Covich 1991). Bimonthly samples were collected from September 1993 to July 1994, using a 0.04-m3 (300-in3) Petite Ponar Dredge. Dredge samples were collected from both sides and the middle of the canal at both the upper and lower ends of each station, for a total of 6 samples. If, after 3 attempts, no substrate or organisms were obtained in a dredge sample, no additional sampling was conducted at that station. A 500-µm sieve bucket was used to remove sediment fines (i.e., silt) from each sample. Each sample was preserved with 10% formalin or 70% ethanol. We used Rose Bengal® powder to stain each sample. Then, each sample was rinsed with water using a 250-µm sieve and placed in a shallow specimen tray. Individuals from each taxon were identified, counted, and stored in vials with 70% ethanol. Taxonomic classifications were based on Barnes (1968) and Arnett (1985). Aquatic Consulting and Testing, Inc. processed 1/3 of our samples for quality control purposes. Zooplankton. For the purposes of our study, zooplankton were defined as invertebrates found in the water column that float, drift, or weakly swim (Thorp and Covich 1991). Invertebrates found in the water column included true zooplankton, aquatic and terrestrial insects, and non-insect species. Quarterly zooplankton samples were collected from 8 stations on the Arizona Canal (Appendix C) between December 1992 and July 1994 to estimate seasonal zooplankton abundance and percent species composition. Using a portable water pump or a bucket, 3 samples were collected from each station from a depth of about 0.5 m. Twenty liters of water were filtered through an 80-µm, Wisconsin- type plankton net using a portable water pump or a bucket. Samples were rinsed with deionized water, stored in clear polyethylene bottles, and preserved in 70% ethanol. Samples were sent to Aquatic Consulting and Testing, Inc. for identification and enumeration using taxonomy based on Barnes (1968). To maintain decimal precision from low total counts, mean densities were recorded as numbers of organisms per 20 L, rather than numbers per liter. Public Opinion Surveys In May 1994, Behavioral Research Center, Inc. conducted 2 separate telephone surveys (Appendix D) to determine Maricopa County residents' attitudes toward the use of the SRP canals as an urban fishery. The first survey interviewed 300 licensed anglers, while the second survey targeted 600 individuals of the general public. Licensed anglers were chosen randomly from a list of current state or urban fishing license holders. The general public respondents from both urban and rural regions of Maricopa County were selected at random from a list of phone numbers by Behavior Research Center, Inc.'s automated system. The surveys examined the following aspects: regional representation, current angling participation, respondent interest in an Urban Canal Fishing Program (UCFP), demographic status, fish species preference, willingness to pay, and level of use. Projected angler-use days, potential new anglers, and revenues were calculated. Study Area Mapping The study area was mapped using an ARC/INFO Geographic Information System (GIS), ground-truthed observations, Phoenix area maps, and Salt River Valley Water Users' Association's maps (1993a, b). A map of physical structures and potential public access sites along the Arizona Canal was created (Appendix A). Habitat features and qualitative flow regimes were also mapped (Appendix B). Velocity measurements were not available for our sampling sites on the Arizona Canal. Instead, we used terms from Orth (1983) to define flow regimes within the Arizona Canal: (1) riffles are high velocity, turbulent water; (2) runs or glides are steady, laminar flows; and (3) pools are low velocity or still water. 16 ARIZONA GAME & FISH DEPARTMENT, TECH. REP. 18 B. R. WRIGHT AND J. A. SORENSEN 1995